Chronic Rupture of the Extensor Apparatus
Often, the clinical picture is very suggestive of a chronic deficiency of the extensor mechanism. Typical symptoms relate to the extensor lag, episodes of giving way, and disability with stairs and rising from a seated position. Clinical examination should focus on the degree of extensor lag, the restriction to passive extension (flexion contracture), and patellar height. In particular, patellar mobility should be assessed. If the patella cannot be mobilized proximally, it indicates that the patellar tendon is retracted.