膝关节半月板脱位的MRI诊断

目的 探讨膝关节半月板脱位的MRI表现及诊断价值。方法 回顾性分析20例经临床手术证实的膝关节半月板脱位均经MRI检查。主要临床表现为膝关节疼痛。结果 膝关节半月板脱位并半月板撕裂15例；同时膝关节半月板脱位并骨关节炎14例。MRI征象：半月板脱离膝关节面。伴有撕裂可见T2WI稍高信号。T1WI为等信号。结论 膝关节半月板脱位MRI可提供准确的诊断。     

膝关节的MRI检查

MRI由于具有软组织的良好对比,所以是膝关节内外结构的无创伤性检查方法,对半月板病变诊断,更具有优越性。本文报道25例病人的膝关节MRI检查。50个半月板22个有撕裂。另有3个盘状半月板,1个半月板囊肿,2个后纵韧带损伤。手术9例,8例符合MRI,1例假阳性。T1及质子密度像显示半月板撕裂好,T2加权像显示半月板囊肿和韧带损伤好。     

探讨半月板边缘部垂直撕裂与前交叉韧带损伤的关系

目的 探讨半月板边缘部垂直撕裂对诊断前交叉韧带(ACL)损伤的价值.方法 回顾性分析经关节镜证实的149例半月板撕裂的膝关节MRI结果,判断半月板撕裂的形态、位置以及前交叉韧带的情况.结果 149例半月板撕裂膝关节中,34个膝关节共36个半月板撕裂(其中2个膝关节内、外侧半月板同时撕裂),MRI显示为半月板边缘部垂直撕裂类型,其中29个膝关节同时伴有前交叉韧带损伤.其余115个膝关节,MRI显示为其他半月板撕裂类型,其中49例膝关节同时伴有前交叉韧带损伤.膝关节半月板边缘部垂直撕裂类型与其他的半月板撕裂类型比较,其合并前交叉韧带损伤的发生率分别为85.3%及42.6%,两者间具有显著性差异(χ2=19.2,P＜0.01).半月板边缘部垂直撕裂提示膝关节前交叉韧带损伤的敏感性、特异性和阳性似然比分别为37.2%、93.0%和5.3.结论半月板边缘部垂直撕裂大部分合并有ACL损伤.     

膝关节半月板桶柄样撕裂的MR诊断

目的　研究膝关节半月板桶柄样撕裂的MR表现。方法　分析 38例经关节镜证实为半月板桶柄样撕裂的患者术前MR的特征性表现。结果　38例中 30例可见典型的撕裂半月板髁间窝内移位,半月板缺失或部分缺失征象; 5例仅显示半月板撕裂Ⅲ级信号; 3例无异常发现。结论　膝关节半月板桶柄样撕裂典型的MRI表现为撕裂半月板的游离缘关节内移位征象,但是当撕裂的游离缘未发生移位时,仅表现半月板撕裂的 3级信号,且与半月板的上下关节面均相通。     

膝关节半月板损伤移位的MRI表现

膝关节半月板损伤移位是半月板损伤的一种亚型,需行手术修复或切除。作者收集1993～1997年经MR检查提示为半月板损伤移位的25例患者,其中24例经关节镜证实,就其MR表现、外科所见、结合文献复习,进行分析。采用1.5T MR设备,正交膝线圈,有半月板手术史的患者不包括在内。 半月板损伤移位分为盖状撕裂、桶柄状撕裂及游离性移位。该组25例中包括3例盖状撕裂,2例游离性移位,15例内侧和5例外侧半月板桶柄状撕裂移位。分析半月板撕裂时,应熟悉膝关节正常解     

膝关节半月板撕裂的MRI诊断

目的 探讨膝关节半月板撕裂的MRI诊断价值.方法 收集并分析经关节镜证实的60例膝关节半月板撕裂的MRI表现,并参考Stoller分级方法,提出半月板损伤的4级分法.结果 60例65个半月板撕裂中,内侧撕裂15个,外侧撕裂40个,两侧同时撕裂5例10个.合并外侧盘状半月板15个.MRI诊断准确率为90.8%.39例出现合并症,伴随病变有韧带撕裂,骨挫伤,关节积液,骨折,半月板囊肿等.结论 MRI能够准确诊断半月板撕裂,还能发现多种合并症.     

间接法MRI膝关节造影对半月板撕裂的评价

目的　评价间接法MRI膝关节造影对半月板撕裂的诊断价值。方法　回顾性分析 75例常规MRI膝关节扫描和 6 4例间接法MRI膝关节造影病例资料 ,以膝关节镜检查为诊断金标准 ,对比分析常规MRI和间接法MRI膝关节造影对半月板撕裂的诊断。结果　间接法MRI膝关节造影对内侧半月板撕裂的诊断敏感性、特异性、准确性、阳性预测值和阴性预测值分别为 72 %,10 0 %,89.1%,10 0 %和 84.8%;对外侧半月板撕裂分别为 83.8%,90 .9%,87.5 %,89.6 %和 85 .7%。与常规MRI比较 ,间接法MRI膝关节造影对内外侧半月板撕裂的诊断能力都没有统计学差异。结论　尽管间接法MRI膝关节造影对内外侧半月板撕裂诊断价值很高 ,但与常规MRI比较没有统计学差异。     

半月板根部放射状撕裂MR表现

目的 探讨半月板根部放射状撕裂的MRI表现.方法 回顾性分析17例经关节镜证实半月板根部放射状撕裂MRI表现.结果 17例半月板根部放射状撕裂中,16例位于内侧半月板后角,1例位于外侧半月板后角.MRI表现为根部横断位和冠状位后角条状高信号和矢状位表现为后角弥漫性高信号.同时检出继发征象,包括半月板膨出11例,关节面下骨挫伤13例.17例患者均伴有膝关节退行性改变.结论 膝关节半月板根部放射状撕裂主要发生在内侧半月板后角,MRI可以依据多方位成像显示其多种征象,熟悉这些征象可以帮助放射诊断医师作出正确诊断指导临床治疗方案的实施.     

膝关节MRI平扫与直接法造影诊断半月板损伤准确性分析

目的:比较分析MRI平扫与造影MRI对半月板损伤诊断的准确性。方法:100例疑似半月板损伤患者,行MRI矢状位T1WI、T2WI GRE、STIR、PD+Fatsat,冠状位T2WI GRE,平扫后立即在直接关节腔内注射对比剂行矢状位、冠状位、轴位T1WI,层厚4mm、层距1mm。结果:94例经关节镜或手术确诊为半月板撕裂,其中,MRI GRE序列诊断撕裂84例,膝关节MRI造影诊断83例。6例经关节镜或手术确诊为正常或变性,MR GRE序列和膝关节MRI造影也为正常或变性。结论:MRI平扫与MRI造影对半月板损伤的诊断准确性差异无统计学意义(P>0.05)。     

膝关节半月板撕裂的CT扫描（附108例）

膝关节半月板撕裂的ＣＴ扫描（附１０８例）于万泉，张解港，王振忠，冯永章，张元和膝关节半月板撕裂是常见病。占膝关节病变的２／３。利用ＣＴ进行膝关节扫描，能清晰显示半月板撕裂的部位及程度。作者搜集了１０８例膝关节半月板ＣＴ扫描，现将结果报道如下：１一般资...     

Reversed double PCL sign: unusual location of a meniscal fragment of the knee observed by MR imaging

A 36-year-old woman with tears of the anterior cruciate ligament and medial meniscus received a meniscectomy. The MR images obtained prior to the partial meniscectomy showed a bucket-handle meniscal tear with centrally displaced fragment lying anterior to the posterior cruciate ligament (PCL), representing a "double PCL sign"; however, after the meniscectomy, MR images demonstrated a fragment in the space posterior to the PCL where no structure is generally recognized except for the ligament of Wrisberg. This article reports a "reversed" double PCL sign, caused by inadequate surgical clearance of a bucket-handle tear of the medial meniscus.     

Reversed double PCL sign: unusual location of a meniscal fragment of the knee observed by MR imaging

A 36-year-old woman with tears of the anterior cruciate ligament and medial meniscus received a meniscectomy. The MR images obtained prior to the partial meniscectomy showed a bucket-handle meniscal tear with centrally displaced fragment lying anterior to the posterior cruciate ligament (PCL), representing a "double PCL sign"; however, after the meniscectomy, MR images demonstrated a fragment in the space posterior to the PCL where no structure is generally recognized except for the ligament of Wrisberg. This article reports a "reversed" double PCL sign, caused by inadequate surgical clearance of a bucket-handle tear of the medial meniscus.

     

Potential pitfalls of a double PCL sign

The double posterior cruciate ligament (PCL) sign is seen on a midline sagittal MR image of the knee as a low-signal-intensity linear band paralleling the antero-inferior part of the PCL. Although the sign has a high specificity for a displaced bucket-handle tear of the medial meniscus, it can be mimicked by several normal and abnormal structures in the intercondylar region. Familiarity with these variants and identifying the other features supportive of meniscal injury will help to make a confident diagnosis of bucket-handle tear of the medial meniscus     

Bucket-handle meniscal tears of the knee: sensitivity and specificity of MRI signs

OBJECTIVE: To determine the sensitivity and specificity of reported MRI signs in the evaluation of bucket-handle tears of the knee. DESIGN AND PATIENTS: A retrospective analysis of 71 knee MR examinations that were read as displaying evidence of a bucket-handle or "bucket-handle type" tear was performed. We evaluated for the presence or absence of the absent bow tie sign, the coronal truncation sign, the double posterior cruciate ligament (PCL) sign, the anterior flipped fragment sign, and a fragment displaced into the intercondylar notch. Sensitivity and specificity were calculated relative to the gold standard of arthroscopy. RESULTS: Forty-three of 71 cases were surgically proven as bucket-handle tears. The absent bow tie sign demonstrated a sensitivity of 88.4%. The presence of at least one of the displaced fragment signs had a sensitivity of 90.7%. A finding of both the absent bow tie sign and one of the displaced fragment signs demonstrated a specificity of 85.7%. The double PCL sign demonstrated a specificity of 100%. The anterior flipped meniscus sign had a specificity of 89.7%. CONCLUSIONS: Bucket-handle tears of the menisci, reported in about 10% of most large series, have been described by several signs with MRI. This report gives the sensitivity and specificity of MRI for bucket-handle tears using each of these signs independently and in combination. MRI is shown to be very accurate for diagnosing bucket-handle tears when two or more of these signs coexist.     

Double PCL sign does not always indicate a bucket-handle tear of medial meniscus

The discoid medial meniscus is an extremely rare anomaly. Bilateral discoid medial menisci are much more rare but intermittently reported. We report the first case of bilateral discoid medial menisci with positive double PCL sign, which typically indicates a bucket-handle tear of medial meniscus. A literature review was also conducted on bilateral discoid medial menisci. Level of evidence IV.     

Pitfalls and limitations of Magnetic Resonance Imaging in bucket-handle tears of knee menisci

PURPOSE: The aim of the present study was to assess the accuracy of magnetic resonance imaging (MRI) in the diagnosis of bucket-handle tears of the knee menisci, determining the sensitivity and specificity of the imaging for each of the signs typical of these tears. MATERIALS AND METHODS: MR examinations of 495 patients suffering from knee traumas were assessed retrospectively. Forty-eight patients had arthroscopically-proven bucket-handle tears of the meniscus. MR examinations were performed using a 0.5-T superconducting magnet, with T1-weighted spin-echo (SE) and gradient-echo (GE) T2*-weighted sequences. Imaging findings used for the diagnosis were: a) double posterior cruciate ligament sign; b) flipped meniscus sign; c) presence of a displaced fragment of the meniscus in the intercondylar notch, visible in coronal and axial images; d) truncated triangular shape of the peripheral non-displaced portion of the meniscus, visible in coronal images. RESULTS: A total of 43 out of 48 bucket-handle tears of the meniscus were correctly diagnosed at MR, thus overall MR accuracy was 98%. In 12 (28%) cases three signs were present simultaneously the double posterior cruciate ligament (sensitivity 28%, specificity 99%, accuracy 93%) + the displaced fragment in the intercondylar notch (sensitivity 69.8%, specificity 98.7%, accuracy 96.2%) + the truncated triangular shape of the peripheral portion of the meniscus (sensitivity 74.4%, specificity 98%, accuracy 96%). In 18 (42%) cases two signs were present together the displaced fragment of the meniscus + the truncated triangular shape of the peripheral portion of the meniscus. In 13 (30%) cases only one sign was presenting two cases the truncated triangular shape of the peripheral portion of the meniscus and in 11 cases the flipped meniscus sign (sensitivity 25.6%, specificity 93.4%, accuracy 87.5%). No statistically significant differences were found comparing the results for tears of the medial meniscus with those for the lateral meniscus. CONCLUSIONS: MR imaging is highly accurate in diagnosing bucket-handle tears of the menisci due to its ability to identify a displaced fragment of the meniscus in the intercondylar notch or flipped over the anterior horn of the meniscus of origin. We speculate that bucket-handle tears not found by MR imaging are cases where the meniscus was displaced after MR examination.     

Hemi-bucket-handle tears of the meniscus: appearance on MRI and potential surgical implications

Objectives

To describe a type of meniscus flap tear resembling a bucket-handle tear, named a “hemi-bucket-handle” tear; to compare its imaging features with those of a typical bucket-handle tear; and to discuss the potential therapeutic implications of distinguishing these two types of tears.

Materials and methods

Five knee MR examinations were encountered with a type of meniscus tear consisting of a flap of tissue from the undersurface of the meniscus displaced toward the intercondylar notch. A retrospective analysis of 100 MR examinations prospectively interpreted as having bucket-handle type tears yielded 10 additional cases with this type of tear. Cases of hemi-bucket-handle tears were reviewed for tear location and orientation, appearance of the superior articular surface of the meniscus, presence and location of displaced meniscal tissue, and presence of several classic signs of bucket-handle tears.

Results

A total of 15/15 tears involved the medial meniscus, had tissue displaced toward the notch, and were mainly horizontal in orientation. The superior surface was intact in 11/15 (73.3%). In 1/15 (6.7%) there was an absent-bow-tie sign; 6/15 (40%) had a double-PCL sign; 14/15 (93.3%) had a double-anterior horn sign.

Conclusion

We describe a type of undersurface flap tear, named a hemi-bucket-handle tear, which resembles a bucket-handle tear. Surgeons at our institution feel this tear would likely not heal if repaired given its predominantly horizontal orientation, and additionally speculate the tear could be overlooked at arthroscopy. Thus, we feel it is important to distinguish this type of tear from the typical bucket-handle tear.     

The double ACL sign: an unusual bucket-handle tear of medial meniscus

Several characteristic magnetic resonance imaging (MRI) signs of meniscal bucket-handle tears are well known and widely used. This case report presents a new MRI sign of a meniscal bucket-handle tear. A 17-year-old boy visited our hospital because of the pain in his left knee. Preoperative MRI on sagittal view showed a tear in the anterior horn of the medial meniscus and a displaced fragment of the medial meniscus in front of the original anterior cruciate ligament (ACL), which looks like another ACL. Under arthroscopic examination, the bucket-handle medial meniscus displaced parallel to the ACL was observed. A longitudinal tear was extended from the anterior horn to the posterior horn of medial meniscus. To our knowledge, this new MRI sign of bucket-handle tear, “the double ACL sign”, has not been previously reported. Level of evidence V.     

MR imaging of meniscal bucket-handle tears: a review of signs and their relation to arthroscopic classification

Our objective was to review the MR imaging signs of meniscal bucket-handle tears and assess the relevance of these signs to the arthroscopic classification of displaced meniscal tears. Forty-five menisci in 42 patients who had a diagnosis of bucket-handle tear either on MR imaging or on subsequent arthroscopy (in which Dandy's classification of meniscal tears was used) were retrospectively analyzed for MR imaging findings of double posterior cruciate ligament (PCL), fragment within the intercondylar notch, absent bow tie, flipped meniscus, double-anterior horn, and disproportional posterior horn signs. Arthroscopy, which was considered as the gold standard, revealed 41 bucket-handle tears (either diagnosed or not diagnosed by MR imaging) in 38 patients (33 males, 5 females). There was a stastistically significant male preponderance for the occurrence of meniscal bucket-handle tears. Overall, sensitivity and positive predictive value of MR imaging for the detection of meniscal bucket-handle tears were calculated as 90%. Common MR imaging signs of meniscal bucket-handle tears in arthroscopically proven cases of such tears were the fragment in the notch and absent bow tie signs (98% frequency for each). Double-PCL, flipped meniscus, double-anterior horn, and disproportional posterior horn signs, however, were less common (32, 29, 29, and 27%, respectively). An arthroscopically proven bucket-handle tear was found in all patients who displayed at least three of the six MR imaging signs of meniscal bucket-handle tears. The presence of three or more MR imaging signs of meniscal bucket-handle tears is highly suggestive of this condition. Electronic Publication     

MR imaging of meniscal malformations of the knee mimicking displaced bucket-handle tear

We report two cases of patients with lateral meniscal malformations of the knee that were found incidentally. Magnetic resonance imaging (MRI) of both cases showed a fragment-like meniscus structure located in the intercondylar notch, very similar to the "fragment in the intercondylar notch sign" observed in displaced bucket-handle tear. Arthroscopic examinations revealed a ring-shaped lateral meniscus in one case, and "flipped-over" lateral meniscus in the other. In the latter, a similar lateral meniscal malformation was observed contralaterally at MR arthrography.