Poster 254: Osteochondral Allograft Transplantation Using Dowell Technique for the Treatment of Steroid-Associated Osteonecrosis of the Femoral Condyles: Arthroplasty-Free Survival at 5 and 10 Years

OBJECTIVES: Steroid-associated osteonecrosis of the femoral condyles is a known complication of long- term or high dose steroid exposure. This is a not infrequent situation for patients with inflammatory conditions such as Lupus or Ulcerative Colitis and in patients with malignancies leukemia requiring bone marrow transplant. Historically, osteonecrosis was a contraindication for osteochondral allograft transplantation (OATS), however, recent evidence has indicated OATS maybe a durable treatment option. While results using the shell OATS technique has been reported in the steroid-associated osteonecrosis population, there is a dearth of information on the long-term survival for the newer dowel OATS technique. The aim of this study was to retrospectively analyze survival of OATS using the dowel technique for the treatment of steroid-associated osteonecrosis of the femoral condyles. METHODS: Institutional database was queried to identify eligible patients. Inclusion criteria included diagnosis of aseptic or secondary osteonecrosis of the distal femur, osteochondral allograft transplantation surgical treatment, dowel OATS technique, and history of steroid use for a medical condition. Exclusion criteria included previous cartilage restoration or arthroplasty surgery and incomplete records. No age criteria were used to exclude patients. Patient charts were reviewed for demographic details, information about underlying pathologic condition and steroid exposure, surgical details, and revision OATS or conversation to arthroplasty. Primary outcomes were arthroplasty-free survival and revision-free survival. RESULTS: 27 knees in 25 patients with an average age of 27.6 years (range 16-59 years) were identified with an average follow up of 6.2 years (range 0.7-22 years). Medical conditions included 10 malignancies (5 post-bone marrow transplant) and 13 autoimmune diseases. Distribution of osteonecrosis of the femoral condyles included 1 isolated medial condyle, 5 isolated lateral condyles, 21 medial and lateral condyles. All patients underwent dowel OATS technique. Patients received on average of 2.2 grafts (range 1-5 grafts) with an average combined graft area of 6.67 cm2 (range 1.5 to 20.4 cm2). 10 patients had concomitant procedures and 10 patients had supplemental graft fixation. All patients were treated between 2006 and 2020. Arthroplasty-free survival was 88%, 85%, 60% at 5, 8, 10 years. Revision OATS or arthroplasty free survival was 81%, 77%, 55% at 5, 8, 10 years. Graft failures included 1 revision OATS at 7.7 years secondary to cartilage delamination and 4 conversions to total knee arthroplasty at 1.6, 1.9, 8.7, 9.5 years. CONCLUSIONS: Osteochondral Allograft Transplantation is an acceptable and durable treatment option in patients with steroid-associated osteonecrosis with 88% arthroplasty-free survival at 5 years and 60% arthroplasty-free survival at 10 years. Future studies should capture patient reported outcomes and investigate factors leading to arthroplasty conversion such as age at time of OATS, etiology of osteonecrosis, extent of osteonecrosis.