Osseointegration study of porous nitinol versus titanium orthopaedic implants

The functionality of a new metallic interbody fusion implant manufactured out of porous nitinol (PNT) was evaluated in sheep and compared to a conventional titanium (TiAIV) intervertebral cage packed with autologous iliac crest bone. Both device types were implanted at two non-contiguous intervertebral lumbar sites. The objective was to evaluate the osseointegration capacity after 3, 6 and 12 months of implantation in the presence of these two implant types subjected to the same mechanical loads. Two-dimensional radiology, computer tomography and histology were used as techniques of parameter evaluation. The results indicated that PNT obtained a better intervertebral osseointegration capacity compared to the TiAlV cage. The functional difficulties of the titanium implant were related to its instability at the implantation site possibly due to a biofunctionality problem. The biocompatibility of both implants seemed comparable, however.     

多孔钽棒植入治疗股骨头坏死的适应证及临床疗效观察

目的探讨多孔钽棒植入治疗股骨头坏死的适应证并观察其临床疗效。方法2008年5月至2008年11月,治疗股骨头坏死患者25例29髋,男14例17髋,女11例12髋;年龄29—48岁,平均36岁;根据Steinberg分期：Ⅰ期10髋,Ⅱ期16髋,Ⅲ期3髋。采用侧方小切口入路,行髓心减压及多孔钽棒植入术。术后3周内禁止负重,3周后可部分负重,然后逐步过渡至完全负重。采用Harris评分系统评估术后患髋功能的改善情况;术后3、6、12个月摄正、侧位x线片,观察股骨头修复情况及有无坏死进展。结果23例27髋获得随访,随访时间12—18个月,平均15个月。术后12个月或末次随访进行疗效评估,优：17例19髋,良：4例5髋,可：2例3髋。患者的Harris评分由术前的49～83分,平均（65．3±8．6）分,提高至术后的75～100分,平均（88．2±9．3）分（P〈0．001）。Ⅰ期由术前70～83分,平均（73．7±5．6）分,提高至术后79～100分,平均（94．5±6．4）分;Ⅱ期由术前51～72分,平均（63．4±6．1）分,提高至术后76—99分,平均（87．1±9．0）分;Ⅲ期由术前49—65分,平均（56．8±7．3）分,提高至术后74—89分,平均（81．7±8．2）分。各组提高分数之间显著差异。髋关节影像学表现稳定,股骨头无坏死进展。结论髓心减压及多孔钽棒植入术治疗股骨头缺血性坏死适合于SteinbergⅠ、Ⅱ期及较小塌陷的Ⅲ期股骨头坏死患者。     

多孔涂层钽金属棒系统治疗早期非创伤性股骨头坏死的临床对比研究

目的对比分析保守治疗与髓芯减压多孔钽棒植入术治疗早期非创伤性股骨头坏死患者的短、中期疗效。 方法回顾性收集2012年6月至2017年1月青岛大学附属医院关节外科收治的60例股骨头坏死患者（80髋）。根据治疗方式的不同分为保守治疗组（保守组,30例40髋）与髓芯减压多孔钽棒植入术（钽棒组,30例40髋）。观察两组患者术后并发症及患肢功能、Harris评分、影像学分析内植物状态、绘制股骨头生存曲线。 结果保守组获得随访27例（36髋）,失访3例（4髋）,钽棒组获得随访20例（27髋）,失访10例（13髋）,平均随访时间为（26±6）个月（3~62个月）。两组Harris评分比较：保守组和钽棒组治疗前、治疗后12个月、末次随访进行重复测量设计的方差分析显示,两组间差异有统计学意义（F=3046.153,P<0.001）,组别与时间点间存在交互作用（F=5883.563,P<0.001）,各时间点除治疗前外,差异均有统计学意义;钽棒组各时间点间的差异有统计学意义（F=2563.841,P<0.001）。两组生存曲线比较,差异有统计学意义（Log rank=87.432,P<0.001）。 结论多孔涂层钽金属棒植入可获得较好的短、中期疗效,优于保守治疗。     

多孔钽金属棒治疗股骨头坏死的短期临床疗效

目的探讨多孔钽金属棒治疗股骨头坏死的短期临床疗效。方法从2008年8月至2009年12月,使用多孔钽金属棒植入治疗股骨头坏死26例共33髋,男14例18髋,女12例15髋。根据Steinberg分期：Ⅱ期15髋、Ⅲ期16髋和Ⅳ期2髋。术中经外侧小切口行髓芯减压,必要时在坏死腔中置入不规则颗粒人工骨,最后植入多孔钽金属棒。术后禁止负重4周后开始部分负重4周,随后逐渐过渡到完全负重。定期随访X线及Harris评分,评估术后患髋功能的改善情况。结果所有26例共33髋全部获得随访。平均随访24.2（20.0～30.5）个月。术后末次随访Harris评分为（85.7±7.9）分,较术前（65.9±10.1分）改善为19.8分（P〈0.05）。关节功能优11髋（33.3%）,良16髋（48.5%）,可4髋（12.1%）,差2髋（6.0%）。仅1髋术后2年出现关节面塌陷,余各假体位置良好,股骨头无进一步塌陷。结论多孔钽金属棒为股骨头坏死患者（Ⅲ期前及ⅢA期）提供了一种新的治疗选择。     

骨质疏松对卵巢切除大鼠骨折愈合影响的超微结构研究

目的 探讨骨质疏松对骨折愈合的影响。方法 选择8个月龄雌性SD大鼠24只,随机分为假手术组和卵巢切除骨质疏松组,每组12只,分别行假性手术和双侧卵巢切除术;3个月后,于股骨中部制造骨折模型,采用透射电镜对两组骨折后3、7、14、21、28和42d骨痂进行观察。结果 两组骨折愈合早期（21d前）参与修复细胞类型,超微结构变化及细胞功能状态几乎相同;术后28d,卵巢切除组钙化软骨骨痂仍未完全吸收和被新的纺织骨取代,可见大量坏死软骨细胞包埋于钙化的软骨基质中,此后,破骨细胞性骨吸收逐渐加剧,伴骨细胞发现肝溶解现象。结论 骨质疏松对卵巢切除大鼠骨折愈合影响主要发生在骨折愈合后期,表现为软骨内化骨迟缓,骨改建过程中破骨细胞性骨吸收增加;骨细胞性骨溶解现象加剧了这一骨吸收过程。     

切除家兔性腺对骨代谢的影响

本文选用家兔为实验模型，切除性腺后分成两组，即卵巢切除组１２只，睾丸切除组１２只，通过对钙、磷、碱性磷酸酶、尿羟脯氨酸及骨计量学、骨矿物质测定，分别观察术后４周、７周及１０周对骨质的影响。结果表明，卵巢切除后家兔骨质丢失明显增加，各指标与睾丸切除组比较有明显差异，说明卵巢功能障碍可导致骨质疏松，而睾丸功能障碍对骨质影响较小。     

A new mode of clinical failure of porous tantalum rod

The area of osteonecrosis of the head of femur affected by the disease process varies from a small localized lesion to a global lesion. Without specific treatment 80% of the clinically diagnosed cases will progress, and most will eventually require arthroplasty. Therefore the goal is to diagnose and treat the condition in the earliest stage. A number of surgical procedures have been described to retard or prevent progression of the disease and to preserve the femoral head. An implant made of porous tantalum has been developed to function as a structural graft to provide mechanical support to the subchondral plate of the necrotic femoral head, and possibly allow bone growth into the avascular region. Porous tantalum implant failure with associated radiological progression of the disease is reported in the literature; however, there is no report of clinical failure of the implant without radiological progression of the disease. We report a case of clinical failure of porous tantalum implant, seven months after surgery without any radiological progression of the disease, and with histopathological evidence of new bone formation around the porous tantalum implant. The patient was succesfully treated by total hip arthroplasty.     

Autologous osteoblasts enhance osseointegration of porous titanium implants.

The goal of this study was to assess the osseointegration of porous titanium implants by means of coating with autologous osteoblasts. Titanium implants (8 x 5 x 4 mm) having drill channels with diameters of 400, 500, and 600 microm were coated with autologous osteoblasts obtained from spongiosa chips. The implants were inserted into the distal femora of 17 adult Chinchilla Bastard rabbits (group I). Uncoated implants were inserted as controls in the contralateral femur (group II). The animals were sacrificed after 5, 11, and 42 days. Intravital fluorochrome labeling and microradiography were used for the assessment of bone ingrowth into the titanium channels. In both groups, no bone tissue was formed in the channels up to day 5. On day 11, group I exhibited significantly more (p<0.05) bone tissue (19.8+/-14.0% vs. 5.8+/-9.1%) with greater bone-implant contact (13.3+/-15.1% vs. 5.7+/-5.3%, p<0.05) at the channel mouths than group II. Bone tissue was formed mainly between day 15 and 30 in group I, in group II between day 25 and 40. Six weeks after implantation, bone tissue filled on an average 68.8+/-15.1% of the mouths of the drill channels in implants in group I, the filling for group II was 49.8+/-18.1% (p<0.05). The average bone-implant contact at the channel mouths after six weeks was 56.5+/-13.5% in group I, 40.2+/-21.9% in group II (p<0.05). 600-microm channels showed at this time point the best osseous integration (p<0.05). Coating with autologous osteoblasts accelerates and enhances the osseointegration of titanium implants and could be a successful biotechnology for future clinical applications.     

新型骨质疏松大鼠骨生物力学测试方法:股骨干骺端弯曲试验

 目的 建立一种新的骨生物力学测试方法用以评价去卵巢骨质疏松大鼠股骨干骺端生物力学的变化。方法 20只 5月龄雌性 SD大鼠随机分为去卵巢组和假手术组。术后 12周, 对全部大 鼠进行股骨骨密度和股骨远端骨组织计量学测定。所有大鼠取一侧股骨行中段三点弯曲试验, 另一侧 股骨行干骺端弯曲试验, 测定生物力学指标(最大载荷、屈服载荷、刚度)。对各生物力学指标和骨密度 及骨组织计量学指标行 Pearson相关分析。结果 去卵巢组股骨骨密度、骨组织计量学指标(骨小梁面 积百分比、骨小梁数量、骨小梁厚度)和生物力学参数(最大载荷、屈服载荷、刚度)较假手术组均明显降 低。在股骨干骺端弯曲试验中, 两组最大载荷和屈服载荷的差值明显大于三点弯曲试验所得的相应差值。 Pearson相关分析显示骨生物力学各参数与骨密度、骨组织计量学指标均呈正相关, 且股骨干骺端 弯曲试验的生物力学参数与骨密度、骨组织计量学指标的相关性明显强于股骨干三点弯曲试验。结论 建立了新型骨质疏松大鼠骨生物力学测试方法, 即股骨干骺端弯曲试验, 可用来评估去卵巢骨质疏松 大鼠股骨干骺端生物力学性能, 与股骨干三点弯曲试验相比, 其敏感度更高, 与骨密度和骨组织计量学 参数的相关性更强。     

Osseointegration of porous titanium implants with and without electrochemically deposited DCPD coating in an ovine model

Background

Alendronate (ALN) is the most common form of bisphosphonates used for the treatment of osteoporosis. Osteoprotegerin (OPG) has also been shown to reduce osteoporotic changes in both humans and experimental animals after systemic administration. The aim of this current study was to test if the anti-resorption effects of ALN may be enhanced when used in combination with OPG.

Objectives

To investigate the effects of ALN, OPG or combined on bone mass and bone mechanical properties in ovariectomized (OVX) rats.

Methods

OVX rats were treated with ALN, OPG-Fc, or OPG-Fc and ALN. Biochemical markers, trabecular bone mass, biomechanics, histomorphometry and RANKL expression in the bone tissues were examined following the treatments.

Results

The treatment of ALN, OPG-Fc and ALN+OPG-Fc all prevented bone loss in the OVX-rats, there was no statistical difference among the three treatment groups in terms of vertebrae BMD, mineralizing surfaces, mineral apposition rate, BFR/BS. The ALN+OPG-Fc treatment group had significantly increased the mechanical strength of lumber vertebral bodies and femoral shafts when compared to the ALN and OPG-Fc treatment groups. The RANKL protein expression in the vertebral bones was significantly decreased in the ALN and ALN+OPG-Fc treatment groups, suggesting the combined use of OPG-Fc and ALN might have amplified inhibition of bone resorption through inhibiting RANKL-dependent osteoclastogenesis.

Conclusion

The combined use of OPG-Fc and ALN may be a new treatment strategy for reversing bone loss and restoring bone quality in osteoprotic disorders.     

Osseointegration of hollow cylinder based spinal implants in normal and osteoporotic vertebrae: a sheep study

Introduction Osteoporosis is not only responsible for an increased number of metaphyseal and spinal fractures but it also complicates their treatment. To prevent the initial loosening, we developed a new implant with an enlarged implant/bone interface based on the concept of perforated, hollow cylinders. We evaluated whether osseointegration of a hollow cylinder based implant takes place in normal or osteoporotic bone of sheep under functional loading conditions during anterior stabilization of the lumbar spine.Materials and methods Osseointegration of the cylinders and status of the fused segments (ventral corpectomy, replacement with iliac strut, and fixation with testing implant) were investigated in six osteoporotic (age 6.9 ± 0.8 years, mean body weight 61.1 ± 5.2 kg) and seven control sheep (age 6.1 ± 0.2 years, mean body weight 64.9 ± 5.7 kg). Osteoporosis was introduced using a combination protocol of ovariectomy, high-dose prednisone, calcium and phosphor reduced diet and movement restriction. Osseointegration was quantified using fluorescence and conventional histology; fusion status was determined using biomechanical testing of the stabilized segment in a six-degree-of-freedom loading device as well as with radiological and histological staging.Results Intact bone trabeculae were found in 70% of all perforations without differences between the two groups (P = 0.26). Inside the cylinders, bone volume/total volume was significantly higher than in the control vertebra (50 ± 16 vs. 28 ± 13%) of the same animal (P<0.01), but significantly less (P<0.01) than in the near surrounding (60 ± 21%). After biomechanical testing as described in Sect. ”Materials and methods”, seven spines (three healthy and four osteoporotic) were classified as completely fused and six (four healthy and two osteoporotic) as not fused after a 4-month observation time. All endplates were bridged with intact trabeculae in the histological slices.Conclusions The high number of perforations, filled with intact trabeculae, indicates an adequate fixation; bridging trabeculae between adjacent endplates and tricortical iliac struts in all vertebrae indicates that the anchorage is adequate to promote fusion in this animal model, even in the osteoporotic sheep.     

皮瓣外科的过去、现在和未来

目的 通过对3D打印钛孔结构与实体钛结构椎体植入猪腰椎后进行体外生物力学测试,评价其活动范围情况及即刻生物力学稳定性。方法 选取18具新鲜成年猪脊柱标本（L₁~L₆）随机分配到以下三组：对照组（未置换）、钛孔结构椎体置换组（取出L₃椎体行钛孔结构椎体植入,简称钛孔结构组）、实体钛结构椎体置换组（取出L₃椎体行实体钛结构椎体植入,简称实体钛组）。测试标本的前屈、后伸、侧屈、轴向旋转角位移运动变化。结果 实体钛组、钛孔结构组分别与对照组在各方位角位移运动范围比较,差异均有统计学意义（均P<0.05）;钛孔结构组与实体钛组在各方位的角位移运动范围比较,差异均无统计学意义（均P>0.05）,且两种固定状态下各方位的即刻稳定指数比较,差异均无统计学意义（均P>0.05）。结论 两种3D打印人工椎体方法均能获得良好的即刻稳定性,但3D打印的钛孔结构人工椎体在融合方面优于实体钛结构。     

卵巢切除后大鼠骨小梁重建过程的电镜观察

目的：建立大鼠卵巢切除后骨质疏松模型，观察在卵巢切除诱发骨质疏松条件下骨小梁重建的电镜变化，分析骨小梁节点数减少而游离末端数增加的原因。方法：3月龄雌性Wistar大鼠36只，分4、8、12周组，每组分OVX(卵巢切除组)和SHAM(假手术组)两小组。用扫描电镜、透射电镜对胫骨近干骺端骨小梁的微结构进行观察。结果：①骨小梁骨重建活动分布于骨小梁微构筑各个部位，但以St、Nd-St区最显著；②OVX后骨小梁穿孔、断裂多见于水平骨小梁，骨小梁网状结构4周时完整，第8周和第12周后逐渐被破坏，12周最严重；OVX后骨小梁表面的胶原纤维逐渐变得杂乱、稀薄。结论：OVX后St、Nd-St区骨重建最活跃，这可能是骨质疏松时骨小梁节点数减少而游离末端数增加的原因。     

骨质疏松绵羊模型松质骨及皮质骨的微观结构及力学性能变化的研究

目的观察去势手术对绵羊皮质骨和松质骨的骨密度、骨小梁结构及力学性能的影响。方法20只雌性成年绵羊（4±1.5）随机分为去势4个月组（OVX-4months）（4只）、去势12个月组（OVX-12months）（8只）和假手术（Sham）组（8只）。OVX组行双侧卵巢切除术,假手术组仅显露双侧卵巢,术中测定腰椎骨密度。分别与术后4、12个月处死动物,测定股骨颈、股骨干及股骨髁的骨密度,并行MicroCT分析及生物力学测试。结果去势12个月后（OVX-12months）组腰椎、股骨颈及股骨髁的骨密度较对照组显著降低,而皮质骨骨密度无明显降低。其松质骨的相对骨体积（BV/TV）、骨小梁厚度（Tb.Th）、骨小梁数目（Tb.N）较对照组显著降低,表面积体积比（BS/BV）、骨小梁间隙（Tb.Sp）则较对照显著增高。生物力学测试表明,去势12个月后,腰椎松质骨的最大压缩应力分别较Sham组和OVX-12months组下降82.5%和85.9%,力学强度显著下降,而皮质骨的力学强度无显著变化。结论去势12个月后,绵羊腰椎、股骨部的松质骨BMD及骨小梁空间结构参数明显降低,力学强度也显著下降,可以作为骨质疏松的大动物模型。而皮质骨的骨密度和力学强度下降不明显,需要更长的去势时间。     

多孔钽材料细胞毒性、生物相容性及体内成骨性研究

 目的 探讨国产多孔钽材料的细胞毒性和生物相容性,并通过兔骨内植入成骨示踪观察其成骨作用。方法 扫描电镜观察并测量多孔钽的形态学特征。来源于新西兰胎兔颅盖骨的成骨细胞以多孔钽浸提液（实验组）及完全培养基（对照组）培养,MTT法检测多孔钽的细胞毒性及其对增殖的影响。成骨细胞与多孔钽体外复合培养,观察成骨细胞的黏附、生长及增殖。雄性新西兰大白兔24只,制备股骨髁上多孔钽棒植入模型;4只动物于术后第5天和第19天分别肌肉注射荧光素钙黄绿素和茜素红,术后10 周取材,于488 nm（钙黄绿素激发光）和543 nm（茜素红激发光）波长处,激光扫描共聚焦显微镜观察多孔钽-骨界面成骨;20只动物于术后2、4、8和12 周取材行大体及硬组织切片观察。结果 多孔钽表面及断面可见均匀分布的三维立体连通孔隙结构。MTT法检测显示实验组与对照组细胞随培养时间的延长,其OD值的差异均无统计学意义。扫描电镜显示复合培养早期,细胞在多孔支架表面和孔壁上黏附,相互连接;晚期汇合成片并分泌细胞外基质覆盖材料表面。体内成骨实验显示植入的多孔钽棒与宿主骨结合紧密。硬组织切片显示术后2、4周时多孔钽-骨界面已出现新生骨及小血管,并向孔隙内生长;8、12周时多孔钽表面和孔隙内已长满新生骨组织,新生骨小梁已发育成熟并与材料直接接触。激光共聚焦扫描显微镜显示多孔钽-骨界面及孔隙内可见绿色荧光（钙黄绿素）和红色荧光（茜素红）标记的新生骨组织,红色荧光带位于绿色荧光带周围,早期均呈不连续性,晚期则融为一体。结论 国产多孔钽材料无细胞毒性,具有良好的生物相容性,多孔钽-骨界面为接触及传导性成骨并呈时间依赖性。     

Effect of zoledronate acid treatment on osseointegration and fixation of implants in autologous iliac bone grafts in ovariectomized rabbits

One main problem associated with alveolar bone augmentation in implant dentistry is resorption of grafted bone, which may be further compromised by systemic skeletal disorders such as osteoporosis. Zoledronate acid (ZOL) is the most potent bisphosphonate to treat osteoporosis and therefore it is hypothesized to be able to invert the negative effect of osteoporosis on osseointegration and fixation of dental implants in autologous bone grafts. In this study, 56 rabbits received bilateral ovariectomy (OVX) (40 rabbits) or sham operation (16 rabbits). Three months later, 8 animals from each group were sacrificed for bone mineral density (BMD) examination. Then the remaining animals underwent bilateral autologous iliac bone grafting with simultaneous implantation of titanium implants in tibiae and were divided into 5 groups (n = 8): Sham, OVX, Loc-ZOL (local treatment), Sys-ZOL (systemic treatment) and Loc + Sys-ZOL (local plus systemic) group. At 3 months after implantation, all animals were sacrificed and specimens were harvested for examinations. Both BMD and histological examinations of femurs showed osteoporotic changes after ovariectomy, while systemic treatment with ZOL restored mineralized bone. Micro-CT examination demonstrated that OVX group showed significant decrease of mineralized bone and implant-bone contact when compared with sham control, whereas both systemic and local treatments of ZOL significantly increased mineralized bone and implant-bone contact in ovariectomized animals. However, the best effects were observed in Loc + Sys-ZOL group (combined use of ZOL) and most of bone indices were similar to (IBCR, p > 0.05) or higher than (BV/TV, Conn.D and Tb.N) (p < 0.01) those of the sham group, except Tb.Th, which was still significantly lower (p < 0.01), and Tb.Sp, which was further decreased (p < 0.01). The aforementioned effects were also confirmed by histomorphometric analysis of bone indices on implant-bone contact and mineralized bone. In addition, biomechanical testing further supported the beneficial effect of ZOL treatment and maximal removal torque of titanium implants was observed in Loc + Sys-ZOL group. In conclusion, our study suggests that both systemic and local treatments with ZOL can invert negative effect of osteoporosis and promote osseointegration and fixation of dental implants in autologous bone grafts under osteoporotic condition. Combined systemic and local use of ZOL exerts best effects when compared to their single use.     

Effects of surface roughness of titanium implants on bone remodeling activity of femur in rabbits

We investigated the bone remodeling activity on titanium implants with different surface roughnesses using a confocal laser scanning microscope (CLSM). Two kinds of implants were used, the machined smooth-surfaced titanium and the plasma-sprayed rough-surfaced titanium. These implants were randomly inserted in a rabbit's femur from the lateral aspect of the diaphysis bicortically. Rabbits were killed at 6, 16, and 42 weeks after surgery. The implant-bone blocks were embedded in polyester resin, and were prepared to make undecalcified ground sections. Histomorphometric analyses were performed at the cortical bone-implant interface using the image obtained by CLSM. Percentages of direct bone-implant contact and bone volume (BV/TV) around the implant was greater in rough-surfaced titanium compared with the smooth-surfaced titanium at 42 weeks after implantation. On the contrary, the eroded surface (ES/BS) appeared to be less in the rough-surfaced titanium than in the smooth-surfaced titanium at 6 weeks after implantation, but thereafter, no difference was found between the two kinds of implants. Mineralizing surface (MS/BS) and mineral apposition rate (MAR) showed no significant differences throughtout the experimental period. These results indicate that increased bone volume in the rabbits of rough-surfaced titanium implants is due to less remodeling activity during the early stage after implantation compared with the smooth-surfaced implants. The surface roughness of titanium is one factor which helps in determining the balance between bone formation and resorption of remodeling at the interface of the bone implants.     

短期低钙饮食对去卵巢大鼠股骨生物力学特性的影响

目的 考察短期低钙饮食对去卵巢大鼠股骨生物力学特性的影响.方法 大鼠假手术或去卵巢处理5周后,按照饮食中钙含量不同,分作4组：假手术常钙饮食组（SN）;假手术低钙饮食组（SL）;去卵巢常钙饮食组（ON）;去卵巢低钙饮食组（OL）.设C组为正常对照组.分食喂养两周,收集尿液,腹主动脉取血,收集股骨,低温保存.对股骨中段进行三点弯曲生物力学实验,并通过Western blotting检测近端股骨蛋白表达.结果双因素方差分析表明,去卵巢可显著提高血清ALP水平（P＜0.001）和尿液DPD水平（P＜0.01）,并降低股骨弹性模量（P＜0.05）和材料韧性（P＜0.05）等材料力学特性.单独短期低钙饮食因素对股骨生物力学影响不显著,但去卵巢大鼠配以低钙饮食后（OL组）,可显著降低股骨硬度、能量吸收、韧性等生物力学指标.低钙饮食组大鼠近端股骨维生素D受体（VDR）蛋白表达提高.结论 大鼠去卵巢后体内呈现高骨转换状态;短期低钙饮食可加重大鼠由于去卵巢后股骨生物力学性能的损害;低钙饮食对骨矿代谢有一定影响.     

肌腱周边缝合方法的生物力学研究

目的　比较三种肌腱周边缝合方法 ,即连续法、Cross- Stitch法和 Halsted法的生物力学特性。方法　将 60只新鲜成年猪后蹄 区趾屈肌腱造成切割伤 ,按手术先后随机分成 6组 ,每组 10只。第1～ 3组用 Kessler法进行核心缝合 ,第 4～ 6组用 Tang法进行核心缝合。各组均加用周边缝合修复腱周 :第 1、4组用连续缝合法 ,第 2、5组用 Cross- Stitch法 ,第 3、6组用 Halsted法。术后即刻应用材料力学测定仪测定修复肌腱被拉伸至出现 2 mm间隙时 ,其 2 mm间隙形成负荷及最大负荷 ;并根据位移 -负荷曲线计算其刚度及最大功耗。结果　同一核心缝合法时 ,Halsted法的 2 - mm间隙形成负荷、最大负荷、最大功耗最高 ;Cross- stitch法次之 ;连续缝合法最低。Halsted法的刚度与 Cross- stitch法相近而连续法较差。结论　 Halsted周边缝合法对肌腱抗张能力的作用最大 ,能够满足肌腱手术后早期活动所需的抗张力要求。     

改良式股骨转子问外翻截骨术的生物力学研究:三维有限元素分析

目的 应用有限元素方法比较分析传统的股骨转子下封闭楔形外翻截骨术与自行改良的“Z”形转子间外翻截骨术的术后力学差异。方法利用标准人造股骨的计算机断层扫描影像，建立术前股骨颈夹角分别为120°、110°、100°和90°的4个股骨颈内翻的实体模型，分别经传统的转子下封闭楔形外翻截骨术与自行改良的“Z”形转子间外翻截骨术两种不同的外翻截骨矫正手术后，将股骨颈夹角一致矫正为15005并据此建立有限元素模型。模型施力条件为单脚站立；材料设定为线性、均质，截骨界面设定为接触形态给予摩擦系数，并针对两种不同截骨术在4种不同外翻角度条件下，两者术后的股骨形态、截骨面及固定钢板的应力分布情况进行比较分析。结果术前股骨颈夹角90。情况下，以传统式截骨术矫正为150。后，股骨整体严重变形，且邻近截骨区域有明显应力集中现象；而改良“z”形截骨术矫正4种不同术前股骨颈夹角的股骨为150。后，四者间的股骨表面应力分布无明显差异；术前股骨颈夹角为90°时，“Z”形截骨术后股骨变形较小，截骨面的应力较高。结论 以“Z”形转子间截骨术矫治较大角度的股骨颈内翻更具临床优势。