The Frequency of Subtalar Joint Instability in Adult Patients Who Underwent Surgical Correction of First Metatarsophalangeal Joint Surgery-A Retrospective Radiographic Evaluation

Abstract

Objective: Subtalar joint instability creates misalignment of talus on the calcaneus. The loss of talar alignment and stability leads to a prolonged period of foot pronation during the stance phase of the gait cycle. Over or hyperpronation is known as a contributing factor to the progression of hallux valgus (HV) and hallux limitus/rigidus (HL/R). The purpose of this retrospective radiographic study is to evaluate the number of adult patients (feet) diagnosed with HV and HL/R who underwent surgical correction within a one year period.Methods: Pre-operative weightbearing radiographs for one-hundred five feet, that met the inclusion criteria, were retrospectively analyzed. Both transverse (talar second metatarsal (T2M)) and sagittal (talar declination (TD)) plane angular measurements were independently calculated and compared to normal values based on literature.Results: In this study, 97 (92.38%) of 105 feet with HV and HL/R had values above normal for at least one of the T2M and/or TD angle indicating an abnormal talar alignment. The mean T2M was 21.88 ± 7.95 (range 1.13 to 50.58 degrees) and the mean TD was 23.45 ± 3.94 (range 14.75 to 34.24 degrees). Forty (38.1%) feet exhibited a single plane deformity and 57 (54.28%) comprised of a both transverse and sagittal plane deformities.Conclusion: This supports the hypothesis that a correlation between subtalar joint instability and HV or HL/R exists. This hind foot deformity should be considered as a contributing factor in the progression of 1st MPJ pathology.