Three-Dimensional Distance and Coverage Mapping of the First Ray in Hallux Valgus

metatarsal, with 10% of each end defined to be in contact with the opposing bone. The nearest distance was calculated for this region, with regions of 5 mm or less defined as covered and >5 mm defined as uncovered. Sagittal TMT 1 angle was calculated as a marker of TMT instability. Welch's t-test and Mann-Whitney U were used for statistical analysis.ResultsHallux valgus patients demonstrated significantly increased coverage along the dorsal lateral and plantar lateral quadrant of the MTP joint relative to controls (28.59%, P=.002 and 14.47%, P=.007, respectively) and decreased coverage along the dorsal medial and plantar medial quadrant (-42.63%, P=.002 and -46.69%, P<.001, respectively). No differences in distance mapping at the MTP joint or contact and distance mapping at the TMT joint were observed between groups (Table 1). Sagittal TMT 1 angle was higher in the HV group (1.36° vs 0.6°, P=.02).DiscussionThere is notable discrepancy in coverage at the MTP joint in HV patients relative to those without HV, consistent with subluxation of the hallux MTP joint in HV. Contrary to our hypothesis, no discernable difference was noted at the TMT joint with respect to DM and CM. While sagittal plane angulation was higher in HV, it did not result in appreciable changes in contact and distance mapping at the TMT joint.Level of EvidenceIII: Retrospective case control.