Investigation for Lesional Onset Site and Patellofemoral Joint Anatomy in Juvenile Femoral Trochlear Osteochondritis Dissecans : A Case Control Study

Abstract Background: Femoral trochlear osteochondritis dissecans is an uncommon disease, and its cause remains unknown. We investigated the site of osteochondritis dissecans lesions and the patellofemoral joint anatomy of femoral trochlear osteochondritis dissecans in 15 knees, and assessed the clinical outcomes of the surgical treatments. Methods: We conducted a retrospective study of 15 knees in 14 patients who underwent surgery. The mean age was 13.2 ± 1.0 years at the time of surgery. All patients played athletic sports and experienced no traumatic events. We determined the site of osteochondritis dissecans lesions using the modified Cahill and Berg classification on magnetic resonance imaging scans. We also evaluated the patellofemoral structures with sulcus angle, facet ratio, patellar tilt, patellar height, and tibial tubercle-trochlear groove distance. Results: We performed osteochondral autograft transplantation surgery in nine knees, internal fixation in four knees, and drilling in two knees. The mean follow-up period was 34.5 ± 14.0 months, and the period of return to sports was 6.1 ± 1 months. At the final follow-up, the mean Tegner activity scale was 7.2 ± 1.4 (preoperative score was 7.7 ± 1.0), and the Lysholm knee score was 98.5 (range, 89-100). The area of most preponderance was in the medial portion of the lateral femoral condyle in the frontal view, and in the segment superior two-thirds of the anterior region in the lateral view. There were no anatomical abnormalities in the patellofemoral structures. Conclusions: Femoral trochlear osteochondritis dissecans lesions occurred in virtually identical sites, and there were no anatomical abnormalities. This disease seemed to be related to the repetitive and persistent loading from the patella at slight knee flexion. In almost all cases, satisfactory postoperative results were obtained for osteochondritis dissecans regardless of the stage or surgical method.