TABLE V.

The Mean Change in External Rotation with Varying Neck Lengths and According to Hip Position^*

THA Compared with Intact			THA Compared with THA
Neck Length and Hip Position	Difference† (deg)	P Value‡	Comparison	Difference† (deg)	P Value‡
Extension-abduction
0 mm	15 ± 10	0.008§	0 > +5 mm	4 ± 6	0.243
+5 mm	11 ± 11	0.063	0 > +10 mm	10 ± 5	0.001§
+10 mm	4 ± 8	0.678	+5 > +10 mm	7 ± 5	0.015§
Standing
0 mm	13 ± 9	0.007§	0 > +5 mm	6 ± 5	0.014§
+5 mm	6 ± 8	0.124	0 > +10 mm	14 ± 12	0.018§
+10 mm	−1 ± 9	1.000	+5 > +10 mm	8 ± 10	0.131
Heel strike
0 mm	6 ± 5	0.028§	0 > +5 mm	11 ± 4	<0.001§
+5 mm	−5 ± 5	0.061	0 > +10 mm	23 ± 5	<0.001§
+10 mm	−17 ± 7	<0.001§	+5 > +10 mm	13 ± 6	0.001§
Sitting
0 mm	5 ± 13	1.000	0 > +5 mm	9 ± 3	<0.001§
+5 mm	−4 ± 15	1.000	0 > +10 mm	18 ± 5	<0.001§
+10 mm	−13 ± 15	0.091	+5 > +10 mm	9 ± 3	<0.001§
Flexion-adduction
0 mm	4 ± 13	1.000	0 > +5 mm	7 ± 3	<0.001§
+5 mm	−4 ± 16	1.000	0 > +10 mm	17 ± 4	<0.001§
+10 mm	−13 ± 16	0.112	+5 > +10 mm	10 ± 3	<0.001§

^*The effects depended on the hip position (p = 0.004): for THA compared with intact, positive values indicate the hip was hypermobile after THA, while negative values imply nonphysiological restriction. For THA-THA comparisons, the greater-than symbol (>) indicates which head size had the greater range of external rotation.

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

^‡T test.

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