Relationship Between Metatarsal Head Translation and Unintended Increase in Diaphyseal-Intermetatarsal Angle in MICA Technique for Hallux Valgus Correction: A Retrospective Study

Abstract

Objectives

The aim of this study is to retrospectively analyze patients who underwent hallux valgus correction surgery using the Minimally Invasive Chevron and Akin (MICA) technique and assess the degree of metatarsal head translation, preoperative and postoperative inter-metatarsal angle (IMA), and postoperative diaphyseal-intermetatarsal angle (D-IMA). The hypothesis of this study is that, following hallux valgus correction using the MICA technique, an undesired increase in D-IMA may occur and that this increase is directly correlated with the percentage of first metatarsal head translation.

Materials and Methods

In total, 20 patients who underwent hallux valgus correction with the MICA technique were analyzed. Preoperative and postoperative dorso-plantar weight-bearing x-rays of the feet were evaluated: preoperative and postoperative IMA, postoperative D-IMA, and the percentage of metatarsal head translation were calculfasated. The Pearson correlation coefficient was calculated to assess the relationship between metatarsal head translation and the increase in postoperative D-IMA.

Results

The difference between preoperative IMA and postoperative D-IMA was statistically significant with P < .0001. From preliminary analysis, it has emerged that the relationship is linear and the increase in D-IMA is directly correlated with the degree of metatarsal head translation, r = .83.

Conclusion

From this initial retrospective analysis, it emerges that despite the recognized effectiveness of the MICA technique in correcting hallux valgus and reducing IMA, a portion of metatarsal head translation does not lead to a decrease in IMA but rather to an increase in D-IMA. This study suggests a positive linear correlation between the percentage of metatarsal head translation and the increase in D-IMA.