Operative Fixation of Chondral Loose Bodies in Osteochondritis Dissecans in the Knee

Abstract

Background: Osteochondritis dissecans (OCD) can progress to loose body formation, with or without subchondral bone attachment to the lesion. The efficacy of internal fixation of chondral loose bodies has not been determined. Hypothesis: Operative fixation of cartilaginous loose bodies would result in (1) healed OCD at second-look arthroscopy, (2) restored cartilage appearance on magnetic resonance imaging (MRI), and (3) nearly normal knee function, as determined by patient-reported outcome scores. Study Design: Retrospective case series; Level of evidence, 4. Methods: Five patients who underwent cartilaginous loose body fixation were identified. Lesions were located on the lateral trochlea (n = 2) and medial femoral condyle (n = 3) (mean size, 2.5 cm2). Loose bodies were reattached with compression screws through mini-arthrotomy or arthroscopy. Patients were nonweightbearing for 12 weeks postoperatively. After 12 weeks, screws were removed arthroscopically, and OCD stability was evaluated. Three patients underwent MRI to determine articular cartilage status. Images were evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) score. Patients were interviewed and completed the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Results: Four patients had stable lesions at 12 weeks after surgery. One patient had slight motion to one-third of the lesion and stability to the remaining two-thirds. Three patients underwent an MRI. The mean time from surgery to MRI was 3.1 years. Mean MOCART score was 72.0 ± 10.4. One patient required repeat arthroscopy 1 year after initial fixation for debridement and arthroscopic drilling of an incompletely healed area of the lesion. Four patients completed the KOOS questionnaire. The mean time to KOOS completion was 4.6 years. Mean KOOS subscales for knee pain (91.0 ± 8.9), knee symptoms (83.0 ± 7.9), and function in activities of daily living (91.9 ± 10.6) were similar to published age-matched controls; however, scores for sports and recreation function (70.0 ± 17.8) and knee-related quality of life (67.2 ± 12.9) were lower. Conclusion: Operative fixation of chondral loose bodies, without macroscopically visible subchondral bone attachment, resulted in lesion stability at second-look arthroscopy. At final follow-up, patients had no substantial pain and normal function in activities of daily life compared with controls; however, knee-related quality of life and sport and recreation function were reduced, and 1 patient required reoperation for an unhealed portion of the lesion.