Outcomes of Minimally Invasive Proximal Chevron Metatarsal Osteotomy for Moderate to Severe Hallux Valgus Deformity

CATEGORY: Midfoot/Forefoot INTRODUCTION/PURPOSE: The effectiveness of minimally invasive surgery (MIS)-distal chevron metatarsal osteotomy (DCMO) for the correction of moderate to severe hallux valgus deformity is unclear. Traditionally, proximal chevron metatarsal osteotomy (PCMO) has been considered a reliable procedure for correcting severe hallux valgus deformity. This study aimed to clarify the clinicoradiographic outcomes of our novel MIS-PCMO technique and compared its outcomes to those of MIS-DCMO performed during the same timeframe. We addressed the following research questions: (1) can the MIS-PCMO technique be an effective option for correcting moderate to severe hallux valgus deformity?; (2) are there differences in the extent of deformity correction possible with MIS-PCMO and MIS-DCMO?; and (3) what points should be considered before performing the MIS-PCMO technique? METHODS: We prospectively compared the outcomes of patients who underwent MIS-PCMO (n=20 patients; 22 surgeries) and those of patients who underwent MIS-DCMO (n=23 patients; 26 surgeries) for moderate to severe hallux valgus deformity (hallux valgus angle [HVA] >=30o) between January 2017 and December 2018. The minimum follow-up duration for inclusion in this study was 18 months. The HVA, first-to-second intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), relative length of the second metatarsal, medial sesamoid position, and Meary angle were measured preoperatively and at the final follow- up. RESULTS: Compared to MIS-DCMO, MIS-PCMO resulted in significantly greater correction of the HVA (P<0.001) and IMA (P=0.01), along with Meary angle improvement (P<0.001); however, the DMAA worsened (P=0.01). Furthermore, there was a significantly greater change in the relative second metatarsal length in the MIS-DCMO group (P=0.01). There were no significant between-group differences in the correction of the medial sesamoid position (P=0.445). CONCLUSION: MIS-PCMO can be a better option for correcting moderate to severe hallux valgus deformities than MIS-DCMO. However, this technique should be applied carefully when the preoperative DMAA is already large because the DMAA can become worse postoperatively.