MID-TERM RESULTS FOR THREE CONTEMPORARY TOTAL KNEE REPLACEMENT DESIGNS - A COMPARATIVE STUDY OF 104 PATIENTS WITH PRIMARY OSTEOARTHRITIS

Aims: The purpose of this study was to compare retrospectively the mid-term clinical and radiological results of three contemporary knee designs in cohorts operated on in the same hospital during the same time period. Materials and Methods: We evaluated mid-term clinical and radiographic outcome of three contemporary total knee designs (the AGC V2, the Duracon and the Nexgen) in 104 consecutive patients (129 knees) operate on for primary knee osteoarthritis at our hospital. The mean indexed age at the time of the operation was 69.2 years (range, 49.3 to 81.1 years). The mean follow-up time was 6.0 years (range, 0.2 to 7.9). All patients were followed for at least three years or until the first revision. In the survival analyses, the end point was defined as, revision for any reason. Results: The Kaplan-Meier survival analysis showed a 98% (95% CI 94-100) survival rate for the NexGen, a 98% (95% CI 93-100) for the AGC and a 90% (95% CI 81-99) for the Duracon design at six years. Both the mean KSS for pain, KSS for function and the mean clinical knee score improved significantly in all three groups. There was no difference between the three designs in mid-term survivorship. Conclusions: Most of the revisions could be directly linked to perioperative surgical errors. In conclusion, the most recently introduced knee replacements of the present study (Duracon and Nexgen) did not show any clinically significant benefit over the older design (AGC) in the mid-term.