Reconstruction of a 2‑year neglected chronic patellar tendon rupture using peroneus longus autograft with suture anchor and cerclage wire augmentation

Rationale: Chronic patellar tendon rupture with complete tendon loss is difficult to reconstruct when primary repair is impossible. We report reconstruction using an ipsilateral peroneus longus (PL) autograft in a 4-strand “M-shaped” configuration with suture-anchor fixation and temporary cerclage augmentation. Patient concerns: A 17-year-old male had progressive anterior knee pain, instability, and inability to actively extend the left knee for 2 years after trauma. Diagnoses: Examination showed patella alta, a palpable infrapatellar gap, and complete loss of active extension. Radiographs showed an Insall–Salvati ratio of 1.28. Magnetic resonance imaging confirmed chronic complete patellar tendon rupture without a repairable stump. Interventions: A 21-cm ipsilateral PL autograft was folded into a 4-strand construct and anchored to the inferior patella and tibial tubercle. Patellar height was deliberately overcorrected, and a transpatellar–tibial cerclage wire protected the reconstruction during staged rehabilitation. Outcomes: At 1 year, after wire removal, the Insall–Salvati ratio was 1.08. The patient regained full active extension without lag, near-full flexion, and recreational activity participation without pain or donor-site morbidity. Asymptomatic wire breakage occurred at 6 months. Lessons: A multi-strand PL autograft with anchor fixation and temporary cerclage augmentation may restore patellar height and extensor function in chronic patellar tendon rupture with complete tendon loss.