Percutaneous minimally invasive Akin osteotomy in hallux valgus interphalangeus: a case series

Purpose Phalangeal Akin osteotomy of the greater toe is a frequently used surgical procedure for correcting hallux valgus interphalangeus deformity. However, previous research did not investigate percutaneous techniques of the Akin osteotomy. It was the aim of this study to investigate feasibility, corrective potential, and safety of a percutaneous minimally invasive Akin osteotomy. Methods We present a series of 81 feet, in which a percutaneous Akin technique was performed using a high-speed burr but no fixation device. The most important outcome parameters were determined as the proximal to distal phalangeal articular angle (PDPAA) (corrective effect of the osteotomy), the osteotomy healing (full, partly, no visibility of the osteotomy gap), and the integrity of the lateral cortical hinge. Results With regard to the main hypothesis we found significant changes in the PDPAA over the whole period of time (p < 0.001). Post-hoc tests determined that the PDPAA changed from 10 degrees pre-operatively (Md, IQR 4.3) to 2.3 degrees post-operatively (Md, IQR 3.7) (p < 0.001). Post-operatively no significant changes in PDPAA were found within the first six weeks and from six weeks to three months (no loss of correction). Osteotomy healing was satisfactory as well. Three months post-operatively, there were no patients with a fully visible osteotomy gap, 28.3% with a partly visible osteotomy gap, and 71.7% had no visible gap. Interestingly, we could not observe a statistically significant correlation between bone healing and the integrity of the lateral cortical hinge. Conclusion From our findings we conclude that the minimally invasive Akin osteotomy without osseous fixation provides effective deformity correction without significant loss of correction thereafter. This procedure appears to be safe with regard to osseous healing. Surprisingly, the healing process of the osteotomy showed no dependence on the integrity of the lateral cortical hinge.