A Rare Case of Anterior Osteochondroma of Distal Femur with Quadriceps Rupture: A Case Report

Despite osteochondromas being fairly common around the knee, cases causing mechanical disruption and being associated with fractures or tears of the Quadriceps are rare.

A 27-year-old male presented after a fall under the influence of alcohol, along with pain in the knee and inability to bend it. Radiographs revealed an undisplaced vertical split type of Patellar fracture with an osteochondroma of the distal femur located anteriorly, and growing towards the knee joint. Patient had a previous history of mechanical symptoms, occasional knee pain, limited range of motion and repeated falls. Computed tomography and magnetic resonance imaging showed an associated incomplete, non-insertional quadriceps rupture. The patella fracture eventually healed conservatively in the cylindrical cast before the patient underwent surgery for mechanical problems around his knee. Patient consented to undergo surgical intervention after a period 1 month since injury in the form of exostosis excission en bloc, extra-periosteally, followed by repair of the quadriceps tendon, with an uneventful post-surgery rehabilitation phase.

The unusual location of the osteochondroma along with the fact that it was directly impinging on the upper part of the Patella and the distal quadriceps tendon makes this an interesting case. The long history of "pseudo locking" and instability in this cases should have prompted earlier diagnostic interventions, which were delayed due to his alcohol dependence. The anterior location of the osteochondroma at the knee may have relevance in causing patellar degeneration and instability and lead to associated tears of the quadriceps even with lesser trauma.