Radiographic measurements for the assessment of metatarsus adductus (MTA) have a broad range of interpretation without a consensus regarding surgical indications. The "Plumbline" (PL) radiographic assessment method helps identify MTA and determines if physical space is available to align the first metatarsal to the longitudinal foot axis without the need to realign the lesser metatarsals. Forty-five neutral weight-bearing anterior-posterior (AP) radiographs of patients scheduled for surgical intervention for isolated hallux valgus (HV) or combined MTA/HV deformities were reviewed. The cohort was grouped based on the presence of MTA using a Sgarlato's angle (SA) of 15°, with 23 patients in the HV-only group and 22 patients in the MTA group. A mean preoperative SA of 8.7° (SD: 2.1; range: 5.4-13.4) and 26.6° (SD: 5.1; range: 18.2-36) were found in the HV-only and MTA groups, respectively. Subjects with an SA ≤ 15° (N = 22) were found to have a negative PL (100%) and subjects with an SA > 15° (N = 23) displayed a positive PL (100%). The PL technique provided a simple method and clear visual reference for determining the presence of MTA in HV patients without the need to measure traditional radiographic angles.Level of Evidence: Retrospective, Level IV, Diagnostic.
Keywords: Hallux valgus; Metatarsus adductus; Plumbline; Sgarlato angle.