Outcomes of Salvage Endoprostheses in Revision Total Knee Arthroplasty for Infection and Aseptic Loosening: Experience of a Specialist Centre.

BACKGROUND

We aimed to evaluate the clinical and radiographic outcomes of complex salvage knee revision arthroplasty (rTKA) using endoprostheses with segmental bone loss.

METHODS

A consecutive study of patients who underwent salvage distal femoral replacement (DFR) or proximal tibial replacement (PTR) with a minimum 2- year follow-up (2005-2018). Patients who had acute DFR for periprosthetic fractures were excluded. Clinical outcomes, complications, reoperations, revision for any cause, loosening and mortality data were collected. Knee Society Score (KSS) at final follow up was used as a patient-reported-outcome-measure.

RESULTS

Thirty three consecutive patients were included; average age 79.6 years (range 58-89); 15 males/18 females. All had AORI-III massive bone defects and were reconstructed using DFRs; 6 patients had concurrent PTRs. The indication for salvage rTKA was infection in 16/33 (48.5%) and aseptic-loosening in the remaining 17 patients (51.5%). Complications rate was 12.1%; two patients had significant extensor lag; 1 patella dislocation and one recurrent infection. Median follow-up was 5 years (range 2-15) with median arc of flexion- extension of 100° (range 60-120). KSS was available for 29/33 patients with an average of 73.2 (range 51-86). Patients with infection as their indication had poorer KSS scores (66.1 vs. 81.6; P < 0.0001). Eleven patients have died at median 4 years postoperatively (range 2-7) for unrelated causes, none of the components have been revised to date with overall 80% patients' survivorship at 5 years.

CONCLUSIONS

The use of endoprostheses in salvage knee arthroplasty led to satisfactory medium-term clinical outcomes with an acceptable complication rate for this challenging group of patients with poorer functional scores for infection compared to aseptic loosening.

LEVEL OF EVIDENCE

Level IV.