TABLE II.

The Mean Change in Internal Rotation with Various Head Sizes^*

THA Compared with Intact			THA Compared with THA
Head Size	Difference† (deg)	P Value‡	Comparison	Difference† (deg)	P Value‡
28 mm	39 ± 23	0.003§	28 > 32 mm	6 ± 6	0.053
32 mm	33 ± 19	0.002§	28 > 36 mm	8 ± 9	0.074
36 mm	32 ± 16	0.001§	32 > 36 mm	2 ± 7	1.000

^*Data are given as the average across all hip positions (main effect). No interaction was detected (p = 0.199); rather, there was a small effect of head size across all hip positions (p < 0.001). For THA compared with intact, positive values indicate the hip was hypermobile after THA. For THA-THA comparisons, the greater-than symbol (>) indicates which head size had the greater range of internal rotation.

^†The values are given as the mean and the 95% confidence interval.

^‡T test.

^§The difference was significant (p < 0.05).