Early diagnosis of the condition is important as delay in treatment (>2 weeks) is associated with less satisfactory clinical outcomes (1).
A patient usually presents with a history of tripping or giving away of the knees (1)
- it is associated with a ‘Pop’ sound at time of injury together with acute onset of pain
- the amount of force required for rupture may vary from strenuous weight lifting to descending stairs
- in cases of complete rupture, inability to extend the knee of the affected extremity can be observed (1)
Physical examination finding include:
- swelling of the knee
- tenderness at the inferior pole of the patella or along the patella tendon
- palpable defect in the tendon (may not be felt in cases with swelling or increased soft-tissue mass)
- asymmetric patella alta (proximal migration of the patella) - characteristic picture for patellar tendon rupture, more visible with knee flexion
- active knee extension may be completely absent
Additional diagnostic studies include:
- plain radiographs -
- “tooth sign” caused by degenerative changes close to patellar tendon origin
- patella alta may also be visible
- ultrasonograph and magnetic resonance imaging - maybe useful in patients with unclear or delayed diagnosis (1)
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