Chondral osseous replacement (COR) technique for femoral defects (SS-44)

      Localized, full-thickness articular cartilage defects of the femoral condyle are often found unexpectedly. An arthroscopic repair technique that transplants chondral osseous plugs to fill the defect (COR technique) offers an immediate solution for these lesions. The purpose of this study is to review the clinical and radiographic results of chondral osseous replacement for full-thickness articular cartilage lesions. Methods: A prospective two center study of full-thickness articular cartilage lesions was initiated in 1995. All knees were evaluated both pre and postoperatively by physical examination, radiographs, Lysholm and Tegner knee scores. Inclusion criteria were full-thickness femoral condyle defects >1 cm and <3.5 cm in diameter, and a minimum 24 months follow-up. Exclusion criteria were associated tibial defects, patellar defects, or generalized arthritic change. ACL tears, concurrent ACL surgery, and meniscal tears were not contraindications. Grafts harvested from the superior and lateral femoral notch were press fit into holes drilled into the defect placed adjacent to the articular cartilage margin. Cancellous bone bridges were maintained between grafts. Relook arthroscopic examinations were done when possible. Results: 39 patients met the inclusion criteria with an average follow-up of 48 months (24–89 months). The average age was 45. There were 20 males and 19 females. The MFC was involved in 30 and the LFC in 9. The average Lysholm score increased from 43 preoperatively to 84 at follow-up. The average Tegner score at follow-up was 4.9. Relook arthroscopies were obtained in 14 of the 39 and demonstrated good incorporation of the grafts in all cases. Biopsies of these grafts over time demonstrated viable chondral and osseous components at intervals out to 12 months. Radiographic examinations demonstrated early arthritic changes in some patients. Discussion: The technique successfully transplants chondral osseous grafts within the knee that remain viable. Despite reducing symptoms, arthritic changes were observed to increase radiographically over time. It is unclear if these radiographic changes are related to the initial traumatic and what their future significance might be. The midterm clinical response was favorable for these patients. Further investigation of the long-term results is required.