Ceramic-on-ceramic vs ceramic-on-polyethylene, a comparative study with 10-year follow-up

Table 1 Baseline characteristics and operation information

	CoPE, n = 27 (100%)	CoC, n = 34 (100%)	P value
Female gender, n (%)	21 (78%)	22 (65%)	0.27
Right side, n (%)	19 (76%)	17 (50%)	0.11
Diagnosis, n (%)			0.01
Primary OA	23 (85%)	19 (56%)
Other	4 (15%)	15 (44%)
Age, in years, mean (SD)	64.2 (5.3)	55.7 (8.5)	< 0.001
BMI, in kg/m2 mean (SD)	27.6 (4.1)	26.9 (4.1)	0.52
Cup size in mm, mean (SD)	52.1 (3.4)	53.6 (3.5)	0.10
Inclination cup in degrees, mean (SD)	46.8 (6.7)	44.6 (5.0)	0.22
HHS, mean (SD)	50.2 (13.3)	47.5 (13.4)	0.44

BMI: Body mass index; CoPE: Ceramic-on-polyethylene; CoC: Ceramic-on-ceramic; HHS: Harris hip score; OA: Osteoarthritis; SD: Standard deviation.

Table 2 Potential predictive values for polyethylene wear in beta-coefficient (range)

Potential predictive factors for PE wear	Beta-coefficient (95%CI)	P value
Gender	0.06 (-1.18; 1.29)	0.93
Age	-0.01 (-0.10; 0.08)	0.82
Operation side	-0.40 (-1.53; 0.73)	0.46
BMI	-0.05 (-0.20; 0.10)	0.46
Diagnosis, primary OA vs other	1.10 (-0.42; 2.61)	0.14
Cup size	-0.06 (-0.23; 0.12)	0.52
Cup inclination	0.08 (0.02; 0.15)	0.02

BMI: Body mass index; CI: Confidence interval; OA: Osteoarthritis; PE: Polyethylene.

Table 3 Radiological findings in DeLee and Charnley zones I, II and III at 10-yr

	CoPE, n = 17			CoC, n = 25
Zones	I	II	III	I	II	III
Radiolucent lines	0	0	0	0	0	0
Osteolysis cup	0	1 (6%)	0	2 (8%)	3 (12%)	0
Atrophy	2 (12%)	3 (18%)	0	5 (19%)	5 (19%)	0
Hypertrophy	0	0	0	0	0	0

CoPE: Ceramic-on-polyethylene; CoC: Ceramic-on-ceramic.