BARCELONA – A cartilage transplant procedure known as osteochondral allografting for femoral condyle lesions eased pain and improved function in the majority of patients, with grafts lasting as long as 20 years in more than half the recipients studied, according to Dr. Yadin Levy of Tel Aviv Medical Center, who conducted the study while a research fellow at the Scripps Clinic in La Jolla, Calif.
For this follow-up study, Dr. Levy used data from the Scripps Clinic’s osteochondral allografting (OCA) outcomes program, which has information on 614 OCA knee transplantations in 536 patients. Of these, 122 patients (129 knees) who had undergone OCA transplantation of the femoral condyle and were at least 10 years on from their initial surgery were eligible for this analysis. Most (91%) of these patients had over 10 years of follow-up. The average patient age was 31 years, and 85% were younger than 45 years.
Patients underwent surgery for pathologies including osteochondritis dissecans (45%), traumatic cartilage injury (22.5%), degenerative chondral lesion (15.5%), avascular necrosis (14.7%), and osteochondral fracture (2.3%), he said at the World Congress on Osteoarthritis.
Clinical outcome measures included the modified D’Aubigne and 18-point Postel score, the International Knee Documentation Committee (IKDC), the Knee Society (KS) function score, and subjective patient satisfaction with the outcome of their procedure. Reoperations were recorded by frequency and type, and graft survivorship was also assessed.
A mean follow-up of 14.4 years (2.4-27.5) showed that 24% of knees failed with a mean time to failure of 7.2 +/- 5.2 years.
IKDC pain scores dropped from a mean of 7.0 preoperatively to 3.8 (P less than .001) postoperatively. Function also showed improvement over the follow-up period from a mean IKDC function score of 3.4 preoperatively to 7.2 postoperatively (P less than .001). KS function improved from 65.6 to 82.5 (P less than .001). The vast majority (72%) of patients rated their operation outcome as "extremely satisfied."
With respect to graft survival, results showed that 82% survived intact for 10 years and 66% for 20 years. Patients who were older than 30 years were 3.5 times more likely to fail than patients who were younger (P less than .05). Also, patients who had experienced over two operations were 2.8 times more likely to fail than patients who had undergone one or no previous operations (P less than .05).
"The results demonstrate that this is a good treatment modality for young patients," remarked Dr. Levy.
"Firstly, [OCA] successfully treats the condition and allows the majority of patients to return to their daily activities, and secondly, it postpones the need for arthroplasty or graft removal," he added.
Many short-term follow-up studies exist providing evidence of clinical results, but very few long-term follow-up studies were available that address graft survivorship and durability, he said.
Dr. Levy explained the principle of OCA. "We basically transfer a structured articular cartilage with viable chondrocytes on the surface and underneath the bone, which acts as a scaffold," he said at the congress, sponsored by the Osteoarthritis Research Society International.
The operation is suitable for large and small chondral and osteochondral defects and can be clinically applied for cartilage repair and in complex reconstructions. "In complex reconstruction we are trying to repair the bone underneath the cartilage as well as the cartilage," he said.
"Since there is cartilage wear, the joint surfaces are not smooth and gliding, which will lead to accelerated wear and ultimately to osteoarthritis," Dr. Levy pointed out.
Cartilage problems pose a treatment challenge because the tissue is incapable of self-repair and self-regrowth. Both artificial and biological modalities exist, but according to Dr. Levy, biological treatment modalities, such as OCA, are a viable option before artificial joint replacement especially in young patients for whom there is a high risk of revision.
"ACI [autologous chondrocyte implantation] and OCA are commonly used for large lesions, of more than 4 cm. The advantage of OCA is the ability to perform a single-stage operation for large bone defect," he said.
A major advantage of the method was that, even if the first allograft failed, patients could reconvert to another allograft in the revision surgery, which would again postpone the need for arthroplasty, Dr. Levy added.
Reoperations were conducted in 47% of knees. The number of reoperations was roughly equal for graft-related and non-graft-related reasons: 23% of patients required non-graft-related reoperations including arthroscopy, such as hardware removal, while graft-related reoperations were required by 24% of patients, the majority of which (48%) were OCA revision. "The majority of failures were because of pain and radiographic fragmentation of the allografts," reported Dr. Levy.