Distraction osteogenesis is widely used for leg lengthening, but often requires a long period of external fixation which carries risks of pin-track sepsis, malalignment, stiffness of the joint and late fracture of the regenerate. We present the results of 20 cases in which, in an attempt to reduce the rate of complications, a combination of external fixation and intramedullary nailing was used. The mean gain in length was 4.7 cm (2 to 8.6). The mean time of external fixation was 20 days per centimetre gain in length. All distracted segments healed spontaneously without refracture or malalignment. There were three cases of deep infection, two of which occurred in patients who had had previous open fractures of the bone which was being lengthened. All resolved with appropriate treatment. This method allows early rehabilitation, with a rapid return of knee movement. There is a lower rate of complications than occurs when external fixation is used on its own. The time of external fixation is shorter than in other methods of leg lengthening. The high risk of infection calls for caution

Femoral lengthening using the Intramedullary Skeletal Kinetic Distractor is a new technique. However, with intramedullary distraction the surgeon has less control over the lengthening process. Therefore, 33 femora lengthened with this device were assessed to evaluate the effect of operative variables under the surgeon’s control on the course of lengthening. The desired lengthening was achieved in 32 of 33 limbs. Problems encountered included difficulty in achieving length in eight femora (24%) and uncontrolled lengthening in seven (21%). Uncontrolled lengthening was more likely if the osteotomy was placed with less than 80 mm of the thick portion of the nail in the distal fragment (p = 0.052), and a failure to lengthen was more likely if there was over 125 mm in the distal fragment (p = 0.008). The latter problem was reduced with over-reaming by 2.5 mm to 3 mm. Previous intramedullary nailing also predisposed to uncontrolled lengthening (p = 0.042), and these patients required less reaming.

Using the Intramedullary Skeletal Kinetic Distractor, good outcomes were obtained; problems were minimised by optimising the position of the osteotomy and the amount of over-reaming performed.