Simultaneous Bilateral Quadriceps Tendon Rupture After Low-Energy Trauma in a 78-Year-Old Woman: Delayed Diagnosis, Ultrasound Confirmation, and Single-Stage Repair.

Simultaneous bilateral quadriceps tendon rupture (BQTR) is an uncommon extensor mechanism injury, with particularly few reports in elderly women without major systemic risk factors. We present the case of a 78-year-old woman who sustained sequential BQTRs after a low-energy fall. The initial assessment at another facility attributed her symptoms to knee osteoarthritis, resulting in a one-week delay in diagnosis. Re-evaluation revealed bilateral loss of active knee extension and palpable suprapatellar defects, and musculoskeletal ultrasound confirmed complete bilateral rupture. The patient underwent single-stage bilateral surgical repair using transosseous patellar tunnels and high-strength sutures, performed by two surgical teams simultaneously. Mobilization and supervised rehabilitation were started on the first postoperative day. At follow-up, the patient regained functional ambulation with satisfactory knee motion. This case highlights a clinically relevant diagnostic pitfall in elderly patients with pre-existing degenerative knee disease and demonstrates that simultaneous bilateral repair can be feasible even after a short diagnostic delay.