Better function for fusions versus above-the-knee amputations for recurrent periprosthetic knee infection

Abstract

Background: Treatment of chronic periprosthetic joint infections (PJIs) after TKA is limited to fusions, above-the-knee amputations (AKAs), revision TKA, and antibiotic suppression and is often based on the patient's medical condition. However, when both fusion and AKA are options, it is important to compare these two procedures with regard to function.

Questions/purposes: Do patients receiving a knee fusion for PJI after TKA have better function compared to patients receiving an AKA?

Methods: We retrospectively reviewed patients who were eligible for either fusion or AKA after PJI TKA. Thirty-seven patients underwent a fusion for PJIs after TKA between 1999 and 2010. Nine patients died postoperatively and eight patients were lost to followup, leaving 20 patients. Patients completed a specialized questionnaire about their fusion, and functional capability was assessed by the SF-12. We compared fusions to a previously published group of six patients who underwent AKA for recurrent PJI after TKA.

Results: For patients with fusion, community ambulators increased from five to 10 and nonambulators decreased from three to one. For patients with AKA, nonambulatory patients increased from zero to two, and community ambulators decreased from four to one. The SF-12 physical component summary measurements were higher for fusions (51) than for AKAs (26). The mental component summary was also higher in fusions (60) than in AKAs (44). Seventy percent of patients indicated they would undergo a fusion again instead of undergoing an amputation if they were presented with both options after undergoing their operation.

Conclusions: Patients receiving knee fusions for treating recurrent PJIs after TKA have better function and ambulatory status compared to patients receiving AKA.

Level of evidence: Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Fig. 1

A flowchart illustrates the study design for patients undergoing fusion versus AKA for treatment of PJI after TKA.

Fig. 2

A graph shows ambulatory status for patients receiving fusion or AKA before and after surgery. Patients were stratified according to their ability to ambulate outside of the home (community ambulator), ambulate only within the home (household ambulator), or not ambulate (nonambulator). For patients with fusion, community ambulators increased from five to 10 and nonambulators decreased from three to one. For patients with AKA, nonambulatory patients increased from zero to two, and community ambulators decreased from four to one. Preop = preoperative; Postop = postoperative.

Fig. 3

A graph compares SF-12 PCS and MCS scores between patients receiving fusion and those receiving AKA. Both the PCS and MCS measurements were higher (p < 0.001) for fusions than for AKAs.