Spatial Distribution of Biomechanical Characteristics for Trabecular Bone in the Femoral Head with Osteonecrosis / 医用生物力学

Objective To explore the spatial distribution of microstructural parameters and mechanical properties for trabecular bone in the femoral head with osteonecrosis. Methods Microstructural parameters and mechanical properties of trabecular bone in different regions were analyzed by combined use of imaging measurements and numerical simulation method, and the spatial distribution of biomechanical properties for trabecular bone along coronal, sagittal and vertical directions was investigated. Results Microstructural characteristics and mechanical properties of trabecular bone were Y-shaped distributed along coronal and sagittal directions, and mechanical properties of trabecular bone in Y-shaped region were higher than those in the other regions. Such distribution characteristics was consistent with the location of principle compressive group in the femoral head. Conclusions Necrotic lesions in Y-shaped region had a greater influence on stress distribution of the femoral head and might cause the deterioration of osteonecrosis. The spacial correlation between necrotic lesions and Y-shaped region should be fully considered during clinical diagnosis.

Preclinical Study of Cell Therapy for Osteonecrosis of the Femoral Head with Allogenic Peripheral Blood-Derived Mesenchymal Stem Cells

PURPOSE: To explore the value of transplanting peripheral blood-derived mesenchymal stem cells from allogenic rabbits (rPBMSCs) to treat osteonecrosis of the femoral head (ONFH). MATERIALS AND METHODS: rPBMSCs were separated/cultured from peripheral blood after granulocyte colony-stimulating factor mobilization. Afterwards, mobilized rPBMSCs from a second passage labeled with PKH26 were transplanted into rabbit ONFH models, which were established by liquid nitrogen freezing, to observe the effect of rPBMSCs on ONFH repair. Then, the mRNA expressions of BMP-2 and PPAR-γ in the femoral head were assessed by RT-PCR. RESULTS: After mobilization, the cultured rPBMSCs expressed mesenchymal markers of CD90, CD44, CD29, and CD105, but failed to express CD45, CD14, and CD34. The colony forming efficiency of mobilized rPBMSCs ranged from 2.8 to 10.8 per million peripheral mononuclear cells. After local transplantation, survival of the engrafted cells reached at least 8 weeks. Therein, BMP-2 was up-regulated, while PPAR-γ mRNA was down-regulated. Additionally, bone density and bone trabeculae tended to increase gradually. CONCLUSION: We confirmed that local transplantation of rPBMSCs benefits ONFH treatment and that the beneficial effects are related to the up-regulation of BMP-2 expression and the down-regulation of PPAR-γ expression.

Correlation study on biomechanics of three-foot weight bearing canine model with femoral head osteonecrosis / 医用生物力学

Objective To study changes in biomechanical characteristics of the femoral head during the progression of avascular osteonecrosis and investigate the mechanism of these biomechanical changes. Methods Twenty-four three-foot weight bearing canine models with osteonecrosis of the femoral head (ONFH) were established by fixing one fore limb of the canine. Osteonecrosis was induced in all experimental animals by randomly injecting 5 mL pure ethanol into one side of the femoral head, and the contralateral femoral head was injected with an equal amount of normal saline as the control group. The canines were killed at 1st, 3rd, 6th, and 12th week after the injection of ethanol, with six canines in each group. The radiographic, histological changes and biomechanical characteristics of the femoral head were observed and analyzed. Results At 3rd week, 29% reduction of indentation stiffness and 32.9% reduction of elastic modulus in the cancellous bone were found in the infected femoral heads compared to the control heads, and a low density area was detected only in MRI and osteonecrosis was the main histological characteristics. At 6th and 12th week, the indentation stiffness in the infected femoral heads was reduced by 45.5% and 48.7%, respectively, and the elastic modulus of the cancellous bone in the infected femoral heads was reduced by 34.1% and 32.4%, respectively, compared to the control heads. At 6th week, uneven bone density of the femoral head was detected in radiographs, and the progression of osteonecrosis and bone healing was found at the same time. At 12th week, areas of reduced bone mineral density beneath the load bearing position of the femoral head were observed on radiographs. Collapse of the articular cartilage surface and narrowing of the joint space were the main histological findings. Conclusions Biomechanics is an important factor in the progression of ONFH. The decreased mechanical properties may be a direct reason leading to the late collapse of the femoral head. The treatment of ONFH should focus not only on acceleration of the bone healing, but also on provision of a favorable and stable biomechanical environment for the infected femoral head.

Long-term follow-up of osteonecrosis of the femoral head with repair and reconstruction / 中国矫形外科杂志

[Objective]To evaluated the clinical results of treatment of osteoneerosis of the femoral head(ONFH)with repair and reconstruction through long-term follow-up.[Methods]A total of 313 patients(382 hips)operated on from November 1986-March 1997 who had a mean age of 36.4 years(range,18～65 years)were reviewed retrospectively.The hips were 151 Ficat and Arlet stage Ⅱ,142 stage Ⅲ,89 stage Ⅳ.All patients were followed up for a mean of 12.1yrs(range,10～20 yrs) and were assessed clinically and radiologically according to Harris scoring and variation of Ficat stage respectively.The patients were analyzed by the Kaplan-Meier method with replacement for any reason as the end-point.[Results]Ninteen hips underwent total hip replacement postoperatively.Preoperative and postoperative Harris score were 56.2 and 85.8.Clinical success rate was 85.6%and radiological success rate was 75.4%.Kaplan-Meier survivorship curves showed there was a lower long-term survival on stage-IV、abuse of hormone alcolutic indulger and above 55 years old patients.[Conclusion]The long-term efficacy is satisfactory to be confirmed by repair and reconstruction in treatment of osteonecrosis of the femoral head.This procedure will improve the curative effect of preserving head treatment of ONFH and early-middle clinical results being satisfied.

Advanced alcoholic osteonecrosis of femoral head / 中国矫形外科杂志

[Objective]To discuss the relation-ship between AAONFH(advanced alcoholic osteonecrosis of femoral head)and extended overdose drinking.[Method]Reviewed 165 cases of total hip arthroplasty,to analyzed the clinical data among 27 AAONFH cases,reviewed the literatures,discussed the pathogenesis of AAONFH and the relation-ship between blood biochemistry and blood cloting funtion and compared the experimental results among literatures.[Result]Theres various factors resulted in osteonecrosis of the femoral head associated with alcohol long-term over intake.Individuals consuming more than 750 ml of alcohol daily were at greater risk of double or half ONFH,Theres no change in biochemical test,but blood clotting funtion in this case would degrade,osteoarthritis of hip would synchronize.[Conclusion]Individuals consuming more than 750 ml of alcohol daily have the potentiality of ONFH;Its no specificity significance in biochemical test,the necrosis extent of the femoral head is relative to the capacity and times of alcohol intake.THR(total hip replacement)is the best treatment for AAONFH,but theres more staxis potentiality in this cases.

Extension of Necrotic Area by Recurrent Ischemic Episodes in Osteonecrosis of the Femoral Head: A Report of Three Cases / 대한정형외과학회잡지

We describe three cases of osteonecrosis of the femoral head (ONFH) in which the extent of necrosis increased after repeated episodes of ischemic attack. In all cases the evidence for two different ischemic attacks was clearly seen on MR images. The significance of the recurrent ischemic attacks is not clear yet but the detectable incidence of recurrence seems to be very low. We discuss the possibility that the increased extent of osteonecrosis may be the result of multiple ischemic attacks.