Bifocal disruption to the extensor mechanism of the knee: A case report

Bifocal disruptions to the extensor mechanism of the knee are extremely rare injuries that are difficult to repair due to the lack of ligamentotaxis. There is a paucity of literature on surgical technique and clinical outcomes following repair. Here we present a variant of this injury previously undescribed. A 24-year-old male landscaper presented to the emergency department following a bifocal disruption to his left knee extensor mechanism from a motorcycle accident. Diagnosis was confirmed on Magnetic Resonance Imaging (MRI). He underwent surgical repair utilising trans-osseous tunnels through the patella and tensioning of both repairs simultaneously. Post-operatively he was allowed to weight-bear as tolerated in a range of motion (ROM) brace locked in extension for 6 weeks with a gradual increase in his ROM. By four months the patient had a full ROM, no extensor lag and symmetrical quadriceps strength and was allowed to return to full duties at work. Bifocal disruptions to the extensor mechanism of the knee are extremely rare injuries with only case reports in literature. To the best of our knowledge this case represents a novel and undescribed variant. Surgical repair should be undertaken with careful consideration to appropriate soft tissue tensioning.