Osteochondritis dissecans of the patellofemoral joint.

Osteochondritis dissecans of the patellofemoral joint is an uncommon condition that may be the cause of anterior knee pain or crepitus. We present the clinical features of 37 patients with osteochondritis dissecans lesions of the patellofemoral joint (24 on the patella, 13 on the trochlear groove), including two patients with medial trochlear groove lesions, which have not, to our knowledge, been previously reported. The osteochondral lesions involved the convex articular surfaces. The median age of patients when first examined was 15 years, and 54% of patients had open epiphyses. These lesions were more common in male patients than in female patients (four-to-one ratio). Osteochondritis dissecans of the patellofemoral joint can be overlooked unless quality radiographs are viewed with care and, at arthroscopy, both the patella and trochlear groove are assessed. Treatment depends on the symptoms, site, and nature of the lesion and the patient's age. Nonoperative management includes patellar taping and vastus medialis obliquus muscle exercises. Operative intervention is indicated for patients with mechanical symptoms and includes arthroscopy, consisting of chondroplasty and removal of loose bodies, and lateral retinacular release. In this study treatment generally improved the symptoms, but patients with articular cartilage loss had persistent patellofemoral crepitus and discomfort.