MR diagnosis of meniscal tears of the knee: analysis of error patterns

Purpose Despite high accuracy of magnetic resonance imaging (MRI) for diagnosing meniscal tears, MR findings do not always agree with surgical findings. We performed a blinded, retrospective study to analyze the nature and frequency of errors in the MR diagnosis of meniscal tears. Materials and methods Medical records of 100 consecutive patients who underwent MR and arthroscopy of the knee at our institution were reviewed. Twelve patients underwent prior meniscal surgery. Twenty-three patients had 27 discrepancies between MR and surgical findings. These were independently reviewed by two additional musculoskeletal radiologists in a double blinded fashion. Original incorrect diagnoses were categorized as either unavoidable, interpretation error or equivocal for meniscal tear. Results MR accuracy was 88% for the medial and 85% for the lateral meniscus. Of 27 incorrect MR diagnoses, 12 (44%) were unavoidable, 10 (37%) equivocal and 5 (19%) interpretation errors. Of the 67 medial meniscal tears, 12 (18%) were missed. Eight (67%) of these 12 were categorized as equivocal, including three postoperative menisci. Of 30 lateral tears, 12 (40%) were missed, 7 (58%) of which were categorized as unavoidable. Of these 12, 11 (92%) showed fraying of the inner edge, which was shaved at arthroscopy (n = 8) or had stable tear treated conservatively (n = 3). There were three false-positive diagnoses, all occuring in the lateral meniscus, two of which were unavoidable and one interpretation error. Conclusion Of all missed lateral meniscal tears, most are unavoidable and related to confusion between what represents fraying and what represents a tear. Unavoidable false-positive diagnoses are infrequent and may be related to incomplete arthroscopic evaluation. Subtle or equivocal findings still make MR diagnosis difficult, even for experienced radiologists.     

Outcome of repaired unstable meniscal tears in children and adolescents

Background

Unstable meniscal tears are rare injuries in skeletally immature patients. Loss of a meniscus increases the risk of subsequent development of degenerative changes in the knee. This study deals with the outcome of intraarticular meniscal repair and factors that affect healing. Parameters of interest were type and location of the tear and also the influence of simultaneous reconstruction of a ruptured ACL.

Methods

We investigated the outcome of 25 patients (29 menisci) aged 15 (4–17) years who underwent surgery for full thickness meniscal tears, either as isolated lesions or in combination with ACL ruptures. Intraoperative documentation followed the IKDC 2000 standard. Outcome measurements were the Tegner score (pre- and postoperatively) and the Lysholm score (postoperatively) after an average follow-up period of 2.3 years, with postoperative arthroscopy and MRT in some cases.

Results

24 of the 29 meniscal lesions healed (defined as giving an asymptomatic patient) regardless of location or type. 4 patients re-ruptured their menisci (all in the pars intermedia) at an average of 15 months after surgery following a new injury. Mean Lysholm score at follow-up was 95, the Tegner score deteriorated, mean preoperative score: 7.8 (4–10); mean postoperative score: 7.2 (4–10). Patients with simultaneous ACL reconstruction had a better outcome.

Interpretation

All meniscal tears in the skeletally immature patient are amenable to repair. All recurrent meniscal tears in our patients were located in the pars intermedia; the poorer blood supply in this region may give a higher risk of re-rupture. Simultaneous ACL reconstruction appears to benefit the results of meniscal repair.Isolated meniscal tears in the skeletally immature patient are rare but well-recognized injuries (Hede et al. 1990). Meniscal tears are frequently seen in association with a ruptured ACL (Bellisari et al. 2011, Samora et al. 2011). The menisci reduce contact stress and buffer axial, rotational, and shearing forces, thereby protecting the articular cartilage (Kurosawa et al. 1980). In the classic paper by Fairbank (1948), early osteoarthritis was clearly shown to be the inevitable outcome of total medial menisectomy. This led to the development of various techniques of meniscal repair in order to improve long-term outcome. This is particularly desirable in the immature patient, as early degenerative changes in this population have profound consequences in the long term. There are a variety of all-inside arthroscopic techniques that are relatively easy to master and that can be quick to perform as compared to the more technically demanding inside-out and outside-in methods (Haas et al. 2005, Kotsovolos et al. 2006).The results of meniscal repair in adults have been reported to be fair to good (Barber 1987, Eggli et al. 1995), while there have been few published data for children and adolescents (Krych et al. 2008). In this retrospective study, we assessed the outcome in a cohort of children and adolescents undergoing meniscal repair and determined whether there was any relationship between the type of meniscal injury and the outcome.     

Reliability of clinical diagnosis in meniscal tears

This retrospective study was conducted to analyse the reliability of clinical diagnosis in meniscal tear injuries. All patients attending our clinic with knee pain from January 2003 to December 2004 underwent systematic and thorough clinical assessment. One hundred and fifty patients were clinically diagnosed to have meniscal tears. All these patients underwent therapeutic arthroscopic knee surgery. The clinical diagnosis was confirmed during this procedure. The accuracy, sensitivity and specificity were calculated based on these arthroscopic findings. The accuracy of clinical diagnosis in our study was 88% for medial meniscal tears and 92% for lateral meniscal tears. The results of this study demonstrate that clinical diagnosis of meniscal tears is as reliable as the results published by other authors for magnetic resonance imaging (MRI) scan. We recommend the use of MRI for more doubtful, difficult and complex knee injuries.

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Résumé Cette étude rétrospective analyse la fiabilité du diagnostic clinique dans les lésions méniscales. De janvier 2003 à décembre 2004 tous les patients présentant des gonalgies ont eu un examen clinique minutieux. 150 avaient des signes de déchirure méniscale et ils ont eu une arthroscopie thérapeutique qui a permis de calculer l’exactitude, la sensibilité et la spécificité du diagnostic. L’exactitude était de 88% pour les lésions méniscales médiales et de 92% pour les lésions latérales. Les résultats montrent que le diagnostic clinique était aussi fiable que le diagnostic par IRM d’après des résultats publiés par d’autres auteurs.

     

The accuracy of joint line tenderness by physical examination in the diagnosis of meniscal tears

Purpose: The purpose of this study was to document the accuracy of joint line tenderness in the diagnosis of meniscal tears. Type of Study: Prospective cohort study. Methods: There were 104 male recruits (age range, 18 to 20 years; mean, 19.2 years) with suspected meniscal lesions who underwent arthroscopy. A thorough history and physical examination was performed on each patient by a physician with 4 years’ experience on arthroscopic knee surgery. Twenty-six (25%) patients sustained injuries while in the Turkish Army, and 78 patients (75%) sustained injuries before they came to the army. On physical examination, assessment of joint line tenderness at the lateral and medial joint lines was performed with the patient’s knee flexed 90°. The accuracy, sensitivity, specificity, and positive and negative predictive values of joint line tenderness for medial and lateral sides were calculated based on arthroscopic findings. Results: In 104 knees, the diagnosis was correct in 71 (68%) and incorrect in 33 (32%) knees. A total of 37 medial meniscal tears and 27 lateral meniscal tears were identified at arthroscopy. Other pathology included 11 anterior cruciate ligament (ACL) tears, 5 medial femoral chondral lesions, 4 chondromalacia patellae, and 1 medial plica. No discernable abnormalities were seen in 21 knees. A preoperative diagnosis of a medial meniscal tear was made in 54 knees and 32 were confirmed at arthroscopy. A lateral meniscus tear was suspected in 27 knees and confirmed in 25. Five medial meniscus and 2 lateral meniscus tears were seen at arthroscopy. These had not been suspected with tenderness over the joint line. The accuracy of the test was lower with the presence of ACL lesions and condromalacia patella. Conclusions: I concluded that joint line tenderness as a test for lateral meniscal tears is accurate (96%), sensitive (89%), and specific (97%). However, for medial meniscal tears, rates are lower.     

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.     

Signs of knee osteoarthritis common in 620 patients undergoing arthroscopic surgery for meniscal tear

Background and purpose — Recent evidence has questioned the effect of arthroscopic knee surgery for middle-aged and older patients with degenerative meniscal tears with or without concomitant radiographic knee osteoarthritis (OA). We investigated the prevalence of early or more established knee OA and patients’ characteristics in a cohort of patients undergoing arthroscopic surgery for a meniscal tear.

Patients and methods — 641 patients assigned for arthroscopy on suspicion of meniscus tear were consecutively recruited from February 2013 through January 2015. Of these, 620 patients (mean age 49 (18–77) years, 57% men) with full datasets available were included in the present study. Prior to surgery, patients completed questionnaires regarding onset of symptoms, duration of symptoms, and mechanical symptoms along with the knee injury and osteoarthritis outcome score (KOOS). At arthroscopy, the operating surgeon recorded information about meniscal pathology and cartilage damage. Early or more established knee OA was defined as the combination of self-reported frequent knee pain, cartilage damage, and the presence of degenerative meniscal tissue.

Results — 43% of patients (269 of 620) had early or more established knee OA. Of these, a large proportion had severe cartilage lesions with almost half having a severe cartilage lesion in at least 1 knee compartment.

Interpretation — Based on a definition including frequent knee pain, cartilage damage, and degenerative meniscal tissue, early or more established knee OA was present in 43% of patients undergoing knee arthroscopy for meniscal tear.     

Relevance of history of injury to the diagnosis of meniscal tears.

A consecutive series of 217 arthroscopic meniscectomies has been reviewed in order to investigate the incidence of significant meniscal lesions without obvious precipitating injury. There were 10 bucket handle tears out of 117 (9%) with a mean age of 32 years with no significant injury; 18 flap tears out of 69 (26%) with a mean age of 40 years; and 7 out of 19 (37%) radial tears with a mean age of 36 years also had no significant injury. This study indicates that the absence of a history of injury in the young patient with a symptomatic knee does not exclude significant meniscal tears, such as a bucket handle, and therefore has implications for history taking and diagnosis.     

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.     

Ultrasound scanning for the diagnosis of meniscal lesions of the knee joint.

We report on the efficacy of ultrasound scanning as a noninvasive method of the preoperative diagnosis of meniscal lesions of the knee joint, using the 7.5-Hz head of a real-time scanner. In studies on cadaveric knee joints we found a high efficacy in diagnosing meniscal lesions using ultrasound. Comparative clinical studies on 51 patients who had undergone preoperative ultrasound scanning showed a strong correlation of ultrasound diagnosis with intraoperative findings. Arthrography was performed in 24 of the 51 patients, yet ultrasound studies proved to be more effective than arthrography in diagnosing meniscal lesions. Consequently, we believe that ultrasonic scanning as a noninvasive method of diagnosis is more helpful in identifying meniscal lesions of the knee joint.     

A comparison of accuracy between clinical examination and magnetic resonance imaging in the diagnosis of meniscal and anterior cruciate ligament tears

A prospective 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 clinically 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.     

Threshold for lateral meniscal body extrusion on MRI in middle-aged and elderly patients with symptomatic knee osteoarthritis

PurposeTo determine the MRI-based threshold of lateral meniscal body extrusion (LMBE) that are associated with meniscal damage, cartilage damage and radiological knee osteoarthritis (OA).Materials and methodsA total of 142 patients (59 men and 83 women) with a mean age of 57.2 ± 7.9 (SD) years (range: 41–77 years) with symptomatic knee OA were included. Radiological assessment was performed using the Kellgren-Lawrence scoring system. Meniscus and cartilage damage were assessed using the whole-organ magnetic resonance imaging score. Meniscal extrusion was quantified on coronal sections of intermediate-weighted MRI sequences. Differences between medial and lateral compartments in meniscal extrusion and incidence of tibiofemoral OA-related structural changes were assessed using Wilcoxon signed rank test and Bowker test. Receiver operating characteristic curves and Youden index were used for determining thresholds for meniscal extrusion.ResultsA total of 142 knees were assessed. Meniscal body extrusion distances between medial and lateral compartments were significantly different in the entire sample, and in subjects with and without radiological knee OA (P < 0.05 for all). The incidence of structural changes between medial and lateral compartments were significantly different (P = 0.003 for meniscal damage; P = 0.001 for femoral cartilage damage). Three mm and 2 mm were determined to be the optimal thresholds for medial and lateral meniscal body extrusion, respectively.ConclusionMedial and lateral meniscal body extrusion were associated with the incidence of OA-related knee structural changes in symptomatic patients with knee OA. A threshold of 2 mm for LMBE with respect to meniscal damage, cartilage damage and radiological knee OA was determined.     

Bilateral bucket handle medial meniscal tears of the knee: A case report

INTRODUCTIONMeniscal tears may cause knee pain and functional impairment. Bilateral bucket-handle meniscal tears is an uncommon condition.PRESENTATION OF CASEThis report presents the case of a 35-year-old male patient with bilateral bucket handle medial meniscal tears that occurred nonsimultaneously. The lesions were treated arthroscopically with partial resection in one knee and meniscal suture in the other.DISCUSSIONBucket handle meniscal tear of meniscus without underlying meniscal, ligamentous pathology or lower limb deformity is a rare condition.CONCLUSIONTo our knowledge, bilateral bucket handle medial meniscal tears without underlying meniscal anomalies have been reported in only two cases before, and our case is the third one.     

Degenerative meniscus tears and mobility impairment in women with knee osteoarthritis

OBJECTIVE: Meniscus tears are often presumed to be associated with a traumatic event, but they can also occur as a result of the cartilage degeneration process in osteoarthritis (OA). The aim of this paper is to describe the prevalence and clinical correlates of degenerative meniscus tears in women with knee OA. METHOD: The subjects were women screened for a double-blind, sham-exercise controlled clinical trial for women over 40 years of age with OA in at least one knee, according to American College of Rheumatology (ACR) clinical criteria. The presence of meniscus tears was assessed via a 3T Intera (Philips Medical Systems) magnetic resonance image (MRI). Clinical examination included a history of arthritis onset and physical examination of the lower extremities. Physical assessments included body composition, muscle strength, walking endurance, gait velocity, and balance. In addition, pain and disability secondary to OA, physical self-efficacy, depressive symptoms, habitual physical activity level and quality of life were assessed via questionnaires. RESULTS: Almost three-quarters (73%) of the 41 subjects had a medial, lateral, or bilateral meniscus tear by MRI. Walking endurance and balance performance were significantly impaired in subjects with a degenerative meniscus tear, compared to subjects without tears, despite similar OA duration, symptoms, and disability, body composition, and other clinical characteristics. CONCLUSION: Meniscus tears, diagnosed by MRI, are very common in older women with knee OA, particularly in the medial compartment. These incidentally discovered tears are associated with clinically relevant impairments of balance and walking endurance relative to subjects without meniscus tears. The explanation for this association requires further study.