Dislocation after primary arthroplasty for subcapital fracture of the hip. Wide range of movement is a risk factor. Dislocation is the most frequent serious complication following total hip replacement for subcapital femoral fracture. We report a prospective study, using matched groups, which compared the range of hip movement following hip replacement for arthritis and for fracture. The range of movement was significantly greater in the fracture group. We suggest that this is a predisposing factor for dislocation. 