Comparison of patient reported outcomes after Triathlon(®) and Kinemax Plus prostheses

INTRODUCTION: The Triathlon(®) (Stryker, Kalamazoo, MI, US) total knee replacement was designed to improve patient function and survivorship. The aim of this study was to determine whether the Triathlon(®) prosthesis produces better patient reported outcomes than a previous design by the same manufacturer, the Kinemax Plus. METHODS: The outcome of 233 knees of patients with a mean age of 68 years (range: 40–80 years) who received the Kinemax Plus prosthesis were compared with the outcomes of 220 knees of patients with a mean age of 70 years (range: 42–90 years) who received the Triathlon(®) prosthesis. Data were collected via postal questionnaire prior to surgery as well as at 8–12 weeks and at 1 year following surgery. Validated questionnaires were used including the WOMAC(®) (Western Ontario and McMaster Universities) pain and function scales, the Knee injury and Osteoarthritis Outcome Score quality of life scale and the self-administered patient satisfaction scale. RESULTS: This study found that patients who had the Triathlon(®) prosthesis had significantly better pain relief (p<0.0001), function (p=0.028), knee related quality of life (p<0.0001) and satisfaction (p=0.0003) at three months after surgery than those who received the Kinemax Plus prosthesis. In addition, knee related quality of life (p=0.002) and satisfaction (p=0.021) were significantly higher at one year after surgery in Triathlon(®) patients. CONCLUSIONS: The findings suggest that return to function and reduction in pain may occur more quickly in patients with a Triathlon(®) prosthesis than in those with the Kinemax Plus.