The trabecular heterogeneity of femoral head in male osteoporotic fracture

Objective: The aim of this study was to investigate the femoral head trabecular heterogeneity in Chinese male patients with osteoporotic fracture and their effects on osteoporotic fracture. Methods: Human femoral heads were obtained from 11 male osteoporotic fracture (OP) patients ranged from 51 to 82 years old [average age (65±9) years old], and 7 male trauma (TM) patients ranged from 46 to 75 years old [average age (61±11) years old] who underwent total hip arthroplasty within two hours after either osteoporotie or trauma hip fracture. The OP was defined as having a fragility fracture. After laying femoral head as living body position and locating mark, nine trabecular specimens were obtained from femoral heads, each of 6 mm x 6 mm x 7 mm. The cortical shell was not included in each specimen. One cube was selected as the primary compressive trabecular region and the other 8 specimens as non-primary compressive trabecular region. These cubes were scanned using high-resolution microcomputed tomography scanner (μCT). After scanning, the data of total cubes, primary compressive trabecular region and non- compressive trabecular region were used for analysis by t test. Results: In OP group volumetric bone mineral density(vBmD) [(182.15 ± 66.00) mg/mm3 vs (223.97±70.92) mg/mm3, t=3.041], tissue bone mineral density (tBMD) [(538.76±64.72) mg/mm3 vs (580.01±63.86) mg/mm3, t=3.160], bone volume fraction (TV/BV) [(0.22±0.06)% vs (0.26±0.07)%, t=2.821], trabecular thickness (Tb. Th.) [(161.07±42.75) μm vs (205.47±74.44) μm, t=3.233] were significantly decreased while bone surface/bone volume (BS/BV) [(13.75±2.55) mm-1 vs (12.28±2.70) mm-1, t= -2.777] was significantly increased in the non-primary compressive trabecular region than that in the primary compressive trabecular region (P<0.05). vBMD [(182.15±66.00) mg/mm3 vs (248.05± 105.48) mg/mm3 t=-3.598] tBMD [(538.76±64.72) mg/mm3 vs (570.54±100.32) mg/mm3 t=-2.108], TV/BV [(0.22±0.06)% vs (0.28±0.12)%, t=-3.466], Th. Th. [(161.07± 42.75) μm vs (200.31±96.63) μm, t=-2.866], trabecular number (Tb. N.) [(1.46±0.23)/mm3 vs (1.57±0.29)/mm3, t=-2.396] were significantly decreased while trabeeular separation (Tb. Sp.) [(780.82±144.85) μm vs (653.09±119.64) μm, t=5.470], degree of anisotropy (DA) (1.57± 0.20 vs 1.47±0.18, t=2.930) were significantly increased in OP than in TM in the non-compressive trabecular region (P<0.05). No significant differents were found between OP and TM for any of the parameters measured in the primary compressive trabeeular region. Tb. Th. [(199.37±68.22) μm vs (176.33±71.21) μm, t=2.060, P<0.05] were significantly increased in the primary compressive trabecular region than that in the non-primary compressive trabecular region and no significant differences were found in the other parameters in the all 18 specimens. Conclusions: The femoral head trabecular had a heterogenic distribution in OP. Bone loss in OP primarily takes place in non-compressive trabeeular region. Femoral neck fracture cannot be prevented though the bone microstructure do not loss in the primary compressive trabecular region. Tb. Th. in the femoral head could be an interesting parameter which is closely related to the femoral neck fracture. (authors)