Patellar tendon rupture (PTR) is one of the extensor mechanism of the knee injuries and occurs almost invariably at either the patellar or tibial insertion of the patellar tendon, when in the setting of trauma, and is often associated with a small avulsion fracture. Most commonly, it is at the superior attachment to the inferior pole of the patella. When secondary to systemic illness, then mid-substance tears are more frequent.
Predisposing factors include:
- chronic microtrauma (tendinopathy): also known as jumper's knee
- prior therapeutic intervention
- direct injection of steroids (for treatment of jumper's knee)
- previous ACL repair
- systemic illness
Other features include blurring of the posterior margin of the patella tendon into Hoffa's fat pad and presence of an avulsion fracture.
A tendon rupture may be seen as a hypoechoic region.
Treatment and prognosis
Early surgical repair is necessary to ensure good functional outcome.