Displaced fatigue fractures of the femoral shaft.

Abstract

For this study, all displaced fatigue fractures of the femoral shaft treated during a 20-year period at a national military hospital were analyzed. Ten previously healthy male recruits sustained displaced femoral shaft fatigue fractures, the incidence being 1.5 per 100,000 person-years in military service. The median age of the patients was 19 years (range, 18-20 years). None had any previous fatigue fractures. The median body mass index was normal. Before the fracture displacement, nine recruits experienced thigh or knee pain for 1 to 6 weeks. Six of the 10 fractures were located in the distal third of the diaphysis. Only one fracture occurred in the proximal third. Six fractures showed a noncomminuted, oblique, or oblique-transverse configuration. Five fractures were treated using an intramedullary nail, four fractures with a dynamic compression plate, and one with a dynamic condylar screw-plate. The bone at the site of fracture proved to be abnormally brittle. In six patients this resulted in additional comminution intraoperatively. Two reoperations were necessary to exchange a nail and a screw because of technical faults. The median time to solid bony union was 3.5 months (range, 3-5 months). The recruits returned to light duty military service 6 weeks postoperatively, on the average. Two were exempted from military service for 2 years. Displacement is a rare, highly undesirable consequence of fatigue osteopathy of the femoral shaft among young recruits during basic military training. Preventive methods should focus on early, effective detection of developing fatigue fractures to avoid a displaced fracture, with subsequent prolonged morbidity and possible complications. Gentle handling of the bone during the fracture fixation procedure is imperative because of the extraordinary brittleness of the fracture fragments.