Background: Minimally invasive techniques of Akin osteotomy have grown in popularity, as early results suggest faster recovery, earlier return to work, and minimized wound healing problems. Preserving lateral cortex integrity during first phalanx osteotomy thereby presents a challenge because of the lack of direct visual control. This retrospective comparative study investigated clinical and radiographic outcomes of minimally invasive and open Akin osteotomy with different fixation methods and analyzed whether or not intraoperative violation of the lateral cortex caused loss of correction or delayed bone healing.
Methods: One hundred eighty-four patients (210 feet) with symptomatic hallux valgus and pathologic interphalangeal angle (IPA) of at least 10 degrees underwent surgery combined with Akin osteotomy. Minimally invasive Akin osteotomies were fixed in 124 feet with 2 crossing percutaneous K-wires and compared to 86 Akin osteotomies by open technique with double-threaded (head and shank) screw fixation. At 1 day and 6 and 12 weeks postoperatively, IPA and bony consolidation were radiographically and clinically assessed.
Results: Mean preoperative IPA was 13.4 ± 3.6 degrees in minimally invasive (MI) and 13.3 ± 3.5 degrees in open surgery (OS) cases (P > .05). Intraoperative breach of the lateral cortex occurred in 12 (13.9%) in OS and 64 (51.6%) in MI cases. Whereas the breach occurred in open technique mainly during manual correction by applying a medial closing force, it was caused predominantly by the use of the burr in minimally invasive technique. After 12 weeks, the mean IPA was 4.1 ± 1.4 degrees in MI and 4.8 ± 1.2 degrees in OS cases (P > .05). Bony consolidation was complete after 6 and 12 weeks in OS and MI, respectively. Three deep infections occurred in the OS Group after Lapidus arthrodesis and 2 deep infections were registered in the MI Group after minimally invasive chevron and Akin osteotomy. The infections were not at the site of the Akin osteotomy.
Conclusion: Breach of the lateral cortex did not impair bone healing or correction of IPA. Minimally invasive Akin osteotomy with K-wire fixation provided equivalent correction of IPA compared to open surgery with screw fixation.
Level of evidence: Level III, retrospective comparative series.
Keywords: Akin osteotomy; bunion; burr; fracture; hallux valgus; minimally invasive surgery.