Bone Graft Augmentation in Fourth Generation Percutaneous Hallux Valgus Surgery Tom Lewis, Lily Fletcher, Clare Watt, Evelyn Murphy, Min Jia Chua, Andreas Toepfer, Peter Lam

King’s College Hospital NHS Foundation Trust

Introduction: Minimally invasive or percutaneous surgery (MIS) for hallux valgus correction has demonstrated excellent clinical and radiographic outcomes. However, there are rare occasions where there is limited bone formation and remodelling despite successful union. This study investigated whether prophylactic bone graft augmentation could improve bone formation compared to standard percutaneous technique. Method: A retrospective comparative study of patients undergoing fourth-generation percutaneous hallux valgus correction with Bone Graft Augmentation (BGA group) or without (NBG group) demineralized bone fibre augmentation. Primary outcome was radiographic healing assessed at 6 weeks, 3 months, and 6 months using a validated classification system. Secondary outcomes included patient reported outcome measures (MOXFQ, EQ-5D-5L, VAS Pain), and radiographic parameters (intermetatarsal angle, hallux valgus angle). Results: Between September 2022 and July 2024, 215 patients (191 female; 24 males; 316 feet) underwent fourth generation percutaneous metatarsal extra-capsular transverse osteotomy for hallux valgus correction. Patients were divided into bone graft augmentation (BGA; 222 feet) and non-bone graft (NBG; 94 feet) groups. Radiographic follow-up was available for 75.2% (167 feet) of BGA and 79.8% (75 feet) of NBG cases. The BGA group showed significantly improved radiographic union scores at 3 and 6 months (p=0.005-0.027) but not 6 weeks (p=0.06), with both groups achieving 100% union by 6 months. There were no significant differences between groups in terms of patient reported outcome measures or radiographic deformity correction (p>0.05). The additional cost of bone graft augmentation was USD$1990 per procedure Conclusions: The addition of demineralized bone matrix to the lateral healing zone, led to significantly improved radiographic healing rates at three and six months following percutaneous hallux valgus surgery."