Table 4.

Summary of UHMWPE particle concentration, size and shape in TDR and THA.

Implant number	Tissue weight (gram)	Number of particles (×109/gram)	Particles per year (×109/gram/yr)	ECD mean ± sem, median	Aspect ratio mean ± sem, median	Roundness mean ± sem, median
TDR
Maa003	0.0267	1.794	0.287	0.481 ± 0.004, 0.376	2.062 ± 0.011, 1.864	0.536 ± 0.002, 0.536
Maa009	0.0238	1.488	0.146	0.476 ± 0.007, 0.360	1.870 ± 0.013, 1.709	0.579 ± 0.003, 0.585
Maa010	0.0223	1.990	0.235	0.334 ± 0.012, 0.266	1.848 ± 0.024, 1.652	0.590 ± 0.006, 0.605
Maa013	0.0224	1.523	0.119	0.633 ± 0.007, 0.521	1.859 ± 0.011, 1.670	0.585 ± 0.003, 0.599
Maa018	0.0207	1.308	0.124	0.396 ± 0.009, 0.299	1.809 ± 0.018, 1.647	0.601 ± 0.004, 0.607
Mean ± sem		1.621 ± 0.121	0.182 ± 0.034	0.464 ± 0.050	1.890 ± 0.044	0.578 ± 0.011
THA
CWH002	0.0252	2.262	0.173	0.618 ± 0.009, 0.376	1.903 ± 0.009, 1.736	0.570 ± 0.002, 0.576
RIH120	0.0246	2.481	0.159	0.701 ± 0.004, 0.564	2.002 ± 0.007, 1.791	0.552 ± 0.001, 0.558
RIH426	0.0240	3.237	0.294	0.468 ± 0.002, 0.399	1.785 ± 0.005, 1.678	0.594 ± 0.001, 0.596
RIH134	0.0263	1.798	0.127	0.407 ± 0.005, 0.307	2.039 ± 0.015, 1.791	0.553 ± 0.003, 0.558
RIH369	0.0246	1.881	0.145	0.454 ± 0.011, 0.344	2.207 ± 0.037, 1.810	0.551 ± 0.006, 0.555
Mean ± sem		2.332 ± 0.258	0.180 ± 0.030	0.529 ± 0.055	1.987 ± 0.070	0.564 ± 0.008
p-values		0.03	0.60	0.60	0.35	0.35

Abbreviations: ECD, equivalent circular diameter; sem, standard error of the mean.