1、Normal radiographs of the knee with anteroposterior(a),lateral(b),and axial(c)biew demonstrate normal patellar position and morphology.The anteroposterior projection(a)is useful for evaluting the femur and proximal tibia,femoral and tibial plateaus.The lateral projection is useful for evaluating pat
2、ellar height,patellofemoral compartment,suprapatellar recess(SR),quadriceps tendon(QT),patellar tendon(PT).The axial view of the patella helps in assessment of the shape of the patella,note media(MF)and lateral(LF)patellar facets and median ridge(MR).Also note normal and rough anterior patellar cort
3、ex(blue arrow).1 Fig.1:Normal knee radiographs图1：正常膝关节2 Sagittal proton density(a)and axial fat-suppressed T2-weighted(b)MR images of a normal knee.Note the low signal patellar(PT)and quadriceps(QT)tendons and the thick,homogeneous-appearing patellar cartillage(red arrows).Note the lateral and media
4、 retinacula,passive stabilizers of the patella.3 Fig.2:Normal MR images图2：正常膝关节MR图像4 In 1941,Wiberg classified patellar shape into three different morphologies:Type I(a)demonstrates roughly symmetric and equal-sized,concave medial(MF)and lateral(LF)patellar facets.Type II(b)shows a medial facet that
5、 is slightly smaller than the lateral facet and a concave lateral facet.Type III(c)also shows a smaller and more vertically oriented medial patellar facet,which is associated with maltracking disorders 18.5 Fig.3:Variations in patellar morphology图3：髌骨形态变异6 5-year-old male with hereditary osteo-onych
6、odysplasia(nail-patella syndrome).AP(a),later(b),and axial(c)views of the knee demonstrate complete absence of the bilateral patellar ossification centers.7 Fig.4:Patellar aplasia图4：髌骨发育不良 5岁男孩遗传性指(趾)甲-髌骨综合征（nail-patella syndrome）8 Anteroposterior and axial radiographs(a)show bilateral,well-corticat
7、ed ossified fragments in the superolateral aspect of the patellas(arrows).Coronal and axial T2-weighted fat-suppressed MR image(b)show the well-corticated ossified fragment.Note the normal bone marrow signal and cartilage across the synchondrisis,The well-corticated nature of the fragment and lack o
8、f abnormal marrow signal help to differentiate this entity from a patellar fracture.9 Fig.5:Bipartite patella图5：二分髌骨10 Anteroposterior,lateral,and axial radiographs(s)show a lucent,round lesion with well-defined margins at the superolateral aspect of the patella(arrows).Sagittal proton density and a
9、xial T2-weighted fat-suppressed MR images(b)show a focal subchondral osseous defect with intact-appearing overlying cartilage;the cartilage is thickened,and fills the defect.There is normal bone marrow signal and smooth,homogeneous signal of the articular cartilage.11 Fig.6:Dorsal defect of the pate
10、lla图6：髌骨背侧缺损（DDP）12 Congenital patella alta is an anatomic risk factor for patellofemoral instability.The insall-Salvati index is the ratio of the length of the patella(PL)to the patellar tendon(PT).The normal value is between 1.0 and 1.2,with increased values indicating patella alta and decreased v
11、alue indicating patella baja.Lateral radiograph(a)at approximately 30 degrees of knee flxion shows a noemally placed patella,with Insall-Salvati index of 1.1.Lateral radiograph(b)of an 8-year-old male shows patella alta,with Insall-Salvati index measuring 1.8.Axial T2-weighted tubro spin echo MR ima
12、ge(c)form this same patient shows finding of a lateral patellar dislocation.There is bone marrow edema of the medial aspect of the patella(arrow)and disruption of the medial patellar retinaculum(asterisk).This patient had a history of recurrent dislocations,likely due to his congenital patella alta.
13、13 Fig.7:Patella alta图7：高位髌骨 a图正常位置髌骨，髌韧带长度（PT）/髌骨长度（PL）正常比值为1.0-1.2（国内文献一般小于0.8提示低位髌骨，大于1.2提示高位髌骨）；b图PT/PL比值为1.8；c图示髌骨脱位状态，局部骨髓水肿。高位髌骨通常无症状，尽管它是膝关节不稳定的重要解剖危险因素之一。14 Anteroposterior(a)and lateral(b)radiographs of a 15-year-old female patient with cingenital right-sided patella baja.Lateral radiograp
14、hs of a patient one year following total knee arthroplasty demonstrates patella baja.The patellar tendon is scarred to the upper tibia(arrow).Patella baja may also be seen in association with neuromuscular diseases.Fromtal(c)and lateral(d)radiographs in this patient with a history of polio show mark
15、ed patella baja.Also nite that the bine are osteopenic and gracile and that there is a paucity of soft tissues,in keeping with the patients history of polio.15 Fig.8:Patella baja图8：低位髌骨 a,b图，15岁女孩右膝先天性低位髌骨。c,d图，低位髌骨也见于神经肌肉疾病；患者既往有脊髓灰质炎病史。e图，人工膝关节置换后患者一年复查，侧位片提示低位髌骨；箭头是髌韧带疤痕形成。16 Trochlear dysplasia
16、is among the most significant anstomic factors contributing to patellar maltracking Lateral radiograph(a)depicts one sign,the crossing sign,in which the line of the deepest aspect of the trochlear groove crosses over the antenor aspect of the femoral condyles(arrow).Sagittal proton density image(b)d
17、epicts another hnding of trochlear dysplasia.The ventral trochlear prominence(vtp)has been detined as the distance between the line paralleling the ventral cortical surface of the distal femur and the most anterior point of the femoral trochlear floor.In this image is seen a step-like deformity at t
18、he intertace of the anterior femoral cortex and trochiea with a vte measuring 9 mm,consistent with trochlear dysplasia.Axial T2-weighted fat-suppressed image(c)shows a congenitaly dysplastic trochlea with a markedly shallow trochiear depth(arrow),consistent with trochlear dysolbsia Addisanally noted
19、 is marked asymmetry of the medial(MF)and lateral(LF)trochlear facets.A lateral to medalfemoral facet.rano ot greater than 1.75 is generally considered diagrosnc for trochlear dysplasia.In this case the ratio measures23.representing another tinding of trochlear doplasia17 Fig.9:Trochlear dysplasia图9
20、：（股骨）滑车发育不良 股骨滑车发育不良是指滑车沟前部的几何外形和深度存在的解剖学异常。可引起髌骨轨迹不良或慢性膝关节不稳。18 Trochlear depth assessed on axial T2-weighted fat-suppressed images.A line is first drawn parallel to the posterior temoral condies(A).Lines drawn perpendicular to this indicate the anteroposterior dimensions of the lateral(B)and media
21、l(C)trochlear facets and of the deepest portion of the lemoral trochlea(D)Calculate trochlear depth with the equaion(BC/2)-D.Trochlear depth of 3 mm or less indicates trochlear dysplasia.image(a)shows a normal trochlear depth,image(b)shows a dysplasnc trochlea with marked flattening19 Fig.10:Trochle
22、ar dysplasia measurement of trochlear depth图10：滑车发育不良-滑车深度的测量 计算公式：（B+C/2）-D；小于3mm提示滑车发育不良。a图是正常的滑车深度，b图是滑车发育不良，呈扁平状。20 The distance from the tibial tubercle to the trochilear groove is measured on axial MR images.A distance of 20 mm indicates considerable lateralization and is almost always associa
23、ted with patellar instability.Axial MR images in the top row(a)show a normal tibial-tubercle groove distance(blue double-headed arrow).Images in the second row(b)show markedly lateral position of the tibial tubercle in relation to the trochlear groove(blue double-headed arrow).21 Fig.11:Lateralizati
24、on of the tibial tubercle图11：胫骨结节的偏侧性 胫骨结节的偏侧性通过测量胫骨结节-股骨滑车间距离来定性，测量方法：分别选择通过胫骨结节的横断面图像，及通过股骨髁间窝呈“罗马拱门”形态的层面；勾画出胫骨结节的层面，通过软件和股骨髁间窝层面图像融合，在此新的图像上标记股骨后髁的切线作为参考线，然后分别过股骨滑车最低点和胫骨结节中点作股骨后髁切线的垂线，2条垂线的距离即为胫骨结节-股骨滑车间距离。意义：反映施加于膝关节的屈伸装置的外翻矢量。小于15mm正常；15-20毫米临界；大于20mm诊断髌骨不稳。a图是正常，b图提示髌骨不稳。22 30-vear old femal
25、e former long distance runner presents with progressively increasing knee pain for 3 years,now sugnihcantly limiting her actinty Lateral radiograph(a)shows subchondral sclerosis(blue arrow)of the patela.Sagittal proton density(b),sagittal T2-weighted fat-suppressed(cl,and anial T2-weighted fat-suppr
26、essed(d)images show muitifocal areas of full-thickness cartilage fissuring along the patelitlafwhite arrows).with subjacent areas of marrow edema(red arrows)and subcortical cystic change.Note the normal carhlage elsewhere.23 Fig.12:Chondromalacia patellae图12：髌骨软化症女，30岁，长跑运动员，进行性膝关节疼痛3年；运动受限就诊。a图蓝箭示髌
27、骨软骨下骨质硬化；b，c，d图示多发局灶性全层软骨裂隙伴相软骨下骨髓水肿和皮质下囊变。24 15-year-old male patient with knee pain.Lateral(a)and axial(b)radiographs show irregularity and a defect along the patellar apex(arrows).Sagittal proton density(c)and axial T2-weighted fat-suppressed(d)images show an osteochondral lesion in the mid patel
28、la at the apex with bone marrow edema(asterisk).Sagittal proton density image(e)from MRI performed 6 years latershows interval resolution of the lesion.25 Fig.13:Osteochondritis dissecans图13：剥脱性骨软骨炎15岁男孩，膝关节痛。a，b图示髌骨下级不规则 缺损；c，d图示局部骨软骨游离伴软骨下骨髓水肿；e图示6年后复查，病灶修复。26 13-year-old female presenting with kn
29、ee pain.Sagittal proton density(a),sagittal fat suppressed proton density(b),and axial fat-saturated proton density(c)MR images show an osteochondritis dissecans lesion.There is surrounding high signal(black arrows)with small cystic change and focal cartilage defect.Sagittal proton density image(d)f
30、rom four months later,following arthroscopic lesion repair,shows a well:incorporated bone graft.27 Fig.14:Unstable osteochondritis dissecans lesion图14：不稳定的剥脱性骨软骨炎13岁女孩膝关节疼痛；a，b，c图示髌骨局部骨软骨病灶周围见液体信号影；d图关节镜修复后4个月复查，显示移植骨愈合良好。28 16-year-old male with a history of acute lymphoblastic leukemia(now in remi
31、ssionl,diabetes melitus,and obesity.Anteroposterior(a),lateral(b),and axial(c)radiographs show a lucent area in the central posterior region of the right patella,with a halo of sclerosis.Sagital proton density(d),and coronal(e)and acial(f)T2 weighted fat-suppressed images demonstrate a lesion of int
32、ermediate and low signal intensity,surounded bya peripheral margin of low signal intensity Dark areas represent bone infarcts.29 Fig.15:Patellar osteonecrosis图15：髌骨骨坏死16岁男孩；急性淋巴结细胞性白血病（现缓解期）、糖尿病、肥胖病史。30 Axial radiograph(a)showing slight lateral subluxation of patella with corticated body along the m
33、edial patellar facet(arrow),stigmata of dislocation.Axial radiograph(b)in a different patient shows normal alignment.Note the mild heterogeneity involving lateral aspect of the lateral femoral condyle(white arrow)and the subtle depression in the articular surface of the medial patellar facet(blue ar
34、row,findings reflective of a recent patellar dislocation.Coronal fat-suppressed proton density(c)and axial fat-suppressed T2-weighted(d,elimages demonstrate bone marrow contusions along the medial patellar facet(white arrow)and the lateral aspect of the lateral femoral condyle(blue arrow).There is a
35、 partial tear of the medial patellar retinaculum(asterisk),and there is a moderate sized joint effusion with a fluid-fluid level(red arrow)representing hemarthrosis.These findings are typical for lateral patellar dislocation.31 Fig.16:Lateral patellar dislocation图16：髌骨外侧脱位 慢性不稳定/复发性脱位患者，如果不积极治疗可能导致进
36、行性软骨损伤和严重骨性关节炎。32 Anteroposterior(a)and lateral(b)radiographs in a patiernt presenting with a direct fall onto the patella showa comminuted fracture of the patella,with 8 mm of distraction at the mid bone.33 Fig.17:Acute fracture of the patella图17：髌骨骨折34 Three images of a 12-year-old male following
37、a fall who presented with anterior knee pain,swelling,and decreased ambulation.Lateral radiograph(a)shows a minimally displaced fracture of the interior patelia(arrow)with thickening of the patellar tendon and a small knee joint effusion.Sagirtal proton density image(b)shows a tracture at the inferi
38、or pole of the patella(arrow)with edema of the patellar tendon.Axtial T2-weighted fat-suppressed image(c)shows edema at the inferior pole.35 Fig.18:Patellar sleeve avulsion fracture图18：髌骨袖套状撕脱骨折 是儿童特有的一种髌骨骨折。因为髌骨软骨骨转化过程中的髌骨骺生长板，位于其骨化核周缘，骺板的增殖、肥大细胞带和初级钙化带薄弱，常不能耐受剪式应力而分离损伤。当膝关节处于半屈曲位股四头肌强烈收缩时，牵引髌骨向上，而
39、髌韧带固定髌骨形成作用力和反作用力，髌骨下部的软骨受股四头肌强烈收缩而发生的撕脱性骨折，带有少量骨组织或无骨组织被拔除，呈套状。36 34-vear-old male presenting with persistent anterior right knee pain,associated with knee swelling.locking,and buckling.Sagittal proton density(a)and sagittal(b)and axial(c)T2-weighted fat-suppressed images were obtained showing seve
40、re thickening of the proximal patellar tendon and increased signal(arrows),consistent with severe tendinopathy of the proximal patellar tendon.44-year-old male former professional basketball player with chronic knee pain.Lateral radiograph(d)shows diffuse thickening and heterogeneity of the patellar
41、 tendon(arrow),with a small mature calcification within the proximal aspect,findings representing chronic tendinopathy.37 Fig.19:Patellar tendinopathy图19：髌腱末端病（髌腱腱病）38 38year-old male following injury to his left knee while playing softball;reports feeling a tearing sensation.Lateral radiograph(a)sh
42、ows soft issue prominence along the inftrapatellar tencon(astersk)and a subtle transverse lucenm in the inferior pateltla(white arrow).There is patella alta Sagiftal proton density(b)and sagirtal T2-weighted fat-suppressed(c)MR images show a complete tear of the patellar tendon at the inferior-most
43、aspect of the patela(arrowsl.with retraction inferiorly.There is prominent patella alta.39 Fig.20:Patellar tendon rupture图20：髌韧带断裂40 Active 13-year-old male presenting with ongoing left knee pain.Lateral radiograph(a)shows a small fragment of bone adjacent to lower portion of left patella(arrow)and
44、mild infrapatellar edema.MR sagittal T2-weighted(b)and coronal fat-suppressed proton density(c)images show fragmentation of the inferior patella and mild tendinosis at the patellar insertion of the patella tendon(arrow).50-year-old patient with chronic anterior knee pain.Lateral radiograph(d)and sag
45、ittal proton density MR(e）image show abnormal morphology of the inferior patellar pole with adjacent mature calcification,consistent with chronic sequelae of Sinding-Larsen-Johansson syndrome.41 Fig.21:Sinding-Larsen-Johansson syndrome图21：辛丁一拉森一约翰逊氏病（髌骨骨软骨炎）与胫骨结节骨软骨炎发病机制相同。42 Lateral(a)and axial(b)r
46、adiographs show significant soft tissue swelling anterior to the patella(arrows).Sagittal T2-weighted(c)and axial T2-weighted fat-suppressed(d)images show an oval-shaped fluid signal structure anterior to the patella representing the fluid-filled prepatellar bursa(asterisk).43 Fig.22:Prepatellar bursitis图22：髌前滑囊炎44
