***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Eight patients with ganglion cysts arising from the cruciate ligaments of the knee joint underwent arthroscopic excision after the MR examination . The MR findings , clinical features and arthroscopic findings were evaluated comparatively . Résumé Après un examen IRM , huit patients présentant des kystes se développant à partir des ligaments croisés du genou , ont subi une excision arthroscopique . Les résultats de l’examen IRM , de l’examen clinique et de l’examen arthroscopique ont été comparés Magnetic resonance imaging ( MRI ) was used to diagnose acute and chronic intraarticular knee pathology in 23 knees . The results were compared with arthroscopic findings of meniscal , ligamentous , and articular cartilaginous pathology using a double-blind prospect i ve protocol . The overall accuracy for meniscal tears was 78 % , with a sensitivity of 88 % and a specificity of 72 % ; for cruciate ligaments , MRI was 82 % accurate , with a sensitivity of 67 % [ anterior cruciate ligament ( ACL ) only ] and a specificity of 86 % . In select clinical situations , MRI of the knee is a useful diagnostic tool Amongst a series of 332 patients undergoing a prospect i ve evaluation of the influence of magnetic resonance imaging ( MRI ) on diagnosis and outcome , arthroscopic correlation became available in 92 knees ( 91 patients ) . The MRI report , the arthroscopic findings and the patient 's case notes were review ed by a consensus panel . With respect to the menisci and cruciate ligaments , the formal radiological report was at variance with the arthroscopic findings in 22/349 sites where there had been no previous surgery ( 10 medial meniscus , six lateral meniscus and six anterior cruciate ligament ) . 12 of these 22 errors were considered , on review , to be genuine MRI errors . However , considerable controversy remains as to whether the other 10 " errors " were true or false . There are several factors which contribute to such controversy . These include technically difficult arthroscopies , delays between MRI and arthroscopy , and ambiguities in the wording of both the referral letter and the radiological report . These factors should be considered when evaluating the diagnostic performance of both MRI and arthroscopy A prospect i ve double-blind study was undertaken to evaluate the usefulness of magnetic resonance imaging in the accurate interpretation of pathological intra-articular changes in the knee . Forty-seven patients who were scheduled to have arthroscopy and three patients who wer to have arthrotomy volunteered for magnetic resonance imaging preoperatively . The radiologists had no clinical or roentgenographic information about the patients before the evaluation of the magnetic resonance images , and the radiologists ' interpretations were unknown to the surgeon before the arthroscopy or arthrotomy was done . Our important observations were limited to the findings in the menisci and in the anterior cruciate ligament . Magnetic resonance imaging had a positive predictive value of 75 per cent , a negative predictive value of 90 per cent , a sensitivity of 83 per cent , and a specificity of 84 per cent for pathological findings in the menisci . For complete tears of the anterior cruciate ligament , the positive predictive value was 74 per cent ; the negative predictive value , 70 per cent ; the sensitivity , 61 per cent ; and the specificity , 82 per cent . We believe that magnetic resonance imaging , when combined with clinical and roentgenographic examination , provides the most accurate non-invasive source of information that is currently available for pathological findings in the menisci and in the anterior cruciate ligament In a prospect i ve study , magnetic resonance imaging was performed before arthroscopy for all patients ( n = 121 ) with a meniscal tear ( n = 125 ) . Criteria of the study were stable cruciate and collateral ligaments , absence of pathologic radiographic findings , and absence of prior surgical interventions of the involved knee joint . In 43 knees ( 34 % ) , the clinical diagnosis of a meniscal tear was discarded because of the results of the magnetic resonance imaging examination . Synovitis was diagnosed in 16 patients ( 13 % ) , articular cartilage damage in 10 patients ( 8 % ) , bone bruise injuries in 10 patients ( 8 % ) , osteochondritis dissecans in 3 patients ( 2 % ) , disruption of the inner layer of the medial collateral ligament in 3 patients ( 2 % ) , and osteonecrosis in 1 patient . The use of magnetic resonance imaging in establishing diagnosis of disorders of the knee joint altered treatment in a significant proportion of patients . Magnetic resonance imaging should be done before arthroscopy of the knee in all cases in which the clinical diagnosis has been reduced to a suspected meniscus injury In children , compulsory arthroscopy for hemarthrosis after knee trauma is not justified because ligamentous and meniscal damage is rare . In a prospect i ve study , we analyzed the diagnostic value of radiography , magnetic resonance imaging ( MRI ) , and arthroscopy in 51 patients up to 14 years of age with acute knee trauma . Plain radiography revealed 16 osseous lesions ( 5 metaphyseal , 3 patellar , 4 physeal fractures , 3 avulsions of the tibial spine , and 1 osseous ligamentous tear ) . In 29 patients , the cause of hemarthrosis remained unclear . All patients were evaluated by  MRI .  A diagnosis could be assigned to all 29 patients . MRI  demonstrated lesions in 38 patients . In addition , the following lesions were discovered : 8 patellar dislocations , 13 bruises , 1 rupture of the anterior cruciate ligament , 1 osteochondritis dissecans , and 13 joint effusions . In 13 patients , MRI was followed by arthroscopy to confirm the diagnosis . Both , MRI and arthroscopy missed two osteochondral fractures . In addition , three chondral lesions were not picked up by MRI . MRI is a reliable tool for assessing the extent of knee lesions in children OBJECTIVE To compare partial flexion true sagittal ( FS ) magnetic resonance ( MR ) images with extension sagittal oblique ( ESO ) MR images with regard to delineation of the anterior cruciate ligament ( ACL ) in the knee . DESIGN To establish the appropriate degree of flexion of the knee joint , two human cadaveric knee joints were used as a supplementary technique . FS and ESO images then were performed in 17 knees with an intact ACL and six knees with a torn ACL . In 22 of the 23 knees in which the MR diagnosis of intact or torn ACL corresponded to that derived from arthroscopy , the paired MR images were rated by a three-point scale . RESULTS FS images were rated superior to ESO images in 53 % , 41 % and 47 % of cases with regard to femoral attachment sites , midportions and tibial attachment sites of intact ACLs , respectively . FS images allowed better assessment of disrupted ACLs and residual ligamentous structures . Overall the FS images were either equal to or better than the ESO in the majority of cases . CONCLUSION FS images are useful when the ACL is not well visualized in initial ESO images OBJECTIVES The aim of the study reported here was to investigate whether the use of magnetic resonance imaging ( MRI ) impacts on the clinical management of patients presenting with chronic knee problems , reduces costs , and improves patient outcome . METHODS A single-center r and omized controlled trial was conducted . Patients attending with knee problems in whom surgery was being considered were r and omized either to investigation using an MRI scan or to investigation using arthroscopy .  The study investigated benefits in terms of avoidance of surgery and patient health-related quality of life ( using SF-36 and EQ-5D ) . Costs were assessed from the perspectives of the National Health Service and patients . All analyses were by intention to treat . RESULTS The trial recruited 118 patients . No statistically significant differences were found between groups in terms of health outcome . However , the use of MRI was associated with a positive diagnostic/therapeutic impact : a significantly smaller proportion of patients in the MRI group underwent surgery  ( MRI = 0.41 , No-MRI = 0.71 ; p value = .001 ) . There was a similar mean overall cost for both groups . CONCLUSIONS The use of MRI in patients with chronic knee problems , in whom surgery was being considered , did not increase costs overall , was not associated with worse outcomes , and avoided surgery in a significant proportion of patients A prospect i ve and retrospective study was undertaken to compare the accuracy of magnetic resonance imaging ( MRI ) with clinical examination in diagnosing meniscal and anterior cruciate ligament ( ACL ) tears . Pathological findings were then confirmed during arthroscopy . One hundred fifty-four patients clinical ly diagnosed with a meniscal or ACL tear who ultimately had arthroscopic knee surgery were evaluated ; 100 patients underwent clinical examination followed by MRI , and 54 underwent clinical examination alone .  The presence or absence of meniscal and ACL tears was confirmed during arthroscopy . The accuracies of clinical examination and MRI  were compared for the 100 patients who underwent both clinical examination and MRI .  The accuracy of MRI  was 75 % for medial meniscal tears , 69 % for lateral meniscal tears and 98 % for ACL tears . The accuracy of clinical examination was 82 % for medial meniscal tears , 76 % for lateral meniscal tears and 99 % for complete tears of the ACL . Furthermore , the accuracy of clinical examination for the 54 patients who underwent clinical examination alone was not significantly different from the accuracy of clinical examination in the 100 patients who also underwent MRI . There was no significant difference between the accuracy of clinical examination and MRI in the diagnosis of meniscal and ACL tears and , overall , MRI  contributed to treatment in only 16 of 100 cases . Based on these findings , we feel that MRI , except in certain circumstances , is an expensive and unnecessary diagnostic test in patients with suspected meniscal and ACL pathology Rapidly progressing medical technology sometimes obscures the importance of history and physical examination . This study was design ed to assess the value of MRI and clinical examination in the diagnosis of ligamentous and meniscal knee injuries in comparison with arthroscopic findings . In the year 2003 - 2004 , we conducted a prospect i ve , single blind study to assess ligamentous and meniscal injuries of the knee in patients with acute knee trauma . The mean age was 27.9 years . The sex distribution was 81.4 % male and 18.6 % female ; 42.9 % of injuries affected the right knee and 57.1 % the left knee . All the included patients were ordered a MRI , executed in five separate centres . All patients underwent arthroscopy by the author . Arthroscopic findings were the diagnostic reference . Clinical examination was accurate in 91.4 % , and  MRI  in 88.5 % of anterior cruciate ligament injuries . For posterior cruciate ligament injuries , clinical accuracy was 100 % and MRI 94.6 % . Clinical examination was accurate in 96.9 % and  MRI  in 85.9 % of medial meniscal injuries . For lateral meniscus injuries , clinical accuracy was 85.4 % and MRI 73.8 % . MRI findings showed the lowest correlation with arthroscopic findings in lateral meniscus injuries ( r = 0/47 ) . Clinical diagnostic performance was poorest in case of combined cruciate ligament and meniscal injuries . We found an excellent correlation between  MRI and clinical findings . However , when MRI is normal , high clinical suspicion and a skilled clinical examination are more reliable A blind and prospect i ve study was conducted to assess the accuracy of magnetic resonance imaging ( MRI ) for diagnosing  patellar cartilage lesions . Thirty-three consecutive patients undergoing knee arthroscopy were examined by MRI prior to surgery . Imaging was performed in the axial plane on a 1.5-Tesla unit with spinecho and gradient-echo T1 and T2 sequences . The MRI and arthroscopic data were compared using a four- grade classification and a patellar map which divided the patellar surface into four quadrants . The overall sensitivity of MRI  was 84.7 % and the specificity 97.2 % . The same pit-fall led to two MRI false positives . A perfect correlation of grading was obtained in 76.5 % . When discordance was found , the tendency with MRI was commonly to underestimate the grade of the lesions . The  MRI accuracy was high in this study in spite of a high rate of low- grade lesions which are difficult to assess . Related criteria for cartilage assessment with MRI and arthroscopy are suggested for further studies OBJECTIVE Meniscal resection decreases the ability of the meniscus to evenly distribute forces placed on it . These forces are oriented centrifugally on the meniscus by normal weight-bearing and are distributed by circumferentially oriented fibers . This alteration may predispose the knee to radial tears after surgery . SUBJECTS AND METHODS One of three musculoskeletal radiologists prospect ively interpreted 100 consecutive postoperative MRI examinations of the knee . A prospect i ve MRI report was generated for the referring orthopedic surgeon , and prospect i ve MRI interpretations were correlated with arthroscopic findings ( n 
    Output:
    
RESULTS MRI is highly accurate in diagnosing meniscal and anterior cruciate ligament ( ACL ) tears .
It is the most appropriate screening tool before therapeutic arthroscopy .
It is preferable to diagnostic arthroscopy in most patients because it avoids the surgical risks of arthroscopy .