Effect of pathology on union of first metatarsophalangeal joint arthrodesis.

Background: Arthrodesis is an established treatment for symptomatic degeneration of the first metatarsophalangeal (MP) joint. The published case series have often been small with different surgeons using a variety of joint preparation and fixation methods. The nonunion frequency comparing the different pathologies has not been described. We describe the senior author's results comparing the union of an MP arthrodesis in hallux valgus, hallux rigidus, inflammatory arthropathy, and salvage surgery with identical joint preparation and fixation methods. Methods: The logbook of the senior author was used to identify the first MP joint arthrodeses from 2003 to 2011. The radiographic data were reviewed on the Picture Archiving and Communication system to assess the severity of deformity, radiographic union, type of fixation, and need for revision surgery. If there was no definite radiographic union of the last radiograph, the medical notes were reviewed. In all, 134 MP joint arthrodeses were performed in 78 females and 38 males, with a mean age of 65 +/- 12 years (range, 20-94). Fixation was achieved by crossed screws (124) and dorsal plate (10). The primary diagnoses were hallux valgus in 49 joints (36.6%), hallux rigidus in 46 joints (34%), inflammatory arthropathy in 34 joints (25.4%), and salvage surgery in 5 joints (3.7%). Results: The overall radiographic union rate was 91.8% (123/134). There were significantly more nonunions in the hallux valgus group (14.3% vs 0%, OR 16, P = .05). Conclusion: Biplanar cuts and crossed screw fixation gave similar union frequencies to published case series. Hallux valgus was associated with higher nonunion frequencies in this single surgeon series. It may be that the hallux valgus group needs a stronger construct to achieve comparable union frequencies to the hallux rigidus group.