Floating Knee Arthrodesis After Prosthetic Knee Infection: A Report of 48 Cases

Knee arthrodesis is a means of avoiding above-knee amputation after a prosthetic joint infection (PJI). The objective of this study was to analyze the results of floating knee arthrodesis in patients who had a history of aprosthetic knee infection. The analysis consisted of determining reinfection rates, functional results, and the survival of arthrodesis. There were 48 patients who underwent a cemented floating knee arthrodesis in cases of PJI retrospectively included in the study, having been operated on between 2012 and 2020. In addition to being evaluated clinically, analytically, and radiographically, the patients were assessed functionally by means of a newly-created scale. At a mean follow-up of 4 years (1 year to 9 years), 7 patients suffered reinfection (14.6%). The recurrence of infection was not observed to be significantly affected by sex (P = .16), age(P = .09), or the type of surgery previously undergone (P = .18), nor was the McPherson Host Grade (P = .4) observed to have a significant effect. Patients who had a McPherson Limb Grade 3 were more likely to suffer reinfection than those with a McPherson Limb Grade 2 (P = .034). There were 26 patients (54%)fully evaluated and scored on the Knee Arthrodesis Functional Scale(BAOR). For 11 patients (42%), the results were evaluated as excellent, for 11 (42%) acceptable, for 3 (12%) low, and for 1(4%) poor. The arthrodesis nail is an effective and safe procedure for patients who have a recurrent PJI, providing an effective alternative when the criteria for a new revision total knee arthroplasty are not met.