Quadriceps tendon rupture - emergency department summary
Definition and mechanism
A quadriceps tendon rupture is an acute disruption of the knee extensor mechanism, most commonly at the osteotendinous junction where the quadriceps tendon inserts on the superior pole of the patella. It usually results from a sudden, forceful contraction of the quadriceps while the foot is planted and the knee is partially flexed.
Quadriceps tendon ruptures are more common than patellar tendon ruptures and, when complete, typically require orthopaedic assessment and often surgical repair.
Typical presentation
- Patients commonly describe an acute tearing sensation or a “pop” at the front of the knee with immediate pain.
- Rapid swelling and a knee effusion are common; ecchymosis may develop later.
- Pain is localised to the anterior knee over the quadriceps tendon and the superior pole of the patella.
- There is a functional deficit with weakness of, or inability to, actively extend the knee. Inability to perform a straight‑leg raise (SLR) is the single most useful bedside indicator of an interrupted extensor mechanism.
Predisposing factors
- Degenerative tendon changes associated with older age increase the risk of rupture.
- Systemic conditions such as diabetes mellitus, chronic renal failure and hyperparathyroidism increase risk.
- Chronic corticosteroid use and prior fluoroquinolone exposure are recognised risk factors.
- Bilateral ruptures are uncommon but are more likely in the presence of systemic...