The Research On The Difference Of Bone Quality Of The Femoral Head And Biochemical Indicators Between No-traumatic Osteonecrosis And Assaultive Fractures Patients

OBJECTIVE:To research on the differences of the bone quality in the femoral head and bone metabolism between no-traumatic osteonecrosis and assaultive fractures patients and find the change characteristics of the no-traumatic osteonecrosis in the development process.METHODS:Human femoral heads were obtained from 97 assaultive fractures patients with the femoral neck fracture (n=20, mean age 60.5±11.1 years, male:9, female: 11, male:female= 1:1.2) and non-traumatic femoral head necrosis (n=77, mean age 56.6±12.4 years, male:41, female:36, male:female= 1.1:1). The femoral head was collected in two hours after hip replacement. After laying femoral head as living body position and locating primary loading region as the mark, nine trabecular specimens, each of 6×6|×7mm3, were obtained from which were orientated along the vertical plane of the primary compressive in the maximum diameter of femoral heads. The cortical shell was not included in each specimen. The DXA, microCT, ash weight, demineralization, mechanical experiments and form measurement were performed to obtain parameters as bone mass, micro-structural parameters, inorganic and organic parameters and biomechanical parameters. The differences in bone mass and bone quality of osteoporosis group and the necrosis group were analyzed for the bone mechanical strength and morphology differences between the two different diseases. The serum samples and urine specimen of 31 cases were obtained from assaultive fractures patients while the serum samples and urine specimen of 105 cases were obtained from nontraumatic osteonecrosis patients, then the biochemical indicators of bone turnover were measured and the differences about the two kind of diseases were analyzed.RESULTS:Compared with the nontraumatic osteonecrosis group, in the assaultive fractures group there was significantly lower in bone trabeculae thickness(0.14±0.06 VS 0.12±0.03μm), trabecular separation (0.38±0.29VS 0.27±0.20μm), bone volume fraction (0.28±0.10VS 0.25±0.05%), percentage of ash content (40.11±8.37 VS 35.74±6.50 %), elastic stress (7.75±5.29VS 5.96±2.79 N/mm2), elastic modulus (243.44±158.82 VS 176.51±78.93 N/mm2),maximum stress (10.25±6.61 VS 7.53±3.29 N/mm2),microcrack surface density in unfatigue test specimen (7.04±4.86 VS 4.64±2.41μm/%), microcrack surface density in fatigue test specimen (6.41±4.05 VS 4.00±1.01μm/%) (p≤0.05), while the bone area density ((21.42±10.08 VS 26.48±8.01 mm-1), volumetric organic content (0.44±0.10 VS 0.50±0.10 mg/mm3), percentage of organic content (59.89±8.37 VS 64.27±6.50%), were significantly higher (p≤0.05).The statistically differences in change of tissue BMD, volumetric BMD, trabecular number, structure model index, degree of anisotropy, volumetric ash content, height after fatigue test and bone biochemical indicators were not significant.CONCLUSION:The mechanical properties and degree of mineralization of nontraumatic osteonecrosis group is above the assaultive fractures group, and the bone trabeculae thickness increases in nontraumatic osteonecrosis group.