O2454 EUROPEAN MULTICENTRE PROSPECTIVE STUDY OF 287 “NATURAL™” PRIMARY TOTAL KNEE REPLACEMENTS

Abstract

Purpose of the study: The Natural Knee (NK) SystemTM for cementless þxation, has been developed by A. Hofmann in the USA since 1988: aim of this study was to provide early results of this implant prospectively performed by a multicentre group of European surgeons. Material and Methods: Over a 2.6year period, 287 NKñs were implanted in 283 patients by 8 orthopaedic teams in 4 european countries. Mean age and body mass index was 69 years (35–91) and 29 (16–41), repectively. Diagnosis was primary arthrosis (87%), rheumatoid (9%) and post-traumatic arthritis (4%), with previous in 30%. Approach was sub-vastus in 58% and medial-patellar in 42%. Posterior cruciate ligament (PCL) was preserved in 94% of knees and patella was resurfaced in 56%: Cemented/ cementless þxation ratios were; femur, 14/86%; tibia, 24/76%; patella (160 resurfaced), 43/57%. 75.3% of knees were all cementfree. Lateral release was performed in 20% of knees. Regularly monitored clinical and radiographic follow-up data were prospectively collected with use of a FDA-Approved form with computer centralization for statistical analysis. Results: 275 knees (96% of index cohort) were clinically reviewed at 60 month average follow-up (range, 26–95 months). Radiographically (268 knees), aseptic loosening has been observed in 2 cementless TKAñs (0.7%). At 7 years, survivorship of the index group of 287 NKñs with reoperation for any cause (7 knees) and revision for aseptic loosening (2 knees) as end points was 95.7% and 97.65%, respectively. Conclusion: In non-originators orthopaedists hands, the Natural Knee system TM has provided thus far general satisfying early results as normally expected in primary TKR with such modern modular prosthesis.