Poster 256: Is There a Difference Between Medial and Lateral Femoral Condyle Allografts? An Outcome and Survivorship Analysis

Objectives: Focal chondral and osteochondral defects in the knee are problematic and are often difficult to treat. One solution is the use of osteochondral allograft (OCA) transplantation. A majority of the literature deliberates lesions located to the medial femoral condyle (MFC), but little is discussed regarding the lateral femoral condyle (LFC). Given the limited data, the purpose of this study was to compare graft survivorship and patient-reported outcomes (PROs) among patients who underwent OCA transplantation of the MFC or LFC. Methods: A total of 208 patients who underwent primary OCA transplantation of the MFC and 111 patients who underwent primary OCA transplantation of the LFC between 1997 and 2021 were identified from a prospectively collected single-surgeon cartilage registry. Overall, 66% were male and the mean age was 30.5 years. Most patients presented for OCA for osteochondritis dissecans (57%). Mean allograft size was 6.7 cm2. All patients had a minimum 2-year follow-up. Reoperations following the OCA transplantation were captured. Failure of the allograft was defined as removal of the graft (OCA revision or conversion to arthroplasty). PROs were measured both pre and postoperatively using the Knee Injury and Osteoarthritis Outcomes Scores (KOOS), International Knee Documentation Committee (IKDC), and Merle d’Aubigné-Postel scales. Patient satisfaction was also assessed. Results: Patients with MFC grafts were older than patients with LFC grafts (33 years and 26 years respectively; p<0.001) and had a slightly higher BMI (25.6 and 24.4 respectively; p=0.039). There were no differences between groups in regard to diagnosis, sex, number of allografts transplanted, or size of the allograft. Reoperations occurred in 27.9% of patients with MFC grafts and 26.1% of patients with LFC grafts (p=0.737). OCA failure occurred in 12% of MFC grafts and 9% of LFC grafts (p=0.413). The 10-year survivorship was 88% for MFC grafts and 92.9% for LFC grafts (p=0.543) (Figure 1). Among patients who had the allograft in situ at latest follow-up, the mean follow-up duration was 9.4 years for MFC grafts and 8.6 years for LFC grafts (p=0.313). At latest follow-up, KOOS, IKDC, and Merle d’Aubigné-Postel scores were similar between patients with MFC and LFC grafts. Patients with MFC grafts reported a slightly higher rate of satisfaction compared to patients with LFC grafts (93.7% and 86.3% respectively, p=0.041). Conclusions: Little data is available comparing treatment of medial and lateral femoral condyle lesions with osteochondral allografts. Clinical perception is that LFC lesions have inferior outcome to MFC lesions, but we did not find this to be true. We found little difference in reoperation rates and survivorship, as well as patient-reported clinical outcomes as measured on the KOOS, IKDC, and Merle d’Aubigné-Postel scales. There was a small difference in patient satisfaction. We conclude that there is similar outcome when using allografts for either medial or lateral femoral condyle lesions.