SAN DIEGO — Restricted patellar mobility in patients with anterior knee pain is associated with chondral damage in the patellofemoral compartment, results from a large study demonstrated.
Knees with patellar tightness were three times more likely to have severe patellofemoral damage compared with those without tightness, Dr. J. Richard Steadman reported at a symposium sponsored by the International Cartilage Repair Society.
Many causes for patellar immobility exist, including compartmentalization by plica, suprapatellar scarring, and anterior interval contracture. “If you look at the patellar tendon and its relationship to the tibia going into flexion you'll find that patellar tendon actually separates from the tibia,” explained Dr. Steadman, of the Steadman Hawkins Research Foundation, Vail, Colo. “So if you have a scarring … between the patellar tendon and the tibia, you've eliminated the slack in the joint that allows you to have noncompressed cartilage as you go through a range of motion.”
Preoperatively, he and his associates subjectively measured and documented patellar tightness in the superior, inferior, medial, or lateral directions in 410 knees between November 2004 and November 2005. At surgery, the researchers collected data on knee pathology and documented chondral defects in all compartments of the knee. Grade 3 or 4 defects on the Outerbridge classification system were considered severe chondral damage.
Slightly more than half of the study participants (52%) were female and their average age was 44 years.
Dr. Steadman reported that preoperatively, 41% of patients had patellar tightness in at least one direction, 24% had patellar tightness in all four directions, 9% had inferior and superior tightness only, and 3% had medial and lateral tightness only. At surgery, 40% of patients had severe chondral damage of the patellofemoral compartment.
In addition, 54% of knees with patellar tightness had severe patellofemoral chondral damage while only 29% without patellar tightness had severe patellofemoral chondral damage.
Knees with patellar tightness were three times more likely to have severe patellofemoral damage compared with those without tightness. The highest odds of severe patellofemoral defects were associated with superior tightness (3.0) and inferior tightness (2.4).