Cartilage changes of femoral head osteonecrosis in stage Ⅱ and Ⅲ as detected by dGEMRIC

Objective To detect the cartilage changes of hip joint with osteonecrosis of femoral head (ONFH) in stages Ⅱ and Ⅲ and provide evidence for understanding cartilage changes of femoral head of osteonecrosis before collapse. Methods The cartilage changes of ONFH were determined by delayed gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC). According to ARCO classification of ONFH, the samples were divided into three groups: Group A, 11 hips, stageⅡ; Group B,13 hips, stage Ⅲ; Group C, 10 hips, normal. All participates underwent the tests by dGEMRIC. And the data of T1Gd were collected and analyzed. Results The values of T1Gd were 420 ±60 (Group A) ,361 ±54(Group B) and 538 ±26 (Group C) respectively. There was a significant difference among three groups.The values of T1Gd in the ONFH patients were lower than their healthy counterparts. The values of T1Gd of Group B was 14% lower than those of Group A. And the difference was significant statistically. Conclusion Cartilage of the femoral head undergoes abnormal metabolic changes before collapse. There is a loss of GAG in the cartilage and it aggravates with the worsening of ONFH.     

Cartilage changes of femoral head osteonecrosis in stage Ⅱ and Ⅲ as detected by dGEMRIC

Objective To detect the cartilage changes of hip joint with osteonecrosis of femoral head (ONFH) in stages Ⅱ and Ⅲ and provide evidence for understanding cartilage changes of femoral head of osteonecrosis before collapse. Methods The cartilage changes of ONFH were determined by delayed gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC). According to ARCO classification of ONFH, the samples were divided into three groups: Group A, 11 hips, stageⅡ; Group B,13 hips, stage Ⅲ; Group C, 10 hips, normal. All participates underwent the tests by dGEMRIC. And the data of T1Gd were collected and analyzed. Results The values of T1Gd were 420 ±60 (Group A) ,361 ±54(Group B) and 538 ±26 (Group C) respectively. There was a significant difference among three groups.The values of T1Gd in the ONFH patients were lower than their healthy counterparts. The values of T1Gd of Group B was 14% lower than those of Group A. And the difference was significant statistically. Conclusion Cartilage of the femoral head undergoes abnormal metabolic changes before collapse. There is a loss of GAG in the cartilage and it aggravates with the worsening of ONFH.     

Vascularized iliac bone grafting for avascular necrosis of the femoral head

Objective To evaluate the indications for vascularized iliac bone grafting in the treatment of osteonecrosis of the femoral head and operative results. Methods From October 1993 to August 2000, Twenty-six hips of 18 patients with osteonecrosis of the femoral head underwent vascularized iliac bone grafting. Clinical evaluation was made according to Harris Hip Score and ARCO staging system. Results Twenty-three hips of 16 patients were followed up for 31. 5 months (6-74 months) on average. The mean Harris hip score was 76peints (mean 61.7). Thirteen hips (medial 8 hips,central3 hips,lateral 2 hips). were graded >80 points by Harriship score were. The incidence of radiographic collapse 20% was (medial),40% (central) and 75% (lateral) respectively. Conclusion Vascularized iliac bone grafting is effective for the treatment of osteonecrosis of the femoral head in short and middle term. We recommend this procedure for the patients with ONFH in ARCO stage Ⅰ , stage Ⅱ A, Ⅱ B medial and central, and stage Ⅱ C     

骨髓干细胞和伞状支撑骨移植治疗股骨头坏死的动物实验研究报告

目的 探讨骨髓干细胞移植和伞状支撑骨移植治疗股骨头坏死的效果.方法 取6只健康山羊,采用液氮冷冻法制作单侧股骨头坏死动物模型,8周后在坏死侧行骨髓干细胞移植和伞状支撑骨移植术.分别于术后3、6个月做放射学检查,观察股骨头内骨质变化.结果 实验动物一般状况良好.液氮冷冻法8周后达成股骨头坏死模型,模型侧后肢出现跛行.骨髓干细胞移植和伞状支撑骨移植术后3个月X线显示,股骨头外形恢复,股骨头内囊性低密度区消失,可见骨柱影,股骨头内骨质愈合状况良好,原塌陷已修复,股骨头无再塌陷.6个月时,治疗侧股骨头外形正常,骨密度基本均匀,骨柱影已模糊,植骨已融合,股骨头无再塌陷.正常对照侧股骨头无异常变化.结论 骨髓干细胞移植和伞状支撑骨移植术可以有效治疗骨坏死,防治股骨头塌陷,效果良好. Abstract： Objective To study the usefulness to treat the osteonecrosis of the femoral head (ONFH) with bone marrow mesenchymal stem cell transplantation and umbrella strut bone grafting. Methods Six goats were established of osteonecrosis of the femoral head models on one side by method of liquid nitrogen frozen, and then they were taken into bone marrow mesenchymal stem cell transplantation and umbrella strut bone grafting after 8 weeks. The radiological examination was made at 3 and 6 months after the bong grafting, and observed changes of bone union in the femoral head. Results The general state of the experimental animal was fine after the operation. The model of ONFH was reached on 8 weeks after liquid nitrogen frozen, and limping. After 3 months of bone marrow mesenchymal stem cell transplantation and umbrella strut bone grafting, X-ray film showed that low bone density disappeared, the shape of the femoral heads, grafting strut bone and initial bone union were fine in the head, and no repeated collapse of the head. The X-ray film showed that the shape of the femoral heads was normal, grafting strut bone was union in the head, and no repeated collapse of the head after 6 months. There was normal on the control side. Conclusions The ONFH can be treated effectively by bone marrow mesenchymal stem cell transplantation and umbrella strut bone grafting, and the collapse of the femoral head is prevented.     

股骨头坏死早期的关节软骨改变

目的:探讨早期股骨头坏死关节软骨的改变,为深入了解股骨头坏死的病理机制及制定合理治疗提供实验与临床依据。方法:采用软骨延迟增强核磁成像(delayed gado1inium-enhanced magnetic resonance i maging ofcartilage-dGEMRIC)技术,对Ⅱ、Ⅲ期成人股骨头坏死的关节软骨进行检测。20髋激素性股骨头坏死患者中,以国际骨坏死与循环协会(ARCO)分期标准,股骨头坏死Ⅱ期患者为11髋,股骨头坏死Ⅲ期患者为9髋,5名健康志愿者作测试为对照组。对每名受试者进行钆增强延迟核磁共振(1.5T)扫描,分别获得T1Gd数据,应用Matlab和mri mapper软件对每位受试者的影像数据进行分析。结果:股骨头坏死Ⅱ期患者的MRITl Gd值(441.13士41.32)与健康志愿者的T1Gd值(544.2士27.83)有显著差别(P0.001)。股骨头坏死Ⅲ期患者的T1Gd值(363,11士56.39)与健康志愿者的T1Gd值也有显著差别(P0.001)。股骨头坏死Ⅲ期与股骨头坏死Ⅱ期患者的T1Gd值比较下降17.7%,两者有显著性差别(P0.05)。结论:股骨头坏死早期患者的关节软骨已经开始发生代谢变化。说明骨坏死早期可以影响软骨的代谢和功能,并随着坏死程度加重而加大。     

A modified technique of bone grafting pedicled with femoral quadratus for alcohol-induced osteonecrosis of the femoral head

Background Quadratus femoris pedicled bone grafting has yielded satisfactory long-term clinical outcome for osteonecrosis of the femoral head （ONFH） in pre-collapse ONFH without extensive lesion. However, for pre-collapse ONFH with extensive necrotic area, it is still challenging to preserve the femoral head. The current study aimed to introduce a new technique of deliquesce strut with titanium mesh containing bone grafting pedicled with the femoral quadratus and to evaluate its short-term outcomes.Methods From January 2008 to December 2008, 10 ONFH patients （12 hips） underwent operations by a new technique of deliquesce strut with titanium mesh containing bone grafting pedicled with the femoral quadratus （group A）.According to the ARCO classification system, there were two hips in stage Ⅱ B and 10 hips in stage Ⅱ C. Also in the same period, 12 ONFH patients （16 hips） underwent operations by the conventional procedure of quadratus femoris pedicled bone grafting （group B）. There were 6 hips in stage Ⅱ B and 10 hips in stage Ⅱ C. All patients were males and suffered from alcohol induced ONFH. For the new technique, the necrotic area was evaluated, and a titanium mesh piece of the same size （range from 2.5 cm×2.8 cm to 2.8 cm×3.4 cm） was obtained and shaped to match the contour of the head. The cancellous bone was first placed underneath the subchondral bone and was densely impacted （about 1 to 2 mm thick）.Then the titanium mesh piece was inserted. The length of the decompressive trough was measured. A titanium cylinder mesh cage with a diameter of 1.6 cm of the same length was obtained, with a ＂U＂ shaped window in the wall being created to make room for the muscle pedicle. The muscle pedicle bone was inserted into the titanium mesh cage to form a bone graft-titanium cage complex and, then the complex was inserted. The hundred percent score method was used for outcome evaluation. Clinical and radiographic outcomes were compared between group A and group B.Results The average operative time was 150 minutes （130 to 185 minutes） in group A, with an average of 130 minutes （120 to 180 minutes） in group B. The mean blood loss was 400 ml （300 to 500 ml） in group Aand 350 ml （250 to 500 ml）in group B. Group A patients were followed up for an average of 19.2 months （14 to 24 months）, with an average of 18.5 months （12 to 24 months） for Group B. Full weight bearing was allowed 5 to 7 months postoperatively. Pain and function were obviously improved. For group A, pain score improved from a mean of 9.8 points preoperatively to an average of 24.6 points postoperatively, and function score improved from a mean of 9.0 points preoperatively to an average of 17.4 points postoperatively. In group B, pain score improved from a mean of 9.5 points preoperatively to an average of 24.2 points postoperatively and function score improved from a mean of 9.2 points preoperatively to an average of 17.2 points postoperatively. The range of motion changed the least, with score improvement from a preoperative mean of 13.9 points to postoperative 16.8 points for group A and from a preoperative mean of 13.7 points to postoperative 16.5 points for group B. Radiographic score improved from preoperative 31 points to postoperative 38 points for group A, in comparison with an improvement from preoperative 31 points to postoperative 37 points for group B. At the latest follow up, 11 hips were rated as excellent and 1 hip was better for group A, with 14 hips being rated as excellent and 2 hips being better in group B. There was no statistically significant difference between groups A and B in clinical and radiographic outcomes.Conclusion For ONFH in stage ARCO llC, satisfactory clinical outcome can be achieved by the new technique in the short-term period while the long-term clinical outcome has yet to be determined.     

打压支撑植骨术治疗围塌陷期股骨头坏死66例

目的:观察打压支撑植骨术治疗围塌陷期股骨头坏死(ONFH)的临床疗效,分析影响治疗结果的原因。方法:选择连续性ONFH患者66例96髋,其中激素性坏死27例43髋,酒精性31例41髋,创伤性患者5例7髋,特发性3例5髋。按ARCO分型,ⅡA 7髋,ⅡB 21髋,ⅡC 8髋,ⅢA 32髋,ⅢB 23髋,ⅢC 5髋。两组患者均接受打压支撑植骨术治疗,术后服用中药。随访5～25个月,平均19.01个月。结果:Harris评分,术前56.67±13.97,末次随访时84.63±7.277,其中优28髋(29.2%),良52髋(54.2%),可11髋(11.2%),差5髋(5.2%),优良率83.3%,有效率94.8%。ARCOⅡ期髋治疗结果优于Ⅲ期,坏死范围越大、坏死部位越靠近股骨头外侧,预后越差,差异有统计学意义。而采用自体腓骨与同种异体腓骨治疗,差异无统计学意义。结论:采用打压支撑植骨术加中药治疗围塌陷期ONFH能明显改善患者髋关节功能,并能有效减少术后股骨头塌陷及并发症的产生。股骨头坏死的分期、范围、部位对治疗结果有预测意义。     

磁共振成像对股骨头坏死后塌陷的预测

目的:探讨一种临床上实用的磁共振成像(MRI)检测手段来预测股骨头坏死(osteonecrosis of thefemoral head,ONFH)的塌陷。方法:选择37例ARCO分期为Ⅰ期和Ⅱ期的ONFH患者,在MRI的中部冠状位和矢状位图像上分别测量坏死角度,根据公式计算坏死范围指数,比较塌陷组和未塌陷组该指数的差异,并根据该指数对患者发生股骨头塌陷的危险程度进行分级。平均随访期为25个月。结果:塌陷组和未塌陷组的坏死范围指数分别为56.13±17.65和18.34±10.87,差异有统计学意义。随访中无一例股骨头发生塌陷的低危组,其股骨头坏死范围指数均小于30;股骨头均发生塌陷的高危组,其股骨头坏死范围指数均大于40;而中危组的坏死范围指数介于30~40,股骨头塌陷发生率为45%。结论:利用MRI测量和计算ONFH的坏死范围指数是预测ONFH患者是否发生股骨头塌陷的有效方法。     

骨髓间充质干细胞治疗早期股骨头坏死临床应用进展

<正>股骨头坏死(osteonecrosis of femoral head,ONFH)是一种骨科常见病、多发病,由不同病因致血供破坏,进而致股骨头软骨下骨变性、坏死,最终股骨头塌陷。ONFH致残率极高、严重影响患者的生活水平,常累及中青年,呈进展性和致残性发展,大部分患者因错过早期治疗或早期治疗失败最终因股骨头变形、     

髓芯扩大减压联合打压植骨治疗围塌陷期股骨头坏死的中短期疗效观察

目的探讨经大转子行股骨头髓芯钻孔扩大减压联合异体腓骨条打压植骨治疗股骨头坏死围塌陷期(ARCOⅡ、Ⅲ期)的中短期临床疗效。方法选取我校附一院骨科ONFH患者87例,均行髓芯钻孔减压加异体腓骨条移植治疗股骨头早中期缺血坏死,采用Harris评分法,随访5~20个月,平均14.24个月。分别对病人根据术前及术后末次随访的关节功能进行评分。结果术前Harris评分55.8±6.1,术后末次随访时87.1±4.8,髋关节功能优良率86.2%。术后末次随访时Harris评分明显高于术前(P0.01)。结论髓芯扩大减压联合打压植骨治疗围塌陷期(ARCOⅡ、Ⅲ期)股骨头坏死的手术方式,创伤较小,术后中短期疗效显著,能明显减轻患者髋关疼痛并改善髋关节功能,有效减少术后股骨头塌陷的发生,值得临床推广。其远期疗效尚无法确定。     

人工全髋关节置换术治疗成人晚期酒精性股骨头坏死62例

酒精性股骨头坏死(osteonecrosis of the femoral head, ONFH)已成为临床上常见的难治性疾病.发病1～4 a后可发生股骨头塌陷,进展至3期或以上晚期病变的股骨头塌陷严重,致残率极高.1995年以来作者采用人工全髋关节置换术(total hip arthroplasty,THA)治疗成人晚期酒精性ONFH 62例72髋,获得良好效果,报道如下.     

磁共振T2 map成像对不同ARCO分期股骨头软骨变性的评估价值

目的测量正常及不同ARCO分期条件下坏死股骨头软骨T2 map值的变化,评估其临床应用价值。方法搜集不同ARCO分期坏死股骨头(ARCOI期、ARCOII期、ARCOIII期)及正常股骨头各20例,年龄20-50岁,所有病例均行MRI检查。测量各期坏死及正常股骨头软骨的T2 map值的定量学数据。所有选取坏死及正常研究对象均排除骨质疏松及其他影响观察的基础性疾病。结果随着病情进展,坏死股骨头ARCO分期越高,软骨T2 map值越高,软骨的损害也就越明显;经LSD检验分析提示坏死股骨头ARCOIII期软骨与正常股骨头、ARCOI期、ARCOII期软骨T2 map值之间的差异有统计学意义,P值小于0.05。结论正常股骨头软骨的T2 map的数值大约可界定为(49.39±8.158)之间,临床上可将此区间值作为可能性参考标准;随着股骨头坏死病程的进展,股骨头软骨损伤变性的程度有逐渐加重趋势。     

股骨头缺血性坏死的微创治疗进展

股骨头缺血性坏死(avascular necrosis of the femoral head,ANFH)是骨科的常见病和多发病,好发于青壮年,病变导致关节软骨破坏和股骨头塌陷,最终导致髋关节功能丧失。各种原因所导致的股骨头坏死均以股骨头局部缺血为其最终病理改变,因而如何改变股骨头局部血供、促进血管再生     

股骨头坏死的发病机制及干细胞治疗进展

股骨头坏死(osteonecrosis of the femoral head,ONFH)亦称缺血性或无菌性股骨头坏死,好发于青壮年,病程进展迅速,如不积极治疗致残率高。股骨头坏死的发病机制有早期的脂肪栓塞学说、微血管内凝血学说和骨内高压学说等[1]。股骨头坏死的主要     

ONFH早期的磁共振征象与定量坏死体积测量对预测股骨头坏死塌陷的临床意义

目的探讨股骨头坏死(ONFH)早期的磁共振征象与定量坏死体积测量对预测股骨头塌陷的临床意义。方法选取自2012年7月至2014年7月期间于我院确诊的股骨头坏死早期(ARCO分期Ⅰ、Ⅱ期)患者65例(共78髋),确诊时接受X线摄片判定股骨头塌陷情况,并进行MRI扫描汇集ONFH早期病情数据,包括关节腔积液量、骨髓腔水肿、坏死形态和股骨头坏死体积。初次检查后,患者每6个月来院接受一次X线摄片检定股骨头是否出现塌陷。根据随访中是否出现股骨头坏死塌陷将其分为塌陷组和未塌陷组,比较两组研究对象早期的各项MRI影像学指标,分析各项指标与股骨头塌陷结局的关联性。结果塌陷组患者股骨头总坏死体积百分比明显高于未塌陷组,除PIM象限外的其余各象限坏死体积百分比也明显高于未塌陷组;关节腔积液程度甚于未塌陷组;出现骨髓腔水肿的病例数多于未塌陷组;周围型股骨头坏死比例高于未塌陷组,差异均有显著性统计学意义(P0.01)。结论 ONFH早期的MRI征象和定量坏死体积测量对预测股骨头坏死塌陷具有重要的临床价值。     

多孔钽棒置入联合髓芯减压治疗成人早期股骨头坏死近期疗效观察

目的：探讨多孔钽棒置入联合髓芯减压治疗早期股骨头坏死（ONFH）的近期临床效果。方法：采用多孔钽棒置入联合髓芯减压治疗成人早期ONFH 11例11髋,其中ⅠB期1髋,ⅠC期1髋,ⅡA期2髋,ⅡB期6髋,ⅡC期1髋。术前Harris评分平均（53.8±9.7）分。随访时以Harris评分、影像学检查及股骨头生存率作为疗效评价指标。结果：手术时间30-50 min,出血量50-100 ml。术后随访12-21个月。术后Harris评分为（84.2±7.3）分,较治疗前明显提高（P〈0.01）。1例伴有系统性疾病长期服用激素患者术后9个月发生了股骨头塌陷及关节间隙狭窄,其余病例股骨头外形完整,无股骨头变扁、塌陷或坏死加重。结论：多孔钽棒置入联合髓芯减压治疗成人早期ONFH能有效避免坏死区股骨头塌陷,近期疗效满意。     

晚期糖基化终末产物与股骨头坏死进展的相关性研究

背景　股骨头坏死（ONFH）是骨科临床难治性疾病，由于诊断不及时，塌陷进程快，很多患者不可避免地要面临人工全髋关节置换术的结局，寻找科学诊断早期ONFH的方法具有非常重要的现实意义。目的　分析国际骨循环学会分期（ARCO）Ⅱ~Ⅳ期ONFH患者的血浆晚期糖基化终末产物（AGEs）水平，研究其与ONFH发展进程的相关性。方法　2016年6-12月随机选取广州中医药大学第一附属医院三骨科住院治疗的ONFH患者为试验组，广州中医药大学第一附属医院体检中心进行体检的健康成年人为对照组，收集试验组患者的影像资料，按ARCO标准分为ARCO Ⅱ期、ARCO Ⅲ期、ARCO Ⅳ期。使用酶联免疫吸附测定（ELISA）检测所有研究对象的AGEs水平，分析两组间、试验组内不同坏死原因、不同ARCO分期及塌陷前后患者的AGEs水平。结果　试验组AGEs水平〔（2.87±0.73）mg/L〕高于对照组〔（2.33±0.94）mg/L〕（t=3.692，P<0.001）。不同ARCO分期、塌陷前后、病因ONFH患者AGEs水平比较，差异均有统计学意义（P<0.05）；其中ARCO分期Ⅱ期AGEs水平低于Ⅳ期，创伤性（T）病因患者AGEs水平高于酒精性（AI）、激素性（SI）、特发性（ID）（P<0.05）。Spearman相关性分析结果显示，AGEs水平与ARCO分期呈正相关（rs=0.274，P=0.007）。ROC曲线下面积为0.651（0.567，0.729），AGEs水平切点为2.419 mg/L时，灵敏度为72.45%，特异度为59.09%。结论　AGEs与ONFH的进展过程密切相关，对于诊断ONFH及病情监测具有一定参考价值。     

兔髋臼发育不良软骨增厚及纤维化的实验研究

Background The order and mechanism of pathological changes in acetabular dysplasia are still unclear. This study investigated cartilage changes in rabbit acetabular dysplasia models at different ages.Methods Twenty-seven 1-month-old New Zealand rabbits underwent cast immobilization of the left hind limb in knee extension. Serial acetabular dysplasia models were established by assessment of the acetabular index and Sharp＇s angle on radiographs. The thickness of the acetabular cartilage was measured under a microscope, and fibrosis was observed. Ultrastructural changes were investigated with scanning electron microscopy and transmission electron microscopy. The messenger RNA expression of collagen Ⅰ and Ⅱ, β1 integrin, and caspase-9 were measured by real-time fluorescence quantitative polymerase chain reaction.Results In an immature group of rabbits, the acetabular index of the treated hip increased with animal growth. The cartilage on the brim of the left acetabulum was significantly thicker than that on the right side. The collagen fibrils on the surface of the cartilage became gross, and the chondrocytes in the enlargement layer underwent necrosis. In a mature group of rabbits, the left Sharp＇s angle increased in the rabbits with 6-week casting. The cartilage on the brim of the left acetabulum underwent fibrosis. The chondrocytes were weakly stained, and the number of lysosomes was much larger than normal. The messenger RNA expression of collagen Ⅰ and Ⅱ, β1 integrin, and caspase-9 in the cartilage differed significantly at different ages.Conclusions Increasing thickness followed by fibrosis may be the order of pathological cartilage changes in acetabular dysplasia, with changes in ultrastructure and collagen expression contributing to the process.     

钽棒植入治疗围塌陷期股骨头坏死的疗效

目的评估钽棒治疗围塌陷期股骨头坏死的临床疗效,分析股骨头生存率的影响因素。方法回顾性分析30例30髋围塌陷期股骨头坏死接受钽棒植入术患者的临床资料,其中国际骨循环协会(ARCO)ⅡA期2髋,ⅡB期12髋,ⅡC期11髋,ⅢA期5髋。以股骨头塌陷>4 mm作为研究终点,通过VAS评分评估关节疼痛程度,根据Harris评分评估髋关节功能;通过分析坏死部位及坏死范围对钽棒植入术后股骨头生存率的影响,探讨钽棒植入的适应证。结果术前至术后末次随访,VAS评分从(4.37±1.69)分下降至(1.13±0.97)分,差异有统计学意义(P<0.01);整体Harris评分从(84.91±6.95)分提高至(93.89±2.88)分,差异有统计学意义(P<0.05)。当坏死范围超过67%时,患髋生存率为25.0%;当正位分型为C2型时,其生存率只有22.2%。结论钽棒植入术是治疗围塌陷期股骨头坏死的有效方法。正位分型中的C2型或改良坏死指数超过67%建议采用其他治疗方法。     

Dynamic gadoteridol-enhanced MR imaging in the end of growing long bone of piglets

Background It is of value to identify the non-invasive means that can accurately reflect the blood supply of epiphysis and is more sensitive in detection of early ischemia of epiphysis than the conventional gadoteridol （Gd）-enhanced SE TlWI. The aim of this study was to evaluate the blood supply of various anatomic regions at the end of normal growing long bone using dynamic Gd-enhanced MR imaging and compare the sensitivities between dynamic Gd-enhanced MR imaging and conventional Gd-enhanced SE TlWl in the detection of decreased blood perfusion of early epiphyseal ischemia. Methods Twenty-seven two-week-old piglets were used in this study. For the study of the end of normal growing long bone, unilateral MR imaging of the distal femur and proximal tibia was performed on eleven piglets. The comparison was made among various anatomic regions （physeal and epiphyseal cartilage, metaphyseal spongiosa, the secondary ossification center and metaphysis） using MRI in terms of the enhancement ratio and speed. Their relationships with the histological findings, including RBC/mm^2 and vessel distribution, were evaluated. To examine ischemic femoral head, 16 piglets were divided into two groups, with the control group having 8 piglets （involving 16 normal hips） and an ischemic group having 8 piglets （involving 16 hips with hyperabduction）. In the ischemic group, MR imaging was performed on the hips in the hyperabduction immobilized persistently for 30 minutes. After MRI, the piglets were allowed to ambulate freely for 1 day and the same MR scanning was then repeated in a neutral position. The difference in enhancement ratio and speed of the femoral head between the control and ischemic group were evaluated. Results With regard to the end of normal growing long bone, the enhancement ratio of the metaphyseal spongiosa was greatest among all the anatomic regions （P 〈0.001）. The enhancement ratio of physeal cartilage was greater than that of epiphyseal cartilage （P 〈0. 001）, which was the lowest in al