patellar tendon rupture
Patellar tendon rupture 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.
- 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 the Hoffa fat pad and presence of an avulsion fracture.
Best imaged with longitudinal scans using high-frequency linear transducers; the tendon normally appears as a continuous well-defined hyperechoic fibrillar structure bridging the patella and the tibial tuberosity while tears usually appear as hypoechoic areas of interruption of the fibrillar pattern .
Treatment and prognosis
Early surgical repair may be necessary to ensure good functional outcome.