Jumper's Knee refers to a spectrum of disorders that occur in patients with degeneration and/or tearing of the patellar tendon. It is one of the most common tendon abnormalities in athletically active individuals, and as the name implies, is most common in jumping athletes such as basketball and volleyball players. In the non-athlete, rheumatoid arthritis, the seronegative arthropathies, and treatment with exogenous steroids are known to predispose to this condition.
fat-suppressed proton density-weighted sagittal images in a basketball player who sustained an acute injury reveal marked edema about the patellar tendon with a fluid filled gap (arrows) at the central tendon, compatible with a complete rupture. The retracted proximal and distal ends (arrowheads) are markedly thickened, indicating severe tendinosis. The vast majority of patellar tendon ruptures occur in patients with pre-existing patellar tendinosis.