Mean bulk lubricant temperature ±95% confidence limits under elevated temperature conditions, data associated with 'Wear and Friction of UHMWPE-on-PEEK-OPTIMA' paper. Plate Material Protein concentration in lubricant (%) Mean bulk lubricant temperature (°C) CoCr 0 35.3 ± 1.7 PEEK Optima 0 35.7 ± 1.2 CoCr 5 35.4 ± 0.3 PEEK Optima 5 36.2 ± 0.6 CoCr 25 37.2 ± 3.1 PEEK Optima 25 37.0 ± 1.6 CoCr 90 35.4 ± 0.5 PEEK Optima 90 36.2 ± 0.4