Relationship of Radiographic and Clinical Parameters With Hallux Valgus and Second Ray Pathology

Background: Hallux valgus is frequently associated with additional forefoot pathologies, including hammertoes and midfoot osteoarthritis (OA). However, the pathogenesis of these concurrent pathologies remains to be elucidated. We sought to determine whether there is a relationship between demographic and radiographic parameters and the incidence of secondary pathologies in the setting of a bunion, with an emphasis on second tarsometatarsal (TMT) OA and hammertoes. Methods: A total of 153 patients (172 feet) who underwent reconstruction for hallux valgus were divided into 3 groups: (1) bunion only (61 patients), (2) bunion with hammertoe without second TMT joint OA (78 patients), and (3) bunion with second TMT joint OA (14 patients). Preoperative age, sex, and body mass index (BMI) as well as hallux valgus angle (HVA), intermetatarsal angle (IMA), metatarsus adductus angle (MAA), ratio of second to first metatarsal length, and Meary's angle were recorded. One-way analysis of variance (normality demonstrated) and Kruskal-Wallis (normality not demonstrated) tests were used to assess differences in continuous variables. Post hoc tests were conducted with the Bonferroni technique. Associations between discrete variables and the study groups were analyzed using (2) tests. Following the univariate analysis, multinomial logistic regression models were built to determine potential risk factors for hammertoe or TMT OA group placement. Results: Patients in the hammertoe and TMT OA groups were significantly older than patients in the bunion only group (P < .001 for both pairwise comparisons) and had significantly higher BMIs (P = .024 and P < .001, respectively). Patients in the TMT OA group had a significantly higher mean HVA than patients in the bunion-only group (P = .004) and a significantly higher mean MAA relative to both other study groups (P .001 for both comparisons). IMA, Meary's angle, and the ratio of second to first metatarsal length did not differ significantly between groups. In the multivariate analysis, hammertoe group assignment was predicted only by age and HVA, while midfoot OA group assignment was predicted by age, HVA, BMI, and MAA. Conclusion: Our data show that older age and increased HVA were predictors of both second ray pathologies studied. Higher BMI and MAA were predictive only of TMT joint OA. These data may help identify patients with hallux valgus who are at greater risk for developing secondary pathologies. Level of Evidence: Level III, retrospective comparative series.