Bioabsorbable Fixation of Unstable Osteochondritis Dissecans Lesions

Background: Osteochondritis dissecans lesions of the knee in adult patients frequently require surgical intervention. However, the ideal method of osteochondral fragment fixation remains uncertain.

Purpose: This study was undertaken to determine the clinical, functional, and radiographic outcomes of bioabsorbable fixation for unstable osteochondritis dissecans lesions involving the femoral condyles of the knee in skeletally mature patients.

Study Design: Case series; Level of evidence, 4.

Methods: Skeletally mature patients with an unstable osteochondritis dissecans lesion of the femoral condyle (Ewing and Voto stages II-IV) treated with bioabsorbable internal fixation and minimum 1-year follow-up were included in this retrospective study cohort. Pre- and postoperative radiographs were reviewed and postoperative Lysholm and International Knee Documentation Committee (IKDC) scores were documented.

Results: A total of 21 knees in 21 patients satisfied the inclusion criteria, and 3 patients were lost to follow-up. The remaining 18 patients were evaluated at a mean of 59 months after surgery (range, 12-154 months). The 14 male and 4 female patients had a mean age of 19 years at the time of surgery (range, 14-39 years). Ewing and Voto classification included 8 stage II lesions, 9 stage III lesions, and 1 stage IV lesion. Fragment fixation methods included bioabsorbable nails (11), pins (3), darts (2), screws (1), and combined screws and darts (1). Mean postoperative Lysholm and IKDC scores were 85 and 82, respectively. Fragment union occurred in 12 knees (67%); the remaining 6 knees (33%) required removal of the loose fragment. Of the 11 patients treated with bioabsorbable nails, 2 (18%) required reoperation for nail back-out.

Conclusion: The authors recommend caution when using bioabsorbable fixation for osteochondritis dissecans lesions in skeletally mature patients because of the low rate of clinical healing and high complication rate. Failure with unthreaded fixation devices may be caused by inadequate compression and not necessarily be related to bioabsorbability.