Patellar tendon rupture is not uncommon in active adults, although it
occurs less often than rupture of the ligaments. The diagnosis is easi
ly missed on initial examination. Delay of surgical treatment leads to
a complicated repair and a less functional outcome. The key physical
finding is inability to actively extend the affected leg. Patients may
also have severe, rapid swelling and depression in the infrapatellar
region. The mechanism of injury usually involves forced hyperflexion o
r rapid extension from a weight-bearing position. Radiographic finding
s include patella alta and possible subluxation. This case report desc
ribed an infrapatellar tendon rupture in a patient with no underlying
systemic disease or history of repetitive trauma.