Internal fixation of the McMurray osteotomy with a trifin nail.

necessitates immobihisation in a plaster spica for several weeks. In order to avoid this, and to allow early activity, various forms of internal fixation have been used. Most of these consist of some form of modified “ blade plate “ which is screwed to the femoral shaft. They all have disadvantages. The length and the extent of the operation are increased, and fixing the plate to the femur tends to reduce the medial displacement of the shaft-indeed, if the displacement is adequate, access to the femoral shaft is usually a difficult matter. The “ blade plate ‘ ‘ must be adjustable in two dimensions to allow for varying degrees of hip deformity and, if it has to be removed at a later date, this too may be a major procedure. If the osteotomy is made sufficiently high-as indeed it must be to ensure permanent relief of pain-the upper end of the lower fragment consists mainly of cancellous bone and, like cancellous bone elsewhere, can be fixed with a trifin nail, driven from the greater trochanter into the upper end of the shaft (Fig. 1). This method of fixation is quick and relatively easy; it requires no special instruments and can be adapted to any degree of hip deformity. It also allows minor adjustments of position in the postoperative period and the pin can, if necessary, be removed easily at a later date.