Purpose The purpose of this study was to determine the origin of the medial patellofemoral ligament (MPFL) relative to the distal femoral physis by use of an indirect radiologic method.

Methods Twenty radiographs from adolescent male and female subjects (10 samples from each group) were used. The subjects studied were all skeletally immature, with an open distal femoral physis. The radiographic technique described by Schöttle et al. was used to identify the origin of the MPFL. Imaging software was used to determine the approximate distance of the MPFL origin relative to the open growth plate of the subjects involved.

Results In all 20 radiographs the medial physis was found to be distal to the average MPFL insertion point. The mean location for the female physis was 2.7 ± 1.1 mm distal to the MPFL origin. The mean location for the male physis was 4.6 ± 2.4 mm distal to the MPFL origin.

Conclusions Based on an indirect radiographic technique, we found that the origin of the MPFL is just proximal to the femoral physis. Clinical Relevance: This information may be useful when planning medial retinacular surgical procedures in skeletally immature athletes to help avoid clinically significant physeal injury.