Extensor Mechanism Ruptures of the Knee

Discussion

• extensor mechanism includes quadriceps, quadriceps tendon, medial & lateral
  • retinaculum, patellofemoral & patellotibial ligaments, patellar tendon & tibial tubercle
• superficial location of extensor mechanism make 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 discoloration, & ↓ skin temperature)