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

Accuracy of cartilage-specific 3-Tesla 3D-DESS magnetic resonance imaging in the diagnosis of chondral lesions: comparison with knee arthroscopy

Background

Arthroscopy is considered as “the gold standard” for the diagnosis of traumatic intraarticular knee lesions. However, recent developments in magnetic resonance imaging (MRI) now offer good opportunities for the indirect assessment of the integrity and structural changes of the knee articular cartilage. The study was to investigate whether cartilage-specific sequences on a 3-Tesla MRI provide accurate assessment for the detection of cartilage defects.

Methods

A 3-Tesla (3-T) MRI combined with three-dimensional double-echo steady-state (3D-DESS) cartilage specific sequences was performed on 210 patients with knee pain prior to knee arthroscopy. Sensitivity, specificity, and positive and negative predictive values of magnetic resonance imaging were calculated and correlated to the arthroscopic findings of cartilaginous lesions. Lesions were classified using the modified Outerbridge classification.

Results

For the 210 patients (1260 cartilage surfaces: patella, trochlea, medial femoral condyle, medial tibia, lateral femoral condyle, lateral tibia) evaluated, the sensitivities, specificities, positive predictive values, and negative predictive values of 3-T MRI were 83.3, 99.8, 84.4, and 99.8 %, respectively, for the detection of grade IV lesions; 74.1, 99.6, 85.2, and 99.3 %, respectively, for grade III lesions; 67.9, 99.2, 76.6, and 98.2 %, respectively, for grade II lesions; and 8.8, 99.5, 80, and 92 %, respectively, for grade I lesions.

Conclusions

For grade III and IV lesions, 3-T MRI combined with 3D-DESS cartilage-specific sequences represents an accurate diagnostic tool. For grade II lesions, the technique demonstrates moderate sensitivity, while for grade I lesions, the sensitivity is limited to provide reliable diagnosis compared to knee arthroscopy.

Accuracy of cartilage-specific 3-Tesla 3D-DESS magnetic resonance imaging in the diagnosis of chondral lesions: comparison with knee arthroscopy

BACKGROUND

Arthroscopy is considered as "the gold standard" for the diagnosis of traumatic intraarticular knee lesions. However, recent developments in magnetic resonance imaging (MRI) now offer good opportunities for the indirect assessment of the integrity and structural changes of the knee articular cartilage. The study was to investigate whether cartilage-specific sequences on a 3-Tesla MRI provide accurate assessment for the detection of cartilage defects.

METHODS

A 3-Tesla (3-T) MRI combined with three-dimensional double-echo steady-state (3D-DESS) cartilage specific sequences was performed on 210 patients with knee pain prior to knee arthroscopy. Sensitivity, specificity, and positive and negative predictive values of magnetic resonance imaging were calculated and correlated to the arthroscopic findings of cartilaginous lesions. Lesions were classified using the modified Outerbridge classification.

RESULTS

For the 210 patients (1260 cartilage surfaces: patella, trochlea, medial femoral condyle, medial tibia, lateral femoral condyle, lateral tibia) evaluated, the sensitivities, specificities, positive predictive values, and negative predictive values of 3-T MRI were 83.3, 99.8, 84.4, and 99.8 %, respectively, for the detection of grade IV lesions; 74.1, 99.6, 85.2, and 99.3 %, respectively, for grade III lesions; 67.9, 99.2, 76.6, and 98.2 %, respectively, for grade II lesions; and 8.8, 99.5, 80, and 92 %, respectively, for grade I lesions.

CONCLUSIONS

For grade III and IV lesions, 3-T MRI combined with 3D-DESS cartilage-specific sequences represents an accurate diagnostic tool. For grade II lesions, the technique demonstrates moderate sensitivity, while for grade I lesions, the sensitivity is limited to provide reliable diagnosis compared to knee arthroscopy.

Mapping tibiofemoral gonarthrosis: an MRI analysis of non-traumatic knee cartilage defects

OBJECTIVE

Arthroscopy is "the gold standard" for the diagnosis of knee cartilage lesions. However, it is invasive and expensive, and displays all the potential complications of an open surgical procedure. Ultra-high-field MRI now offers good opportunities for the indirect assessment of the integrity and structural changes of joint cartilage of the knee. The goal of the present study is to determine the site of early cartilaginous lesions in adults with non-traumatic knee pain.

METHODS

3-T MRI examinations of 200 asymptomatic knees with standard and three-dimensional double-echo steady-state (3D-DESS) cartilage-specific sequences were prospectively studied for early degenerative lesions of the tibiofemoral joint. Lesions were classified and mapped using the modified Outerbridge and modified International Cartilage Repair Society classifications.

RESULTS

A total of 1437 lesions were detected: 56.1% grade I, 33.5% grade II, 7.2% grade III and 3.3% grade IV. Cartographically, grade I lesions were most common in the anteromedial tibial areas; grade II lesions in the anteromedial L5 femoral areas; and grade III in the centromedial M2 femoral areas.

CONCLUSION

3-T MRI with standard and 3D-DESS cartilage-specific sequences demonstrated that areas predisposed to early osteoarthritis are the central, lateral and ventromedial tibial plateau, as well as the central and medial femoral condyle.

ADVANCES IN KNOWLEDGE

In contrast with previous studies reporting early cartilaginous lesions in the medial tibial compartment and/or in the medial femoral condyle, this study demonstrates that, regardless of grade, lesions preferentially occur at the L5 and M4 tibial and L5 and L2 femoral areas of the knee joint.

Diagnostic performance of magnetic resonance imaging and pre-surgical evaluation in the assessment of traumatic intra-articular knee disorders in children and adolescents: what conditions still pose diagnostic challenges?

BACKGROUND

Diagnosis of intra-articular lesions in children based on clinical examination and MRI is particularly challenging.

OBJECTIVE

To evaluate the diagnostic performance of MRI and pre-surgical evaluation of the knee in pediatric patients relative to arthroscopic evaluation as the gold standard. We report diagnoses frequently missed or inaccurately diagnosed pre-operatively.

MATERIALS AND METHODS

We conducted a retrospective review of MRI and pre-surgical evaluation in children and adolescents ages 1-17 years who were treated by knee arthroscopy during a 2½-year period. All MRIs were reviewed by a pediatric radiologist blinded to clinical findings. Pediatric orthopedic clinic notes were reviewed for pre-surgical evaluation (based on physical exam, radiograph, MR images and radiologist's MRI report). Arthroscopic findings were used as the gold standard. We calculated the percentages of diagnoses at arthroscopy missed on both MRI and pre-surgical evaluation. Diagnostic accuracy between children and adolescents and in patients with one pathological lesion vs. those with >1 lesion was analyzed. We performed a second review of MR images of the missed or over-called MRI diagnoses with knowledge of arthroscopic findings.

RESULTS

We included 178 children and adolescents. The most common diagnoses missed on MRI or pre-surgical evaluation but found at arthroscopy were: discoid meniscus (8/30, or 26.7% of cases); lateral meniscal tears (15/80, or 18.8% of cases); intra-articular loose bodies (5/36, or 13.9% of cases), and osteochondral injuries (9/73, or 12.3% of cases). Overall diagnostic accuracy of MRI and pre-surgical evaluation was 92.7% and 95.3%, respectively. No significant difference in diagnostic accuracy between children and adolescents was observed. When multiple intra-articular lesions were present, lateral meniscal tears were more likely to be inaccurately diagnosed (missed or over-called) on both MRI (P = 0.009) and pre-surgical evaluation (P < 0.001).

CONCLUSION

Overall diagnostic accuracy of MRI and pre-surgical evaluation was quite high. The traumatic intra-articular knee lesions that still pose a diagnostic challenge for MRI and pre-surgical evaluation are lateral discoid meniscus, lateral meniscal tears, intra-articular loose bodies and osteochondral injuries. Special attention should be given to those diagnoses when evaluating a pediatric knee MRI. In children with multiple intra-articular injuries, there is significantly more inaccuracy in pre-arthroscopic diagnosis of lateral meniscal tears on both MRI and pre-surgical evaluation.

Management strategies for osteochondritis dissecans of the knee in the skeletally immature athlete

SYNOPSIS

Osteochondritis dissecans (OCD) is a disorder resulting in focal breakdown of the subchondral bone, with potential disruption of the overlying articular cartilage. The femoral condyles of the knee are the most common locations for OCD, and the incidence of OCD appears to be increasing among active children. Juvenile OCD (JOCD) can be distinguished from adult OCD by the presence of open growth plates. Due to a lack of evidence on its early diagnosis, optimal treatment, and long-term course of healing, JOCD presents a unique challenge for the health care team. Approximately 50% to 67% of stable JOCD lesions heal successfully with nonoperative treatment. For unstable lesions and stable lesions that fail nonoperative treatment, a variety of surgical interventions can be utilized to stimulate bony healing and address articular cartilage lesions. It is recommended that rehabilitation of JOCD be tailored to the individual patient, based on the stage and radiographic status of the lesion and the mode of surgery employed when surgically addressed. Although there is a growing body of literature on this condition, the etiology and optimal methods for treatment, rehabilitation, and evaluating outcomes remain inconclusive due to a lack of quality evidence.

LEVEL OF EVIDENCE

Therapy, level 5.

Correlation of clinical examination, ultrasound sonography, and magnetic resonance imaging findings with arthroscopic findings in relation to acute and chronic lateral meniscus injuries

PURPOSE

The aim of this study was to evaluate whether ultrasound sonography (USS) performed by orthopedic surgeons is a reliable method of investigating lateral meniscus (LM) knee lesions as compared to magnetic resonance imaging (MRI), and arthroscopy, which is the gold standard in clinical practice.

METHODS

In total, 107 patients were involved in this study. They were hospitalized for arthroscopy due to LM injury of the knee. Clinical examination (McMurray's, Apley's, and joint line tenderness tests), USS, and MRI were performed prior to arthroscopy. We compared the results of clinical examination, USS, and MRI with the arthroscopic findings for the knee, which were considered the reference values.

RESULTS

McMurray's clinical test, which is the most sensitive method of detecting lateral meniscus lesions, gave the same sensitivity rate for both acute and chronic LM injuries: 65%. USS was observed to be more sensitive and specific for chronic LM injuries (85 and 90%, respectively) than for acute LM injuries (71 and 87%). MRI also yielded higher values of sensitivity and specificity for chronic lateral meniscus injuries (75 and 95%, respectively) than for acute LM injuries (68 and 87%).

CONCLUSIONS

The accuracy of ultrasound examination is demonstrated by the high reliability of this method in the diagnosis of lateral meniscus lesions of the knee, and the evaluation performed in this study showed that ultrasound is a useful clinical tool for diagnosing knee pathology.

The clinical utility and diagnostic performance of MRI for identification and classification of knee osteochondritis dissecans

BACKGROUND

Magnetic resonance imaging (MRI) is a common clinical tool used to diagnose and monitor the progression and/or healing of osteochondritis dissecans of the knee. The purpose of this study was to systematically review the literature relative to the following questions: (1) Is MRI a valid, sensitive, specific, accurate, and reliable imaging modality to identify knee osteochondritis dissecans compared with arthroscopy? (2) Is MRI a sensitive tool that can be utilized to characterize lesion severity and stability of osteochondritis dissecans fragments in the knee?

METHODS

A systematic search was performed in December 2010 with use of PubMed MEDLINE (from 1966), CINAHL (from 1982), SPORTDiscus (from 1985), Scopus (from 1996), and EMBASE (from 1974) databases.

RESULTS

Seven studies, four Level-II and three Level-III investigations, met the specified inclusion criteria. No randomized controlled studies were identified. Because of inconsistencies between imaging techniques and methodological shortcomings of many of the studies, a meta-analysis was not performed.

CONCLUSIONS

The limited available evidence, methodological inconsistencies in imaging techniques, and lack of standardized grading criteria used in current studies prevent clear conclusions regarding the diagnostic and specific staging equivalency of MRI with arthroscopy. However, available evidence supports the use of MRI to detect the stability or instability of the lesion. Given the benefits of the use of MRI as a noninvasive tool to diagnose, predict lesion progression, and assess clinical outcomes of treatment, there is a pressing need for high-level, systematic, sound, and thorough studies related to the clinical utility of MRI for assessing osteochondritis dissecans of the knee.

The concordance of MRI and arthroscopy in traumatic meniscal lesions in children

INTRODUCTION

Traumatic meniscal lesions in children must be diagnosed quickly and efficiently as a priority in order to conserve the meniscus and safeguard the future of the knee. They are often isolated and difficult to identify clinically. In the diagnostic work up stage, an excessive resort to diagnostic arthroscopy has given way to increasing use of MRI by radiologists without pediatric specialization. The present study examined the agreement between MRI aspect and arthroscopic exploration in traumatic meniscal lesions in children.

PATIENTS AND METHODS

Sixty-nine knees in children aged 9 to 16 years having undergone MRI followed by arthroscopy for knee trauma between 1995 and 2008 were included in a retrospective design. Discoid meniscus was excluded. Files were reviewed by a single clinician and MRI scans by a radiologist specialized in pediatric pathology. Cases of epiphyseal fusion were excluded. All files were analyzable. Agreement with arthroscopic findings as reference was assessed for presence, location and type of meniscal lesion.

RESULTS

Overall agreement with arthroscopy was respectively 78% and 82% on first and second MRI readings: 77% and 80% for the medial, and 78% and 84% for the lateral meniscus. On the first reading, there were 13 false positives for the medial and 5 for the lateral meniscus, versus 9 and 0 respectively on second reading. Overall sensitivity was 70% on first reading and 64% on second, and overall specificity 81% and 90%, respectively.

DISCUSSION

The present results, in line with the literature, may appear encouraging, but hide considerable disparity between analysis of the medial and of the lateral meniscus: MRI overestimated medial and underestimated lateral meniscus lesions.

CONCLUSION

MRI serves only as a support and does not provide sure diagnosis of meniscus lesion. Interpretation should take account of the clinical examination and the pediatric orthopedic specialist's experience.

Diagnosis and treatment of osteochondritis dissecans

This clinical practice guideline is based on a series of systematic reviews of published studies in the available literature on the diagnosis and treatment of osteochondritis dissecans of the knee. None of the 16 recommendations made by the work group is graded as strong; most are graded inconclusive; two are graded weak; and four are consensus statements. Both of the weak recommendations are related to imaging evaluation. For patients with knee symptoms, radiographs of the joint may be obtained to identify the lesion. For patients with radiographically apparent lesions, MRI may be used to further characterize the osteochondritis dissecans lesion or identify other knee pathology.

[Diagnostic approaches to acute knee injury in childhood and adolescence. Yesterday and today]

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.

Meniscal tears and discoid meniscus in children: diagnosis and treatment

The incidence of traumatic meniscal tears in children is on the rise, likely because of increased sports participation and more accurate diagnostic modalities. The increased vascularity of the developing meniscus is believed to enable greater healing potential. Meniscal tears in children are often amenable to repair, and excellent clinical results have been reported. Knee size must be considered when determining the optimal method of repair. Discoid menisci represent a spectrum of morphologic abnormalities and instability of the lateral meniscus. Highly unstable variants often present with the classic "snapping knee syndrome," whereas stable variants may remain asymptomatic until a tear develops. Asymptomatic discoid menisci should be observed, whereas symptomatic discoid menisci are best treated with saucerization and repair. Early to midterm reports on saucerization and repair of discoid lateral meniscus in children are promising.

The condylar cutoff sign: quantifying lateral femoral condylar hypoplasia in a complete discoid meniscus

We describe the condylar cutoff sign, a radiographic sign in knees with a discoid lateral meniscus, for diagnosis of complete discoid meniscus. We retrospectively reviewed tunnel-view radiographs of 100 patients (100) knees including 50 with complete discoid lateral meniscus and 50 with normal menisci. All patients were 18 years of age or older. All of the knees were arthroscopically examined. We developed a method to measure the prominence of the femoral condyle adjacent to the intercondylar notch on a tunnel view of the knee. The prominence ratio, the ratio of the medial and lateral condylar prominence, was compared and analyzed. The measurements were performed by three observers on two separate occasions to determine reliability. The intraobserver and interobserver variability study revealed high reliability with correlation coefficients ranging from 0.86 to 0.99. Using a cutoff ratio of 0.8, we observed a major difference between the two groups and found the ratio had 76% sensitivity, 96% specificity, 95% positive predictive value, and 80% negative predictive value in every set of measurements. The sign has high specificity and reliability but might not apply to younger patients.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Computed tomography of the shoulders in patients with obstetric brachial plexus injuries: a retrospective study

Background

Scapular hypoplasia, elevation, and rotation (SHEAR) deformity and posterior subluxation of the humeral head are common tertiary sequelae of obstetric brachial plexus injuries (OBPI). Interpretations of images from bilateral computed tomography (CT) scans of the upper extremities are critical to the diagnosis and treatment plan for patients with these bony deformities resulting from OBPI.

Methods

We conducted a retrospective study to investigate the accuracy of radiologic reports in the diagnosis of SHEAR or posterior subluxation of the humeral head in OBPI patients. CT studies from 43 consecutive patients over a 33-month period were used in the study. For each patient, we compared the results from the radiologic report to those from a clinical examination given by the attending surgeon and to measurements taken from the CT studies by biomedical researchers.

Results

A comparison of SHEAR measured from the 3-D CT images to the diagnoses from the radiologists, revealed that only 40% of the radiological reports were accurate. However, there was a direct correlation between the use of the 3-D CT images and an accurate SHEAR diagnosis by the radiologists (p < 0.0001). When posterior subluxation was measured in the affected and contralateral shoulders, 93% of the patients that had greater than a 10% difference between the two shoulders did not have their deformity diagnosed. The radiological reports diagnosed 17% of these patients with a 'normal' shoulder. Only 5% of the reports were complete, accurately diagnosing SHEAR in addition to posterior subluxation.

Conclusion

Due to the low incidence rate of OBPI, many radiologists may be unfamiliar with the sequelae of these injuries. It is therefore critical that radiologists are made aware of the importance of an accurate measurement and diagnosis of the SHEAR deformity. Due to their lack of completeness, the radiological reports in this study did not significantly contribute to the clinical care of the patients. In order for OBPI patients to receive the highest standard of care, the final diagnosis from their radiological imaging should be deferred to a brachial plexus specialist who is experienced with these types of injuries.

Knee chondral lesions: incidence and correlation between arthroscopic and magnetic resonance findings

PURPOSE

To determine the incidence and morphologic characteristics of knee chondral lesions found at arthroscopy and their correlation with magnetic resonance imaging (MRI).

METHODS

This is a prospective study on 190 consecutive knee arthroscopic procedures performed between March 2003 and February 2004 by the same surgical team. The study group's age average was 34.8 years (14 to 77 years). The indication for surgery included anterior cruciate ligament tears, meniscal tears, and anterior knee pain. Patients without a preoperative MRI study were excluded. MRI reports were performed by qualified radiologists in all the cases. Chondral lesions were classified according to the International Cartilage Repair Society (ICRS) classification and were included in a database along with the MRI reports. The results were analyzed statistically with analysis of variance, Pearson, kappa, and chi-square tests.

RESULTS

One hundred fifteen chondral lesions in 82 patients were found during the arthroscopic procedure. Most of them were single lesions (72%) located on the medial femoral condyle (32.2%) or medial patellae (22.6%); 62.6% of the lesions were classified as ICRS type 2 or 3-A, with an average surface of 1.99 cm2. We found a significant direct correlation between the patient's age and the size of the lesion (P = .001). MRI sensitivity was 45% with a specificity of 100%. The sensitivity increased with deeper lesions (direct relation with the ICRS classification). Our results showed a statistical power of 100%.

CONCLUSIONS

Although unenhanced MRI using a 1.5-Tesla magnet with conventional sequences (proton density-weighted, T1-weighted, and T2-weighted) is most accurate at revealing deeper lesions and defects at the patellae, our study shows that a considerable number of lesions will remain undetected until arthroscopy, which remains the gold standard.

LEVEL OF EVIDENCE

Level III, diagnostic study of nonconsecutive patients.

The diagnosis of meniscus tears: the role of MRI and clinical examination

Magnetic resonance imaging (MRI) and clinical examination are tools commonly used in the diagnosis of meniscus tears. It has been suggested routine MRI before therapeutic arthroscopy for clinically diagnosed meniscus tears will reduce the number and cost of unnecessary invasive procedures. We designed a systematic review of prospective cohort studies comparing MRI and clinical examination to arthroscopy to diagnosis meniscus tears. Thirty-two relevant studies were identified by a literature review. Careful evaluation by an experienced examiner identifies patients with surgically treatable meniscus lesions with equal or better reliability than MRI. MRI is superior when indications for arthroscopy are solely diagnostic. However, the methods by which such a clinician arrives at a conclusion have not been identified. To create an evidence-based algorithm for the diagnosis of a meniscus tear future investigations should prospectively assess the value of commonly used aspects of the patient history and meniscus tests. MRI is useful, but should be reserved for situations in which an experienced clinician requires further information before arriving at a diagnosis. Indications for arthroscopy should be therapeutic, not diagnostic in nature.

Can CT determine the site of traumatic osteochondral defects in the paediatric knee?

Currently the ability of pre-operative CT imaging to determine the origin of traumatic osteochondral lesions (OCL) in the knee in children is yet to be established. The surgical approach to the knee will to some extent be determined by the origin of the lesion. It is important to directly determine the site of the lesion from pre-operative scanning both to facilitate surgery, to have a better cosmetic result for the patient and have a quicker rehabilitation period. In a tertiary referral centre, from May 2004 to April 2005, eight patients were diagnosed as having an OCL. The initial reporting was done by either a senior registrar or consultant paediatric radiologist. Those children that had an OCL underwent an arthroscopy or definitive open surgery. The exact site of the lesion was then determined and recorded in the operative notes. All the original pre-operative CT scans were given to a senior paediatric radiologist. The consultant on this occasion had no access to operative findings, or original CT reports. CTs reported by the paediatric radiology department are only able to correctly identify the site of origin of the OCL 50% of the time. Recent MR scanning techniques have improved the visualization of OCL. We authors therefore feel that in the future MRI should be used to assess the paediatric knee when an acute OCL is suspected.