Five-year survivorship and patient-reported outcome of the Triathlon single-radius total knee arthroplasty

Purpose: The Triathlon single-radius total knee arthroplasty (TKA) was used in 11 % of primary procedures in England and Wales in 2011 making it the third most common prosthesis implanted. To date, there has been no independent report of survivorship or outcome for this implant. The aim of this study was to report the 5-year survival and patient-reported outcome of the Triathlon TKA in a single independent centre.

Methods: Four hundred and sixty-two consecutive Triathlon TKAs were implanted at the study centre from 2006 to 2007. The mean age was 68.7 (21–89) years, and 290 patients were women (62.7 %). The Short Form 12 and Oxford Knee Score (OKS) were obtained pre-operatively and at 1 and 5 years post-operatively when satisfaction was also assessed and radiographs reviewed.

Results: Forty-one had died and nine were lost to follow-up. There were three aseptic failures: two cases of tibial aseptic loosening and one of secondary instability. There were five additional septic failures. OKS improved by a mean of 17.4 points at 1 year from 41.3 pre-operatively (p < 0.001). This was unchanged at 5 years (n.s.). Patient satisfaction was high with 88 % being satisfied or very satisfied at 1 and 5 years. Kaplan–Meier analysis demonstrated a 5-year survival of 97.6 % (95 % CI 95.6–99.6) for failure for any reason, and 99.5 % (95 % CI 98.7–100) for aseptic loosening.

Conclusion: The Triathlon TKA offers good mid-term survivorship and functional outcome, which is reflected by a high patient satisfaction rate. Level of evidence: Therapeutic, Level IV.