OARSI 2011

SAN DIEGO – The more severe an anterior cruciate ligament injury, the more likely patients are to develop arthritis in the injured knee; structural changes might even be seen within 4 years of the trauma, a small study has shown.

In results presented at the World Congress on Osteoarthritis, patients who had had anterior cruciate ligament (ACL) reconstruction were four times more likely to have abnormal joint space narrowing by then if they also had a defect that extended more than halfway through their femoral cartilage (International Cartilage Repair Society grade III injury), a menisectomy, or both (odds ratio 4.11; 95% confidence interval 1.01-39.55, P = .05).

"These people were highly functioning; they were all athletic people. They had no symptoms of osteoarthritis," said lead investigator Timothy Tourville of the University of Vermont Center for Clinical and Translational Science in Burlington.

"Historically, most studies haven’t been able to demonstrate differences in [less than] 10 or 15 years. I think being able to pick them up at 4 years and identifying those who are at high risk for structural change is very important," rheumatologist David Hunter said in an interview.

"If, at the time of the injury, there is more substantive damage to either [the patient’s] cartilage or their meniscus, you are going to be more cautious about encouraging them to return to high physical activity and potentially redamaging their" knee, said Dr. Hunter, professor of medicine at the University of Sydney (Australia).

The 38 ACL patients in the study, about half women, were under 51 years of age and not obese. Their ACLs were reconstructed within a half-year of their injury, and none had gotten intra-articular injections. Other than their injury, they were in good health with no other joint problems. Baseline radiographs were compared with films at 3-4 years.

More than 60% (8/13) of those with grade III cartilage injuries had abnormal joint space narrowing at that point, compared with 28% (7/25) of those with no more than grade II injuries – defects extending less than halfway through their femoral cartilage – and intact menisci in both compartments.

"Abnormal" meant that the joint space difference between patients’ injured and uninjured knees fell outside the 95% confidence interval of bilateral differences measured in 32 matched controls.

The conference was sponsored by the Osteoarthritis Research Society International. Mr. Tourville and Dr. Hunter said they had no relevant financial disclosures. The National Institute of Arthritis and Musculoskeletal and Skin Diseases supported the work.

SAN DIEGO – The more severe an anterior cruciate ligament injury, the more likely patients are to develop arthritis in the injured knee; structural changes might even be seen within 4 years of the trauma, a small study has shown.

In results presented at the World Congress on Osteoarthritis, patients who had had anterior cruciate ligament (ACL) reconstruction were four times more likely to have abnormal joint space narrowing by then if they also had a defect that extended more than halfway through their femoral cartilage (International Cartilage Repair Society grade III injury), a menisectomy, or both (odds ratio 4.11; 95% confidence interval 1.01-39.55, P = .05).

"These people were highly functioning; they were all athletic people. They had no symptoms of osteoarthritis," said lead investigator Timothy Tourville of the University of Vermont Center for Clinical and Translational Science in Burlington.

"Historically, most studies haven’t been able to demonstrate differences in [less than] 10 or 15 years. I think being able to pick them up at 4 years and identifying those who are at high risk for structural change is very important," rheumatologist David Hunter said in an interview.

"If, at the time of the injury, there is more substantive damage to either [the patient’s] cartilage or their meniscus, you are going to be more cautious about encouraging them to return to high physical activity and potentially redamaging their" knee, said Dr. Hunter, professor of medicine at the University of Sydney (Australia).

The 38 ACL patients in the study, about half women, were under 51 years of age and not obese. Their ACLs were reconstructed within a half-year of their injury, and none had gotten intra-articular injections. Other than their injury, they were in good health with no other joint problems. Baseline radiographs were compared with films at 3-4 years.

More than 60% (8/13) of those with grade III cartilage injuries had abnormal joint space narrowing at that point, compared with 28% (7/25) of those with no more than grade II injuries – defects extending less than halfway through their femoral cartilage – and intact menisci in both compartments.

"Abnormal" meant that the joint space difference between patients’ injured and uninjured knees fell outside the 95% confidence interval of bilateral differences measured in 32 matched controls.

The conference was sponsored by the Osteoarthritis Research Society International. Mr. Tourville and Dr. Hunter said they had no relevant financial disclosures. The National Institute of Arthritis and Musculoskeletal and Skin Diseases supported the work.

SAN DIEGO – The more severe an anterior cruciate ligament injury, the more likely patients are to develop arthritis in the injured knee; structural changes might even be seen within 4 years of the trauma, a small study has shown.

In results presented at the World Congress on Osteoarthritis, patients who had had anterior cruciate ligament (ACL) reconstruction were four times more likely to have abnormal joint space narrowing by then if they also had a defect that extended more than halfway through their femoral cartilage (International Cartilage Repair Society grade III injury), a menisectomy, or both (odds ratio 4.11; 95% confidence interval 1.01-39.55, P = .05).

"These people were highly functioning; they were all athletic people. They had no symptoms of osteoarthritis," said lead investigator Timothy Tourville of the University of Vermont Center for Clinical and Translational Science in Burlington.

"Historically, most studies haven’t been able to demonstrate differences in [less than] 10 or 15 years. I think being able to pick them up at 4 years and identifying those who are at high risk for structural change is very important," rheumatologist David Hunter said in an interview.

"If, at the time of the injury, there is more substantive damage to either [the patient’s] cartilage or their meniscus, you are going to be more cautious about encouraging them to return to high physical activity and potentially redamaging their" knee, said Dr. Hunter, professor of medicine at the University of Sydney (Australia).

The 38 ACL patients in the study, about half women, were under 51 years of age and not obese. Their ACLs were reconstructed within a half-year of their injury, and none had gotten intra-articular injections. Other than their injury, they were in good health with no other joint problems. Baseline radiographs were compared with films at 3-4 years.

More than 60% (8/13) of those with grade III cartilage injuries had abnormal joint space narrowing at that point, compared with 28% (7/25) of those with no more than grade II injuries – defects extending less than halfway through their femoral cartilage – and intact menisci in both compartments.

"Abnormal" meant that the joint space difference between patients’ injured and uninjured knees fell outside the 95% confidence interval of bilateral differences measured in 32 matched controls.

The conference was sponsored by the Osteoarthritis Research Society International. Mr. Tourville and Dr. Hunter said they had no relevant financial disclosures. The National Institute of Arthritis and Musculoskeletal and Skin Diseases supported the work.

SAN DIEGO – Structural damage due to osteoarthritis appears to be more common, and more severe, in the patellofemoral joint than in the tibiofemoral joint, making the patellofemoral joint the predominant one affected by knee osteoarthritis, according to findings from a magnetic resonance imaging–based study involving nearly 1,000 people.

It’s important that future research "not only address the tibiofemoral joint, but also the patellofemoral joint," said lead investigator Joshua Stefanik, Ph.D., a research associate in Boston University’s Clinical Epidemiology, Research, and Training Unit, said at the World Congress on Osteoarthritis.

The findings are surprising because "historically, everybody focuses on the tibiofemoral joint. We are probably missing a lot of disease" by relying on radiographs and clinical exams for diagnosis; they aren’t very good at picking up problems in the patellofemoral joint (PFJ), said Dr. David Hunter in an interview.

But even if it does a better job, "I wouldn’t encourage people to do an MRI if they have knee osteoarthritis." The results won’t change clinical management, and if meniscal tears are found, patients may end up in the operating room having an unnecessary meniscectomy, "which doesn’t do them any favors. Typically, the meniscus isn’t the problem." Tears are common and generally asymptomatic, said Dr. Hunter, a professor of medicine at the University of Sydney.

"Once clinicians are better educated about [such] dangers, MRI may be a good way to pick up [PFJ] disease," he said. Patellofemoral braces and PFJ-modifying shoe inserts are among the management options.

The 970 subjects in the study were part of the Framingham (Mass.) Osteoarthritis Study and were recruited from that community without regards to knee pain or osteoarthritis. Their mean age was 63.4 years and mean body mass index was 28.6 kg/m²; 57% were women, and 22% complained of knee pain. Cases of inflammatory arthritis were excluded. One knee was studied in each patient.

Radiographs found tibiofemoral joint (TFJ) damage in 11.9% of subjects, PFJ damage in just 1.4%, and damage in both joints in 5.9%.

The prevalence of PFJ problems was much higher on MRI; 20.4% had PFJ cartilage damage (WORMS [Whole-Organ Magnetic Resonance Imaging Score] greater than or equal to 2); 10.4% TFJ damage; and 44.2% damage in both joints. When both joints were involved, the most severe lesions were usually in the PFJ.

Similarly, 18.6% of subjects had PFJ cartilage damage extending down to bone (WORMS 2.5, greater than or equal to 5); 8% had TFJ damage down to bone; and 7.8% damage down to the bone in both joints.

The team found PFJ bone marrow lesions (WORMS greater than or equal to 1) in 17.9% of subjects; TFJ lesions in 16.5%; and lesions in both joints in 21.8%. Again, the most severe lesions were usually in the PFJ.

Finally, 15.2% of the Framingham subjects had both bone marrow lesions and cartilage damage down to bone in their PFJs, while only 8.8% had both problems in their TFJs; 4.4% had them in both joints.

Patterns were similar for men and women, and in knees with pain. The researchers used 1.5 T MRI with turbo spin-echo, fat-suppressed images in the sagittal, coronal, and axial planes.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Stefanik and Dr. Hunter reported no financial disclosures. The National Institutes of Health and the Arthritis Foundation funded the work.

SAN DIEGO – Structural damage due to osteoarthritis appears to be more common, and more severe, in the patellofemoral joint than in the tibiofemoral joint, making the patellofemoral joint the predominant one affected by knee osteoarthritis, according to findings from a magnetic resonance imaging–based study involving nearly 1,000 people.

It’s important that future research "not only address the tibiofemoral joint, but also the patellofemoral joint," said lead investigator Joshua Stefanik, Ph.D., a research associate in Boston University’s Clinical Epidemiology, Research, and Training Unit, said at the World Congress on Osteoarthritis.

The findings are surprising because "historically, everybody focuses on the tibiofemoral joint. We are probably missing a lot of disease" by relying on radiographs and clinical exams for diagnosis; they aren’t very good at picking up problems in the patellofemoral joint (PFJ), said Dr. David Hunter in an interview.

But even if it does a better job, "I wouldn’t encourage people to do an MRI if they have knee osteoarthritis." The results won’t change clinical management, and if meniscal tears are found, patients may end up in the operating room having an unnecessary meniscectomy, "which doesn’t do them any favors. Typically, the meniscus isn’t the problem." Tears are common and generally asymptomatic, said Dr. Hunter, a professor of medicine at the University of Sydney.

"Once clinicians are better educated about [such] dangers, MRI may be a good way to pick up [PFJ] disease," he said. Patellofemoral braces and PFJ-modifying shoe inserts are among the management options.

The 970 subjects in the study were part of the Framingham (Mass.) Osteoarthritis Study and were recruited from that community without regards to knee pain or osteoarthritis. Their mean age was 63.4 years and mean body mass index was 28.6 kg/m²; 57% were women, and 22% complained of knee pain. Cases of inflammatory arthritis were excluded. One knee was studied in each patient.

Radiographs found tibiofemoral joint (TFJ) damage in 11.9% of subjects, PFJ damage in just 1.4%, and damage in both joints in 5.9%.

The prevalence of PFJ problems was much higher on MRI; 20.4% had PFJ cartilage damage (WORMS [Whole-Organ Magnetic Resonance Imaging Score] greater than or equal to 2); 10.4% TFJ damage; and 44.2% damage in both joints. When both joints were involved, the most severe lesions were usually in the PFJ.

Similarly, 18.6% of subjects had PFJ cartilage damage extending down to bone (WORMS 2.5, greater than or equal to 5); 8% had TFJ damage down to bone; and 7.8% damage down to the bone in both joints.

The team found PFJ bone marrow lesions (WORMS greater than or equal to 1) in 17.9% of subjects; TFJ lesions in 16.5%; and lesions in both joints in 21.8%. Again, the most severe lesions were usually in the PFJ.

Finally, 15.2% of the Framingham subjects had both bone marrow lesions and cartilage damage down to bone in their PFJs, while only 8.8% had both problems in their TFJs; 4.4% had them in both joints.

Patterns were similar for men and women, and in knees with pain. The researchers used 1.5 T MRI with turbo spin-echo, fat-suppressed images in the sagittal, coronal, and axial planes.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Stefanik and Dr. Hunter reported no financial disclosures. The National Institutes of Health and the Arthritis Foundation funded the work.

SAN DIEGO – Structural damage due to osteoarthritis appears to be more common, and more severe, in the patellofemoral joint than in the tibiofemoral joint, making the patellofemoral joint the predominant one affected by knee osteoarthritis, according to findings from a magnetic resonance imaging–based study involving nearly 1,000 people.

It’s important that future research "not only address the tibiofemoral joint, but also the patellofemoral joint," said lead investigator Joshua Stefanik, Ph.D., a research associate in Boston University’s Clinical Epidemiology, Research, and Training Unit, said at the World Congress on Osteoarthritis.

The findings are surprising because "historically, everybody focuses on the tibiofemoral joint. We are probably missing a lot of disease" by relying on radiographs and clinical exams for diagnosis; they aren’t very good at picking up problems in the patellofemoral joint (PFJ), said Dr. David Hunter in an interview.

But even if it does a better job, "I wouldn’t encourage people to do an MRI if they have knee osteoarthritis." The results won’t change clinical management, and if meniscal tears are found, patients may end up in the operating room having an unnecessary meniscectomy, "which doesn’t do them any favors. Typically, the meniscus isn’t the problem." Tears are common and generally asymptomatic, said Dr. Hunter, a professor of medicine at the University of Sydney.

"Once clinicians are better educated about [such] dangers, MRI may be a good way to pick up [PFJ] disease," he said. Patellofemoral braces and PFJ-modifying shoe inserts are among the management options.

The 970 subjects in the study were part of the Framingham (Mass.) Osteoarthritis Study and were recruited from that community without regards to knee pain or osteoarthritis. Their mean age was 63.4 years and mean body mass index was 28.6 kg/m²; 57% were women, and 22% complained of knee pain. Cases of inflammatory arthritis were excluded. One knee was studied in each patient.

Radiographs found tibiofemoral joint (TFJ) damage in 11.9% of subjects, PFJ damage in just 1.4%, and damage in both joints in 5.9%.

The prevalence of PFJ problems was much higher on MRI; 20.4% had PFJ cartilage damage (WORMS [Whole-Organ Magnetic Resonance Imaging Score] greater than or equal to 2); 10.4% TFJ damage; and 44.2% damage in both joints. When both joints were involved, the most severe lesions were usually in the PFJ.

Similarly, 18.6% of subjects had PFJ cartilage damage extending down to bone (WORMS 2.5, greater than or equal to 5); 8% had TFJ damage down to bone; and 7.8% damage down to the bone in both joints.

The team found PFJ bone marrow lesions (WORMS greater than or equal to 1) in 17.9% of subjects; TFJ lesions in 16.5%; and lesions in both joints in 21.8%. Again, the most severe lesions were usually in the PFJ.

Finally, 15.2% of the Framingham subjects had both bone marrow lesions and cartilage damage down to bone in their PFJs, while only 8.8% had both problems in their TFJs; 4.4% had them in both joints.

Patterns were similar for men and women, and in knees with pain. The researchers used 1.5 T MRI with turbo spin-echo, fat-suppressed images in the sagittal, coronal, and axial planes.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Stefanik and Dr. Hunter reported no financial disclosures. The National Institutes of Health and the Arthritis Foundation funded the work.

SAN DIEGO – To at least some extent, findings seen on magnetic resonance imaging indicate the source of pain in osteoarthritic knees, according to University of Pittsburgh researchers.

Medial joint line knee pain, they found, is associated with bone marrow lesions in the medial compartment. Medial regional knee pain is associated with medial bone marrow lesions, meniscal extrusions, and meniscal damage, according to Dr. Kent Kwoh, a professor in the division of rheumatology and clinical immunology at the University of Pittsburgh.

"If you have pain on the inner side of your knee, and you’re biomechanically loading that side too much, you [know] that there’s pathology there."

There were trends, as well, including one toward lateral regional knee pain being associated with lateral meniscal extrusions, but they didn’t reach statistical significance, probably because of the small number of patients in the trial with lateral regional pain and other specific findings, he said.

Nonetheless, the findings mean that "the location of pain is where the pathology is. We haven’t known that. It’s an important observation," said Dr. David Felson after Dr. Kwoh’s presentation.

"If you have pain on the inner side of your knee, and you’re biomechanically loading that side too much, you [know] that there’s pathology there, and that you can diminish the pain and perhaps help the pathology by focusing on the biomechanical abnormalities," with bracing, wedging, or other targeted interventions, said Dr. Felson, a professor of medicine and epidemiology at Boston University. He also is director of the Research in Osteoarthritis in Manchester (ROAM) group the University of Manchester (England).

The 177 subjects in the study had mild to moderate pain on most days. Their age averaged 52 years, their mean body mass index was 29 kg/m², and 46% were women. Half had medial joint space narrowing, and about 20% had lateral joint space narrowing. Slightly more than half had medial osteophytes, and slightly less than half had lateral osteophytes.

The Pittsburgh team used MRI to look at where patients said it hurt, or the general region if they could not point to the exact place.

The relative risk ratio for medial bone marrow lesions in the 83 patients with local medial joint line pain was 9.89. The risk ratios for medial bone marrow lesions, meniscal damage, and meniscal extrusion in the 36 patients with regional medial pain were 12.10, 3.72, and 8.77, respectively. The findings were statistically significant.

Right knee medial joint line pain and right knee lateral joint line pain with patellar and medial joint line components were the most common localizable pain types. Left knee patellar and left knee medial pain were the most common regional types.

The congress was sponsored by the Osteoarthritis Research Society International.

Dr. Kwoh and Dr. Felson said they have no disclosures. The University of Pittsburgh and Coca-Cola Co.’s Beverage Institute paid for the work.

SAN DIEGO – To at least some extent, findings seen on magnetic resonance imaging indicate the source of pain in osteoarthritic knees, according to University of Pittsburgh researchers.

Medial joint line knee pain, they found, is associated with bone marrow lesions in the medial compartment. Medial regional knee pain is associated with medial bone marrow lesions, meniscal extrusions, and meniscal damage, according to Dr. Kent Kwoh, a professor in the division of rheumatology and clinical immunology at the University of Pittsburgh.

"If you have pain on the inner side of your knee, and you’re biomechanically loading that side too much, you [know] that there’s pathology there."

There were trends, as well, including one toward lateral regional knee pain being associated with lateral meniscal extrusions, but they didn’t reach statistical significance, probably because of the small number of patients in the trial with lateral regional pain and other specific findings, he said.

Nonetheless, the findings mean that "the location of pain is where the pathology is. We haven’t known that. It’s an important observation," said Dr. David Felson after Dr. Kwoh’s presentation.

"If you have pain on the inner side of your knee, and you’re biomechanically loading that side too much, you [know] that there’s pathology there, and that you can diminish the pain and perhaps help the pathology by focusing on the biomechanical abnormalities," with bracing, wedging, or other targeted interventions, said Dr. Felson, a professor of medicine and epidemiology at Boston University. He also is director of the Research in Osteoarthritis in Manchester (ROAM) group the University of Manchester (England).

The 177 subjects in the study had mild to moderate pain on most days. Their age averaged 52 years, their mean body mass index was 29 kg/m², and 46% were women. Half had medial joint space narrowing, and about 20% had lateral joint space narrowing. Slightly more than half had medial osteophytes, and slightly less than half had lateral osteophytes.

The Pittsburgh team used MRI to look at where patients said it hurt, or the general region if they could not point to the exact place.

The relative risk ratio for medial bone marrow lesions in the 83 patients with local medial joint line pain was 9.89. The risk ratios for medial bone marrow lesions, meniscal damage, and meniscal extrusion in the 36 patients with regional medial pain were 12.10, 3.72, and 8.77, respectively. The findings were statistically significant.

Right knee medial joint line pain and right knee lateral joint line pain with patellar and medial joint line components were the most common localizable pain types. Left knee patellar and left knee medial pain were the most common regional types.

The congress was sponsored by the Osteoarthritis Research Society International.

Dr. Kwoh and Dr. Felson said they have no disclosures. The University of Pittsburgh and Coca-Cola Co.’s Beverage Institute paid for the work.

SAN DIEGO – To at least some extent, findings seen on magnetic resonance imaging indicate the source of pain in osteoarthritic knees, according to University of Pittsburgh researchers.

Medial joint line knee pain, they found, is associated with bone marrow lesions in the medial compartment. Medial regional knee pain is associated with medial bone marrow lesions, meniscal extrusions, and meniscal damage, according to Dr. Kent Kwoh, a professor in the division of rheumatology and clinical immunology at the University of Pittsburgh.

"If you have pain on the inner side of your knee, and you’re biomechanically loading that side too much, you [know] that there’s pathology there."

There were trends, as well, including one toward lateral regional knee pain being associated with lateral meniscal extrusions, but they didn’t reach statistical significance, probably because of the small number of patients in the trial with lateral regional pain and other specific findings, he said.

Nonetheless, the findings mean that "the location of pain is where the pathology is. We haven’t known that. It’s an important observation," said Dr. David Felson after Dr. Kwoh’s presentation.

"If you have pain on the inner side of your knee, and you’re biomechanically loading that side too much, you [know] that there’s pathology there, and that you can diminish the pain and perhaps help the pathology by focusing on the biomechanical abnormalities," with bracing, wedging, or other targeted interventions, said Dr. Felson, a professor of medicine and epidemiology at Boston University. He also is director of the Research in Osteoarthritis in Manchester (ROAM) group the University of Manchester (England).

The 177 subjects in the study had mild to moderate pain on most days. Their age averaged 52 years, their mean body mass index was 29 kg/m², and 46% were women. Half had medial joint space narrowing, and about 20% had lateral joint space narrowing. Slightly more than half had medial osteophytes, and slightly less than half had lateral osteophytes.

The Pittsburgh team used MRI to look at where patients said it hurt, or the general region if they could not point to the exact place.

The relative risk ratio for medial bone marrow lesions in the 83 patients with local medial joint line pain was 9.89. The risk ratios for medial bone marrow lesions, meniscal damage, and meniscal extrusion in the 36 patients with regional medial pain were 12.10, 3.72, and 8.77, respectively. The findings were statistically significant.

Right knee medial joint line pain and right knee lateral joint line pain with patellar and medial joint line components were the most common localizable pain types. Left knee patellar and left knee medial pain were the most common regional types.

The congress was sponsored by the Osteoarthritis Research Society International.

Dr. Kwoh and Dr. Felson said they have no disclosures. The University of Pittsburgh and Coca-Cola Co.’s Beverage Institute paid for the work.

SAN DIEGO – Even older, heavier, sicker patients, and those with worse mental health, benefit substantially from total hip replacement when indicated, a study has shown.

It’s just that their outcomes aren’t quite as good as those of their younger, leaner, and healthier peers because they also tend to start out with worse preoperative hip pain and function. Even so, they benefit about as much from the operation, gaining in the range of 20 points on the 48-point Oxford Hip Score (OHS), the study found.

Because of that, perhaps physicians should reconsider basing selection of surgery candidates on negative preoperative characteristics; maybe even "patient [body mass index (BMI)] should not be used, as these patients still get substantial improvement following surgery," lead investigator Andy Judge, Ph.D., said at the World Congress on Osteoarthritis, sponsored by Osteoarthritis Research Society International.

The team compared preoperative OHS scores with postoperative scores collected over a 5-year period from 1,375 hip replacement patients who underwent surgery because of osteoarthritis. Each got a cemented Exeter femoral component. Their mean age was 68; 60% were women.

The OHS asks patients 12 multiple-choice questions about pain and function. The five possible answers are scored 0-4, with 0 being the worst possible overall score, and 48 the best.

In general, and regardless of preoperative factors, surgery gave the majority of patients significant relief in the 1st year that was maintained through the 5th year, said Dr. Judge, a senior statistician at the University of Oxford.

There were "small differences in postoperative OHS observed for age, BMI, comorbidity, mental health, and femoral component size, but these patients still received substantial benefit from surgery," he said.

Preoperative hip pain and function was the biggest predictor of how patients fared after the operation. Patients with worse scores tended to have worse postoperative pain and function.

However, even those who entered the operating room with OHS scores below 5 improved, on average, to about 30. Those who entered with scores in the mid-30s improved to the low 40s.

Between-group magnitudes of improvement were similar for other factors taken into account. For instance, average preoperative OHS scores were in the lower teens for those with BMIs at or above 30 kg/m²; postoperative scores were in the mid-30s. Slimmer peers with BMIs below 30 kg/m² entered the operating room with average OHS scores in the upper teens; their postoperative scores improved to about 40 on average.

It was the same story with poorer preoperative mental health scores and higher numbers of comorbidities; patients started and wound up a few points lower on the OHS, but tended to benefit about as much as patients with better mental health and fewer comorbidities.

Patients who were 60-70 years old had the best postoperative scores by a few points, but also started with OHS scores a few points higher than younger and older patients, who, nonetheless, had comparable, roughly 20-point improvements in postoperative OHS scores.

Similarly, patients with larger femoral component sizes (offset of 44 mm or more) also had slightly better outcomes, but also entered the trial with slightly better hip scores. The trial’s findings were statistically significant.

Dr. Judge said he had no relevant financial disclosures. The study was funded by the British National Institute for Health Research.

SAN DIEGO – Even older, heavier, sicker patients, and those with worse mental health, benefit substantially from total hip replacement when indicated, a study has shown.

It’s just that their outcomes aren’t quite as good as those of their younger, leaner, and healthier peers because they also tend to start out with worse preoperative hip pain and function. Even so, they benefit about as much from the operation, gaining in the range of 20 points on the 48-point Oxford Hip Score (OHS), the study found.

Because of that, perhaps physicians should reconsider basing selection of surgery candidates on negative preoperative characteristics; maybe even "patient [body mass index (BMI)] should not be used, as these patients still get substantial improvement following surgery," lead investigator Andy Judge, Ph.D., said at the World Congress on Osteoarthritis, sponsored by Osteoarthritis Research Society International.

The team compared preoperative OHS scores with postoperative scores collected over a 5-year period from 1,375 hip replacement patients who underwent surgery because of osteoarthritis. Each got a cemented Exeter femoral component. Their mean age was 68; 60% were women.

The OHS asks patients 12 multiple-choice questions about pain and function. The five possible answers are scored 0-4, with 0 being the worst possible overall score, and 48 the best.

In general, and regardless of preoperative factors, surgery gave the majority of patients significant relief in the 1st year that was maintained through the 5th year, said Dr. Judge, a senior statistician at the University of Oxford.

There were "small differences in postoperative OHS observed for age, BMI, comorbidity, mental health, and femoral component size, but these patients still received substantial benefit from surgery," he said.

Preoperative hip pain and function was the biggest predictor of how patients fared after the operation. Patients with worse scores tended to have worse postoperative pain and function.

However, even those who entered the operating room with OHS scores below 5 improved, on average, to about 30. Those who entered with scores in the mid-30s improved to the low 40s.

Between-group magnitudes of improvement were similar for other factors taken into account. For instance, average preoperative OHS scores were in the lower teens for those with BMIs at or above 30 kg/m²; postoperative scores were in the mid-30s. Slimmer peers with BMIs below 30 kg/m² entered the operating room with average OHS scores in the upper teens; their postoperative scores improved to about 40 on average.

It was the same story with poorer preoperative mental health scores and higher numbers of comorbidities; patients started and wound up a few points lower on the OHS, but tended to benefit about as much as patients with better mental health and fewer comorbidities.

Patients who were 60-70 years old had the best postoperative scores by a few points, but also started with OHS scores a few points higher than younger and older patients, who, nonetheless, had comparable, roughly 20-point improvements in postoperative OHS scores.

Similarly, patients with larger femoral component sizes (offset of 44 mm or more) also had slightly better outcomes, but also entered the trial with slightly better hip scores. The trial’s findings were statistically significant.

Dr. Judge said he had no relevant financial disclosures. The study was funded by the British National Institute for Health Research.

SAN DIEGO – Even older, heavier, sicker patients, and those with worse mental health, benefit substantially from total hip replacement when indicated, a study has shown.

It’s just that their outcomes aren’t quite as good as those of their younger, leaner, and healthier peers because they also tend to start out with worse preoperative hip pain and function. Even so, they benefit about as much from the operation, gaining in the range of 20 points on the 48-point Oxford Hip Score (OHS), the study found.

Because of that, perhaps physicians should reconsider basing selection of surgery candidates on negative preoperative characteristics; maybe even "patient [body mass index (BMI)] should not be used, as these patients still get substantial improvement following surgery," lead investigator Andy Judge, Ph.D., said at the World Congress on Osteoarthritis, sponsored by Osteoarthritis Research Society International.

The team compared preoperative OHS scores with postoperative scores collected over a 5-year period from 1,375 hip replacement patients who underwent surgery because of osteoarthritis. Each got a cemented Exeter femoral component. Their mean age was 68; 60% were women.

The OHS asks patients 12 multiple-choice questions about pain and function. The five possible answers are scored 0-4, with 0 being the worst possible overall score, and 48 the best.

In general, and regardless of preoperative factors, surgery gave the majority of patients significant relief in the 1st year that was maintained through the 5th year, said Dr. Judge, a senior statistician at the University of Oxford.

There were "small differences in postoperative OHS observed for age, BMI, comorbidity, mental health, and femoral component size, but these patients still received substantial benefit from surgery," he said.

Preoperative hip pain and function was the biggest predictor of how patients fared after the operation. Patients with worse scores tended to have worse postoperative pain and function.

However, even those who entered the operating room with OHS scores below 5 improved, on average, to about 30. Those who entered with scores in the mid-30s improved to the low 40s.

Between-group magnitudes of improvement were similar for other factors taken into account. For instance, average preoperative OHS scores were in the lower teens for those with BMIs at or above 30 kg/m²; postoperative scores were in the mid-30s. Slimmer peers with BMIs below 30 kg/m² entered the operating room with average OHS scores in the upper teens; their postoperative scores improved to about 40 on average.

It was the same story with poorer preoperative mental health scores and higher numbers of comorbidities; patients started and wound up a few points lower on the OHS, but tended to benefit about as much as patients with better mental health and fewer comorbidities.

Patients who were 60-70 years old had the best postoperative scores by a few points, but also started with OHS scores a few points higher than younger and older patients, who, nonetheless, had comparable, roughly 20-point improvements in postoperative OHS scores.

Similarly, patients with larger femoral component sizes (offset of 44 mm or more) also had slightly better outcomes, but also entered the trial with slightly better hip scores. The trial’s findings were statistically significant.

Dr. Judge said he had no relevant financial disclosures. The study was funded by the British National Institute for Health Research.

SAN DIEGO – Male gender, obesity, pain level, and baseline radiographic severity independently predict the progression of knee osteoarthritis, while race and baseline multiple joint involvement, knee misalignment, and physical inactivity do not, according to the results of a large cohort study.

The findings could help drug developers figure out whom to include in trials of drugs aimed at slowing progression. Also, the blood, DNA, and other samples collected in the study, upon further analysis, may suggest new drug targets in people at risk for progression, said lead investigator Dr. Charles Eaton, professor of family medicine at Brown University, Providence, R.I.

"It may be some of the metabolic factors related to obesity," such as inflammation, "make you progress," and could be targeted in drug development, he said.

Meanwhile, it’s a good idea to encourage obese patients who have knee osteoarthritis (OA) to lose weight. Also, "if you have a male coming in complaining of a lot of knee pain, they might be at high risk for progression. Get an x-ray and see if they actually have arthritis, and see how severe it is," Dr. Eaton said at the World Congress on Osteoarthritis.

He and his colleagues used publicly available data from the Osteoarthritis Initiative, a multicenter longitudinal cohort study looking for biomarkers of incidence and progression, to track 1,842 knees in 1,247 knee OA patients. For each knee, the investigators analyzed x-rays taken at baseline and at 4 years of follow-up to see who had medial joint-space narrowing of 0.5 mm or more. The researchers then looked to see what baseline characteristics predicted progression. Subjects were 45-79 years old. Almost 60% of the knees in the study belonged to women.

Compared with women, the adjusted odds ratio for progression among men was 1.27 (95% confidence interval 1.02-1.59).

Patients who entered the study with Kellgren-Lawrence grade 3 disease, instead of grade 2 disease, had twice the risk of progression (OR 2.09, 95% CI 1.72-2.54). Those who enrolled with a body mass index of 30 kg/m² or higher were about 1.5 times more likely to progress than those who entered with a BMI below 25 kg/m² (OR 1.41, 95% CI 1.02-1.96).

Patients with the worst pain at baseline – WOMAC (Western Ontario and McMaster Universities index) pain scores in the fourth quartile – were twice as likely to progress as those who entered with first quartile pain (OR 2.18, 95% CI 1.69-2.82).

Time itself was a factor, too; 4 years into the trial, patients were nine times as likely as in the first year to have progressed (OR 9.14, 95% CI 7.45-11.22).

"Previously, it was thought that females were more likely to progress. Initial studies suggested that African Americans were more likely to progress. But when we adjusted for everything, that was no longer true," Dr. Eaton said. Baseline income, smoking, depression, and Knee Injury and Osteoarthritis Outcome Score (KOOS) functionality were among the other potential risk-factors that did not pan out on multivariate analysis.

"We are trying to understand" the increased risk for men. Men may have entered the trial with a greater burden of meniscal damage than women, and a greater likelihood of past knee surgery; there was a trend in the data toward increased progression risk for previous knee operations, but it dropped out on multivariate analysis.

The meeting was sponsored by the Osteoarthritis Research Society International.

The Osteoarthritis Initiative is funded by the National Institutes of Health, Merck, GlaxoSmithKline, Novartis Pharmaceuticals, and Pfizer. Dr. Eaton said he had no disclosures.

SAN DIEGO – Male gender, obesity, pain level, and baseline radiographic severity independently predict the progression of knee osteoarthritis, while race and baseline multiple joint involvement, knee misalignment, and physical inactivity do not, according to the results of a large cohort study.

The findings could help drug developers figure out whom to include in trials of drugs aimed at slowing progression. Also, the blood, DNA, and other samples collected in the study, upon further analysis, may suggest new drug targets in people at risk for progression, said lead investigator Dr. Charles Eaton, professor of family medicine at Brown University, Providence, R.I.

"It may be some of the metabolic factors related to obesity," such as inflammation, "make you progress," and could be targeted in drug development, he said.

Meanwhile, it’s a good idea to encourage obese patients who have knee osteoarthritis (OA) to lose weight. Also, "if you have a male coming in complaining of a lot of knee pain, they might be at high risk for progression. Get an x-ray and see if they actually have arthritis, and see how severe it is," Dr. Eaton said at the World Congress on Osteoarthritis.

He and his colleagues used publicly available data from the Osteoarthritis Initiative, a multicenter longitudinal cohort study looking for biomarkers of incidence and progression, to track 1,842 knees in 1,247 knee OA patients. For each knee, the investigators analyzed x-rays taken at baseline and at 4 years of follow-up to see who had medial joint-space narrowing of 0.5 mm or more. The researchers then looked to see what baseline characteristics predicted progression. Subjects were 45-79 years old. Almost 60% of the knees in the study belonged to women.

Compared with women, the adjusted odds ratio for progression among men was 1.27 (95% confidence interval 1.02-1.59).

Patients who entered the study with Kellgren-Lawrence grade 3 disease, instead of grade 2 disease, had twice the risk of progression (OR 2.09, 95% CI 1.72-2.54). Those who enrolled with a body mass index of 30 kg/m² or higher were about 1.5 times more likely to progress than those who entered with a BMI below 25 kg/m² (OR 1.41, 95% CI 1.02-1.96).

Patients with the worst pain at baseline – WOMAC (Western Ontario and McMaster Universities index) pain scores in the fourth quartile – were twice as likely to progress as those who entered with first quartile pain (OR 2.18, 95% CI 1.69-2.82).

Time itself was a factor, too; 4 years into the trial, patients were nine times as likely as in the first year to have progressed (OR 9.14, 95% CI 7.45-11.22).

"Previously, it was thought that females were more likely to progress. Initial studies suggested that African Americans were more likely to progress. But when we adjusted for everything, that was no longer true," Dr. Eaton said. Baseline income, smoking, depression, and Knee Injury and Osteoarthritis Outcome Score (KOOS) functionality were among the other potential risk-factors that did not pan out on multivariate analysis.

"We are trying to understand" the increased risk for men. Men may have entered the trial with a greater burden of meniscal damage than women, and a greater likelihood of past knee surgery; there was a trend in the data toward increased progression risk for previous knee operations, but it dropped out on multivariate analysis.

The meeting was sponsored by the Osteoarthritis Research Society International.

The Osteoarthritis Initiative is funded by the National Institutes of Health, Merck, GlaxoSmithKline, Novartis Pharmaceuticals, and Pfizer. Dr. Eaton said he had no disclosures.

SAN DIEGO – Male gender, obesity, pain level, and baseline radiographic severity independently predict the progression of knee osteoarthritis, while race and baseline multiple joint involvement, knee misalignment, and physical inactivity do not, according to the results of a large cohort study.

The findings could help drug developers figure out whom to include in trials of drugs aimed at slowing progression. Also, the blood, DNA, and other samples collected in the study, upon further analysis, may suggest new drug targets in people at risk for progression, said lead investigator Dr. Charles Eaton, professor of family medicine at Brown University, Providence, R.I.

"It may be some of the metabolic factors related to obesity," such as inflammation, "make you progress," and could be targeted in drug development, he said.

Meanwhile, it’s a good idea to encourage obese patients who have knee osteoarthritis (OA) to lose weight. Also, "if you have a male coming in complaining of a lot of knee pain, they might be at high risk for progression. Get an x-ray and see if they actually have arthritis, and see how severe it is," Dr. Eaton said at the World Congress on Osteoarthritis.

He and his colleagues used publicly available data from the Osteoarthritis Initiative, a multicenter longitudinal cohort study looking for biomarkers of incidence and progression, to track 1,842 knees in 1,247 knee OA patients. For each knee, the investigators analyzed x-rays taken at baseline and at 4 years of follow-up to see who had medial joint-space narrowing of 0.5 mm or more. The researchers then looked to see what baseline characteristics predicted progression. Subjects were 45-79 years old. Almost 60% of the knees in the study belonged to women.

Compared with women, the adjusted odds ratio for progression among men was 1.27 (95% confidence interval 1.02-1.59).

Patients who entered the study with Kellgren-Lawrence grade 3 disease, instead of grade 2 disease, had twice the risk of progression (OR 2.09, 95% CI 1.72-2.54). Those who enrolled with a body mass index of 30 kg/m² or higher were about 1.5 times more likely to progress than those who entered with a BMI below 25 kg/m² (OR 1.41, 95% CI 1.02-1.96).

Patients with the worst pain at baseline – WOMAC (Western Ontario and McMaster Universities index) pain scores in the fourth quartile – were twice as likely to progress as those who entered with first quartile pain (OR 2.18, 95% CI 1.69-2.82).

Time itself was a factor, too; 4 years into the trial, patients were nine times as likely as in the first year to have progressed (OR 9.14, 95% CI 7.45-11.22).

"Previously, it was thought that females were more likely to progress. Initial studies suggested that African Americans were more likely to progress. But when we adjusted for everything, that was no longer true," Dr. Eaton said. Baseline income, smoking, depression, and Knee Injury and Osteoarthritis Outcome Score (KOOS) functionality were among the other potential risk-factors that did not pan out on multivariate analysis.

"We are trying to understand" the increased risk for men. Men may have entered the trial with a greater burden of meniscal damage than women, and a greater likelihood of past knee surgery; there was a trend in the data toward increased progression risk for previous knee operations, but it dropped out on multivariate analysis.

The meeting was sponsored by the Osteoarthritis Research Society International.

The Osteoarthritis Initiative is funded by the National Institutes of Health, Merck, GlaxoSmithKline, Novartis Pharmaceuticals, and Pfizer. Dr. Eaton said he had no disclosures.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Lateral wedge shoe insoles reduce the gait load on the inside of the knee but fail to lessen pain long term in patients with medial knee osteoarthritis.

A British research team thinks it may have solved the mystery. It seems the inserts work only in the subset of patients who have flatter feet and who plant their heels more squarely when they walk, rather than rolling their foot to the outside, said lead investigator Graham Chapman, Ph.D., at the World Congress on Osteoarthritis.

Previous studies (BMJ 2011;342:d2912) seem to have "grouped everyone together and assumed they are going to respond to wearing a lateral wedge," said Dr. Chapman, a research fellow in biomechanics at the University of Salford (England).

That was not the case when he and his colleagues analyzed 33 patients who had medial knee osteoarthritis (OA) and a Kellgren-Lawrence grade 2 or 3. Their mean age was 59 years, their mean body mass index was 32.2 kg/m², and 42% (14) were women.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges."

In 13 (39%) of the patients, the inserts did not help. Their use actually increased the load on the inside of the knee, as measured by the external knee adduction moment. In the remaining patients, use of the 5-degree lateral wedge insoles – which look much like any shoe insole except for a "fat bit on outside," Dr. Chapman said – reduced the adduction moment by a mean of 4.1%.

The researchers next looked to see how those who did not benefit from the insoles differed from those who did benefit.

The 13 patients who did not benefit were likely to have more contact on their lateral heel as they walked (about 19 cm² vs. about 17.5 cm²) and higher medial arches (with mean subarch angles of about 104 degrees vs. about 111 degrees in those who benefited from the inserts). The findings were statistically significant.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges. Excluding persons whose foot dynamics make them unlikely to respond to insoles may leave a large group of patients who can experience their potential therapeutic benefits," the researchers concluded in their abstract.

The next step is a randomized trial to see if people who fit the profile of responders truly do have less pain when they wear shoes with lateral wedges rather than control shoes.

The ultimate goal is to help clinicians predict who will benefit from the insoles, Dr. Chapman said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Dr. Chapman said he has no disclosures. The work was funded by Arthritis Research UK.

SAN DIEGO – Lateral wedge shoe insoles reduce the gait load on the inside of the knee but fail to lessen pain long term in patients with medial knee osteoarthritis.

A British research team thinks it may have solved the mystery. It seems the inserts work only in the subset of patients who have flatter feet and who plant their heels more squarely when they walk, rather than rolling their foot to the outside, said lead investigator Graham Chapman, Ph.D., at the World Congress on Osteoarthritis.

Previous studies (BMJ 2011;342:d2912) seem to have "grouped everyone together and assumed they are going to respond to wearing a lateral wedge," said Dr. Chapman, a research fellow in biomechanics at the University of Salford (England).

That was not the case when he and his colleagues analyzed 33 patients who had medial knee osteoarthritis (OA) and a Kellgren-Lawrence grade 2 or 3. Their mean age was 59 years, their mean body mass index was 32.2 kg/m², and 42% (14) were women.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges."

In 13 (39%) of the patients, the inserts did not help. Their use actually increased the load on the inside of the knee, as measured by the external knee adduction moment. In the remaining patients, use of the 5-degree lateral wedge insoles – which look much like any shoe insole except for a "fat bit on outside," Dr. Chapman said – reduced the adduction moment by a mean of 4.1%.

The researchers next looked to see how those who did not benefit from the insoles differed from those who did benefit.

The 13 patients who did not benefit were likely to have more contact on their lateral heel as they walked (about 19 cm² vs. about 17.5 cm²) and higher medial arches (with mean subarch angles of about 104 degrees vs. about 111 degrees in those who benefited from the inserts). The findings were statistically significant.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges. Excluding persons whose foot dynamics make them unlikely to respond to insoles may leave a large group of patients who can experience their potential therapeutic benefits," the researchers concluded in their abstract.

The next step is a randomized trial to see if people who fit the profile of responders truly do have less pain when they wear shoes with lateral wedges rather than control shoes.

The ultimate goal is to help clinicians predict who will benefit from the insoles, Dr. Chapman said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Dr. Chapman said he has no disclosures. The work was funded by Arthritis Research UK.

SAN DIEGO – Lateral wedge shoe insoles reduce the gait load on the inside of the knee but fail to lessen pain long term in patients with medial knee osteoarthritis.

A British research team thinks it may have solved the mystery. It seems the inserts work only in the subset of patients who have flatter feet and who plant their heels more squarely when they walk, rather than rolling their foot to the outside, said lead investigator Graham Chapman, Ph.D., at the World Congress on Osteoarthritis.

Previous studies (BMJ 2011;342:d2912) seem to have "grouped everyone together and assumed they are going to respond to wearing a lateral wedge," said Dr. Chapman, a research fellow in biomechanics at the University of Salford (England).

That was not the case when he and his colleagues analyzed 33 patients who had medial knee osteoarthritis (OA) and a Kellgren-Lawrence grade 2 or 3. Their mean age was 59 years, their mean body mass index was 32.2 kg/m², and 42% (14) were women.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges."

In 13 (39%) of the patients, the inserts did not help. Their use actually increased the load on the inside of the knee, as measured by the external knee adduction moment. In the remaining patients, use of the 5-degree lateral wedge insoles – which look much like any shoe insole except for a "fat bit on outside," Dr. Chapman said – reduced the adduction moment by a mean of 4.1%.

The researchers next looked to see how those who did not benefit from the insoles differed from those who did benefit.

The 13 patients who did not benefit were likely to have more contact on their lateral heel as they walked (about 19 cm² vs. about 17.5 cm²) and higher medial arches (with mean subarch angles of about 104 degrees vs. about 111 degrees in those who benefited from the inserts). The findings were statistically significant.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges. Excluding persons whose foot dynamics make them unlikely to respond to insoles may leave a large group of patients who can experience their potential therapeutic benefits," the researchers concluded in their abstract.

The next step is a randomized trial to see if people who fit the profile of responders truly do have less pain when they wear shoes with lateral wedges rather than control shoes.

The ultimate goal is to help clinicians predict who will benefit from the insoles, Dr. Chapman said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Dr. Chapman said he has no disclosures. The work was funded by Arthritis Research UK.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Induced knee pain appears to have improved strength training in a small, Danish randomized trial.

Researchers injected the right knee infrapatellar fat pads of 13 healthy subjects in their mid-20s with painful, hypertonic saline. Immediately afterward, participants did three sets of leg presses and knee extensions. After three sessions per week for 8 weeks, their right quadriceps were 22% stronger than at baseline. Fourteen controls, injected with nonpainful isotonic saline, increased quadricep strength by 7% (P less than .0001).

The results suggest "maybe it’s not that bad to exercise with pain, at least if it’s not caused by inflammation."

Common wisdom holds that pain diminishes muscle function, inhibits strength training, and may prevent rehabilitation in patients with knee problems, including osteoarthritis. However, "no one has ever proven that is actually the case," said Tina Sorensen, a doctoral candidate at the Institute of Sports Science and Clinical Biomechanics at the University of Southern Denmark in Odense, a physiotherapist who was lead author.

The results suggest "maybe it’s not that bad to exercise with pain, at least if it’s not caused by inflammation"; perhaps they also hint at a role for induced pain in some settings, she said. The researchers are interested now in seeing if their early results hold up in patients with actual knee problems.

Loads used in training were 80% of a given subject’s maximum repetition strength, which was assessed weekly and without pain. Participants worked each set to the point of muscle fatigue, usually 8-12 repetitions, and rested about a minute between sets.

The groups were evenly matched, with no significant differences in height, body mass index, or baseline strength. There were 10 men in the pain group and 6 in the control group, but as with other factors, the difference was not statistically significant.

The injections (1 mL of saline under ultrasound guidance) came after a 10-minute warm-up on a stationary bicycle. The pain from the hypertonic shots diminished as subjects worked through their sets, starting on average at about 25 mm on the 100 mm visual analog pain scale and ending at about 10 mm. Strength was assessed weekly 30 minutes after training.

At the end of the 8 weeks, the right legs of participants in the pain group were 24.6% stronger at 60 degrees of knee extension, 21.6% stronger at 120 degrees, and 19.6% at 180 degrees. Subjects in the control group were 7.5% stronger at 60 degrees of knee extension, 5.0% at 120 degrees and 8.2% at 180 degrees.

"It could be that when you have pain, your type 1 muscle fibers [the endurance fibers,] are inhibited, and your type 2 fibers [the power and speed fibers] are easily recruited, which could explain why the pain group had the larger increase in muscle strength," Ms. Sorensen said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

The researchers noted that hypertonic saline injections mimic many aspects of pathological knee pain "and [are] a well-accepted, efficient, and safe method to" replicate it experimentally.

The work was supported by the Association of Danish Physiotherapists. Ms. Sorensen said she has no disclosures.

SAN DIEGO – Induced knee pain appears to have improved strength training in a small, Danish randomized trial.

Researchers injected the right knee infrapatellar fat pads of 13 healthy subjects in their mid-20s with painful, hypertonic saline. Immediately afterward, participants did three sets of leg presses and knee extensions. After three sessions per week for 8 weeks, their right quadriceps were 22% stronger than at baseline. Fourteen controls, injected with nonpainful isotonic saline, increased quadricep strength by 7% (P less than .0001).

The results suggest "maybe it’s not that bad to exercise with pain, at least if it’s not caused by inflammation."

Common wisdom holds that pain diminishes muscle function, inhibits strength training, and may prevent rehabilitation in patients with knee problems, including osteoarthritis. However, "no one has ever proven that is actually the case," said Tina Sorensen, a doctoral candidate at the Institute of Sports Science and Clinical Biomechanics at the University of Southern Denmark in Odense, a physiotherapist who was lead author.

The results suggest "maybe it’s not that bad to exercise with pain, at least if it’s not caused by inflammation"; perhaps they also hint at a role for induced pain in some settings, she said. The researchers are interested now in seeing if their early results hold up in patients with actual knee problems.

Loads used in training were 80% of a given subject’s maximum repetition strength, which was assessed weekly and without pain. Participants worked each set to the point of muscle fatigue, usually 8-12 repetitions, and rested about a minute between sets.

The groups were evenly matched, with no significant differences in height, body mass index, or baseline strength. There were 10 men in the pain group and 6 in the control group, but as with other factors, the difference was not statistically significant.

The injections (1 mL of saline under ultrasound guidance) came after a 10-minute warm-up on a stationary bicycle. The pain from the hypertonic shots diminished as subjects worked through their sets, starting on average at about 25 mm on the 100 mm visual analog pain scale and ending at about 10 mm. Strength was assessed weekly 30 minutes after training.

At the end of the 8 weeks, the right legs of participants in the pain group were 24.6% stronger at 60 degrees of knee extension, 21.6% stronger at 120 degrees, and 19.6% at 180 degrees. Subjects in the control group were 7.5% stronger at 60 degrees of knee extension, 5.0% at 120 degrees and 8.2% at 180 degrees.

"It could be that when you have pain, your type 1 muscle fibers [the endurance fibers,] are inhibited, and your type 2 fibers [the power and speed fibers] are easily recruited, which could explain why the pain group had the larger increase in muscle strength," Ms. Sorensen said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

The researchers noted that hypertonic saline injections mimic many aspects of pathological knee pain "and [are] a well-accepted, efficient, and safe method to" replicate it experimentally.

The work was supported by the Association of Danish Physiotherapists. Ms. Sorensen said she has no disclosures.

SAN DIEGO – Induced knee pain appears to have improved strength training in a small, Danish randomized trial.

Researchers injected the right knee infrapatellar fat pads of 13 healthy subjects in their mid-20s with painful, hypertonic saline. Immediately afterward, participants did three sets of leg presses and knee extensions. After three sessions per week for 8 weeks, their right quadriceps were 22% stronger than at baseline. Fourteen controls, injected with nonpainful isotonic saline, increased quadricep strength by 7% (P less than .0001).

The results suggest "maybe it’s not that bad to exercise with pain, at least if it’s not caused by inflammation."

Common wisdom holds that pain diminishes muscle function, inhibits strength training, and may prevent rehabilitation in patients with knee problems, including osteoarthritis. However, "no one has ever proven that is actually the case," said Tina Sorensen, a doctoral candidate at the Institute of Sports Science and Clinical Biomechanics at the University of Southern Denmark in Odense, a physiotherapist who was lead author.

The results suggest "maybe it’s not that bad to exercise with pain, at least if it’s not caused by inflammation"; perhaps they also hint at a role for induced pain in some settings, she said. The researchers are interested now in seeing if their early results hold up in patients with actual knee problems.

Loads used in training were 80% of a given subject’s maximum repetition strength, which was assessed weekly and without pain. Participants worked each set to the point of muscle fatigue, usually 8-12 repetitions, and rested about a minute between sets.

The groups were evenly matched, with no significant differences in height, body mass index, or baseline strength. There were 10 men in the pain group and 6 in the control group, but as with other factors, the difference was not statistically significant.

The injections (1 mL of saline under ultrasound guidance) came after a 10-minute warm-up on a stationary bicycle. The pain from the hypertonic shots diminished as subjects worked through their sets, starting on average at about 25 mm on the 100 mm visual analog pain scale and ending at about 10 mm. Strength was assessed weekly 30 minutes after training.

At the end of the 8 weeks, the right legs of participants in the pain group were 24.6% stronger at 60 degrees of knee extension, 21.6% stronger at 120 degrees, and 19.6% at 180 degrees. Subjects in the control group were 7.5% stronger at 60 degrees of knee extension, 5.0% at 120 degrees and 8.2% at 180 degrees.

"It could be that when you have pain, your type 1 muscle fibers [the endurance fibers,] are inhibited, and your type 2 fibers [the power and speed fibers] are easily recruited, which could explain why the pain group had the larger increase in muscle strength," Ms. Sorensen said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

The researchers noted that hypertonic saline injections mimic many aspects of pathological knee pain "and [are] a well-accepted, efficient, and safe method to" replicate it experimentally.

The work was supported by the Association of Danish Physiotherapists. Ms. Sorensen said she has no disclosures.