Surgical Site Infections in Major Lower Limb Amputation (SIMBA): international multicentre study

Surgical site infection (SSI) after major lower limb amputation (MLLA) significantly affects function, mobility, morbidity, and mortality, alongside broader impacts on healthcare services. Limited data exist on the incidence, prevention, and management of SSI after MLLA. Improving outcomes and wound healing have been identified as research priorities for patients following MLLA.

Surgical Site Infection in Major Lower Limb Amputation (SIMBA) is an international, prospective, collaborative observational study. Data were collected for consecutive patients undergoing MLLA over 8 months, with 30-day follow-up. Outcomes included the incidence of SSI (defined using Centers for Disease Control and Prevention criteria), wound dehiscence (defined as any partial or complete separation of the incision or flap, with or without infection), further intervention, mortality, adjunct use, and SSI predictors.

Validated data for 1314 MLLAs from 46 centres in the UK (34), Europe (9), Australasia (2), and Asia (1) were collected, comprising 643 (48.9%) transfemoral, 41 (3.1%) through-knee, and 628 (47.8%) transtibial amputations. The most common indications were ischaemia (56.6%, 742) and uncontrolled infection (22.3%, 293). The incidences of SSI and wound breakdown were 10.9% (135 of 1238) and 16.7% (204 of 1217), respectively. Low glomerular filtration rate, cardiac disease, dirty/infected wound class, and transtibial amputations were independent predictors of SSI. SSI was associated with increased postoperative morbidity, wound breakdown, further intervention, and delays in fitness for discharge. The 30-day mortality rate was 7.0% (92 of 1314), with no significant association with SSI.

SSI and wound breakdown are common following MLLA, and are associated with increased morbidity, delayed recovery, and revision surgery. These findings identify patient- and procedure-specific factors associated with elevated SSI risk, and a lack of procedure-specific evidence, revealing critical gaps in SSI prevention strategies. Addressing these are essential to improve patient outcomes, reduce healthcare costs, and guide future research.