Prosthetic Joint Infection After Total Ankle Arthroplasty: A Propensity-Matched Analysis of Risk Factors and Outcomes.

BACKGROUND: Prosthetic joint infection (PJI) following total ankle arthroplasty (TAA) is a rare but devastating complication associated with high rates of reoperation and poor functional outcomes. The purpose of this study was to identify risk factors for PJI following primary TAA and to characterize associated treatment approaches and clinical outcomes.

METHODS: A single-institution retrospective cohort study was conducted, including 1008 primary TAAs performed between 2010 and 2023. PJI was defined using established microbiologic and clinical criteria consistent with prior literature. Patient demographics, comorbidities, preoperative functional status, and operative characteristics were collected. Infected patients were compared with non-infected controls using 2:1 propensity score matching based on age and sex. Associations with PJI were evaluated using penalized logistic regression (Firth method). Microbiologic profiles, surgical management strategies, and outcomes were analyzed for the infection cohort.

RESULTS: Twenty-seven PJIs treated by 4 surgeons were identified, yielding an overall infection rate of 2.7%. After matching, cohorts were balanced across patient demographics. Concomitant calcaneal displacement osteotomy and cancer history were significantly associated with PJI (P < .05). When adjusting for prior ankle surgery, BMI, diabetes, and tourniquet time, concomitant calcaneal displacement osteotomy was associated with 9.75-fold increased odds of PJI (95% CI 2.5-52.4) demonstrating an area under the curve of 83.7%. Staphylococcus aureus was the most frequently identified organism (36.7%). Eight (29.6%) PJIs were considered chronic (>4 weeks). Two-stage revision TAA was the predominant surgical strategy (59.3%), with limb salvage achieved in 96.2% of cases and arthroplasty retention maintained in 69.2% at a mean follow-up of 4.07 years.

CONCLUSION: PJI following primary TAA occurred at a rate of 2.7%, with calcaneal displacement osteotomies identified as a significant associated procedural risk factor. Despite the severity of this complication, high rates of limb salvage and arthroplasty retention were observed with contemporary treatment strategies at midterm follow-up.

LEVEL OF EVIDENCE: Level III, retrospective cohort study.