COSMIC feasibility study - comparing open scarf osteotomy and minimally invasive chevron osteotomy for hallux valgus correction

A. Pujol Nicolas, M. Kakwani, A. Griffiths, N. Hutt, D. Townshend, A. Murty, R. Kakwani

Background: Minimally invasive surgery (MIS) has gained popularity for hallux valgus correction. Current evidence shows similar outcomes to scarf osteotomy (SO), however there are limited randomised controlled studies (RCT). The aim of this study was to assess the feasibility of conducting a RCT to compare the patient recorded and clinical outcomes for the surgical management of Hallux Valgus between SO and MIS.

Methods: Patients suitable for surgical correction of moderate hallux valgus were invited to participate. Patients completed a validated questionnaire (Manchester Oxford Foot questionnaire and EQ-5D-5L) preoperatively and postoperatively at 6 months and 1 year. Radiological parameters and range of motion (ROM) were measure pre and post operatively.

Results: 31 patients were recruited between Dec 2017 and June 2022. 17 patients were randomised to MIS (15 female, mean age 51) and 14 to SO (13 female, mean age 51). Both groups had a significant improvement in all MOXFQ parameters at 6m and 12m, as well as radiological parameters. VAS improved for SO at 6m (p=0.048) and 12m (p=0.025) but only improvement at 6m was seen for MIS (p=0.059). There was no significant improvement in EQ-5D in either group at 12 months and no significant difference in surgical time (p=0.53). Higher number of complications were seen in MIS with 5 removal of metalwork (29.4%) and 2 superficial infections (11.8%) vs none in SO. The dorsiflexion significantly improved in the SO group at 6months (p=0.04). No patients were lost at follow up.

Conclusion: Both surgical options show similar clinical results, but higher complication rates were seen with MIS. A larger study is needed to evaluate further. This was a difficult study to recruit to. Challenges included: surgeon equipoise, patient preference, prior approval ticket restriction, training requirement and Covid 19- pandemic which could be mitigated in a larger multicentre study