Chondral lesions of the patella evaluated with computed tomography, magnetic resonance imaging, and arthroscopy

Association between Patellofemoral Anatomy and Chondral Lesions of the Knee in Patellofemoral Instability

Chondral injury is a serious consequence of patellar dislocation and patellofemoral instability (PFI). There is limited data on the relationship between radiological features such as sulcus angle and patellar height to the presence, location, and severity of chondral lesions. The purpose of this study was to determine the association of anatomical variants in patellofemoral instability with injuries sustained due to patellar dislocation. A cohort of 101 patients who had four or more episodes of dislocation or instability undergoing isolated arthroscopy or arthroscopies at the time of corrective realignment surgery were identified. The prevalence of chondral, ligamentous, and meniscal injuries was determined and correlated to the sulcus angle, tibial tubercle trochlear groove distance, and patellar height on magnetic resonance imaging (MRI) scans. A total of 101 patients was identified. At arthroscopy, the patella demonstrated the highest incidence of chondral injury (68%) followed by the trochlear groove (40%). Lateral meniscal injuries were noted in 6% of patients, medial meniscal injuries in 2%, and anterior cruciate ligament (ACL) injury in 3%. Chondral injuries were graded using the Outerbridge criteria and there was a correlation between more severe chondral injuries and a greater tilt angle (p = 0.05). The occurrence of injury to the lateral meniscus was associated with a higher Insall-Salvati ratio (p = 0.05). More severe chondral injuries are seen in patients with a greater tilt angle.

Volume index as a new measure of cartilage loss: a retrospective MRI-based study of chondral injury patterns in adult patients with knee pain

BACKGROUND

Knee pain is one of the commonest symptoms in patients who attend the Orthopaedic outpatient clinics. Chondral defects result in a painful knee. Incidence of chondral defect is reported to be between 5 and 10% over the age of 40. It is well documented that chondral defects can lead to osteoarthritis. Early detection of these lesions and cartilage repair surgery can delay the onset of osteoarthritis. The purpose of this study is to highlight the incidence, associations and correlations between opposing cartilage defects in patients who present to the knee clinic with pain.

METHODS

A retrospective analysis was carried out on patients who had Magnetic Resonance Imaging scans for painful knees between June 2017 and May 2019. About 227 consecutive knees were studied for the incidence of chondral defects, number of lesions, grade and size of lesion, geographical location and associated pathology in the knee.

RESULTS

All the 227 patients had chondral lesions. Most patients had 2-3 lesions (66.1%) with patellar lesions (76.6%) being the commonest followed by medial femoral condyle (59.9%). Significant correlation was found in grade and size between opposing surface lesions in patella-trochlea, Medial Femoral Condyle-Medial Tibial Plateau and Lateral Femoral Condyle-Lateral Tibial Plateau. Females were more predisposed to patella lesions. Significance between age and lesions were established.

CONCLUSION

Incidence of cartilage defects in the knee is very high. Kissing lesions must be considered when treating cartilage lesions. Volume index could be a promising method to quantify lesions.

Chondromalacia patellae: current options and emerging cell therapies

Chondromalacia patellae (CMP), also known as runner’s knee, typically occurs in young patients, which is characterized by anterior knee pain (AKP) that is associated with visible changes in patellar cartilage. The initial pathological changes include cartilage softening, swelling, and edema. CMP is caused by several factors, including trauma, increased cartilage vulnerability, patellofemoral instability, bony anatomic variations, abnormal patellar kinematics, and occupation hazards. CMP may be reversible or may progress to develop patellofemoral osteoarthritis. Quadriceps wasting, patellofemoral crepitus, and effusion are obvious clinical indications. Additionally, radiological examinations are also necessary for diagnosis. Magnetic resonance imaging (MRI) is a non-invasive diagnostic method, which holds a promise in having the unique ability to potentially identify cartilage lesions. Modalities are conventionally proposed to treat cartilage lesions in the PF joint, but none have emerged as a gold standard, neither to alleviated symptoms and function nor to prevent OA degeneration. Recently, researchers have been focused on cartilage-targeted therapy. Various efforts including cell therapy and tissue emerge for cartilage regeneration exhibit as the promising regime, especially in the application of mesenchymal stem cells (MSCs). Intra-articular injections of variously sourced MSC are found safe and beneficial for treating CMP with improved clinical parameters, less invasiveness, symptomatic relief, and reduced inflammation. The mechanism of MSC injection remains further clinical investigation and is tremendously promising for CMP treatment. In this short review, etiology, MRI diagnosis, and treatment in CMP, especially the treatment of the cell-based therapies, are reviewed.

Knee morphometric and alignment measurements with MR imaging in young adults with central cartilage lesions of the patella and trochlea

PURPOSE

The goal of this study was to assess whether common measurements of patellar and trochlear morphology and patellar alignment are associated with central cartilage lesions of the patella and trochlea using magnetic resonance imaging (MRI).

METHODS

The MRI examinations of 58 patients (38 women, 20 men; mean age, 28.59 years [range: 19-35 years]) with central cartilage lesions of the patella and trochlea were retrospectively compared to those obtained in 102 control subjects (57 women, 45 men; mean age, 27.05 years [range: 20-35 years]). Patients had Modified Noyes Classification grade IIA, IIB or III cartilage defects whereas control subjects had normal MRI examination of the knee as determined by two radiologists. Patellar measurements of facet asymmetry, patellar tilt, lateral patellofemoral angle, Insall-Salvati ratio, and patellotrochlear cartilage overlap were performed in patients and control subjects along with trochlear measurements of the trochlear depth and width, and sulcal angle. Multivariate logistic regression adjusted for age and body mass index was used to assess associations.

RESULTS

The ratio of the lengths of the medial to lateral facets of the patella (OR=2.7×10^-3; P<0.001), angle of the median eminence of the patella (OR=1.05; P=0.040), lateral patellofemoral angle (OR=0.91; P=0.048), Insall-Salvati ratio (OR=364.4; P<0.001) and edema in the superolateral aspect of Hoffa's fat pad (OR=6.52; P<0.001) were significantly associated with central cartilage lesions of the patella and trochlea.

CONCLUSION

Central cartilage lesions of the patellofemoral joint are associated with patellar and trochlear morphology, and patellar alignment.

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.

Chondral Injury in Patellofemoral Instability

OBJECTIVE

Patellofemoral instability is common and affects a predominantly young age group. Chondral injury occurs in up to 95%, and includes osteochondral fractures and loose bodies acutely and secondary degenerative changes in recurrent cases. Biomechanical abnormalities, such as trochlear dysplasia, patella alta, and increased tibial tuberosity-trochlear groove distance, predispose to both recurrent dislocations and patellofemoral arthrosis.

DESIGN

In this article, we review the mechanisms of chondral injury in patellofemoral instability, diagnostic modalities, the distribution of lesions seen in acute and episodic dislocation, and treatments for articular cartilage lesions of the patellofemoral joint.

RESULTS

Little specific evidence exists for cartilage treatments in patellofemoral instability. In general, the results of reparative and restorative procedures in the patellofemoral joint are inferior to those observed in other compartments of the knee.

CONCLUSION

Given the increased severity of chondral lesions and progression to osteoarthritis seen with recurrent dislocations, careful consideration should be given to early stabilisation in patients with predisposing factors.

Sensitivity of MRI for articular cartilage lesions of the patellae

BACKGROUND AND AIMS

Reliable diagnosis of articular cartilage lesions of the patellae is often based on arthroscopy. However, unnecessary arthroscopies should be avoided. The aim of this study was to assess the sensitivity and applicability of MRI to diagnosing articular cartilage lesions of the patellae.

MATERIALS AND METHODS

We identified 74 consecutive males (mean age 21 years, range 18-28) from the medical records of our institute with the sole diagnosis of articular cartilage lesions of the patellae based on arthroscopy. Magnetic resonance imaging was performed with 1.0 Tesla scanner a mean of 4 weeks before arthroscopy. Sensitivity of symptoms, and MRI for the diagnosis was calculated.

RESULTS

Based on arthroscopy, 20 (27%) cases of cartilage lesions of the patellae were grade-I, 32 (43%) were grade-II, and 22 (30%) were grade-III. MRI revealed cartilage lesions of the patellae in 49 knees (66%), indicating that the sensitivity of MRI was 66% (95% CI: 53%-74%). MRI sensitivity increased with the severity of chondral lesions: all grade III to IV lesions were detected (sensitivity 100%, 95% CI: 85%-100%) by MRI. Grade of articular cartilage lesions of the patellae based on arthroscopy was not associated with clinical symptoms (p=0.61).

CONCLUSIONS

The sensitivity of 1.0 Tesla MRI for detecting grade-I lesions was low and could not be used to confirm the diagnosis of articular cartilage lesions of the patellae. For the detection of more severe grade-II to III lesions, the MRI sensitivity was markedly higher. MRI may thus be considered an accurate diagnostic tool for identifying more severe cases of articular cartilage lesions of the patellae.

Early magnetic resonance imaging in acute knee injury: a cost analysis

PURPOSE

Acute knee injury is common, and MRI is often only used when non-operative management fails because of limited availability. We investigated whether early MRI in acute knee injury is more clinically and cost-effective compared to conventional physiotherapy and reassessment.

METHODS

All patients with acute indirect soft tissue knee injury referred to fracture clinic were approached. Recruited patients were randomised to either the MRI group: early MRI within 2 weeks or the control group: conventional management with physiotherapy. Patients were assessed in clinic initially, at 2 weeks and 3 months post-injury. Management costs were calculated for all patients until surgical treatment or discharge.

RESULTS

Forty-six patients were recruited: 23 in the MRI and 23 in the control group. Male sex and mean age were similar in the two groups. The total management cost of the MRI group was £16,127 and control group was £16,170, with a similar mean cost per patient (NS). The MRI group had less mean physiotherapy (2.5 ± 1.9 vs. 5.1 ± 3.5, p < 0.01) and outpatient appointments (NS). Median time to surgery and time off work was less in the MRI group (NS). The MRI group had less pain (p < 0.05), less activity limitation (p = 0.04) and better satisfaction (p = 0.04).

CONCLUSIONS

Early MRI in acute knee injury facilitates faster diagnosis and management of internal derangement at a cost comparable to conventional treatment. Moreover, patients had significantly less time off work with improved pain, activity limitation and satisfaction scores.

LEVEL OF EVIDENCE

II.

Patellar chondral defects: a review of a challenging entity

PURPOSE

The aim of this study was to perform a review of the management of patellar cartilage defects, identify prognostic factors for better clinical outcomes, and propose a treatment algorithm of this challenging entity.

METHODS

We conducted a review of multiple databases, evaluating the clinical outcomes after patellar cartilage lesion treatment. Because of the heterogeneity of data, a meta-analysis could not be performed.

RESULTS

Twelve studies were identified for inclusion. Based on the clinical outcomes of these studies, a treatment algorithm was proposed. The clinical outcomes after patellar cartilage defects repair depend on the location and size of the articular defect, the age of the patient, the successful reconstruction of the patellar ridge, the repair of extensor mechanism malalignment, and the coexistence of chondromalacia.

CONCLUSION

The optimal treatment for cartilaginous defects of the patella is still elusive. More prospective studies are needed, in order to identify which techniques are cost-effective especially on a long-term basis.

The clinical utility and diagnostic performance of magnetic resonance imaging for identification of early and advanced knee osteoarthritis: a systematic review

BACKGROUND

Current diagnostic strategies for detection of structural articular cartilage abnormalities, the earliest structural signs of osteoarthritis, often do not capture the condition until it is too far advanced for the most potential benefit of noninvasive interventions.

PURPOSE

To systematically review the literature relative to the following questions: (1) Is magnetic resonance imaging (MRI) a valid, sensitive, specific, accurate, and reliable instrument to identify knee articular cartilage abnormalities compared with arthroscopy? (2) Is MRI a sensitive tool that can be utilized to identify early cartilage degeneration?

STUDY DESIGN

Systematic review.

METHODS

A systematic search was performed in November 2010 using PubMed MEDLINE (from 1966), CINAHL (from 1982), SPORTDiscus (from 1985), SCOPUS (from 1996), and EMBASE (from 1974) databases.

RESULTS

Fourteen level I and 13 level II studies were identified that met inclusion criteria and provided information related to diagnostic performance of MRI compared with arthroscopic evaluation. The diagnostic performance of MRI demonstrated a large range of sensitivities, specificities, and accuracies. The sensitivity for identifying articular cartilage abnormalities in the knee joint was reported between 26% and 96%. Specificity and accuracy were reported between 50% and 100% and between 49% and 94%, respectively. The sensitivity, specificity, and accuracy for identifying early osteoarthritis were reported between 0% and 86%, 48% and 95%, and 5% and 94%, respectively. As a result of inconsistencies between imaging techniques and methodological shortcomings of many of the studies, a meta-analysis was not performed, and it was difficult to fully synthesize the information to state firm conclusions about the diagnostic performance of MRI.

CONCLUSION

There is evidence in some MRI protocols that MRI is a relatively valid, sensitive, specific, accurate, and reliable clinical tool for identifying articular cartilage degeneration. Because of heterogeneity of MRI sequences, it is not possible to make definitive conclusions regarding its global clinical utility for guiding diagnosis and treatment strategies.

CLINICAL RELEVANCE

Traumatic sports injuries to the knee may be significant precursor events to early onset of posttraumatic osteoarthritis. Magnetic resonance imaging may aid in early identification of structural injuries to articular cartilage as evidenced by articular cartilage degeneration grading.

Reliability of clinical findings and magnetic resonance imaging for the diagnosis of chondromalacia patellae

BACKGROUND

This diagnostic study was performed to determine the correlation between anterior knee pain and chondromalacia patellae and to define the reliability of magnetic resonance imaging for the diagnosis of chondromalacia patellae.

METHODS

Fifty-six young adults (median age, 19.5 years) with anterior knee pain had magnetic resonance imaging of the knee followed by arthroscopy. The patellar chondral lesions identified by magnetic resonance imaging were compared with the arthroscopic findings.

RESULTS

Arthroscopy confirmed the presence of chondromalacia patellae in twenty-five (45%) of the fifty-six knees, a synovial plica in twenty-five knees, a meniscal tear in four knees, and a femorotibial chondral lesion in four knees; normal anatomy was seen in six knees. No association was found between the severity of the chondromalacia patellae seen at arthroscopy and the clinical symptoms of anterior knee pain syndrome (p = 0.83). The positive predictive value for the ability of 1.0-T magnetic resonance imaging to detect chondromalacia patellae was 75% (95% confidence interval, 53% to 89%), the negative predictive value was 72% (95% confidence interval, 56% to 84%), the sensitivity was 60% (95% confidence interval, 41% to 77%), the specificity was 84% (95% confidence interval, 67% to 93%), and the diagnostic accuracy was 73% (95% confidence interval, 60% to 83%). The sensitivity was 13% (95% confidence interval, 2% to 49%) for grade-I lesions and 83% (95% confidence interval, 59% to 94%) for grade-II, III, or IV lesions.

CONCLUSIONS

Chondromalacia patellae cannot be diagnosed on the basis of symptoms or with current physical examination methods. The present study demonstrated no correlation between the severity of chondromalacia patellae and the clinical symptoms of anterior knee pain syndrome. Thus, symptoms of anterior knee pain syndrome should not be used as an indication for knee arthroscopy. The sensitivity of 1.0-T magnetic resonance imaging was low for grade-I lesions but considerably higher for more severe (grade-II, III, or IV) lesions. Magnetic resonance imaging may be considered an accurate diagnostic tool for identification of more severe cases of chondromalacia patellae.

Knee MR-arthrography in assessment of meniscal and chondral lesions

INTRODUCTION

No study, so far in France, has investigated the diagnosis value of knee MR-arthrography since the recent approval of intra-articular gadolinium use, by this country's healthcare authorities. This study objective is to verify the MR-arthrography superiority on conventional knee MRI, in meniscus and cartilage knee lesions diagnosing accuracy both in regard to sensitivity and specificity.

HYPOTHESIS

MR-arthrography, represents in some pathologic situations, a more accurate source of information than conventional MRI.

MATERIALS AND METHODS

Over a 27 months period, 25 patients, scheduled to undergo a knee arthroscopy volunteered, after having been fully informed of the possible interest and risk of the MR-arthrography examination, to participate in this study. Twenty-one of them were finally included since in four cases the surgical indication was not confirmed. The group consisted of 15 males and six females with an average age of 35.7 years. All of them consecutively underwent conventional MRI, MR-arthrography finally followed by arthroscopy. The MRI and MR-arthrograms results were compared to the arthroscopy findings using the nonparametric Kappa test.

RESULTS

To diagnose meniscal tears, statistical agreement measure for MRI with arthroscopy was good (K=0.69) but not as good as the MR-arthrography/arthroscopy agreement which, by itself was excellent (K=0.84). As a diagnosis tool, the sensitivity and specificity of MR-arthrography (respectively 100 and 89.6%) were much higher than the corresponding values observed in conventional MRI (92.3 and 82.8%, respectively) which nonetheless remain satisfactory. The meniscal tears characterization seemed to be better interpreted using MR-arthrography. As far as the chondral lesions in this series, they were predominantly located on the patellar surface and in the medial femorotibial compartment. For diagnosing the latter, the MRI/arthroscopy agreement was good (K=0.70) but not as good as the MR-arthrography/arthroscopy agreement (K=0.805) which can be rated excellent. The detection sensitivity thus increased by 10% with gadolinium intra-articular injection. However, assessment accuracy of the lesions depth was mediocre, with frequent errors for the intermediary stages.

DISCUSSION

Intra-articular gadolinium injection improved MRI performances for numerous reasons: filling the joint, reinforcing the synovial fluid signal, and enhancing anatomic structures contrast on the T1-weighted sequences images. In this study, MR-arthrography appeared to be superior to conventional MRI in meniscal and cartilaginous lesions diagnosis, confirming the results previously obtained in other countries. In light of these results and other data from the literature, MR-arthrography can be indicated as an alternative to CT-arthrography in various clinical situations: detection of recurrent tears on operated menisci, search for cartilaginous lesions or foreign bodies in the joint space, and preoperative assessment before chondral repair procedures. However, conventional MRI remains the reference examination for studying cartilage, because the low resolution of MR-arthrography limits its performances in quantitative assessment of lesions depth.

Levels of biomarkers correlate with magnetic resonance imaging progression of knee cartilage degeneration: a study on canine

To examine the association between levers of cartilage oligomeric matrix protein (COMP), matrix metalloproteinases-1 (MMP-1), matrix metalloproteinases-3 (MMP-3), tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) in serum and synovial fluid, and MR imaging of cartilage degeneration in knee joint, and to understand the effects of movement training with different intensity on cartilage of knee joint. 20 adult canines were randomly divided into three groups (8 in the light training group; 8 in the intensive training group; 4 in the control group), and canines of the two training groups were trained daily at different intensity. The training lasted for 10 weeks in all. Magnetic resonance imaging (MRI) examinations were performed regularly (2, 4, 6, 8, 10 week) to investigate the changes of articular cartilage in the canine knee, while concentrations of COMP, MMP-1, MMP-3, TIMP-1 in serum and synovial fluid were measured by ELISA assays. We could find imaging changes of cartilage degeneration in both the training groups by MRI examination during training period, compared with the control group. However, there was no significant difference between these two training groups. Elevations of levels of COMP, MMP-1, MMP-3, TIMP-1, MMP-3/TIMP-1 were seen in serum and synovial fluid after training, and their levels had obvious association with knee MRI grades of cartilage lesion. Furthermore, there were statistically significant associations between biomarkers levels in serum and in synovial fluid. Long-time and high-intensity movement training induces cartilage degeneration in knee joint. Within the intensity extent applied in this study, knee cartilage degeneration caused by light training or intensive training has no difference in MR imaging, but has a comparatively obvious difference in biomarkers level. To detect articular cartilage degeneration in early stage and monitor pathological process, the associated application of several biomarkers has a very good practical value, and can be used as a helpful supplement to MRI.

The evaluation of articular cartilage lesions of the knee with a 3-Tesla magnet

PURPOSE

This prospective study was performed to investigate whether 3-Tesla magnetic resonance imaging (MRI) provides an accurate assessment of the articular cartilage in clinical practice.

METHODS

Forty patients with persistent knee pain and suspected cartilage lesions underwent 3-T MRI shortly before arthroscopy with the following sequences: axial/coronal/sagittal proton density-weighted turbo spin echo with spectral fat suppression, axial/sagittal 3-dimensional T1-weighted gradient echo with selective water excitation, and axial T2-weighted gradient echo (Intera 3.0T; Philips Medical Systems, Best, The Netherlands). Knee cartilage surfaces were divided into 6 regions; lesions detected on MRI were classified into stages I to IV and compared with the arthroscopic grading.

RESULTS

For the 240 cartilage surfaces evaluated, the sensitivities, specificities, positive predictive values, and negative predictive values of 3-T MRI were 74%, 95%, 74%, and 95%, respectively, for the detection of grade IV lesions; 63%, 90%, 60%, and 91%, respectively, for grade III lesions; 62%, 90%, 57%, and 92%, respectively, for grade II lesions; and 29%, 95%, 39%, and 92%, respectively, for grade I lesions.

CONCLUSIONS

In these preliminary clinical studies 3-T MRI provided convincing visualization of the hyaline cartilage with comparatively good diagnostic values. Nonetheless, it must be pointed out that the positive predictive values were low for all grades of lesions. Thus, when 3-T MRI suggests a cartilage defect, the probability that the arthroscopic finding corresponds exactly to the MRI result is between 39% and 74%. Therefore, the value of arthroscopy for a detailed assessment and grading of a cartilage disorder with regard to definitive planning of a therapeutic procedure cannot be replaced by 3-T MRI.

LEVEL OF EVIDENCE

Level I, testing of previously developed diagnostic criteria in a series of consecutive patients with universally applied gold standard.

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.

Sensitivity of routine 1.0-Tesla magnetic resonance imaging versus arthroscopy as gold standard in fresh traumatic chondral lesions of the knee in young adults

PURPOSE

The purpose of this study was to evaluate the sensitivity, specificity, and accuracy of routine 1.0-Tesla magnetic resonance imaging (MRI) versus arthroscopy in detecting fresh traumatic chondral lesions of the knee.

METHODS

Over a period of 6 years, 578 consecutive military personnel underwent MRI before arthroscopy of the knee. Of these, 32 patients with arthroscopically proven fresh traumatic chondral lesions of the knee were chosen for further analysis. A supplementary condition was that arthroscopy was performed no later than 6 weeks after the onset of trauma. The original MRIs and hospital records were re-evaluated and the chondral lesions were graded and compared with arthroscopic findings. The arthroscopic results served as the gold standard when the sensitivity, specificity, and accuracy of MRI were calculated.

RESULTS

The age of the patients ranged from 19 to 21 years (mean, 19.6 years). MRI detected cartilage defects with a sensitivity of 36% (95% confidence interval [CI], 23% to 50%), specificity of 91% (95% CI, 85% to 95%), and diagnostic accuracy of 78% (95% CI, 72% to 83%). MRI results were affected by the grade of the chondral lesions.

CONCLUSIONS

This study shows that routine 1.0-T MRI is not sensitive but is specific and somewhat accurate in detecting fresh traumatic articular cartilage lesions. The hypothesis of this study was that 1.0-T MRI could replace diagnostic arthroscopy in the diagnosis of fresh traumatic chondral lesions. Our results fail to support this hypothesis because of the poor sensitivity obtained with MRI.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria.

MR appearance of cartilage defects of the knee: preliminary results of a spiral CT arthrography-guided analysis

The aim of this study was to determine signal intensity patterns of cartilage defects at MR imaging. The MR imaging (3-mm-thick fat-suppressed intermediate-weighted fast spin-echo images) was obtained in 31 knees (21 male and 10 female patients; mean age 45.5 years) blindly selected from a series of 252 consecutive knees investigated by dual-detector spiral CT arthrography. Two radiologists determined in consensus the MR signal intensity of the cartilage areas where cartilage defects had been demonstrated on the corresponding reformatted CT arthrographic images. There were 83 cartilage defects at spiral CT arthrography. In 52 (63%) lesion areas, the MR signal intensity was higher than that of adjacent normal cartilage with signal intensity equivalent to (n=31) or lower than (n=21) that of articular fluid. The MR signal intensity was equivalent to that of adjacent normal cartilage in 17 (20%) lesion areas and lower than that of adjacent cartilage in 8 (10%) lesion areas. In 6 (7%) lesion areas, mixed low and high signal intensity was observed. The MR signal intensity of cartilage defects demonstrated on spiral CT arthrographic images varies from low to high on fat-suppressed intermediate-weighted fast spin-echo MR images obtained with our equipment and MR parameters.

A critical appraisal of quantitative arthroscopy as an outcome measure in osteoarthritis of the knee

BACKGROUND AND OBJECTIVES

To review the performance of arthroscopic assessment of articular cartilage damage in osteoarthritis.

METHODS

The literature was reviewed for publications containing data regarding validity and reliability of arthroscopic systems of cartilage evaluation in knee osteoarthritis.

RESULTS

Fifty-two distinct measurement systems were identified in 60 publications. There were 30 simple severity-scoring systems, 3 global visual analogue scale systems, and 19 composite systems. No systems consisted solely of measurements of lesion size or site, although 13 systems used either or both of these for the calculation of composite scores. Only 6 publications (10%) undertook any reliability evaluation and these generally used inappropriate methods of statistical analysis. Thirty-five publications (58%) evaluated validity. Construct validity was tested using several constructs (clinical in 2, magnetic resonance imaging in 10, radiographs in 10, or other arthroscopic assessments in 5 publications). Criterion validity was ascertained by using several methods including cartilage histology, histochemistry, or biomechanics in 10 publications. Responsiveness was determined in 1 publication.

DISCUSSION

Many publications evaluated composite systems but only a few evaluated fundamental aspects of arthroscopic measurement. Conceptually, composite scoring systems have the best validity; however, at present, there is only enough evidence to support the use of simple chondropathy severity scores and there are little data on the responsiveness of these methods. A proposed program for comprehensive evaluation and development of valid and responsive arthroscopic assessments of articular cartilage is outlined.

MR arthrography in chondromalacia patellae diagnosis on a low-field open magnet system

OBJECTIVE

The purpose of this study was to compare the diagnostic efficacy conventional MRI and MR arthrography (MRA) in the diagnosis of chondromalacia patella (CP) on a low-field open magnet system (LFOMS), correlated with arthroscopy.

SUBJECTS AND METHODS

Forty-two patients (50 knees) with pain in the anterior part of the knee were prospectively examined with LFOMS, including T1-weighted, proton density-weighted and T2-weighted sequences. All were also examined T1-weighted MRI after intraarticular injection of dilue gadopentetate dimeglumine. Two observers, who reached a consensus interpretation, evaluated each imaging technique independently. Thirty-six of the 50 facets examined had chondromalacia shown by arthroscopy, which was used as the standard of reference. The sensitivity, specificity and accuracy of each imaging technique in the diagnosis of each stage of CP were determined and compared by using the McNemar two-tailed analysis.

RESULTS

Arthroscopy showed that 16 facets were normal. Four (30%) of 13 grade 1 lesions were detected with T1. Four lesions (30%) with T2 and three lesions (23%) with proton-weighted images were detected. Seven (53%) of 13 grade 1 lesions were detected with MRA. Grade 2 abnormalities were diagnosed in two (33%) of six facets with proton density-weighted pulse sequences, two (33%) of six facets with T1-weighted pulse sequences, in three (50%) of six facets with T2-weighted pulse sequences, in five (83%) of six facets with MRA sequences. Grade 3 abnormalities were diagnosed in three (71%) of seven facets with proton density- and T1-weighted images, five (71%) of seven facets with T2-weighted pulse sequences, six (85%) of seven facets with MRA sequences. Grade 4 CP was detected with equal sensitivity with T1-, proton density- and T2-weighted pulse sequences, all showing seven (87%) of the eight lesions. MRA again showed these findings in all eight patients. All imaging techniques were insensitive to grade 1 lesions and highly sensitive to grade 4 lesion, so that no significant difference among the techniques could be shown.

CONCLUSION

All imaging technique studied had high specificity and accuracy in the detection and grading of CP; however, MRA was more sensitive than T1-weighted and proton density-weighted MR imaging on a LFOMS. Although the arthrographic techniques were not significantly better than T2-weighted imaging, the number of false-positive diagnosis was greatest with T2-weighted MRI.

Fat-suppressed 3D-T1-weighted-echo planar imaging: comparison with fat-suppressed 3D-T1-weighted-gradient echo in imaging the cartilage of the knee

This study was conducted to compare a three-dimensional (3D) multi-shot echo-planar imaging (EPI) sequence with fat-suppression (FS) with the 3D-fat-suppressed gradient echo (GRE-FS) sequence in imaging the cartilage of the knee. One hundred sixty-nine patients were studied prospectively. The cartilage was imaged in the sagittal plane with: (a) 3D-T1-EPI-FS and (b) 3D-T1-GRE-FS sequences using a 1T MR scanner. The signal-to-noise ratio (SNR) of bone (b) and cartilage (c), and relative contrast (ReCon) between bone and cartilage and meniscus and cartilage were measured in 60 patients with arthroscopically normal cartilage. The imaging accuracy was assessed by comparing with linear regression analysis (length and depth) 32 defects in the cartilage of cadaveric (human and bovine) knees. The 3D-T1-EPI-FS provided better bone marrow signal suppression, better SNRc and better ReCon(bc) and ReCon(cm) (p<0.01). The 3D-T1-EPI-FS showed better accuracy concerning the depth of the defects and the 3D-T1-GRE-FS better accuracy concerning the length of the defects. In conclusion, the 3D-T1-EPI-FS pulse sequence could be included in the routine protocol in imaging the cartilage of the knee because it achieves high SNR of the cartilage and high ReCon compared to the surrounding structures, at a reduced scan time.

Assessment of knee cartilage in cadavers with dual-detector spiral CT arthrography and MR imaging

PURPOSE

To assess dual-detector spiral CT arthrography in the evaluation of the entire knee cartilage obtained from cadavers.

MATERIALS AND METHODS

Two independent observers characterized articular cartilage in 12 cadaver knees in which MR imaging and dual-detector spiral CT arthrography were performed and compared their findings to those found during macroscopic assessment. The sensitivity and specificity of MR imaging and spiral CT arthrography for detecting grade 2A or higher and grade 2B or higher cartilage lesions, the Spearman correlation coefficient between arthrographic and macroscopic grading, and kappa statistics for assessing interobserver reproducibility were determined.

RESULTS

At spiral CT arthrography, sensitivities and specificities ranged between 80% and 88% for the detection of grade 2A or higher cartilage lesions and ranged between 85% and 94% for the detection of grade 2B or higher cartilage lesions. At MR imaging, sensitivities and specificities ranged between 78% and 86% and between 76% and 91% for the detection of grade 2A or higher and grade 2B or higher cartilage lesions, respectively. Spearman correlation coefficients between spiral CT arthrography or MR imaging and macroscopic grading of articular surfaces were 0.797 and 0.702, respectively.

CONCLUSION

Dual-detector spiral CT arthrography of the knee is a valuable method for the assessment of open cartilage lesions of the entire knee.

MRI of patellar articular cartilage: evaluation of an optimized gradient echo sequence (3D-DESS)

Our purpose was to evaluate the diagnostic efficacy of a gradient-echo sequence optimized for cartilage imaging in patellar cartilage abnormalities and to compare it to a standard turbo-spin-echo sequence. Fifty-eight consecutive patients who underwent, within 3 months both MRI and arthroscopy or surgery, were included in the investigation. Two radiologists specializing in musculoskeletal imaging independently assessed axial three-dimensional double-echo steady state (3D-DESS) gradient-echo images and sagittal proton- and T2-weighted turbo-spin-echo images with regard to retropatellar cartilage abnormalities. Possible findings were: 0: normal, 1: cartilage softening, and 2: lesion of the articular surface. Inter- and intraobserver variability was assessed. For cartilage softening, the axial 3D-DESS sequence had a sensitivity of 73%, a specificity of 75%, and an accuracy of 70%. The corresponding results for the sagittal turbo-spin-echo sequence were 53%, 65%, and 62%. For surface lesions, the results for the 3D-DESS sequence were 43%, 92%, and 83% and for the turbo-spin-echo sequence were 60%, 92%, and 86%. Intra- and interobserver agreement was moderate (k = 0.59 and 0.45 [DESS], 0.6 and 0.46 [turbo -spin-echo]). We conclude that the 3D-DESS sequence is moderately accurate in detecting patellar cartilage abnormalities. Compared with the sagittal turbo-spin-echo sequence, the axial 3D-DESS sequence is superior in diagnosing cartilage softening but not surface lesions.

Knee arthrography. Evolution and current status

This article explores arthrography of the knee beginning with a brief historical perspective of conventional knee arthrography and culminating in direct and indirect MR arthrography of the knee. This article discusses the advantages of MR arthrography in the radiologic assessment of the postoperative meniscus, abnormalities of articular cartilage, and synovial-based processes.

Imaging in sports-medicine--knee

Since the last decade, the introduction of Magnetic Resonance Imaging has provided a powerful new tool for the clinician to diagnose sports-related knee injuries. The main objective of this paper is to familiarise the relevant specialists with the proven clinical indications and semiology of MRI of the knee. At the present time, the knee joint is the area in which the advantages of MRI are most spectacularly apparent. The MR appearances of meniscal tears in particular, are first discussed in detail, referring to recent literature and personal experience based on more than ten thousands MR examinations of traumatic knees. Also the mechanisms of injuries and the most commonly involved sports are described. The precise types of meniscal lesions, as visualised at arthroscopy, are abundantly illustrated on MR images: e.g., bucket-handle, radial and horizontal cleavage tears, meniscocapsular separations, discoid menisci and meniscal cysts. We discuss the numerous pitfalls due to neighbouring anatomical structures as well as non clinically or surgically significant intrameniscal hypersignals in athletes. Towards other imaging techniques, MRI is particularly suited for the diagnosis of ligamentous injuries, especially the cruciate ligaments. We develop the currently used direct and indirect signs of rupture, the diagnostic difficulties related to the age of trauma and the detection of associated lesions. Sport-induced tendinous and bursal pathology is another interesting indication of MRI, not only lesions of the more superficial extensor tendons but also the pes anserinus or hamstring tendons. We finally treat the recent developments of MRI in assessment of cartilage, subchondral and medullary bone disorders of traumatic or microtraumatic origin.

The impact of magnetic resonance imaging of the knee on surgical decision making

Although magnetic resonance imaging (MRI) of the knee is known to be an accurate technique for diagnosing soft tissue disorders of the knee, the value of MRI in improving patient outcome is controversial. The purpose of this project was to study the value of MRI in a subgroup of patients with knee pain and disability whose diagnosis was uncertain after standard orthopaedic evaluation. An extensive database was recorded prospectively for each of 208 patients providing clinical data as well as diagnoses from clinical, MRI, and surgical observations. These data were analyzed to determine the effect of MRI on diagnosis and patient outcome regarding surgical decision making. The overall diagnostic accuracy of MRI was determined to be 97% in patients undergoing arthroscopy. MRI differed from the clinical diagnosis in 33% of cases, the most common variance being diagnosis of meniscal tear. After combining the MRI and clinical information, surgical decision making was altered in 27% of cases. In a group of patients with acute knee symptoms, the decision not to proceed with surgery was made in 64% of cases. The study shows that MRI of the knee is a valuable tool for augmenting the diagnostic process. The data further show that MRI is a cost-effective technique for avoiding unnecessary surgery and affects patient outcome by improving surgical decision making.

Cartilage swelling and loss in a spontaneous model of osteoarthritis visualized by magnetic resonance imaging

The objective of this study was to investigate whether the rate of change in cartilage pathology could be effectively monitored by magnetic resonance imaging (MRI) as part of a longitudinal investigation of an osteoarthritis model in vivo, and to define the minimum requirements necessary to establish disease progression. Magnetic resonance images of the knee of eight male Dunkin-Hartley guinea-pigs were obtained at 8, 12, 18, 24, 30, 36 and 52 weeks of age using a two-dimension spin-echo sequence with a TR of 1500 ms and TE of 40 ms. The total thickness of the femoral and tibial cartilage was measured from those images. Over the same time course, sets of spin-spin relaxation-weighted images were acquired from two additional animals of the same age, from which the T2 relaxation times of water in the articular cartilage were estimated and compared with those of muscle and adipose tissue within the same joint. The cartilage thickness of all the animals increased during the first 6 months, then either stayed thicker (4/8) or became progressively thinner (4/8). Up to 18 weeks of age, the cartilage T2 value was between 23-24 ms but became elevated by 30 weeks and the mean value was more than 40 ms at the end of the study, T2 values for the muscle and adipose tissue remained within the range 30-33 ms, or 47 ms, respectively. We concluded that in this model, cartilage thickness measurements from an magnetic resonance image would not provide a reliable marker to stage osteoarthritis progression partly because the cartilage was so thin in a joint of this size, but also because the changes with time were not linear but biphasic. However, quantitation of the T2 relaxation values may provide a more predictable indicator of cartilage pathology for longitudinal studies because the changes were monotonic and independent of cartilage thickness.

Chondral delamination of the knee in soccer players

This study reports on the diagnosis and treatment of chondral delamination in the knees of soccer players. The authors attempted to provide a clinical standard for comparison with emerging cartilage repair techniques. Twenty-three consecutive chondral fractures in a homogeneous population of athletes were evaluated using physical examination, magnetic resonance imaging, and arthroscopic examination. All knees were treated with debridement to a stable border and removal of the calcified cartilage base. Results were graded using the scoring system advocated by proponents of chondral transplant. All patients reported pain that limited soccer activities. Effusions occurred in 48%, joint line tenderness in 33%, and crepitus in 19% of the knees. Results from magnetic resonance imaging correlated with arthroscopic examination in 21% of the knees. Arthroscopic examinations revealed lesions on the medial femoral condyle in eight patients, the patella in six, the lateral femoral condyle in six, and the trochlea in three. Athletes returned to play at an average of 10.8 weeks. Repeat arthroscopic procedures in eight cases revealed fibrocartilage at the initial site. There were 6 excellent, 9 good, 0 fair, and 0 poor results at their 1-year followup examinations (15 knees). The definitive diagnosis of chondral delamination relies on a thorough arthroscopic probing of the articular surface. The early functional results of this treatment compare favorably with the autologous transplantation technique. Caution, however, is recommended when treating articular cartilage injuries because no long-term data exists on whether any treatment modality can prevent the development of degenerative joint disease.

MR imaging before arthroscopy in knee joint disorders?

PURPOSE

To review the current literature examining the relative merits of arthroscopy and MR imaging of the knee.

MATERIAL AND METHODS

All papers comparing MR imaging with arthroscopy published within the last 10 years according to Medline were collected and read.

RESULTS

Technology has improved considerably during recent years allowing detailed non-invasive visualization of the knee. In particular, the development of cheaper whole-body and dedicated low-field MR units has opened up for non-invasive inspection of the knee at reasonable cost. Meniscal tears can be detected with accuracy rates of around 90% and rupture of the anterior cruciate ligament with accuracy rates of around 93% compared to arthroscopy. However, arthroscopy is not the ideal gold standard, since it has weak points, e.g. peripheral meniscal tears or osteochondritis without apparent damage to the cartilage.

CONCLUSION

Based on the overwhelming literature it seems safe to conclude that MR examinations of the knee should be performed before arthroscopy is undertaken.

MR diagnosis of retropatellar chondral lesions under compression. A comparison with histological findings

PURPOSE

The aim of the study was to improve the chondromalacia patellae (CMP) diagnosis by MR imaging under defined compression of the retropatellar cartilage, using a specially designed knee compressor. The results were compared with histological findings to obtain an MR classification of CMP.

METHOD

MR imaging was performed in in vitro studies of 25 knees from cadavers to investigate the effects of compression on the retropatellar articular cartilage. The results were verified by subsequent histological evaluation.

RESULTS

There was a significant difference in cartilage thickness reduction and signal intensity behaviour under compression according to the stage of CMP.

CONCLUSION

Based on the decrease in cartilage thickness, signal intensity behaviour under compression, and cartilage morphology, the studies permitted an MR classification of CMP into stages I-IV in line with the histological findings. Healthy cartilage was clearly distinguished, a finding which may optimize CMP diagnosis.

Viability of chondroscopy as a means of cartilage assessment

Images

Comparison between magnetic resonance imaging and arthroscopy in the diagnosis of patellar cartilage lesions: a prospective study

A blind and prospective 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 spin-echo 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.

The morphology of articular cartilage assessed by magnetic resonance imaging (MRI). Reproducibility and anatomical correlation

Quantitative assessment of cartilage volume and thickness in a formalin-alcohol fixed specimen of a human patella was conducted with magnetic resonance imaging (MRI), as it is still unclear whether the morphology of normal and damaged cartilage can be accurately demonstrated with this technique. MR imaging was carried out at 1.0 T (section thickness 2 mm, in-plane-resolution 0.39-0.58 mm) with the following pulse sequences: 1) T1-weighted spin-echo, 2) 3D-MPRAGE, 3) 3D-FISP, 4) 3D-MTC-FISP, 5) 3D-DESS, 6) 3D-FLASH. Following imaging, the patella was sectioned perpendicular to the articular surface at intervals of 2 mm with a diamond band-saw. The volume of its cartilage was determined from the anatomical sections and the MR images, using a Vidas IPS 10 image analysing system (Kontron). Measurements were carried out with and without the low-signal layer in the transitional zone between the articular cartilage and the subchondral bone. If the low-signal layer was included, the volume was overestimated with MRI by 16 to 19%. Without the low-signal layer the volumes were less than those determined from the anatomical sections: T1-SE-18.2%, MPRAGE -22.6%, FISP -17.1%, MTC-FISP -9.5%, DESS -9.3% and FLASH -6.1%. The coefficient of variation for a 6-fold determination of the volume amounted to between 6.2% (T1-SE) and 2.6% (FLASH). The FLASH sequence allowed the most valid and reproducible assessment of the cartilage morphology. The remaining difference from the real volume of the cartilage may be due to the fact that the calcified zone of the cartilage is not delineated by MRI.

The diagnostic value and limitation of magnetic resonance imaging on chondral lesions in the knee joint

Chondral lesions of the knee joint, which have been detected via arthrotomy or arthroscopy, were examined prospectively and retrospectively through a review of previously obtained magnetic resonance images (MRIs). The study group was composed of 34 men and 29 women whose average age was 24.6 years. Of these 63 patients, there were 72 articular cartilage lesions in 65 knees. On retrospective analysis, the sensitivity of MRI, which was defined as a true positive reading for softening, fragmentation, erosion, and/or a full-thickness loss of cartilage, was 14.3%, 57.3%, 75.0%, and 100%, respectively. Although the sensitivity to early changes of chondral lesions was low, indicating the limitation of MRI at the present stage, it has been demonstrated that MRI can delineate intracartilaginous changes associated with softening and thickening of cartilage that cannot be detected even with arthroscopy. Therefore, it may be worthwhile to perform an MRI as well as arthroscopy to clarify the pathogenesis of internal derangement of the knee.

Chondroscopy: a new method for scoring chondropathy

The purpose of this study was to evaluate the performance (simplicity, reproducibility, relevance) of chondroscopy as a method for evaluating cartilage damage. Chondroscopy consisted in endoscopic evaluation of the knee using a 2.7-mm Storz arthroscope under local anesthesia and recorded on videotape. Scoring of chondropathy was based on physician's overall assessment using a 100-mm-length visual analogue scale (VAS) and size and grade of cartilage lesions. Reproducibility was evaluated by variability (coefficient of variation [CV]) in the reading of chondroscopic evaluations of five patients five times by one physician and one time each by four different physicians. The correlations between scoring of chondropathy (VAS) and radiological articular joint space narrowing, demographic data (sex, age, weight), and disease characteristics (localization, etiology, activity) were studied in 84 outpatients fulfilling the American College of Rheumatology criteria for the diagnosis of osteoarthritis of the knee. The grade and size of the lesions were both correlated with the physician's overall assessment (r = 0.713 and r = 0.816, respectively). These two variables accounted for 72% of the variance of the VAS (multiple regression analysis). Intraobserver reproducibility was better than interobserver reproducibility (CV, 9% and 37%, respectively). There was a strong correlation between the scoring of chondropathy (VAS) and radiological joint space narrowing (r = .646, P < .0001). Moreover, in 17 of 33 patients without radiological joint space narrowing, VAS was > 20 mm. At variance, the body mass index was the single clinical variable found to correlate with the scoring of chondropathy (r = .282, P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

MRI of the knee joint with a 3-D gradient echo sequence. Equivalent to diagnostic arthroscopy?

Three-dimensional (3-D) gradient echo sequences offer the advantage of volume imaging within a few minutes scanning time and creating thin contiguous slices. An optimized sequence (FISP 3D 40) was evaluated for its potential to detect lesions of the menisci, cruciate ligaments, and articular cartilage in 80 patients compared to arthroscopy as the standard. Magnetic resonance imaging showed a sensitivity of 97.9%, a specificity of 97.3%, and an accuracy of 97.5% for meniscal lesions, and a sensitivity of 100%, a specificity of 97.1%, and an accuracy of 97.5% for lesions of the cruciate ligaments. Based upon morphological criteria normal cartilage was identified in 91.5%, but fibrillation of different depths (grades 1-3) was poorly recognized. All full-thickness defects (grade 4) were recognized. Measurement of mean signal intensity (95% confidence intervals) was more useful to discriminate normal from abnormal cartilage (grades 1-3). This method promises the capability to detect early stages of oestoarthritis in future. The present results show MRI of the knee joint with a 3-D fast imaging technique to be a noninvasive alternative to diagnostic arthroscopy.