Risk Analysis of Nonunion After First Metatarsophalangeal Joint Arthrodesis

Objective: The standard therapy for a symptomatic hallux rigidus is still the arthrodesis of the first metatarsophalangeal (MTP) joint. A nonunion of the arthrodesis is a possible postoperative complication. This study aimed to evaluate the incidence of nonunion associated with first MTP joint arthrodesis and identify risk factors influencing this. Methods: This retrospective study included 197 patients who were treated with an isolated first MTP joint arthrodesis. The severity of MTP-related osteoarthritis was assessed clinically and radiologically prior to surgery according to the Waizy classification. Patient characteristics and radiological parameters were evaluated postoperatively. Results: A full clinical and radiological data set was collected from 153 out of 197 patients. We identified 14 cases of nonunion and found that nonunion was associated with higher incidence of male gender (P = .29), comorbidity (P = .035), higher grade of osteoarthritis (P = .01), and increased postoperative great toe dorsiflexion (P = .022). Conclusions: Arthrodesis of the first MTP joint is a safe operative treatment, as demonstrated by a nonunion rate of 9.2%. Negative influencing factors were the presence of preexisting diseases, higher grades of osteoarthritis, and a relative increased dorsiflexion position of the great toe after surgery. These factors should be considered during pre-, intra-, and postoperative planning.Levels of Evidence: Therapeutic, Level IV: Retrospective.