Patellar Tendon Rupture

Patellar tendon rupture (PTR), one of the extensor mechanism of the knee injuries 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.
PTR is less frequent than patellar fracture and quadriceps tendon rupture, and tends to occur in a younger population.
Predisposing factors include:
- chronic microtrauma (tendinopathy) - aka jumper’s knee
- prior therapeutic intervention (e.g: direct injection of steroids (for treatment of jumper’s knee), previous ACL repair )
- systemic illness (e.g: chronic renal faliure, diabetes mellitus, RA, SLE )
On imaging, a complete rupture is usually easily identified, due to significant patella alta, blurring of the posterior margin of the patellar tendon in to Hoffa’s fat pad and presence of an avulsion fracture.
Early surgical repair is necessary to ensure good functional outcome.
References:
1. eMedicine.com
2. WheelessOnline
Credit: Dr Frank Gaillard
http://www.radpod.org