Treffsicherheit der Magnetresonanztomographie zum Nachweis von Meniskusrissen

In order to assure diagnostic accuracy, 172 knee joints were examined prospectively by MRI. After MRI, all knee joints were examined by arthroscopy. Tears of the medial meniscus were found in 102 patients, the lateral meniscus showed a tear in 29 cases. Assuming that arthroscopy represents the golden standard of diagnostic measure concerning the knee joint, it can be stated that false-positive MRI findings on the medial and lateral meniscus were diagnosed in three cases and false-negative MRI findings were diagnosed for two knee joints regarding the medial meniscus and four times regarding the lateral meniscus. For the medial meniscus a sensitivity of 98%, a specificity of 96%, an accuracy of 94%, and the positive and negative value of prediction were calculated at 97% each. Regarding the lateral meniscus, a sensitivity of 85%, a specificity of 98%, an accuracy of 92%, a positive predictive value of 88%, and a negative predictive value of 85% were found. Under the prerequisite that the MRI is carried out correctly and assessed by an experienced radiologist, the accuracy of the MRI for meniscus diagnosis is almost equivalent to the one by arthroscopy. Under these conditions, MRI can be recommended when no safe and sufficient clinical diagnosis can be made. The rate of unnecessary arthroscopies with a pure diagnostic purpose can be lowered significantly by means of MRI.     

膝关节内外侧半月板后根部撕裂的MRI诊断价值

目的:探讨MRI对膝关节内外侧半月板后根部撕裂的诊断价值。方法:回顾性分析2012年1月至2016年1月,关节镜下证实为半月板后根部撕裂的患者43例。其中男25例,女18例;年龄27~69(42.5±8.3)岁;右侧27例,左侧16例。由2名医师采用双盲法独立回顾性分析经关节镜证实的43例半月板后根部撕裂患者的MRI表现,计算MRI对半月板后根部撕裂的诊断敏感性、特异性和准确性,并计算膝关节韧带损伤及半月板脱位等伴随情况。结果:143例中,关节镜手术证实43例半月板后根部撕裂,包括内侧撕裂24例,外侧撕裂19例。医师A诊断内侧半月板后根部撕裂的敏感性、特异性、准确性分别为91.67%、86.6%、83.9%,伴内侧半月板突出19例,伴前交叉韧带撕裂2例;外侧半月板后跟部撕裂的敏感性、特异性、准确性分别为73.7%、79.9%、79%,伴外侧半月板突出4例,伴前交叉韧带撕裂16例。医师B诊断内侧半月板后根部撕裂的敏感性、特异性、准确性分别为87.5%、87.4%、87.4%,伴内侧半月板突出19例,伴前交叉韧带撕裂2例;外侧半月板后跟部撕裂的敏感性、特异性、准确性分别为78.9%、82.3%、82.5%,伴外侧半月板突出4例,伴前交叉韧带撕裂16例。2名医师采用MRI诊断内、外侧半月板后根部撕裂的一致性均好,Kappa值分别为0.81和0.67。结论 :膝关节MRI诊断内外侧半月板后跟部撕裂及其伴随征象具有较大价值,为临床医生术前诊断提供依据,值得临床推广应用。     

Diagnostics of degenerative meniscal tears at 3-Tesla MRI compared to arthroscopy as reference standard

Introduction The goal of this study was to evaluate the diagnostic performance of 3-Tesla MRI for the assessment of degenerative meniscal tears in clinical practice. Materials and methods In patients with chronic knee pain, a negative history of acute trauma and a mean age of 52 years, 3-Tesla MRI were performed a few days prior to arthroscopy. In 86 menisci, diagnostic values of 3-Tesla MRI for the detection of degenerative tears were evaluated using arthroscopy as reference standard. The MRI classification, for meniscus diagnostics, described by Crues was used. Results At arthroscopy, all tears identified (19 horizontal, 7 complex, 3 radial) were degenerative as confirmed by histological examination. MRI grade II lesions had a prevalence of 24% and a rate of 24% of missed tears, whereas grade I lesions were not associated with a torn meniscus at arthroscopy. For meniscal tears, (grade III) sensitivity and specificity of 3-Telsa MRI was 79 and 95% for both menisci, 86 and 100% for the medial meniscus, and 57 and 92% for the lateral meniscus. The best diagnostic performance was found for complex tears, horizontal tears showed relatively good results, poor results were documented for radial tears. Conclusion For the medial meniscus, where horizontal and complex tears were more prevalent, 3-Tesla MRI shows a higher accuracy than for the lateral meniscus. Particularly with regard to the medial meniscus, 3-Tesla MRI could be effectively used when a degenerative tear is suspected. Nevertheless, in regard to a remarkable number of false positive and false negative findings the diagnostic value of a 3-Tesla MRI investigation should not be overestimated.     

MRI preferable to diagnostic arthroscopy in knee joint injuries a double-blind comparison of 47 patients

We compared the findings of low-field MRI of the knee with those of subsequent arthroscopy. in a double-blind set-up, 47 patients with knee joint injuries were enrolled. Two radiologists independently interpreted the MRI examinations and consensus was obtained in case of discrepancy. Arthroscopy was performed without knowledge of the MRI findings.

The accuracy rates of MRI for evaluating the medial meniscus, lateral meniscus and anterior cruciate ligament were 77%, 91% and 96%, respectively, when arthroscopy was considered the “golden standard”. When MRI was considered the standard, the figures for arthroscopy were 74%, 91% and 96%. MRI found the indication for treatment in 18 of 21 patients who were treated at the arthroscopy. in 17 patients, neither MRI nor arthroscopy detected any lesion. in the remaining 9 patients, MRI demonstrated a lesion, but no lesion was found at the subsequent arthroscopy.

Our conclusion is that low-field MRI can be used as a first-line diagnostic examination in patients with suspected meniscus or cruciate ligament injuries and thus a substantial number of negative diagnostic arthroscopies can be avoided.     

Arthroscopy of the knee in children

A review was carried out of arthroscopy of the knee in children. During a 34-month period, 2,378 arthroscopies were performed, 80 of these on children less than 16 years of age. Seventy-one cases were reviewed, which is approximately 2% of all children seen at the clinic. Thirty procedures were carried out in patients with hemarthrosis. Eleven patients required operative repair or reconstruction. There were 13 ruptures of the anterior cruciate ligament (43%), 4 ruptures of the posterior cruciate ligament, 14 ruptures of the medial collateral or posterior oblique ligament, and 5 ruptures of the lateral meniscus. Forty-one arthroscopies were done in patients without hemarthrosis or history of acute trauma. A clinical diagnosis of meniscus tear was correct in only 20%. Only one meniscectomy was performed and another meniscus tear was repaired. The most common diagnostic finding was abnormality of the patellofemoral articulation, which was diagnosed in 31 patients. Arthroscopic shaving of the patella was rarely indicated. As in adults, hemarthrosis indicates significant injury to the knee. Meniscus lesions are rare.     

膝关节半月板撕裂的磁共振表现

目的进一步认识膝关节半月板撕裂的磁共振成像(MRI)表现。方法回顾分析50例膝关节半月板撕裂的MRI资料,所有病例均经关节镜手术证实。采用永磁型MRI机,场强0.2T。结果50例半月板撕裂中,按照部位分类,半月板撕裂位于内侧半月板前角2例,内侧后角37例,外侧半月板前角5例,外侧后角3例,同时累及半月板前角、体部和后角者内侧2例,外侧1例。按照半月板撕裂的形式分为:水平撕裂8例;垂直撕裂4例;斜形撕裂26例;纵形撕裂3例;放射状撕裂4例;桶柄状撕裂2例;复杂撕裂3例。结论MRI能够清楚显示膝关节半月板撕裂的部位和形式,为临床治疗提供可靠的依据,是目前诊断半月板撕裂的最好的影像学检查方法。     

Diagnostisches Vorgehen beim Kniegelenktrauma im Kindes- und Jugendalter

Introduction

Clinical examination of acute knee injury in childhood is often difficult and therefore magnetic resonance imaging (MRI) serves as an additional diagnostic tool. The aim of the present study was to evaluate on the one hand the indications for diagnostic arthroscopy and on the other hand the indications for MRI.

Methods

Of the children treated between 1990 and 1999, 87 (group 1) underwent arthroscopy after clinical examination. Between 2000 and 2006 (group 2) 83 patients were examined using MRI after clinical examination and 53 were subsequently submitted to arthroscopy.

Results

In group 1 the clinical diagnosis was verified by arthroscopy in 79%. In group 2 the clinical and arthroscopic diagnoses were consistent in 60% of the patients. The MRI diagnosis was correctly recognized for patella dislocation in all cases, for ligament injuries in 83% and for meniscus injuries in 56%. Due to the application of MRI before arthroscopy the fraction of diagnostic arthroscopies could be reduced from 22% to 13%.

Conclusion

The number of diagnostic arthroscopies in childhood can be reduced by application of MRI.     

Osteonecrosis of the knee after arthroscopic surgery for meniscal tears and chondral lesions.

PURPOSE: Avascular necrosis of the knee following arthroscopic surgery has been described. The purpose of this article is to report a large series of patients who developed avascular necrosis after arthroscopy of the knee in an effort to delineate casual factors and results of treatment. TYPE OF STUDY: Case series. METHODS AND MATERIALS: The charts, radiographs, and magnetic resonance imaging (MRI) scans of patients who developed osteonecrosis (ON) of the knee after routine arthroscopic surgery were reviewed. Only those patients with no evidence of ON on preoperative MRI performed 6 weeks or longer after symptom onset and who postoperatively developed ON confirmed by repeat MRI and/or by pathological testing (specimens obtained at subsequent total knee arthroplasty) were included in the study. Seven patients with average age of 60 years (range, 41 to 79 years) met these inclusion criteria. RESULTS: The lesions noted at arthroscopy included 4 medial meniscus tears, 3 lateral meniscal tears, 6 chondromalacia of the medial femoral condyle, 2 chondromalacia of the medial tibial plateau, 1 chondromalacia of the lateral femoral condyle, 1 chondromalacia of the lateral tibial plateau, and 2 chondromalacia of the patella. The location of postarthroscopy ON correlated geographically with pre-existing pathology. All 7 patients had meniscal and/or chondral lesions addressed surgically in the compartment that subsequently developed ON. Six of the 7 patients had an adjacent ipsilateral meniscus tear treated with partial meniscectomy (4 medial, 2 lateral). In addition, of the 4 patients who developed ON of the medial femoral condyle, all had overlying chondromalacia, 3 of whom were treated with arthroscopic chondroplasty. Of the 2 patients with lateral meniscal tears, 1 developed ON of the lateral femoral condyle and the other developed ON of the lateral tibial plateau. Three patients went on to require total knee arthroplasty, and 2 high tibial osteotomy. One patient's ON resolved and another patient was lost to follow-up. CONCLUSION: ON should be considered in patients who have worsening symptoms after arthroscopy of the knee. These findings suggest a possible relationship between arthroscopic treatment of chondral and meniscal lesions and later appearance of ON in some patients. The role of arthroscopy in the development of ON needs to be further studied. Those at risk are elderly patients with chondral and meniscus lesions.     

外侧半月板桶柄样撕裂联合缝合技术的应用

 目的 探讨关节镜下自内向外联合全内缝合技术修复外侧半月板桶柄样撕裂的临床效果。方法 2004年11月至2009年11月,应用关节镜下联合缝 合技术修复外侧半月板桶柄样撕裂17例,男10例,女7例;年龄17~42岁,平均27.8岁。使用自内向外缝合技术对外侧半月板腘肌腱前方区域的撕裂进行缝合,使 用全内缝合技术对半月板后角区域的撕裂进行缝合。随访时进行体格检查、MR检查和二次关节镜探查,评估半月板愈合情况。结果 13例患者获得随访,随访时 间1~5年,平均23.7个月。随访期间症状消失者12例（92.3％,12/13）,绞锁复发1例（7.7％,1/13）。MRI证实半月板完全愈合11例（84.6％,11/13）,部分 愈合1例（7.7％,1/13）,不愈合1例（7.7％,1/13）。12例患者行二次关节镜探查,其中完全愈合10例（83.3％,10/12）,部分愈合1例（8.3％,1/12）, 未愈合1例（8.3％,1/12）。结论 应用自内向外联合全内缝合技术修复外侧半月板桶柄样撕裂,经术后MRI和二次关节镜探查证实半月板愈合率超过90%。     

Usefulness of knee arthroscopy for diagnosis of knee pain in pediatric patients: comparison with preoperative clinical diagnosis

Purpose

To investigate the knee arthroscopic findings of pediatric patients with knee pain.

Subjects

Ninety-five knees of 94 patients (46 males and 48 females) aged 15 years or younger who underwent knee arthroscopy during a 4-year period from January 2007 were studied. The mean age at surgery was 13.5 (7–15) years. The mean interval from symptom onset to arthroscopic examination was 6.8 months (5 days to 2 years 10 months).

Results

The most common cause of knee pain was sports-related activities (64 knees). Other causes included falling from a moving bicycle (5 knees), while knee pain appeared with no defined reason in 14 knees. The most frequent final diagnosis based on knee arthroscopic findings was anterior cruciate ligament (ACL) injury (35 knees), followed by discoid lateral meniscus (16 knees), lateral meniscal tear (11 knees), and medial plica syndrome (9 knees), while no arthroscopic abnormality was observed in 8 of 95 knees. Among the 95 knees, the diagnosis based on preoperative physical tests and imaging findings was different from the arthroscopic diagnosis in 16 knees, 8 of which were diagnosed preoperatively as medial meniscal tear.

Conclusion

ACL injury and discoid lateral meniscus were the predominant conditions in pediatric patients who underwent knee arthroscopic surgery for knee pain. Knee arthroscopy is useful to provide a definitive diagnosis for knee pain in pediatric patients. Preoperative evaluations had a diagnostic accuracy of only 83.2 % and failed to diagnose conditions such as medial plica syndrome and chondral injury. Therefore, diagnosis before knee arthroscopy has to be interpreted with caution.     

关节镜下复位缝合富血小板血浆注射治疗陈旧性半月板桶柄样撕裂

[目的]介绍陈旧性内侧半月板桶柄样撕裂镜下复位缝合修复,结合富血小板血浆注射的手术技术与初步结果。[方法]对1例28岁陈旧性内侧半月板桶柄样撕裂23年的患者行镜下复位缝合,同时行富血小板血浆注射。镜下全面探查关节内病变,将半月板撕裂部和关节囊残缘打磨出新鲜创面,采用由内向外"U"形缝合半月板2针,牵拉关节外侧缝线,在关节镜直视下松解半月板前、后角挛缩部分,使半月板桶柄撕裂缘与关节囊缘逐渐靠拢,将缝线打结固定。再采用Fast-fix 360将半月板体部至后角撕裂部分全内缝合。探查半月板缝合后撕裂部分复位满意,稳定性良好。将制备好的PRP共4 ml沿内侧膝关节间隙半月板的体部及后角等部位,多点穿刺注射。[结果]术后患者疼痛和关节交锁等症状消失,逐步恢复伤膝活动。术后2个月,患者恢复运动能力,无明显不适,复查MRI显示左膝内侧半月板形态完整、均质,无明显异常信号。[结论]对陈旧性内侧半月板桶柄样撕裂进行适当松解仍可缝合修复,富血小板血浆注射有利于陈旧性半月板缝合修复后愈合。     

Anomalous insertion of the medial menisci

Many types of meniscal anomalies have been reported. The authors encountered two cases of anomalous insertion of the anterior horn of the medial menisci to the lateral femoral condyle, which ran up along the course of the anterior cruciate ligament (ACL), but was independent of the ACL. These anomalies were noted during arthroscopic examination and surgery of the ipsilateral knee for a torn discoid meniscus and a patellar fracture. A 34-year-old woman had a horizontal tear of the lateral discoid meniscus. We performed arthroscopic partial meniscectomy of the inner torn portion of the lateral discoid meniscus and contoured it to resemble a normal meniscus. An anomalous insertion of the medial meniscus was found on examination of the joint during surgery. A 32-year-old man had a patellar fracture and we performed reduction under arthroscopy and internal fixation with cannulated screws. The same anomalous insertion of the medial meniscus was also found on examination of the joint during surgery. We report the cases with a review of the literature.Arthroscopy 1998 Jul-Aug;14(5):505-7     

Magnetic resonance imaging of the knee in children and adolescents. Its role in clinical decision-making

BACKGROUND: Recent studies have questioned the utility of magnetic resonance imaging in the diagnosis of pediatric knee disorders because of the morphologic changes during growth and the low accuracy of the formal interpretation of the magnetic resonance imaging scan by a radiologist. The purpose of this study was twofold: (1) to report the accuracy of formal interpretations of magnetic resonance imaging scans of the knee in children and adolescent patients by a radiologist, and (2) to determine the benefit, if any, of a personal review of the magnetic resonance imaging scan of the knee by the orthopaedic surgeon, as a routine part of the diagnostic evaluation. METHODS: A three-year prospective study of all patients who underwent knee arthroscopy performed by a single surgeon, at two children's hospitals, was completed. The analysis focused on the six most common diagnoses: anterior cruciate ligament tear, lateral meniscal tear, medial meniscal tear, osteochondritis dissecans, discoid lateral meniscus, and osteochondral fracture. The preoperative diagnosis of the surgeon was determined by integrating the history and the findings on the clinical examination, plain radiographs, and magnetic resonance imaging scans (including the radiologist's interpretation). RESULTS: Ninety-six patients with ninety-six abnormal knees were included. The mean age was 14.6 years at the time of surgery. Relative to operative findings, kappa values for the formal interpretations of the magnetic resonance imaging scans by a radiologist were 0.78 for an anterior cruciate ligament tear, 0.76 for a medial meniscal tear, 0.71 for a lateral meniscal tear, 0.70 for osteochondritis dissecans, 0.46 for discoid lateral meniscus, and 0.65 for osteochondral fracture. Relative to operative findings, kappa values for the preoperative diagnoses by the surgeon were 1.00 for an anterior cruciate ligament tear, 0.90 for a medial meniscal tear, 0.92 for a lateral meniscal tear, 0.93 for osteochondritis dissecans, 1.00 for discoid lateral meniscus, and 0.90 for osteochondral fracture. The preoperative diagnosis by the surgeon was better (p < 0.05) than the formal interpretation of the magnetic resonance imaging scans by the radiologist with respect to an anterior cruciate ligament tear, lateral meniscal tear, osteochondritis dissecans, and discoid lateral meniscus. CONCLUSIONS: Integration of patient information with an orthopaedic surgeon's review of the magnetic resonance imaging scan of the knee in children and adolescent patients improves the identification of pathological disorders in four of the six categories evaluated. This study questions the necessity for and appropriateness of a routine interpretation of a magnetic resonance imaging scan of the knee in children and adolescents by a radiologist.     

Entrapment of the meniscus in a fracture of the intercondylar eminence of the tibia

Summary: Entrapment of the meniscus in a fracture of the tibial intercondylar eminence is very rare. We have experienced 2 cases of it and report on them to emphasize the importance of diagnostic arthroscopy especially for meniscal injuries in tibial intercondylar eminence fracture. Our case series was composed of 2 patients (a 30-year-old man and a 54-year-old woman). Both had been in a car accident and showed a type III fracture of the tibial intercondylar eminence on the initial radiographs. During arthroscopic examination, we found a bucket-handle tear of the lateral meniscus, and, in 1 case, the entire torn portion was displaced medially and entrapped in the fracture site, and in the other case, a longitudinally torn medial meniscus (the mid to anterior horn), of which the torn portion of the medial meniscus was rotated internally and entrapped in the fracture site. They were treated with arthroscopic meniscal repair or partial meniscectomy with pullout suture for the fracture of the tibial eminence. The results were excellent. At 6-month follow-up, the woman denied any pain and limitation of motion. At 1-year follow-up in the other case, the man did not have any complaint except slight limitation of knee flexion due to arthrofibrosis. After arthroscopic fibrolysis in the second-look operation, he showed normal range of motion of the knee. In conclusion, entrapped meniscus can cause pain, lack of full knee extension, and minimal anterior instability. Also, it tends to hinder the reduction of a fracture of the tibial eminence. Thus, arthroscopy should be diagnostic, and release of the trapped meniscus, if present, with partial meniscectomy or meniscal repair would be expected to relieve the symptoms.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 4 (May-June), 2000: pp 7–7     

Diagnostic value of clinical tests and Mri for meniscal injury in patients with anterior cruciate ligament injury: Case series study

Introduction and importanceMeniscal tear is one of the most common knee injuries and knee surgery procedures. It is frequently associated with an anterior cruciate ligament (ACL) injury. We conducted this study, on patients with ACL reconstruction surgeries, which were occasionally accompanied by meniscal tears, in order to determine the diagnostic value of clinical examinations for meniscal tear, both individually and in combination, in correlations to magnetic resonance imaging (MRI) scans, with the goal of improving clinical diagnosis for patients with meniscal injuries in particular, as well as meniscal injuries associated with cruciate ligament knee injuries.Case presentation50 patients were thoroughly clinically examined, using Joint line tenderness, Thessaly test, McMurray's test, Apley's test followed by MRI, before their scheduled ACL reconstruction arthroscopic surgeries. The meniscal tears were then identified during the procedure, and were treated, if necessary. The data before and after the surgery was taken into calculating, with arthroscopic findings serving as the gold standard. Results: the sensitivity, specificity and accuracy of each clinical tests and MRI scans respectively were: for medial meniscus, Joint line tenderness (70%; 53,3%; 60%); McMurray's test (80%; 73,3%: 76%); Apley's test (65%; 70%; 68%); Thessaly test(70%; 76,7%; 74%); MRI (90%; 83,3%; 86%); lateral meniscus: Joint line tenderness (73%; 66,7%; 70%); McMurray's test (69,2%; 75%: 72%); Apley's test (69,2%; 70,8%; 70%); Thessaly test (73,1%; 75%; 74%); MRI (88,5%; 87,5%; 88%). However, when combining at least two positive tests into a single composite test, the diagnostic value is considerably enhanced with sensitivity, specificity and accuracy of 85%, 73,3%, 78% for medial meniscus, 92,3%, 87,5%, 90% for lateral meniscus.Clinical discussionClinical tests are essential for diagnosis of meniscal tears, although inconsistent. A composite test consisting of at least two positive tests can considerably enhance the diagnostic value, even comparable to MRI scans. However, after the clinical examination, MRI is still necessary for the diagnostic process of meniscal injuries in particular, as well as meniscal injuries associated with cruciate ligament knee injuries.ConclusionThe combination of clinical tests and MRI images will give a precise diagnosis as well as surgical indication for meniscus injury in patients with anterior cruciate ligament tear.     

Locked knee caused by meniscal subluxation: magnetic resonance imaging and arthroscopic verification

Subluxation or dislocation of an intact lateral meniscus is a controversial and rarely reported cause of knee pain and locking. We report a case of knee locking caused by lateral meniscal subluxation in the absence of a meniscal tear or true discoid meniscus, with both magnetic resonance imaging (MRI) and arthroscopic verification. A 9.5-year-old child experienced multiple episodes of locking in full flexion of the knee. After 6 months of symptoms, arthroscopy was performed and showed no meniscal tear or a discoid meniscus. The patient’s knee locking recurred after arthroscopy. MRI was performed when the patient presented acutely with the knee locked. MRI showed anterior dislocation of the posterior horn of the lateral meniscus with the knee in the locked position. The MRI was immediately repeated after the author reduced (manipulated) the locked knee into extension. On the repeat MRI, the lateral meniscus had returned to a normal position. On repeat arthroscopy, the posterior horn of the lateral meniscus was hypermobile and could be displaced into the notch and did not show a frank tear. The meniscus was repaired to the capsule with sutures. At the 2-year follow-up evaluation, the patient had no complaints and no clinical signs of locking.     

The use of axial reconstructed images from three-dimensional MRI datasets for morphological diagnosis of meniscal tears of the knee

Introduction In recent years, three-dimensional (3D) MRI has been utilized to detect meniscal tears and has displayed several advantages over 2D MRI. The diagnostic performance to discriminate the type of meniscal tears by 2D MRI (sagittal and coronal images) and axial images from 3D MRI datasets has not been reported yet. The aim of the present study is to evaluate the efficacy of the axial reconstructed images from 3D MRI datasets for the morphological diagnosis of meniscal tears of the knee.Materials and methods Seventy-four menisci in 37 patients who underwent arthroscopic surgery of the knee were studied. All patients were examined by 2D sagittal and coronal MRI and by axial images from 3D MRI datasets prior to surgery. First, we compared the diagnostic performance for meniscal tears by 2D sagittal and coronal MRI to that by axial images from 3D MRI datasets as judged by arthroscopic findings. Second, we compared the correlation of tear types presumed from 2D sagittal and coronal MRI to arthroscopy with those presumed from axial images from 3D MRI datasets to arthroscopy.Results For the diagnostic performance of meniscal tears on 2D MRI, the sensitivity, specificity and accuracy were 93.5%, 88.4% and 90.5%, respectively. On axial images from 3D MRI, the sensitivity, specificity and accuracy were 96.8%, 79.1% and 86.5%, respectively. Nine cases were false-positive on axial images, while 5 cases were false-positive on 2D images. Correlations to arthroscopy were 100% by both scans for longitudinal tears and discoid meniscus tears. Only 29% were correctly diagnosed by 2D sagittal and coronal images for radial tears, however, all radial tears could be correctly diagnosed by axial images. All horizontal tears were correctly diagnosed on 2D sagittal and coronal images, while none of the horizontal tears could be correctly diagnosed from axial images.Conclusion Axial images from 3D MRI datasets were useful in the diagnosis of radial tears, but two limitations are noted concerning the use of axial images. First, medial menisci should be carefully read on axial slices because of the relatively high rate of false-positives on medial menisci. Second, axial images cannot discriminate horizontal tears from other types of meniscus tears.     

Value of computerized tomography and nuclear magnetic resonance tomography in preoperative diagnosis of meniscus lesions and ligamentous lesions of the knee joint

In a prospective study, 53 patients with chronic complaints and acute injuries of the knee joint, were evaluated by clinical examination, CT-scanning and magnetic resonance imaging (MRI). Subsequently, arthroscopy or an open surgical procedure was performed. A total of 21 patients suffered from meniscal lesions. There were 17 ruptures of the medial and 4 ruptures of the lateral meniscus. In patients with meniscus ruptures, the sensitivity of both MRI and CT-scan was 86%, whereas the specificity of MRI was slightly lower than that of CT-scan. The accuracy and the predictive value were also slightly lower, although the difference was not significant. Fifteen patients suffered from acute or chronic ligament ruptures. In patients with anterior cruciate ligament (ACL) ruptures, all complete ACL ruptures had correctly been diagnosed by CT and MRI. Two out of four partial ACL ruptures were missed by MRI; only one was missed by CT-scan. Three medial collateral ligament ruptures were documented by MRI and two by CT-scanning. The high negative predictive value of CT and MRI can realize a reduction of the amount of diagnostic arthroscopies.     

Primary Synovial Chondromatosis Mimicking Medial Meniscal Tear in a Young Man

Magnetic resonance imaging has recently become a noninvasive and cost-effective diagnostic tool for meniscal pathology in the knee. We report an unusual case of primary synovial chondromatosis for which the clinical diagnosis was medial meniscal tear but magnetic resonance imaging also showed a displaced torn meniscus, causing a so-called “double meniscus sign.” The patient was definitely diagnosed and successfully treated with arthroscopy. We discuss the clinical diagnostic and therapeutic challenges, and the possible pathogenesis.     

Bucket handle tear of a discoid medial meniscus. Arthroscopic diagnosis--partial excision. A case report

A case of a rare, large discoid medial meniscus with a bucket-handle tear is described. The radiogram was normal and the clinical impression was torn medial meniscus. A diagnostic arthroscopy revealed an unusually large medial discoid meniscus with a bucket-handle tear. Open partial excision was performed following the arthroscopy.