Periprosthetic Infection of Transfibular Ankle Arthroplasties Managed with Implant Retention: Anatomical Limitations of Surgical Debridement

<b>Background:</b> Prosthetic ankle infection is an infrequent and rarely explored prosthetic joint infection (PJI). In early infection, the debridement of implants inserted using the transfibular approach has certain peculiarities that pose a diagnostic and therapeutic challenge, the impact of which on infection prognosis is still unknown. <b>Methods:</b> This study prospectively collected all cases of transfibular prosthetic ankle infection at a tertiary hospital between 2014 and 2022, describing their demographic, clinical, microbiological, and management characteristics, along with the outcome over a long follow-up. This cohort was compared with a cohort of infected fibular plates without prostheses implanted in the same period of time. <b>Results:</b> Seven cases of ankle PJI were analysed, all of them implanted using a transfibular approach. They were all early prosthetic infections. The median age was 63 years (range 54-74) with a predominance of women (71.4%), three patients with diabetes (42.9%), and one patient with rheumatoid arthritis (14.3%). The aetiology was predominantly staphylococcal (4 [57.1%] methicillin-susceptible <i>S. aureus</i> and 1 [14.3%] <i>S. epidermidis</i>). All cases were managed with irrigation and debridement limited to the fibular plate, four of which failed (57%). By comparison, eleven cases of infected fibular plates without prostheses implanted were analysed. There were no differences in clinical, microbiological, or therapeutic management characteristics between the groups. Failure among infected fibular plates occurred in only two cases (18%). <b>Conclusions:</b> Debridement of infected transfibular ankle prostheses suggests a worse evolution than would be expected for other joint infections. This could be explained by the nature of the debridement, limited to the fibular component. Further detailed studies of the surgical possibilities in prosthetic ankle infections are necessary to improve the prognosis of these infections, given their impact on joint function.