Floating Knee Arthrodesis After Periprosthetic Knee Infection: A Multi-Center Study.

BACKGROUND

Knee arthrodesis is a means of avoiding above-knee amputation after a periprosthetic joint infection (PJI). The objective of this study was to analyze the results of floating knee arthrodesis in patients who had a history of a periprosthetic knee infection and to perform an external validation of the Baeza-Ortega scale. The analysis consisted of determining reinfection rates, functional results, and the survival of arthrodesis.

METHODS

There were 86 patients who had undergone floating knee arthrodesis in cases of PJI who were retrospectively included in the study. The operations were performed between 2012 and 2022 at three different referral centers for complex bone and joint infections in Spain. In addition to being evaluated clinically, analytically, and radiographically, the patients were assessed functionally with the Baeza-Ortega scale, which had been previously validated. At a mean follow-up of 4 years (range, 1 to 9), 13 patients suffered reinfection (15%) and 29% of patients experienced complications with an average of 42 months until a complication appeared.

RESULTS

The recurrence of infection was not observed to be significantly affected by sex (P = 0.13), age (P = 0.1), or the type of surgery previously undergone (P = 0.17), nor was the McPherson Host Grade (P = 0.4) 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 = 0.036). There were 45 patients (53%) who were fully evaluated and scored. For 16 patients (35%), the results were evaluated as excellent, for 22 (48%) acceptable, for six (14%) low, and for one (3%) poor. There was a significant correlation between patient satisfaction and functional outcomes (P = 0.0006).

CONCLUSIONS

The arthrodesis nail without bone-bone fusion is an effective and safe procedure for patients who have a recurrent PJI, providing satisfactory functional results when a knee prosthesis revision cannot be performed.