Correction of Distal Metatarsal Articular Angle in Hallux Valgus Surgery Utilizing a Minimally Invasive Percutaneous First Metatarsal Distal Transverse Osteotomy

Category: Midfoot/Forefoot; Other Introduction/Purpose: Hallux valgus, a common deformity treated by orthopedic foot and ankle surgeons, can frequently present with an increased distal metatarsal articular angle (DMAA), which may require correction in addition to the hallux valgus deformity. Minimally invasive (MIS) percutaneous hallux valgus surgery is becoming more popular and often used in patients with increased DMAA. Additional recent literature has shown low rates of recurrence, minimal pain and high patient functional outcomes with MIS hallux valgus correction. Thus, we investigated the efficacy of MIS percutaneous distal transverse first metatarsal osteotomy procedure, a triplanar correction, in correcting the DMAA in hallux valgus surgery. We hypothesize that give the ability to obtain a triplanar correction with this osteotomy no additional osteotomy will be needed to correct the DMAA. Methods: A retrospective chart review was performed on patients who underwent the hallux valgus reconstruction with a MIS percutaneous distal transverse first metatarsal osteotomy between September 2021 to December 2022. Exclusion criteria included patients with inadequate follow up and all patients not undergoing MIS percutaneous distal transverse first metatarsal osteotomy for hallux valgus correction. Hallux valgus angle (HVA), intermetatarsal angle (IMA) and DMAA were measured on pre- operative and 2-week post-operative radiographs to assess immediate correction of these angles. Univariate analysis was used to describe pre- and post- measurements for DMAA, HVA, and IMA. Differences in pre- and post- measurements were evaluated using paired t-test. Results: In total, 43 minimally invasive surgery (MIS) hallux valgus corrections on 39 patients were included. On average, the DMAA decreased from 9.5 degrees pre-operatively to 4.8 degrees two weeks post-operatively (decrease of 4.7 degrees, p-value < 0.001). The average HVA decreased from 29.9 degrees pre-operatively to 4.2 degrees two weeks post-operatively (decrease of 25.7 degrees, p-value of < 0.001). Lastly, the average IMA decreased from 15.1 degrees pre-operatively to 2.9 degrees 2 weeks post-operatively (decrease of 12.2 degrees, p-value < 0.001). Conclusion: Our study showed that utilizing a MIS percutaneous distal transverse first metatarsal osteotomy for hallux valgus correction was able to significant reduce the DMAA without the need for supplementary metatarsal osteotomies. Additionally significant correction of the IMA and HVA was also obtained. MIS hallux valgus correction may be considered by orthopedic foot and ankle surgeons for those patients that need surgical correction for hallux valgus deformity that also requires DMAA correction