Comparison of Radiographic and Anatomic Distal Metatarsal Articular Angle in Cadaver Feet

BACKGROUND: A few studies report correlations between radiographic and anatomic measurements of the distal metatarsal articular angle (DMAA). However, little is known about how the DMAA correlates with the hallux valgus angle (HVA) and with anatomic and clinical radiographic measurements. METHODS: We dissected, measured, and radiographed 39 cadaveric feet for evidence of hallux valgus and the DMAA. We then correlated these values with paired clinical radiographic measurements made by physician evaluators. RESULTS: Physician measurement of DMAA and anatomic measurement of DMAA were significantly correlated with a mean r = 0.64 (evaluator range, 0.44-0.66). Pairwise correlation between physician evaluators ranged from r = 0.63 to 0.84. Sixty-six percent of physician-measured DMAAs were within 5 degrees of anatomic DMAA. CONCLUSION: The percentage of radiographic DMAAs that were within 5 degrees of anatomic DMAAs was only 66%. Additionally, the DMAA was increased in the specimens with moderate and severe hallux valgus compared with those with normal or mild hallux valgus angles. CLINICAL RELEVANCE: The DMAA is an important consideration in patients with hallux valgus. While it is less reliable than other radiographic measures, it was correlated to deformity severity in specimen with hallux valgus.