The aims of this study were to evaluate wear on the surface of cobalt-chromium (CoCr) femoral components used in total knee arthroplasty (TKA) and compare the wear of these components with that of ceramic femoral components. Optical profilometry was used to evaluate surface roughness and to examine the features created by the wear process in a knee wear simulator. We developed a method of measuring surface changes on five CoCr femoral components and quantifying the loss of material from the articular surface during the wear process. We also examined the articular surface of three ceramic femoral components from a previous test for evidence of surface damage, and compared it with that of CoCr components.Aims
Methods
Total knee arthroplasty (TKA) is an established
and successful procedure. However, the design of prostheses continues
to be modified in an attempt to optimise the functional outcome
of the patient. The aim of this study was to determine if patient outcome after
TKA was influenced by the design of the prosthesis used. A total of 212 patients (mean age 69; 43 to 92; 131 female (62%),
81 male (32%)) were enrolled in a single centre double-blind trial
and randomised to receive either a Kinemax (group 1) or a Triathlon
(group 2) TKA. Patients were assessed pre-operatively, at six weeks, six months,
one year and three years after surgery. The outcome assessments
used were the Oxford Knee Score; range of movement; pain numerical
rating scales; lower limb power output; timed functional assessment
battery and a satisfaction survey. Data were assessed incorporating
change over all assessment time points, using repeated measures
analysis of variance longitudinal mixed models. Implant group 2
showed a significantly greater range of movement (p = 0.009), greater
lower limb power output (p = 0.026) and reduced report of ‘worst
daily pain’ (p = 0.003) over the three years of follow-up. Differences
in Oxford Knee Score (p = 0.09), report of ‘average daily pain’
(p = 0.57) and timed functional performance tasks (p = 0.23) did
not reach statistical significance. Satisfaction with outcome was
significantly better in group 2 (p = 0.001). These results suggest that patient outcome after TKA can be influenced
by the prosthesis used. Cite this article:
