Quadriceps and patellar tendon rupture
Quadriceps and patellar tendon rupture disrupt the extensor mechanism of the knee, presenting after low-impact trauma with acute pain, effusion, ecchymosis, and an inability to actively extend the knee or perform a straight-leg raise, and treatment frequently involves surgical repair.
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What this article covers
- Overview
Quadriceps tendon rupture and patellar tendon rupture are disruptions of the knee extensor mechanism, the tendon-patella-tendon complex that transmits quadriceps force to the tibia and allows active knee extension.
- Epidemiology
Occurs after low-impact trauma, typically in the setting of sport, such as a stumble, a fall onto a flexed knee, or a jump-landing, rather than requiring a high-energy mechanism.
- Risk factors
Fluoroquinolone use, a recognized precipitant of patellar tendon rupture and, by the same tendon-injury mechanism, quadriceps tendon rupture.
- Pathophysiology
The extensor mechanism (quadriceps muscle, quadriceps tendon, patella, and patellar tendon) transmits quadriceps force across the knee to the tibia, and an intact chain is required to actively extend the knee.
- Clinical features
Acute knee pain with effusion after low-impact trauma is the hallmark and defining feature, together with an inability to actively extend the knee or perform a straight-leg raise, which confirms a…
- Differential diagnosis
Quadriceps or patellar tendinopathy (partial tear/tendinosis): chronic activity-related pain reproduced by palpation, without an acute pop, a palpable gap, or loss of active extension.
- Diagnosis
Quadriceps or patellar tendon rupture is a clinical diagnosis confirmed by the combination of acute knee pain and effusion after low-impact trauma, a palpable tendon gap superior or inferior to the…
- Management
First, place the knee in a brace locked in full extension and make the patient non-weight-bearing or protected-weight-bearing with crutches, and refer promptly for orthopedic evaluation, since delay…
- Complications
Re-rupture, more common with delayed initial repair, premature return to full activity, or noncompliance with postoperative bracing.
- Prognosis
Prompt surgical repair of a complete tear generally restores functional knee extension, with outcomes worsened substantially by delay in repair.
- Prevention
Discontinue a fluoroquinolone immediately at the first sign of tendon pain, swelling, or weakness, and avoid all fluoroquinolones thereafter in that patient, since this is a recognized precipitant of extensor tendon rupture.
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