Three-Dimensional Assessment to Hallux Valgus Correction Using Lapicotton Technique

Abstract

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: The first-ray and the medial column play a crucial role in preserving the tripod of the foot. Changes to structural properties of the first-ray, along with collapse of the medial-longitudinal-arch, have been associated with hallux valgus (HV). Thus, restoring the first-ray plays an important role when correcting the mechanical function of the foot tripod in the setting of HV combined with medial-longitudinal-arch collapse. The LapiCotton technique combines the mechanical advantages of Cotton osteotomy and modified Lapidus procedures by maintaining the length of the first-ray and preserving the medial- longitudinal-arch by plantar inclination of the distal part of first-ray. The aim of this study was to evaluate the effectiveness of the LapiCotton procedure in correcting selected radiographic parameters in patients with combined VH with medial-longitudinal arch collapse. Methods: Preoperative and postoperative Weight Bearing CT (WBCT) scans were obtained from HV patients who underwent unilateral LapiCotton procedure. Postoperative scans were obtained roughly three months after the date of surgery. Semi- automatic measurements were applied to 22 WBCT images across a total of 11 patients enrolled into the study using the Disior ® Bonelogic ® Software. Measurements of the hallux valgus angle (HVA), meary sagittal measurement, and intermetatarsal angles were taken from preoperative and postoperative scans. These scans were then compared using intraclass correlation coefficients and paired t-tests to evaluate the efficacy of the Lapicotton technique in treating HV with P-valus < 0.05 being significant. Results: HVA was found to be significantly larger (p=.026) in the preoperational group (Mdn = 27.52) than the postoperational group (Mdn = 20). In addition, the Meary sagittal measurement was found to be significantly different between groups (p=.033), with a larger value seen in the preoperational group (Mdn = -14.28) compared to the post-operational group (Mdn = -11.15). It was also observed that the IMA was significantly larger (p=.003) in the preoperative group (Mdn = 15.68) compared to the postoperative group (Mdn = 11.26). The sesamoid rotation was found to be higher in the preoperative group (Mdn = -17.71) than the post operative group (Mdn = -24.98), however, these values were not significantly different from one another (p=.203). Conclusion: The LapiCotton procedure proved to be effective in correcting radiographic parameters in patients with HV combined with collapse of the medial longitudinal arch. Reliable correction of HV, along with correction of medial longitudinal arch collapse, was quantified based on semi-automated WBCT measurements of HVA, IMA and Meary angle. LapiCotton produced significantly different measurements for both HVA and IMA postoperatively, providing evidence that the LapiCotton procedure can successfully correct medial longitudinal arch collapse in patients with HV, as well as radiographically reduce the severity of the deformity.