Early outcomes using a 'kinematic retaining' total knee replacement - A multicentre prospective study at two years follow-up.

BACKGROUND Although predictable implant longevity in total knee replacement (TKR) is now established, work continues to satisfy the demands of patients who seek full restoration of the painless function of the native knee following TKR. This prospective study examines the early clinical outcomes of 156 patients implanted with a novel 'kinematic-retaining' (KR) implant. METHODS 156 Physica KR TKRs were implanted for primary osteoarthritis at three European centres. Patients were reviewed up to two years using radiographic, clinical and functional evaluations. RESULTS Of the 137 patients retained at two years' follow up, none had been revised. Within 6 post-operative months, 51.7% and 79.9% had excellent clinical and functional KSS values respectively, increasing to 81.8% and 88.3% beyond two years. Mean KSS improvement was 34.8 (from 48.6 to 83.4). All KOOS sub-scores improved significantly with total KOOS improving from a mean of 35.5 (SD ±13.0) to 86.5 (±13.7) at two years post-operatively. Pain and sports KOOS sub-scores improved rapidly during the early post-operative periods, with sustained improvements beyond this. Mean OKS improved by 44.1 (±5.1) at two years. VAS satisfaction scores improved significantly at all time points beyond six weeks. Mean FJS-12 was 75.7 at two years, with no significant effects of age or gender. No progressive adverse radiographic features were noted. CONCLUSIONS Early clinical and radiographic outcomes of this kinematic-retaining knee prosthesis are promising, with improvements in clinical parameters similar to, or exceeding those published in other contemporary TKR designs. LEVEL OF EVIDENCE II, Multicentre Prospective cohort study.