Discussion
- extensor mechanism includes quadriceps, quadriceps tendon, medial & lateral
- retinaculum, patellofemoral & patellotibial ligaments, patellar tendon & tibial tubercle
- superficial location of extensor mechanism makes it susceptible to injury
- extensor mechanism rupture may involve either the quadriceps tendon or patellar tendon & may be either partial or complete
- complete rupture is rare in young athlete unless associated. w/ steroids
- patellar tendon ruptures
- < 40 years of age
- quads tendon ruptures
- > 40 years of age
Risk Factors
- Rheumatoid Arthritis
- Diabetes
- Steroid use
Differential Diagnosis
- Osgood-Schlatter disease
- Sindig-Larsen-Johanssen
- MVA (dashboard injury)
- patellofemoral arthritis
- in those over 40 years
- disproportionate extensor mechanism pain following trauma or surgery
- CRPS
- (disproportionate pain, stiffness, skin discolouration, & ↓ skin temperature)
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.