BACKGROUND: The purpose of this study was to define the anatomic relationship between the femoral origin of the posterior cruciate ligament (PCL) and medial femoral condyle (MFC) osteochondritis dissecans (OCD) lesions.
METHODS: Ninety-four magnetic resonance imaging (MRI) studies of a series of patients with MFC OCDs seen at a single institution from 2004 to 2014 were reviewed. The distances from the center of the PCL to the center of the OCD as well as the shortest distance from the PCL to the OCD were calculated in both the sagittal and coronal planes. The orientation of the OCD relative to the PCL was noted.
RESULTS: The median distance between the center of the PCL origin and the center of the OCD was 14  mm in the coronal plane and 11 mm in the sagittal plane. The median distance from any point on the OCD to any point on the PCL origin was 3 mm in both planes. The OCD was within 1 cm of the PCL in all but 2 patients. 46.8% of OCD lesions were located posterior to the PCL origin in the sagittal plane.
CONCLUSION: The classic medial femoral condyle OCD lesion is consistently in close proximity to the femoral origin of the PCL, and most lesions are medial and posterior to the PCL.
LEVEL OF EVIDENCE: Level III.