TABLE I.

Summary of Micro-CT Data for Tibial Tunnels of the Three Groups^*

	Immobilized	Immediate Loading	Delayed Loading
Tissue mineral density† (mg/mL)
Entire tunnel (new bone)	571.0 ± 3.6	589.7 ± 14.8‡	586.5 ± 12.7‡
Entire tunnel (total bone)	819.4 ± 26.8	827.0 ± 17.2	837.9 ± 29.2
Extra-articular aperture	784.9 ± 26.4	778.4 ± 32.6	813.0 ± 24.9‡§
Mid-tunnel	794.7 ± 32.7	776.3 ± 35.0	792.0 ± 45.8
Intra-articular aperture	837.3 ± 65.6	845.4 ± 45.9	852.6 ± 52.8
Bone volume/total volume (total bone)
Entire tunnel	0.24 ± 0.03	0.20 ± 0.05	0.23 ± 0.06
Extra-articular aperture	0.18 ± 0.06	0.22 ± 0.26	0.15 ± 0.08
Mid-tunnel	0.15 ± 0.07	0.13 ± 0.07	0.10 ± 0.06
Intra-articular aperture	0.27 ± 0.12	0.24 ± 0.07	0.21 ± 0.10
Bone volume/total volume (new bone only)
Entire tunnel	0.13 ± 0.02	0.11 ± 0.02	0.12 ± 0.03
Extra-articular aperture	0.069 ± 0.020	0.057 ± 0.022	0.069 ± 0.031
Mid-tunnel	0.069 ± 0.030	0.057 ± 0.023	0.066 ± 0.027
Intra-articular aperture	0.090 ± 0.030	0.071 ± 0.025	0.079 ± 0.021
Trabecular number (avg./mm)
Extra-articular aperture	2.67 ± 0.47	2.49 ± 0.48	2.95 ± 1.20
Mid-tunnel	3.07 ± 0.65	2.47 ± 0.60	2.88 ± 0.80
Intra-articular aperture	3.62 ± 0.78	3.16 ± 1.15	3.19 ± 1.11
Trabecular thickness (μm)
Extra-articular aperture	99.0 ± 21.8	83.8 ± 16.0	99.5 ± 24.0
Mid-tunnel	106.5 ± 23.0	72.6 ± 10.6#	89.7 ± 21.6
Intra-articular aperture	143.8 ± 27.9	120.6 ± 25.4	127.8 ± 27.9

^*The values are given as the mean and standard deviation.

^†New bone was defined as the bone voxel threshold limit of 300 to 400. Total bone was defined as the bone voxel threshold limit of 300 to 1000.

^‡Significantly different from immobilized group (p < 0.05).

^§Significantly different from immediate-loading group (p < 0.05).

^#Significantly different from immobilized group (p < 0.01).