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Operative technique.

The hybrid advanced fixator (Amplimedical, SpA, Milan, Italy) is a modification of the classic Ilizarov fixator 11 combining Kirschner wires with half-pins and full rings with arches. 4,8,9 The standard apparatus (three rings and one half-ring for the leg) was assembled pre-operatively with the rings being sized directly on to the patient’s legs and the wires and halfpins applied with routine transfixation. The whole construct was connected with threaded rods. 8,9 Two osteotomies with a Gigli saw or multiple drill holes were carried out, one below the tibial tuberosity and the other at the supramalleolar level. A fibular osteotomy was performed at the junction of the middle and distal thirds. A hand-controlled drill with a speed of 0 to 950 revolutions per minute was used for the insertion of the wires and pilot holes were drilled before insertion of the half-pins.

Post-operative care and follow-up.

Lengthening was started on the tenth post-operative day at a rate of 0.75 mm per day (1/4 turn every eight hours) for each tibial osteotomy. Weight-bearing was encouraged on the second post-operative day as tolerated, following a rehabilitation programme of gradual increased load bearing and physiotherapy. Pin care began on the first post-operative day with the use of hydrogen peroxide and betadine, and attention to sterile technique. The patient was discharged with instructions on bi-weekly care of the pin site. Clinical and radiological examinations were carried out every 30 to 40 days in order to assess the formation of new bone, pin sites, patient satisfaction, tibial length and joint movements.

We considered a bilateral leg lengthening of 5 to 8 cm to be satisfactory. The radiological criteria for successful lengthening was complete bone bridging in at least two projections. Bone regeneration was assessed clinically by loosening the connecting rods and applying stress.

If consolidated new bone was confirmed clinically and radiologically, the frames were removed in the clinic, usually without anaesthesia. Fibreglass casts or braces which included the foot were applied for a mean of six weeks.

The patients were reviewed every three months for the first year and then every two years. This included evaluation of patient satisfaction, possible axial deviation, the range movement of the knee and ankle, pronation of the foot, leg-length discrepancy and scars. Based on these parameters and scores given by the patient and physician, the outcome was classified as poor (0 to 4), fair (5 to 9), good (10 to 14) or excellent (15 to 18).

The psychological outcome after treatment was evaluated by determining improvement in self esteem, distress and shyness and quality of life. All the patients were asked if they would undergo the procedure again and whether they would recommend it to others of similar stature.

Results

In the 54 patients undergoing simultaneous leg lengthening, the mean lengthening achieved was 7 cm (5 to 11; Fig. 1) over a mean of nine months and 15 days of treatment in the frame (7 to 18). Treatment in the frame was followed by the wearing of fibreglass casts in 26 patients (48.15%) and of commercial braces including the foot in 28 (51.85%). All had physiotherapy for a mean of six weeks (4 to 8). The mean follow-up was 6.25 years (1 to 16). No patient was lost to follow-up.

An associated varus deformity of the knee was corrected in two patients. In 19 patients (35.2%), bilateral lengthening of the tendo Achillis was necessary for an equinus deformity which developed during distraction. One patient refused this operation.