Corrective osteotomy for combined shortening and rotational malunion of the femur.

Rotational malunion of femoral fractures after intramedullary fixation is surprisingly common. Wiss et al (1986) reported from 10#{176} to 30#{176} external rotational deformity in 7% of 1 12 patients and Br#{226}ten,Terjesen and Rossvoll (1993) found that 21 of 1 10 fractures healed with over 15#{176} deformity. Rotation is often combined with shortening, especially in oblique or comminuted fractures. Tscherne, Haas and Krettek ( 1986) reported shortening of more than 2 cm and rotational malalignment of up to 15#{176} after intramedullary nailing. Rotational malunion of over 10#{176} may give functional and cosmetic problems. Leg-length discrepancy of up to 1 .5 cm is often acceptable to patients (Trafton 1988), but any more shortening may interfere with function. A number of methods for the correction of isolated shortening or rotational deformity have been described. Kempf, Grosse and Abalo (1986) advise osteotomy and exchange nailing. A technique for the correction of both the rotation and shortening has been described by Muller, Strosche and Scheuer (1984), but requires prolonged treatment and two operations. Correction of both deformities by callotasis using an external fixator is complex and treatment is prolonged and subject to many complications (Paley et al I 990). The correction of rotation is not easy, as the centre of rotation of the bone may not be the same as that of the Ilizarov frame. Murray, Kambouroglou and Kenwright (1993) modified the technique of Kempf et al for simple lengthening, describing a step or double-step osteotomy, combined with rotation. A double-step osteotomy is very difficult to cut, and after displacement the osteotomy leaves a very limited part of the circumference of the femur in contact. The resultant large defect has to be made up with bone graft. A single-stage operation for the correction of length and rotation is described. It is based on exchange nailing which provides rigid fixation to allow early mobilisation. Method. Rotation of an oblique cut in a long bone about the axis of an intramedullary nail will cause lengthening as