Upper Limb Lengthening in Achondroplasia Using Unilateral External Fixation.

ABSTRACT

PURPOSE: The purpose of this study was to analyze the long-term results of humeral lengthening in achondroplastic patients and make suggestions on the most appropriate surgical technique to improve patient outcomes. METHODS: Fifty-four humeral lengthening procedures performed in 27 achondroplastic patients were reviewed. Elongations were performed by means of callotasis with unilateral external fixation. Inclusion criteria were achondroplastic patients under 17 years without prior arm operations and minimum follow-up of 36 months. RESULTS: Fifty humeri in 25 patients (13 men and 12 women), aged between 9 and 17 years, met the inclusion criteria. Mean humeral lengthening was 8.82 cm (range 5 to 10.5 cm), which represented an elongation of 54.80% (range 46% to 63%) of the original length. The healing index was 0.91 months (range 0.72 to 1.4 mo) per centimeter gained. Shoulder and elbow range of motion and stability were preserved in 47 limbs. Noncomplicated cases consistently experienced a significant functional improvement in the performance of activities of daily living such as putting on footwear and personal hygiene. Short-term complications included 11 pin-tract infections, 1 radial nerve neuropraxia, and 1 failure of the regenerated bone formation. None of these complications prevented from completion of treatment. Long-term complications included 2 cases of nonunion, 3 elbow flexion contractures, and 2 cases of psychological dissatisfaction, all of them in 4 patients. Factors associated with long-term complications were intraoperative fragment displacement and distal humeral osteotomy. No fractures of the regenerated bone were identified in the long term. CONCLUSIONS: Callotasis with unilateral external fixation is a reliable and well-tolerated procedure for humeral lengthening in achondroplastic patients, with an acceptable complication rate. Guided fixator placement and a proximal humeral osteotomy are strongly recommended technical tips as they may help prevent complications and improve outcomes. LEVEL OF EVIDENCE Level IV-case series.