定量CT评价骨折愈合的有效性

目的 探讨定量CT(quantitative computed tomography,QCT)评价骨折愈合的有效性和准确性.方法 将24只健康新西兰兔随机数字表法分为A组(骨折愈合组,右胫骨中段横形骨折,用克氏针内固定)和B组(不愈合组,右胫骨中段横断骨折,制作5 mm骨缺损后以骨蜡封填断端和髓腔),分别于第2,4,8,12周各处理3只兔:先摄两侧胫骨X线片,拔出克氏针及定量CT检测,之后处死动物,将骨折段切取行组织学分析.以X线片和组织学表现为骨折愈合及不愈合的金标准,以受试者工作特征曲线(ROC)分析定量CT检测参数的评价效能,并以健侧胫骨相应节段为对照,观察定量CT参数结果的变化趋势.结果 A组X线片和组织学证实骨折在第2,4周骨折线清晰,为纤维骨痂填充,8～12周骨折线模糊至消失,骨皮质恢复完整连续性.B组X线片和组织学在第2、4周骨折线清晰,骨化不活跃,8～12周骨折线仍存在,骨细胞和骨小梁稀少.将定量CT检测结果进行ROC分析显示,材料学参数骨痂骨密度(BMD)、骨痂骨矿含量(BMC)的曲线下面积(准确度)为0.781和0.750,结构学参数横截面积(CSA)和截面惯性矩(CSMI)的曲线下面积(准确度)为0.781和0.469(P<0.05),材料学参数和结构学参数乘积引伸所得的横截面积力学强度指数(BSICSA)、截面惯性矩力学强度指数(BSICSMI)的曲线下面积(准确度)分别为0.913和0.813(P<0.05),BMD、CSA、BSICSA三者曲线下面积(准确度)分别为0.905,0.921,0.905(P<0.05).结论 定量技术测量骨折局部形态具有区分和反映骨折愈合与骨折不愈合模型及过程的潜能,所筛选出具有准确度的参数有BMD、CSA和BSICSA,这些参数具有准确、特异的优越性.     

双能X线骨密度仪测定骨痂骨密度变化的实验研究

目的: 研究骨折愈合过程中骨密度的动态变化,判断双能X线骨密度仪评估骨痂骨密度的可行性.材料和方法:30只犬造成右胫骨中段骨折并分断端距离4mm,单边外固定支架固定.分别在术后4、6、8、10、12周取双侧胫骨,以双能X线骨密度仪测定骨折端1cm的骨密度,分析骨密度变化及骨密度增长率的变化.结果:骨折端骨密度随时间呈一定规律增加,在不同时间组间差异有显著意义(P<0.01).自身对照的骨密度比率也随时间增加,在各组间差异有显著意义(P<0.01).12周时骨折端骨密度达到正常侧水平.结论:在犬骨折愈合过程中骨痂骨密度持续增加,双能X线骨密度仪可用于骨愈合中骨痂的骨密度判断.     

骨愈灵胶囊治疗骨质疏松性桡骨远端骨折效果分析

目的：探讨骨质疏松性桡骨远端骨折采用骨愈灵胶囊治疗的临床效果。方法：本次研究选择的对象共772例,均为我院2007-04～2009-04收治的骨质疏松性桡骨远端骨折的患者,按治疗组420例和组对照组342例划分,在常规处理骨折后,对照组采用奶维钙片等口服治疗,治疗组采用骨愈灵胶囊口服治疗,回顾相关资料。结果：治疗组8周后骨痂形成多于对照组,骨折愈合时间显著早于对照组,差异有统计学意义（P〈0.05）。两组BMD治疗前无明显差异,治疗后均有所提高,但治疗组提高幅度显著优于对照组（P〈0.05）。两组均无严重不良反应。结论：骨质疏松性桡骨骨折采用骨愈灵胶囊治疗,可有效促进骨愈合,提高骨密度,显著改善患者生存质量,具有较高的临床应用价值。     

有限切开内固定结合带关节型外固定架治疗难复性桡骨远端粉碎骨折的疗效分析

桡骨远端骨折是指距桡骨远端关节面3cm以内的骨折,是临床常见的骨折,约占全身骨折的17%[1]。各种年龄段均可发生,多见于50岁以上人群。桡骨远端骨折通常采用手法复位石膏外固定治疗来获得满意疗效。但当骨折碎裂严重,手法无法复位,且桡骨远端短缩、骨质疏松、关节面碎裂骨块     

结构性植骨在复杂桡骨远端骨折骨缺损中的应用

目的 探讨采用结构性自体髂骨移植治疗高能量损伤所致伴有关节面的塌陷与干骺端粉碎缺损的桡骨远端骨折的疗效。 方法 选取2007年1月-2010年10月就诊的桡骨远端骨折(AO分类C3型)患者38例,克氏针临时维持固定,使桡腕关节面、桡骨远端长度、掌倾角最大限度恢复。根据骨缺损的形态,取自体3层皮质骨髂骨块嵌入软骨下骨支撑植骨,并取少量松质骨植骨填塞顶压塌陷关节面,尽可能使关节面解剖复位,重建桡骨远端解剖形态。采用改良Gartland和Werley评分标准评定腕关节功能恢复情况。 结果 随访12～ 38个月,无钢板断裂和医源性神经血管损伤。本组骨折愈合时间15～22周,平均18.3周。部分患者经功能康复锻炼后腕关节功能明显改善。按改良Garland和Werley功能评估系统进行疗效评定,优良率为87％。随访中2例患者桡骨远端高度进行性丢失,2例患者桡腕关节面中央凹陷型塌陷,有严重的腕关节屈伸功能障碍。 结论高能量损伤所致复杂桡骨远端骨折需恢复桡腕关节面、桡骨远端长度、掌倾角,采用结构性自体髂骨移植能有效支撑植骨和维持桡腕关节面的平整,恢复桡骨远端的解剖形态,促进腕关节功能的恢复。     

微创内固定支架经皮微创内固定治疗C型老年桡骨远端骨折的临床研究

目的探讨微创内固定支架经皮微创内固定治疗C型老年桡骨远端骨折的临床效果。方法回顾性分析2015年3月—2018年3月厦门大学附属成功医院收治C型老年桡骨远端骨折患者97例,男性62例,女性35例;年龄60~78岁,平均67.4岁。按固定方式不同分为外固定支架组(48例)和微创组(49例),外固定支架组行外固定支架固定治疗,微创组行微创内固定支架经皮微创内固定治疗。比较两组患者手术效果、影像学指标、骨折端骨痂生长愈合情况及术后并发症情况。结果术后6个月,微创组优良率(93.88%)高于外固定支架组(79.17%)(P<0.05),桡骨高度(12.42±4.60)mm高于外固定支架组(8.53±5.59)mm,尺偏角(22.50±5.96)°、掌倾角(11.06±5.82)°大于外固定支架组尺偏角(18.93±5.20)°、掌倾角(8.45±4.78)°(P<0.05);微创组术后1、2个月骨折端骨痂生长愈合情况Lane-Sandhu X线片评分分别为(1.67±0.29)分、(3.78±0.66)分,优于外固定支架组(1.15±0.37)分、(2.82±0.54)分(P<0.05);微创组术后并发症发生率(6.12%)低于外固定支架组(20.83%)(P<0.05)。结论微创内固定支架经皮微创内固定治疗C型老年桡骨远端骨折患者手术效果好,有利于骨折端骨痂生长愈合,术后并发症较少,临床治疗可参考。     

克氏针结合外固定支架与锁定加压钢板对桡骨远端复杂关节内骨折关节功能恢复比较

目的探讨克氏针结合外固定支架与锁定加压钢板对桡骨远端复杂关节内骨折的疗效。方法78例桡骨远端复杂关节内骨折患者按照手术方式不同分为克氏针组(42例)和钢板组(36例)。克氏针组采用克氏针结合外固定支架,钢板组采用锁定加压钢板固定治疗。比较两组患者骨密度变化、骨折愈合、腕关节功能恢复情况及并发症发生率。结果克氏针组与钢板组愈合率、骨折愈合时间、桡骨缩短程度、骨密度比较差异无统计学意义(P0.05)。C1、C2型患者:克氏针组、钢板组手术前后各时段腕关节功能评分比较差异均无统计学意义(P0.05);C3型患者:克氏针组腕关节功能评分明显低于钢板组,两组间比较差异具有统计学意义(P0.05)。克氏针组和钢板组并发症发生率比较差异无统计学意义(P0.05)。结论克氏针结合外固定支架治疗C3型骨折患者疗效明显优于锁定加压钢板。     

桡骨骨钉治疗腕舟骨骨折不愈合

目的探讨桡骨骨钉治疗腕舟骨骨折不愈合的疗效及可行性。方法对我院自1999年4月—2005年9月收治的52例腕舟骨骨折不愈合患者采用桡骨骨钉治疗的情况进行回顾性分析。本组患者均于开放复位后,凿取1.5 cm×0.4 cm×0.4 cm桡骨骨钉进行内固定,术后石膏固定2~3个月。结果全部病例术后随访6个月~1年,52例骨折全部愈合,优27例,良22例,可3例。结论采用桡骨骨钉治疗腕舟骨骨折不愈合,能够牢靠固定骨折,并明显促进骨折愈合,是治疗腕舟骨骨折不愈合的有效方法。     

用MR显微成像及图像处理法对前臂海绵骨容积及结构行非损伤性评价

为进一步应用通过活体桡骨远端MR成像获得海绵骨结构参数这一方法,并衡量这些参数对骨减少者椎体骨折状况的预测能力,作者对36例妇女(平均年龄53.5±8.4岁)进行了研究。用双能X线吸收法(DXA,Lunar公司DPX型)对其进行L_(2～4)椎体及非优势侧桡骨远端骨密度(BMD)测定(测量范围与MR测量时相匹配)。并用GE公司Signa型1.5T MR仪对远端桡骨进行显微成像,应用特制鸟笼形线圈,线圈中心位于尺骨茎突近侧2～3cm处,行三维横断体积扫描,FLASE序列,TR/TE为80/5.7ms,120°翻转角,3.5×7.0cm矩形FOV,层厚     

游离骨折块移位距离对骨折愈合影响的实验研究

目的 探讨长骨干粉碎性骨折游离骨折块移位距离对骨折愈合的影响. 方法 在120只新西兰大白兔右桡骨中部截取楔形骨块,制成实验模型,用2枚克氏针将骨块复位固定并使之与主骨存有一定的间距,并分为五组:A组(原位固定)、B组(骨块与骨干间距为桡骨干直径1/5)、C组(桡骨干直径2/5)、D组(桡骨干直径3/5)、E组(桡骨干直径4/5).每组动物分别于术后2,4,6,8周分批处死,摄X线片观察各组骨折愈合情况,用改进Gary X线评分标准评分;取材HE染色,观察骨折愈合的组织形态学变化,免疫组化测定BMP-2的表达. 结果 (1)X线摄片显示:A、B组骨折愈合无差异,C、D组骨折愈合延迟,E组骨块吸收骨不连.(2)组织形态学观察:A、B组骨折局部形态学变化相同,而其他各组与A组相比,骨痂出现及改建的时间明显较晚,呈延迟愈合和不愈合的表现.(3)BMP-2表达:2周时BMP-2表达B组与A组差异无统计学意义(P＞0.05),C、D、E组与A组比较差异有统计学意义(P＜0.01),4周时只有E组与A组差异有统计学意义(P＜0.01);6周和8周时各组之间差异无统计学意义(P＞0.05). 结论游离骨折块移位距离会影响骨折的愈合,移位距离越大,对骨折愈合产生的影响越明显,当游离骨折块移位距离达到其骨干直径的2/5以上时,骨折将发生愈合障碍.     

Quantitative computed tomography

Quantitative computed tomography (QCT) is an established technique for measuring bone mineral density (BMD) in the axial spine and peripheral skeleton (forearm, tibia). QCT can determine in three dimensions the true volumetric density (mg/cm 3) of trabecular or cortical bone at any skeletal site. However, because of the high responsiveness of spinal trabecular bone and its importance for vertebral strength, QCT has been principally employed to determine trabecular BMD in the vertebral body. QCT has been used for assessment of vertebral fracture risk, measurement of age-related bone loss, and follow-up of osteoporosis and other metabolic bone diseases. This article reviews the current capabilities of QCT at different skeletal sites and the recent technical developments, including volumetric acquisition.     

Differential effects of menopause and metabolic disease on trabecular and cortical bone assessed by peripheral quantitative computed tomography (pQCT)

The usefulness of peripheral quantitative computed tomography (pQCT) was investigated in the diagnosis of metabolic bone diseases, including osteoporosis, and especially in the different diagnostic values in trabecular and cortical components. The subjects were 460 Japanese women aged 20-86 years, including 318 healthy volunteers, 58 osteoporotics with fracture and 84 patients with diseases including amenorrhoea, steroid-induced osteoporosis, renal osteodystrophy (ROD) and primary hyperparathyroidism. Bone mineral density (BMD) was measured for more than 4 years in 74 of the healthy volunteers. BMD was measured by spinal QCT, dual X-ray absorptiometry (DXA) of the spine, radius, and heel, and pQCT of the radius and tibia. High resolution images were obtained for geometry of the radius. Radial pQCT showed a higher correlation with radial DXA than with spinal QCT, and spinal QCT showed a higher correlation with spinal DXA than with radial pQCT. The annual bone loss rates at predominantly trabecular bone sites were accelerated in both the axial and appendicular skeleton. In the fracture study, radial pQCT showed a higher odds ratio (OR = 4.4) than radial DXA, and cortical area ratio seemed to be a good predictor of fracture risk (OR = 5.2). Amenorrhoea and steroid-induced osteoporosis predominantly affected trabecular bone, ROD predominantly affected cortical bone and hyperparathyroidism affected both components, especially the cortical component. pQCT is useful for assessing both trabecular and cortical bone, to provide information on individual bone changes in metabolic bone disease and to estimate the risk of fracture.     

Mid-femur geometry and biomechanical properties in 15- to 18-yr-old female athletes

PURPOSE: Right-leg mid-femur geometry and biomechanical indices of bone strength were compared among elite cyclists (CYC), runners (RUN), swimmers (SWIM), triathletes (TRI), and controls (C)-10 subjects per group. METHODS: Bone cross-sectional areas (CSA), volumes (Vol), and cross-sectional moments of inertia (CSMI) were assessed by magnetic resonance imaging (MRI), and cortical volumetric bone density (volBMD) was determined as the quotient of DXA-derived bone mineral content (BMC) and MRI-derived cortical bone volume. Bone strength index (BSI) was calculated as the product of cortical volBMD and CSMI. RESULTS: RUN had higher (P < 0.05) size- (femur length and body mass) adjusted (ANCOVA) cortical CSA than C, SWIM, and CYC; and higher size, age, and years of sport-specific training- (YST) adjusted cortical CSA than SWIM and CYC. TRI had higher (P < 0.05) size-adjusted CSA than SWIM. SWIM and CYC had significantly larger (P < 0.05) size-adjusted medullary cavity CSA than RUN and TRI, and the difference between CYC and RUN persisted after additional adjustment for age and YST. RUN had significantly (P < 0.05) greater size-adjusted CSMI and BSI than C, SWIM, and CYC; and higher size, age, and YST-adjusted CSMI and BSI than SWIM and CYC. Mid-femur areal bone mineral density (BMD) was significantly (P < 0.05) higher for RUN compared with CYC only, but there were no other differences among groups for BMC, bone volumes, or volumetric total or cortical BMD. CONCLUSIONS: Running, a weight-bearing exercise, is associated with more favorable geometric and biomechanical characteristics in relation to bone strength, compared with the weight supported activities of swimming and cycling. Differences may reflect skeletal adaptations to the specific mechanical-loading patterns inherent in these sports.     

Quantitative computed tomographic evaluation of femoral bone mineral content in renal osteodystrophy compared with radial photon absorptiometry

The computed tomography (CT) numbers of cortical bone at the level of 20 cm (CT20) and of spongiosa in the lateral condyle at the level of 2 cm (CT02) from the distal end of the femur were obtained by a quantitative CT method and compared with the bone mineral density of mostly cortical bone within the radius (BMD) by photon absorptiometry. The study included 47 patients with chronic renal failure not dialyzed or induced to regular hemodialysis within 4 weeks of the study (group 1), 28 patients on regular hemodialysis for more than one month (group 2), and ten healthy volunteers (group 3). The measures of bone mineral content (BMC), namely CT20, CT02, and BMD, were compared in terms of their abilities to distinguish members in the various groups. For group 1 and group 3, the greatest variation in BMC was in the difference in CT02, which was primarily a measurement of the BMC of spongiosa. For groups 1 and 2, the greatest variation was in the difference in BMD, which was primarily a measurement of the BMC of cortex. The reproducibility of CT02 was estimated as almost equal to the difference in CT02 values at intervals of 10 months' duration of hemodialysis. The results indicated that CT02 was a useful measurement for evaluating the progress in the early stage of the renal osteodystrophy, and it is recommended that the bone mineral measurement with this QCT method should be performed once or twice a year.     

Comparative bone density measurements in healthy women and women with osteoporosis

To compare methods of noninvasive measurement of bone mineral content, 40 healthy early postmenopausal women and 68 postmenopausal women with osteoporosis were studied. The methods included mono- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiographic studies were performed and the spinal fracture index calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and moderate correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were moderate in healthy women and poor in osteoporotic women. Measurements resulting from one method were not predictive of measurements obtained by another method for individual patients. The strongest correlation with severity of vertebral fracture was provided by QCT and the weakest by SPA. There was good correlation between single- and dual-energy QCT results. Osteoporotic women and younger healthy women can be distinguished by the measurement of spinal trabecular bone density using QCT, and this method is more sensitive than the measurement of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT.     

健康老年妇女近段股骨骨密度和结构的定量CT研究

目的 采用定量CT(QCT)和双能X线吸收测量(DXA)仪对健康老年妇女近段股骨骨密度(BMD)和骨结构进行研究,并对2种测量方法的结果进行比较.方法 对66名65岁以上健康妇女左侧髋关节进行DXA测量,计算出股骨颈和粗隆区BMD;对其双侧近段股骨进行QCT测量,计算出股骨颈、粗隆区和整体股骨ROI的皮质骨、松质骨和总体骨的BMD和体积;并将QCT三维图像模拟DXA的平面投影计算出模拟DXA股骨颈BMD和模拟DXA股骨粗隆区BMD.对所获数据进行配对t检验或非参数秩和检验,并用Pearson法分析DXA和QCT相对应ROI的相关性.结果 用QCT可以对股骨近段不同ROI(股骨颈、粗隆区和整体股骨区)及不同骨成分(皮质骨、松质骨和总体骨)的BMD及体积等参数进行精确的定量分析.除右侧股骨颈皮质骨BMD[(0.52±0.04)g/cm3]、股骨粗隆区皮质骨BMD[(0.49±0.03)g/cm3]、股骨粗隆区综合骨BMD[(0.22±0.04)g/cm3]大于左侧相应参数[分别为[(0.51±0.04)、(0.48±0.03)、(0.21±0.04)g/cm3],差异均有统计学意义(P值均<0.05),但差别均<3.3%;而模拟DXA股骨颈BMD、模拟DXA股骨粗隆区BMD、股骨颈皮质骨体积、股骨颈松质骨BMD、股骨颈松质骨体积、股骨颈综合骨BMD、股骨颈综合骨体积、股骨粗隆区皮质骨体积、股骨粗隆区松质骨BMD、股骨粗隆区松质骨体积、股骨粗隆区综合骨体积左侧参数分别为(0.52±0.10)g/cm2、(0.78±0.13)g/cm2、5.80 cm3、(0.06±0.03)g/cm3、(5.19±1.40)cm3、(0.25±0.04)g/cm3、15.66 cm3、(21.74±3.43)cm3、(0.08±0.03)g/cm3、(34.27±6.09)cm3、(76.12±11.11)cm3,右侧分别为(0.52±0.10)g/cm2、(0.78±0.13)g/cm2、6.01 cm3、(0.06±0.02)g/cm3、(5.17±1.27)cm3、(0.25±0.04)g/cm3、15.62 cm3、(22.12±3.60)cm3、(0.09±0.03)g/cm3、(34.17±5.94)cm3、(76.53±10.71)cm3,差异均无统计学意义(P值均>0.05).左右两侧近段股骨QCT各相对应参数之间的r值范围在0.656～0.955,均具有相关性(P<0.05).QCT模拟DXA股骨颈和粗隆区BMD与真正DXA测量的相应值之间r值分别为0.685和0.855,具有相关性(P<0.05).结论 利用QCT技术可以对老年妇女近段股骨不同区域和不同成分的BMD和结构进行精确定量分析,QCT是骨质疏松研究中非常有用的测量技术.     

Quantitative computed tomography

Quantitative computed tomography (QCT) was introduced in the mid 1970s. The technique is most commonly applied to 2D slices in the lumbar spine to measure trabecular bone mineral density (BMD; mg/cm³). Although not as widely utilized as dual-energy X-ray absortiometry (DXA) QCT has some advantages when studying the skeleton (separate measures of cortical and trabecular BMD; measurement of volumetric, as opposed to ‘areal’ DXA-BMDa, so not size dependent; geometric and structural parameters obtained which contribute to bone strength). A limitation is that the World Health Organisation (WHO) definition of osteoporosis in terms of bone densitometry (T score ?2.5 or below using DXA) is not applicable. QCT can be performed on conventional body CT scanners, or at peripheral sites (radius, tibia) using smaller, less expensive dedicated peripheral CT scanners (pQCT). Although the ionising radiation dose of spinal QCT is higher than for DXA, the dose compares favorably with those of other radiographic procedures (spinal radiographs) performed in patients suspected of having osteoporosis. The radiation dose from peripheral QCT scanners is negligible. Technical developments in CT (spiral multi-detector CT; improved spatial resolution) allow rapid acquisition of 3D volume images which enable QCT to be applied to the clinically important site of the proximal femur, more sophisticated analysis of cortical and trabecular bone, the imaging of trabecular structure and the application of finite element analysis (FEA). Such research studies contribute importantly to the understanding of bone growth and development, the effect of disease and treatment on the skeleton and the biomechanics of bone strength and fracture.     

Bone mineral content in early-postmenopausal and postmenopausal osteoporotic women: comparison of measurement methods

To investigate associations among methods for noninvasive measurement of skeletal bone mass, we studied 40 healthy early postmenopausal women and 68 older postmenopausal women with osteoporosis. Methods included single- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiography was performed, and a spinal fracture index was calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and modest correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were modest in healthy women and poor in osteoporotic women. Measurements resulting from one method are not predictive of those by another method for the individual patient. The strongest correlation with severity of vertebral fracture is provided by QCT; the weakest, by SPA. There was a high correlation between single- and dual-energy QCT results, indicating that errors due to vertebral fat are not substantial in these postmenopausal women. Single-energy QCT may be adequate and perhaps preferable for assessing postmenopausal women. The measurement of spinal trabecular bone density by QCT discriminates between osteoporotic women and younger healthy women with more sensitivity than measurements of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT.     

Osteonecrosis diagnosed on MR images of the knee. Relationship to reduced bone mineral density determined by high resolution peripheral quantitative CT

Purpose: 
To evaluate if osteonecrosis diagnosed on MR images of the knee relates to reduced bone mineral density (BMD) and may be caused by an insufficiency fracture. Material and Methods: 
Thirty-two consecutive patients (8 men, 24 women; age range 27-82 years, mean 62 years) with MR findings of osteonecrosis of the femoral or tibial condyle were prospectively included. Trabecular and cortical BMD were measured with high resolution peripheral quantitative CT in the non-dominant distal radius and the tibia of the involved extremity. One tibia was not measured due to posttraumatic deformity. Results: 
The mean trabecular BMD of the radius was 81% of the young-adult average peak BMD (range 19-160%). The mean cortical BMD in the radius was 86% (range 63-108%). The mean trabecular BMD in the tibia was 92% (range 28-160%). The mean cortical BMD in the tibia was 86% (range 49-132%). The values of the trabecular bone of the distal radius (tibia) were normal in 11 (15) patients, osteopenic in 12 (4), and osteoporotic in 9 (12), respectively. The cortical bone values of the distal radius (tibia) were normal in 12 (13) patients, osteopenic in 12 (12), and osteoporotic in 8 (6), respectively. Conclusion: 
Osteoporosis and osteopenia are commonly found in patients with osteonecrosis of the knee as diagnosed on MR images. This indicates that for some patients an insufficiency mechanism may be responsible for the MR findings. However, in the patients with normal bone density other reasons for osteonecrosis may be present.