Distal Chevron Osteotomy Increases Anatomic Intermetatarsal Angle in Hallux Valgus

Abstract

Background: Distal chevron metatarsal osteotomy (DCO) is a common technique to address hallux valgus (HV), which involves coronal translation of the capital fragment resulting in a nonanatomic first metatarsal. The purpose of this study was to evaluate the radiographic effect of the DCO on the anatomic vs the mechanical axis of the first metatarsal. Our hypothesis was that patients undergoing DCO would have improvement in the mechanical metatarsal axis but worsening of the anatomic axis. Methods: This was a retrospective case series of consecutive patients who underwent DCO for HV. The primary outcomes were the change in anatomic first–second intermetatarsal angle (a1-2IMA) vs mechanical first–second intermetatarsal angle (m1-2IMA). Secondary outcomes included the change in hallux valgus angle (HVA) and medial sesamoid position. Results: 40 feet were analyzed with a mean follow-up of 21.2 weeks. The a1-2IMA increased significantly (mean, 4.1 degrees) whereas the m1-2IMA decreased significantly (mean, 4.6 degrees) following DCO. There was a significant improvement in HVA (mean, 12.5 degrees). Medial sesamoid position was improved in 21 feet (52.5%). Patients with no improvement in sesamoid position were found to have a larger increase in a1-2IMA (mean, 4.7 vs 3.5 degrees, P = .03) and less improvement in m1-2IMA (mean, 3.8 vs 5.2 degrees, P = .02) compared to patients with improvement in sesamoid position. Conclusion: Distal chevron osteotomy for HV was associated with worsening of the anatomic axis of the first metatarsal despite improvements in the mechanical metatarsal axis, HVA, and medial sesamoid position. Greater worsening of the anatomic axis was associated with less improvement of sesamoid position. Our findings may suggest the presence of intermetatarsal instability, which could limit the power of DCO in HV correction for more severe deformities and provide a mechanism for HV recurrence. Level of Evidence: Level IV, retrospective case series.

Contribution Ratio of Metatarsal Osteotomy and First Tarsometatarsal Joint Reduction in Moderate to Severe Hallux Valgus Correction

“…The difference between the two groups was significant (p < 0.001); however, both of the groups only had a moderate hallux valgus deformity (13 < pre-operative IMA < 20 degrees). Increased post-operative anatomical IMA was also observed in Chevron osteotomy in other reports [23]. We also believe that over-translation of the distal fragment could result in the medialization of the proximal fragment.…”

Outcomes and Surgical Strategies of Minimally Invasive Chevron/Akin Procedures

“…It has been shown with distal chevron osteotomies that there is actually a significant increase in the postoperative proximal diaphyseal 1-2 anatomic intermetatarsal angle, while the mechanical 1-2 IMA is actually significantly improved. 4 In our study, we too noted a significant decrease in our mechanical 1-2 IMA, but we did note that the proximal anatomic 1-2 IMA increased. The increase in anatomic 1-2 IMA led us to investigate whether foot width actually decreased or increased with this procedure, as patients are interested in knowing if their foot width will change after undergoing bunion correction procedures.…”

“…Preoperative and final postoperative radiographs were evaluated to measure the intermetatarsal angles (IMAs), hallux valgus angles (HVAs), and bony and soft tissue foot width. Pre-and postoperative IMA was calculated using the mechanical 1-2 IMA as described by Chan et al 4 The mechanical axis of the first metatarsal was a line from the center of the metatarsal head to the center of the metatarsal base. HVA was similarly calculated by measuring the angle created by the intersection of the line drawn from the middle of the distal and proximal articular surfaces of the proximal phalanx and the line following the mechanical axis of the first metatarsal.…”

First metatarsal single-screw minimally invasive chevron-akin osteotomy: A cost effective and clinically reliable technique

“…The second series was that of using the first metatarsal dual-screw fixation technique. The inclusion criteria were as follows: (1) 18 < age < 65; (2) 15° < Hallux valgus angle (HVA) ≤ 40°; (3) 9° < Intermetatarsal angle (IMA) ≤ 16° ( 11 ); (4) Patients have been well compliant, accept the MICA technique and sign an informed consent form; (5) complete a minimum 2-year follow up; (6) No combined severe cardiopulmonary dysfunction, and able to tolerate surgery and anaesthesia. The exclusion criteria were as follows: (1) HVA > 40° or IMA > 16°; (2) Degenerative disease of the first metatarsophalangeal joint with severe restriction of joint movement; (3) Akin osteotomy only; (4) Patients with combined cardiovascular and cerebrovascular disease who cannot tolerate surgery; (5) Combined autoimmune disease or diabetes mellitus with poor glycaemic control; (6) Those with psychiatric disorders who are unable to cooperate.…”