Functional and Radiographic Outcomes of Juvenile Osteochondritis Dissecans of the Knee Treated With Extra-Articular Retrograde Drilling

Abstract

Background: Osteochondritis dissecans (OCD) lesions of the medial femoral condyle in the adolescent population can cause significant impairment and restriction in physical activity. Studies have established the efficacy of transarticular antegrade drilling for juvenile OCD lesions of the knee, although concerns of consequences from drilling through the articular cartilage remain. Alternatively, retrograde extra-articular drilling avoids drilling the cartilage while ensuring adequate channels for revascularization and healing. Purpose: The authors present the results of 31 skeletally immature patients who underwent retrograde drilling of OCD lesions of the knee with an average follow-up of 4 years. Study Design: Case series; Level of evidence, 4. Methods: The procedure consisted of a standard arthroscopic evaluation of the knee and subsequent percutaneous retrograde drilling obliquely through the condylar epiphysis starting distal to the physis and ending in the center-center of the OCD lesion. Outcome measures included radiographic signs of healing, Lysholm scoring and the Tegner activity scale to measure performance and activity restriction, and visual analog scale (VAS) pain scores. Results: Average follow-up for the 31 patients was 4 years (range, 1.5-7 years). Sixteen of the 34 lesions were grade I or II based on radiographic findings with signs and symptoms greater than 6 months. The remaining 18 were grade III secondary to a sclerotic rim surrounding the defect. Overall, improvement in Lysholm scores (70 to 95; standard deviation [SD] ± 14.95), Tegner scores (4 to 7; SD ± 2.31), and VAS pain scores (6.9 to 1.3; SD ± 2.16) were found to be statistically significant. Radiographs showed stable or improved lesions in all cases. Conclusion: Retrograde extra-articular drilling provided clinical and radiographic improvement in most juveniles with OCD lesions who failed nonoperative management. This method serves to decompress the lesion and allow revascularization without disrupting the articular cartilage surface in stable OCD lesions.