Patellar fatigue fractures

Three cases of patellar fatigue fracture are reviewed. Two fractures presented with acute displacement and were initially thought to represent pathological fractures. Histological appearances in one case, and the clinical course in another, subsequently indicated that these were fatigue fractures. A third patient developed a chronic undisplaced fracture and followed the typical clinical course of fatigue fractures at other sites. The importance of recognizing patellar fatigue fractures and of differentiating spontaneously displaced fatigue fractures from pathological fractures is emphasized.