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Extensor Mechanism Injuries of the Knee


- See:
       - Rupture of the Quadriceps
       - Patellar Tendon Injury
       - Tibial Tubercle Frx

- Discussion:
    - extensor mechanism includes quadriceps, quadriceps tendon, medial & lateral retinaculum, patellofemoral and patellotibial ligaments, Patellar Tendon (ligament), and tibial tubercle;
    - superficial location of extensor mechanism make it suseptable to injury;
    - extensor mechanism rupture may involve either the quadriceps tendon or patellar ligament and may be either partial or complete;
          - complete rupture is rare in young athlete unless assoc w/ steroids;
          - patellar ligament ruptures usually occur in pts < 40 yrs of age & quads tendon ruptures in pts older than 40 years of age;
    - risk factors:
          - RA, long-term diabetes mellitus, and long-term steroid use;
    - Diff Dx:
          - Osgood-Schlatter disease, Sindig-Larsen-Johanssen dz
          - consider anatomic malalignment: Chondromalacia
          - MVA (dashboard injury);
          - patellofemoral arthritis in those over 40 yrs;
          - disproportionate extensor mechanism pain: following trauma or surgery consider sympathetic dystrophy;
                 - disproportionate pain, stiffness, skin discoloration, & decreased skin temperature


Evaluation of the Medial Soft-Tissue Restraints of the Extensor Mechanism of the Knee.

The effect of external load on torque production by knee extensors.

Evaluation of the medial soft-tissue restraints of the extensor mechanism of the knee.

Biomechanical effects of different surgical procedures on the extensor mechanism of the patellofemoral joint.