Comparison of knee motion and callus formation in femoral lengthening with the Wagner or monolateral-ring device.

Twenty-three patients who underwent femoral lengthening had proximal fixation with two Shanz screws; however, the type of distal fixation and site of the osteotomy differed. One group had distal fixation with two Shanz screws attached to a Wagner device and had a midshaft osteotomy; the other group had distal fixation with an Ilizarov ring attached to a modified Wagner device and underwent metaphyseal osteotomy. Patients were compared with regard to callus formation, presence of knee subluxation, and range of motion (ROM) at the knee. The average lengthening achieved was 9.9 cm. The type of bone healing was superior when the osteotomy was performed in the metaphysis rather than to the diaphysis. Knee ROM was poorer in the group with the distal fixation by the Ilizarov wires than the group with the Shanz pins. Multiple adhesions caused by Ilizarov wire impalement of muscles appeared to have caused the excessive stiffness. In instances of simultaneous ipsilateral lengthening of the femur and tibia, interconnection of the Ilizarov ring by means of hinges was successful in reducing the incidence of knee subluxation.