Abstract
Introduction
Many prosthetic design changes have been introduced in attempt to improve outcomes following TKA; however there is no consensus as to whether these changes confer benefits to patients. This study aimed to assess whether patients treated with a modern implant design had an enhanced patient outcome compared to a traditional model in a double blind randomised controlled trial.
Methods
212 consecutive patients were prospectively randomised to receive either a modern (Triathlon) or a traditional (Kinemax) TKA (both Stryker Orthopaedics). 6 surgeons at a single unit performed all procedures in a standardised manner. A single researcher, blinded to implant allocation, performed all assessments. Patients were assessed pre-operatively, and at 6, 26, 52 weeks post-surgery with the Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, goniometry, timed functional assessment, lower limb power (Leg Extensor Power Rig) and pain numerical rating scales (NRS). Change in scores and between group differences were assessed with Two-Way Repeated Measures ANOVAs.
Results
Both groups benefited from TKA demonstrating significant improvement in all parameters (p = < 0.001 in all cases). Significant interaction of the implant was observed in 1 year change score of OKS (F = 4.28, p = 0.04), knee flexion (F = 8.42, p = 0.004), lower limb power output (F = 11.33, p = 0.001) and maximal pain report (F = 7.44, p = 0.001), the modern implant superior in each case. Larger change scores were observed in WOMAC and timed functional assessments, but were not statistically significant.
Conclusions
In a large prospective double blind randomised controlled trial, patients receiving a modern implant design demonstrated a significantly enhanced patient outcome in terms of knee range of motion, lower limb power output, reduced maximal pain report, and a clinically meaningful reduction in the OKS compared to a traditional design.
