1. A series of 100 intracapsular fractures of the femoral neck treated with the Charnley compression screw is reported. 2. There were six deaths, and in patients reviewed long enough (seventy-five) there were eleven undisplaced fractures, with successful union in 8l·8 per cent, and sixty-four displaced fractures, with a union rate of 59·6 per cent. 3. If we exclude six failures of operative technique, there remain fifty-eight patients in whom the fracture was judged radiologically to have united in 65·5 per cent. 4. The Charnley compression screw is an effective method of internal fixation in such fractures, and non-union with this method is usually due to causes other than mechanical failure.
Eighty patients who sustained a fracture of the floor of the acetabulum are reviewed, and the mechanism of the injury was investigated by clinical and experimental studies. The results of the injury in fifty patients are presented, with an account of the three clinical types of acetabular fracture.
