Distraction osteogenesis for brachymetatarsia: Clinical results and implications on the metatarsophalangeal joint

Abstract

Background: Distraction osteogenesis (DO) using external fixation has revolutionized the management of brachymetatarsia, yet not without complications (30-100% incidence), the most common involving the metatarsophalangeal (MTP) joint. Questions/Purposes: What are the clinical outcomes of DO for brachymetatarsia? What are the challenges and outcomes particularly related to the MTP joint? Does the method of stabilizing MTP joint during DO affect the outcome? Materials and Methods: This is a retrospective study of 44 metatarsals (MTs) in 27 patients who underwent DO. Regarding MTP joint stabilization; 43% were fixed with K-wire across the joint, 32% with pinning of phalanges short of joint and attaching the K-wire to the external fixator, 7% by pinning of phalanges and distraction arthroplasty of the MTP joint, 2% no stabilization, and 16% by other methods. Clinical outcomes were analyzed by a nonvalidated 9-item questionnaire at the latest follow-up in addition to a review of postoperative radiographs. Complications, particularly pertaining to MTP joint were recorded. Statistical Analysis: The paired t-test was used to assess the difference in MT length. Fisher's exact test used to evaluate rates of complications by MTP fixation method. McNemar's test was used to measure the difference in outcome questionnaire responses. Cochran-Armitage trend test was used to assess differences in toe-limitation before and after surgery. Results: Postoperatively, MT length showed a significant increase of 12.98 ± 3.74 mm (28.55 ± 9.25%). Problems included MTP stiffness in 64%, MTP subluxation in 27%, and MTP dislocation in 7%, with no significant differences in outcome by MTP joint stabilization. Satisfaction with surgery was reported by 95% of patients. Conclusion: DO is an effective treatment for brachymetatarsia, with high patient satisfaction. The most commonly reported problem was MTP joint stiffness with no functional deficit. There was no significant difference in the rate of MTP joint-specific complications by stabilization method. Larger patient numbers are required for validation of an optimal MTP joint stabilization method. Level of Evidence: IV, Case Series.