Visual Diagnosis, Orthopedics

Diagnose this Condition

The Patient

A 62-year-old male presents to the ER complaining of right knee pain. He was changing a light bulb when he lost his balance and fell from a 6-foot height, landing on his feet. Since then he has been unable to bear weight. Physical exam is remarkable for the findings displayed in the image.

What is the diagnosis?

Quadriceps tendon rupture

The image is most notable for a large suprapatellar defect. This is a classic clinical finding most consistent with a quadriceps tendon rupture. The quadriceps tendon extends from the quadriceps muscle of the thigh to the proximal part of the patella. The patellar tendon attaches distally to the tibial tubercle, and together these two tendons allow for knee extension.

Patients with a complete tear of their quadriceps or patellar tendons cannot achieve or maintain a straight leg raise against gravity while supine. This “straight leg raise test” should be performed on any patient that presents with a knee injury. Radiographs often demonstrate soft tissue swelling and may even reveal an avulsion fracture of the patella. Patella baja (an abnormally low-lying patella) may also be present when compared to the contralateral side.

Most injuries are post-traumatic and occur in persons aged 50 or older. Chronic diseases such as diabetes, lupus, and renal failure — among others — may predispose to bilateral quadriceps tendon rupture. Oral corticosteroids and fluoroquinolones are also associated with rupture.

Tears may occur following a sudden strong contraction of the quadriceps muscle, such as when landing from a height or when a person falls backwards while the foot is fixed to the ground.

ED management includes a knee immobilizer, crutches, and pain control. While not a surgical emergency, complete quadriceps tendon ruptures should seek expedited follow-up with an orthopedic surgeon for operative intervention.