Severe Hallux Valgus Angle Attended With High Incidence of Nonunion in Arthrodesis of the First Metatarsophalangeal Joint: A Follow-Up Study.

The incidence of nonunion after first metatarsophalangeal joint (MTP-1) arthrodesis was found to be high in our clinic. By raising awareness for the problem, making a uniform surgical treatment protocol, banning the commonly used convex-concave reamers, and promoting solely the use of hand instruments to prepare the joint for arthrodesis, we tried to decrease the numbers of nonunion. This prospective cohort study included all patients who underwent MTP-1 fusion between January 2018 and March 2019. Patients were treated according to a standardized protocol, using hand instruments to prepare the joint for fusion. Anthropometric and therapy-related data were collected and compared with an earlier 2015-2016 cohort that was retrospectively assessed. Furthermore, the frequency of nonunion between convex-concave reamers and hand instruments was compared. A total of 53 patients underwent MTP-1 fusion surgery. The incidence of nonunion was 3.8%, significantly lower than the 24.1% in 2015 to 2016 (p = .002). Multivariate regression analysis showed a 7.11 times higher risk of nonunion in 2015 to 2016 compared with 2018 to 2019 (95% confidence interval [CI] 1.55 to 32.55) (p = .012). Furthermore, an increase of 10° in HVA showed a 1.52 risk of occurrence of nonunion (95% CI 1.07 to 2.17) (p = .021). The use of convex/concave reamers was univariately associated with a 3.61 times higher risk of nonunion (95% CI 1.14 to 11.43) (p = .029); however, after correction for preoperative HVA, the preparation method was no longer associated with the occurrence of nonunion (p = .108). Patients suffering from severe hallux valgus had nonunion in 32.1% of cases. Incidence of nonunion after MTP-1 arthrodesis was significantly reduced by raising awareness and by standardizing the treatment protocol. There was no significant difference in nonunion frequency between the methods of joint surface preparation. Severe hallux valgus is prone to nonunion, and more research into this indication for MTP-1 fusion and outcome is needed.