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

Assessing lateral femoral condyle cartilage prior to medial UKA: MRI vs. Valgus stress radiograph

BACKGROUND

The cartilage quality of the lateral compartment needs to be clarified prior to medial unicompartmental knee arthroplasty (UKA). Valgus stress radiograph has been recommended as the preferred tool. Some studies also show that magnetic resonance imaging (MRI) has a higher diagnostic value. So, we conducted this study to compare whether valgus stress radiographic lateral joint space width (LJSW) and MRI grading can accurately reflect cartilage quality and its screening value for UKA-suitable patients.

METHODS

One hundred and thirty eight knees proposed for UKA were enrolled prospectively. Valgus stress radiograph was taken to measure LJSW. LJSW > 4 mm was considered normal and suitable for UKA. For weight-bearing area cartilage of lateral femoral condyle, Recht grade was assessed by MRI preoperatively. Recht grades ≤ 2 were treated as non-high-grade injuries while Recht grades > 2 were treated as high-grade injuries. Outerbridge grade was the gold standard and was assessed intraoperatively. Patients with Outerbridge grades 0-2 (non-high-grade injuries) underwent UKA, and patients with Outerbridge grades 3-4 (high-grade injuries) underwent total knee arthroplasty (TKA). The diagnostic parameters of valgus stress radiograph and MRI for the selection of UKA candidates were calculated, and receiver operating characteristic curves were drawn. P < 0.05 was considered significant.

RESULTS

Of 138 knees, 120 underwent UKAs, and 18 underwent TKAs. In terms of selecting UKA candidates, the sensitivity was close between MRI (95.0%) and valgus stress radiograph (96.7%), and the specificity, accuracy, positive predictive value and negative predictive value of MRI (94.4%, 94.9%, 99.1%, 73.9%, respectively) were higher than that of valgus stress radiograph (5.9%, 85.5%, 88.0%, 20.0%, respectively). The difference in area under the curve (AUC) between MRI (0.950) and LJSW (0.602) was significant (P = 0.001).

CONCLUSION

Compared with valgus stress radiograph, MRI has excellent evaluation value in diagnosing lateral weight-bearing cartilage injuries and can be used as a reliable tool for selecting suitable UKA patients.

Preoperative diagnosis of knee cartilage, meniscal, and ligament injuries by magnetic resonance imaging

PURPOSE

The purpose of the study was to report on the current accuracy measures specific to 1.5-Tesla MRI of the knee in the patient population prone to injuries of the anterior cruciate ligament (ACL), the menisci, and the articular cartilage.

METHODS

We accrued patients between January 2018 through August 2021 who underwent a preoperative MRI and were diagnosed with an articular cartilage injury either due to unevenness of articular cartilage in T2-weighted sequences or due to the irregularity of subchondral bone in T1-weighted sequences. All patients were treated arthroscopically. Sensitivity, specificity, and accuracy were calculated for the detection of ACL, meniscus, and cartilage injuries. A P-value of < 0.05 represented statistical significance.

RESULTS

One-hundred and forty-seven cases which included 150 knee joints were enrolled in this study. The mean age at the time of surgery was 42.9 years-old. The sensitivity in the diagnosis of ACL injuries was significantly greater than that in the diagnosis of cartilage injuries (P = 0.0083). The ratios of the equality of operative indication in 6 recipient sites were found to be between 90.0% and 96.0%. The diagnostic critical point was within a 1 cm in diameter.

CONCLUSION

The diagnostic sensitivity in cartilage injuries was significantly lower than ones of ACL and meniscal injuries. The ratios of the equality of operative indication was determined to be between 90.0% and 96.0%, if we consider the unevenness of articular cartilage or the irregularity of subchondral bone.

LEVEL OF EVIDENCE

Level III, Prospective diagnostic cohort study.

Magnetic resonance imaging is able to detect patellofemoral focal cartilage injuries: a systematic review with meta-analysis

PURPOSE

The purpose of this study was to analyze the diagnostic accuracy of magnetic resonance imaging (MRI) to detect and grade the severity of patellofemoral (PF) cartilage injuries.

METHODS

A systematic review was conducted on PubMed, EMBASE and Cochrane Library databases (up to July 1st 2022) to search for studies that reported the diagnostic accuracy of MRI to detect and grade PF cartilage injuries as compared to diagnostic arthroscopy. Risk of bias was judged using the QUADAS-2 tool. Quantitative syntheses were performed to calculate the diagnostic accuracy metric-sensitivity, specificity, positive likelihood (LR+) and negative likelihood (LR-) ratios, diagnostic odds ratio (DOR)-and presented as median with 25% and 75% percentiles. The summary receiver operating characteristic (SROC) curves were also calculated. Diagnostic accuracy metrics were calculated for all PF cartilage injuries and then sub-grouped by patellar and trochlear lesions. Diagnostic accuracy was also calculated according to the grading of cartilage injuries.

RESULTS

Forty-five studies were included for qualitative analyses and forty studies were included for quantitative synthesis. A total of 3534 participants with a weighted mean age of 38.1 years were included. Diagnostic accuracy was generally high: sensitivity (0.8, 0.6-1.0), specificity (0.9, 0.8-1.0), LR+ (6.4, 3.1-15.3), LR- (0.3, 0.2-0.4) and DOR (21.3, 9.9-121.1). The area under the curve (AUC) of the SROC was 0.9. The diagnostic accuracy was slightly higher for patellar (sensitivity 0.8, specificity 0.8, LR+ 5.3, LR- 0.2, DOR 28.8) than for trochlear lesions (sensitivity 0.7, specificity 0.9, LR+ 5.5, LR- 0.4, DOR 14.3). The sensitivity was generally higher when grading advanced (vs. early or intermediate) cartilage injuries of the patella.

CONCLUSION

The MRI is able to diagnose PF cartilage injuries with reasonably high diagnostic accuracy (as compared to arthroscopy). Clinicians can rely on MRI to reliably diagnose PF cartilage injuries (with some limitations) which will play an important role in deciding for surgical or non-operative treatment.

LEVEL OF EVIDENCE

Level III.

Accuracy measures of 1.5-tesla MRI for the diagnosis of ACL, meniscus and articular knee cartilage damage and characteristics of false negative lesions: a level III prognostic study

BACKGROUND

MRI is the most accurate imaging modality for diagnosing knee pathologies. However, there is uncertainty concerning factors predicting false negative MRI, such as meniscal tear patterns as well as patient factors. The aims of this study were to report 1.5-Tesla MRI accuracy of ACL, meniscus and articular cartilage damage and characterize false negative lesions.

METHODS

Two hundred eighteen consecutive knee arthroscopies performed in our institution between 2013 and 2016 and their respective prospectively-collected MRI reports were reviewed. Inclusion criteria were age > 15 years-old, primary arthroscopy, 1.5-Tesla MRI performed at the same institution, and time interval MRI-surgery < 6 months. Exclusion criteria were revision arthroscopy and arthroscopic-assisted fracture fixation or multiligament surgery. Accuracy measures and Kappa coefficients were calculated comparing the MRI diagnosis to the arthroscopic findings. Moreover, the arthroscopic findings of false negative MRI were compared to the findings of true positive MRI using the Fisher-exact test. Pearson correlation was used for testing the correlation between MRI accuracy and patient age.

RESULTS

The highest accuracy was observed in medial meniscus and in ACL findings. For the medial meniscus sensitivity, specificity, agreement, and Kappa coefficient were 77, 92, 86%, and 0.7, and for the ACL these measures were 82, 97, 87%, and 0.73. MRI accuracy was lower in the lateral meniscus and articular cartilage with Kappa coefficient 0.42 and 0.3, respectively. More specifically, short peripheral tears in the posterior horn of the medial meniscus were characteristic of false negative findings compared to true positive findings of the MRI (p <  0.01). MRI accuracy correlated negatively compared to arthroscopic findings with patient age for the medial meniscus (r = - 0.21, p = 0.002) and for articular cartilage damage (r = - 0.45, p <  0.001).

CONCLUSION

1.5-Tesla MRI will accurately diagnose ACL and medial meniscal tears and can reliably complete the diagnostic workup following physical examination, particularly in young adults. This modality however is not reliable for diagnosing short peripheral tears at the posterior horn of the medial meniscus and partial thickness articular cartilage lesion of the femoral condyles. For these lesions, definitive diagnosis may require cartilage-specific MRI sequences or direct arthroscopic evaluation.

LEVEL OF EVIDENCE

Prognostic study, Level III.

Enabling early detection of osteoarthritis from presymptomatic cartilage texture maps via transport-based learning

Many diseases have no visual cues in the early stages, eluding image-based detection. Today, osteoarthritis (OA) is detected after bone damage has occurred, at an irreversible stage of the disease. Currently no reliable method exists for OA detection at a reversible stage. We present an approach that enables sensitive OA detection in presymptomatic individuals. Our approach combines optimal mass transport theory with statistical pattern recognition. Eighty-six healthy individuals were selected from the Osteoarthritis Initiative, with no symptoms or visual signs of disease on imaging. On 3-y follow-up, a subset of these individuals had progressed to symptomatic OA. We trained a classifier to differentiate progressors and nonprogressors on baseline cartilage texture maps, which achieved a robust test accuracy of 78% in detecting future symptomatic OA progression 3 y prior to symptoms. This work demonstrates that OA detection may be possible at a potentially reversible stage. A key contribution of our work is direct visualization of the cartilage phenotype defining predictive ability as our technique is generative. We observe early biochemical patterns of fissuring in cartilage that define future onset of OA. In the future, coupling presymptomatic OA detection with emergent clinical therapies could modify the outcome of a disease that costs the United States healthcare system $16.5 billion annually. Furthermore, our technique is broadly applicable to earlier image-based detection of many diseases currently diagnosed at advanced stages today.

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.

Arthroscopic verification of objectivity of the orthopaedic examination and magnetic resonance imaging in intra-articular knee injury. Retrospective study

Introduction

Arthroscopy of the knee joint is regarded as the most objective diagnostic method in intra-articular knee joint lesions.

Aim

The purpose of this study was to assess the objectivity and diagnostic value of orthopaedic examination (OE) and magnetic resonance imaging (MRI) in reference to the arthroscopic result.

Material and methods

In a group of 113 patients treated by arthroscopic surgery for post-traumatic knee pathology between 2008 and 2010 in our department, accuracy of clinical and MRI findings that preceded surgery were studied retrospectively using a statistical method. Sensitivity, specificity, accuracy and predictive negative and positive values were the subject of analysis.

Results

In the presented trial, sensitivity values of the orthopaedic examination for injuries of the anterior cruciate ligament (ACL), meniscus medialis (MM), meniscus lateralis (ML) and chondral injuries (ChI) were 86%, 65%, 38% and 51%, respectively. Specificity values were 90%, 65%, 100% and 100%, respectively. The MR sensitivity and specificity values were 80%, 88%, 44% and 32%, and 86%, 64%, 93% and 97%, respectively.

Conclusions

Assessment of intra-articular knee joint lesions is a difficult diagnostic problem. In making a decision about arthroscopy of the knee joint, an appropriate sequence of examinations should be carried out: OE, MRI and arthroscopy. The improvement in the effectiveness of the orthopaedic examination and MRI can limit the too high frequency of diagnostic arthroscopies, which generates the risk of operation treatment and costs.

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.

Is MRI adequate to detect lesions in patients with ankle instability?

BACKGROUND

Chondral lesions, peroneal tendon tears, and other disorders in patients with chronic ankle instability may not be detected by preoperative MRI. Also, MRI often is obtained and interpreted at the referring institution, leading to variability in reading.

QUESTIONS/PURPOSES

We assessed the accuracy of the radiologists' and orthopaedic surgeon's reading of preoperative MRI for diagnosing ankle lesions in patients with ankle instability warranting surgery.

PATIENTS AND METHODS

We retrospectively reviewed 133 patients who underwent 135 surgeries for lateral ankle ligament reconstruction with concomitant ankle arthroscopy and who had preoperative MRI.

RESULTS

We found 72 associated lesions in 66 of the 135 surgeries, including 38 chondral injuries, 18 peroneus brevis tears, seven loose bodies, and nine other miscellaneous abnormalities. Eliminating eight lesions for which the decision to operate was not based on operative findings, there were 127 surgeries with 64 associated lesions that required intraoperative confirmation or were detected intraoperatively. In the original reports, the radiologists identified 39% (15) of the chondral injuries, 56% (10) of the peroneal tears, and 57% (four) of the loose bodies. Radiologists' MRI sensitivity for detecting lesions was 45%. The attending surgeon identified 47% (18) of the chondral injuries, 89% (16) of the loose bodies, 71% (five) of the peroneus brevis tears, and the posterior talus process lesion, with a sensitivity of 63%.

CONCLUSIONS

Our data suggest orthopaedic surgeons should review preoperative MRIs and also suggest the sensitivity of MRI may not be adequate to detect lesions in these patients before surgery.

LEVEL OF EVIDENCE

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

Tibio-femoral cartilage defects 3-5 years following arthroscopic partial medial meniscectomy

OBJECTIVE

Arthroscopic partial medial meniscectomy (APMM) is a common procedure to treat a medial meniscal tear. Individuals who undergo APMM have a heightened risk of developing tibio-femoral osteoarthritis (OA). Cartilage defects scored from magnetic resonance imaging (MRI) scans predict cartilage loss over time. It is not known whether cartilage defects in the early years following APMM are more common or of greater severity than in age-matched controls. This study compared the prevalence and severity of tibio-femoral cartilage defects in patients 3-5 years post-APMM with that of age-matched controls.

METHODS

Twenty-five individuals who had undergone APMM in the previous 46.9+/-5.0 months and 24 age-matched controls participated in this study. Sagittal plane knee MRI scans were acquired from the operated knees of patients and from randomly assigned knees of the controls and graded (0-4) for tibio-femoral cartilage defects. Defect prevalence (score of >or=2 for any compartment) and severity of the cartilage from both tibio-femoral compartments were compared between the groups.

RESULTS

The APMM group had greater prevalence (77 vs 42%, P=0.012) and severity (4.1+/-1.9 vs 2.8+/-1.1, P=0.005) of tibio-femoral cartilage defects than controls. Age was positively associated with tibio-femoral cartilage defect severity for APMM, r=0.523, P=0.007, but not for controls, r=0.045, P=0.834.

CONCLUSION

Tibio-femoral joint cartilage defects are more prevalent and of greater severity in individuals who had undergone APMM approximately 44 months earlier than in age-matched controls.

MRI efficacy in diagnosing internal lesions of the knee: a retrospective analysis

BACKGROUND

Many surgeons tend to believe that MRI is an accurate, non invasive diagnostic method, enough to lead to decisions for conservative treatment and save a patient from unnecessary arthroscopy. We conducted a retrospective study to investigate the accuracy of the MRI of the knee for the detection of injuries of the meniscus, cruciate ligaments and articular cartilage, in comparison with the preoperative clinical examination and intraoperative findings. Between May 2005 and February 2006 102 patients after clinical examination were diagnosed with meniscal or cruciate injury and underwent definitive treatment with arthroscopy. 46 of these patients fulfilled the inclusion criteria. The accuracy, sensitivity, specificity, negative and positive predictive values of the MRI findings were correlated with the lesions identified during arthroscopy. The diagnostic performance of the initial clinical examination was also calculated for the meniscal and cruciate ligament injuries.

RESULTS

The accuracy for tears of the medial, lateral meniscus, anterior and posterior cruciate ligaments and articular cartilage was 81%, 77%, 86%, 98% and 60% respectively. The specificity was 69%, 88%, 89%, 98% and 73% respectively. The positive predictive value was 83%, 81%, 90%, 75% and 53% respectively. Finally, the clinical examination had significant lower reliability in the detection of these injuries.

CONCLUSION

MRI is very helpful in diagnosing meniscal and cruciate ligament injuries. But in a countable percentage reports with false results and in chondral defects its importance is still vague. The arthroscopy still remains the gold standard for definitive diagnosis.

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.

Inter-rater and intra-rater reliability of subchondral bone and cartilage thickness measurement from MRI☆

MRI is often used to visualize and quantify the articular cartilage layer of load bearing joints affected by degenerative diseases, such as osteoarthritis (OA). Although the role played by the subchondral bone in the etiology and/or progression of OA may be important, the ability to visualize and quantify subchondral bone with MRI has received little attention. In this report we examined the inter-rater and intra-rater reliability of subchondral bone and cartilage thickness measurements from MR images of cadaver femoral head specimens. A 3D-SPGR pulse sequence tuned to eliminate chemical shift artifact through phase cancellation was used to image the specimens. Three raters manually segmented four specimens on two different occasions. Subchondral bone and cartilage thickness measurements were calculated from the segmented images. Inter-rater and intra-rater reliabilities were very high (>.98) for both cartilage and subchondral bone thickness measurements. We conclude that subchondral bone thickness can be measured as reliably as cartilage thickness from MR images.

Molecular markers in the evaluation of autologous chondrocyte implantation

PURPOSE

With the help of molecular markers, it has become possible to quantify cartilage repair and degradation in joints. In this study, we attempt to determine whether or not molecular markers in synovial fluid can be helpful in defining the repair process following autologous chondrocyte implantation (ACI).

TYPE OF STUDY

As part of a prospective clinical pilot study, 17 patients were evaluated before, as well as 6 weeks, 3, 6, and 12 months after the ACI. A synovial analysis was performed and molecular markers for bone and cartilage metabolism were determined.

METHODS

A number of parameters, including pyridinium crosslink (PY), deoxypyridinolin (DPD), n-telopeptide (NTX) from type I collagen, MMP-1, MMP-3; TIMP-1, PICP, proteoglycan, and YKL-40 were analyzed. The levels were referenced to the total protein concentration of the synovial fluid. The synovial analyses were compared with clinical parameters (Larson score) and magnetic resonance imaging (MRI) examinations.

RESULTS

The analysis of the data revealed differing trends for the various synovial markers over time. The most remarkable marker was found to be DPD, which increased continuously between surgery and week 12, only to disappear after the repair process had ceased 1 year after surgery. All molecular markers for cartilage degradation increased initially after surgery and dropped off below the original levels 3 to 6 months later.

CONCLUSIONS

The evaluation revealed that the determination of marker levels can provide valuable information regarding the metabolism of bone and cartilage in a joint. They seem to provide a method for monitoring the repair process associated with the various treatment forms for chondral lesions.

Risk factors for progressive cartilage loss in the knee: a longitudinal magnetic resonance imaging study in forty-three patients

OBJECTIVE

To evaluate the rate of progression of cartilage loss in the knee joint using magnetic resonance imaging (MRI) and to evaluate potential risk factors for more rapid cartilage loss.

METHODS

We evaluated baseline and followup MRIs of the knees in 43 patients (minimum time interval of 1 year, mean 1.8 years, range 52-285 weeks). Cartilage loss was graded in the anterior, central, and posterior regions of the medial and lateral knee compartments. Knee joints were also evaluated for other pathology. Data were analyzed using analysis of variance models.

RESULTS

Patients who had sustained meniscal tears showed a higher average rate of progression of cartilage loss (22%) than that seen in those who had intact menisci (14.9%) (P <or= 0.018). Anterior cruciate ligament (ACL) tears had a borderline significant influence (P <or= 0.06) on the progression of cartilage pathology. Lesions located in the central region of the medial compartment were more likely to progress to more advanced cartilage pathology (progression rate 28%; P <or= 0.003) than lesions in the anterior (19%; P <or= 0.564) and posterior (17%; P <or= 0.957) regions or lesions located in the lateral compartment (average progression rate 15%; P <or= 0.707). Lesions located in the anterior region of the lateral compartment showed less progression of cartilage degradation (6%; P <or= 0.001). No specific grade of lesion identified at baseline had a predilection for more rapid cartilage loss (P <or= 0.93).

CONCLUSION

MRI can detect interval cartilage loss in patients over a short period (<2 years). The presence of meniscal and ACL tears was associated with more rapid cartilage loss. Cartilage lesions located in the central region of the medial compartment showed more rapid progression of cartilage loss than cartilage lesions in the anterior and posterior portions of the medial compartment. The findings in this study suggest that patients entering clinical trials investigating antiarthritis regimens may need to be randomized based on location of the lesion.

Structure modification in knee osteoarthritis: methodology and outcome parameters

Managing osteoarthritis (OA) with structure-modifying agents (SMAs) is an important emerging topic receiving increased attention from both lay individuals and health care professionals as a promising alternative in the management of OA.

OBJECTIVE

To review the methodology and outcome parameters purported to be used in the assessment of the structure-modifying potential of various interventions.

DESIGN

A Medline search was performed to select the relevant published articles. This review does not go into detail about various aspects of the design and conduct of structure-modifying studies; however, a vast number of relevant references are provided and may be accessed by interested readers.

RESULTS

Enhancing the feasibility of SMAs trials aimed at documenting efficacy can be accomplished by carefully selecting: (1) the outcome parameters, (2) the imaging methodology, and (3) the patient population. Most of the relevant issues that need to be considered by investigators before embarking on a study of this nature have been addressed in this article.

CONCLUSION

Most of the evidence to date focuses on the superiority of the radiographic-based techniques in measuring joint space narrowing among a homogeneous population of OA patients. More research is warranted before other techniques such as ultrasound, chondroscopy, and magnetic resonance imaging, can be proven to be reliable.

A comparison of magnetic resonance imaging and arthroscopic evaluation of chondral lesions of the knee

This study compared the sensitivity of magnetic resonance imaging (MRI) to arthroscopy in detecting localized chondral lesions of the knee, especially lesion depth, in 28 patients with 32 femoral and tibial lesions. Average patient age was 24.3 years. Chondral lesions were classified according to five grades. The sensitivity of MRI was 100% for grade 3 (deep) and higher lesions, but was less for superficial chondral lesions. Arthroscopic and MRI grades coincided for only three lesions. Magnetic resonance imaging was not so accurate regarding depth even for deep chondral lesions, although subchondral lesions undetectable by arthroscopy often were detected by MRI.

Surgical alternatives for treatment of articular cartilage lesions

Articular cartilage injuries in the knee are common; fortunately, full-thickness articular cartilage defects constitute only a small portion of this group. These lesions may be incidentally encountered during ligament or meniscal surgery, having been silent or asymptomatic for an unknown period of time. However, when they are large and symptomatic, the surgeon may choose from a wide array of techniques available for treatment. The relatively small number of natural history studies regarding full-thickness articular surface lesions complicates the decision-making process. Accurate evaluation and classification of the anatomic defect aids in the development of a clinical algorithm for treatment. Surgical techniques are either reparative or restorative in nature. Reparative techniques fall short of complete reestablishment of the articular cartilage; however, the resultant repairs may remain quite functional for varying periods of time. Restorative techniques attempt to reestablish the native articular surface. To date, no peer-reviewed, prospective, randomized, controlled studies of operative versus nonoperative treatment for full-thickness articular cartilage lesions have been published. Even though the long-term results of surgical treatment for full-thickness articular surface lesions remain unknown, the early results are encouraging.

Clinical significance of magnetic resonance imaging (MRI) for focal chondral lesions

To evaluate the diagnostic potential of magnetic resonance imaging (MRI) and define its role, focal chondral lesions of the femoral surface of the tibiofemoral joint were examined. Full-thickness defects were well detected prospectively (93%) with conventional MRIs initially administered for observation reference of ligaments and menisci. Optimized MRIs, which included right-angled planes to the lesion surface and magnetization transfer contrast (MTC) sequences, delineated the size of lesions (R2 = 0.648,p < 0.0001) and the difference between full-and partial-thickness defects (88% in accuracy). A forward-tilt of 30 degrees to the femoral shaft was the average plane angle that afforded optimal visualization of the chondral lesions. Our findings advocate that routine MRIs are sufficient in detecting severe chondral lesions that require further examination, and the optimized images are highly useful in facilitating the recently developed therapeutic approaches and follow-up studies for articular cartilage defects.

Magnetic resonance imaging of superficial cartilage lesions: role of contrast in lesion detection

Excised patellar cartilage phantoms with artificial surface lesions were imaged in a 2 g/dl albumin solution to determine the effect of cartilage/fluid contrast on detection of early degenerative change. Surface lesions consisted of full-thickness holes, superficial grooves, and coarse abrasion. Phantoms were imaged with a T1-weighted fast low-angle shot (FLASH) and T2*-weighted dual-echo in the steady state (DESS) sequence. Although both sequences were able to identify full-thickness holes, they underestimated the presence of superficial grooves and extent of fibrillation. Despite greater bulk tissue contrast between cartilage and fluid for the FLASH sequence, detection of fibrillation was poorer compared with the DESS images. The results of this study suggest that surface properties of fibrillated cartilage contribute significantly to the insensitivity of magnetic resonance imaging in detecting superficial lesions. In contrast to previous papers suggesting that T1-weighted spoiled gradient-echo imaging provides the greatest accuracy for lesion detection, our results indicate that, in the presence of joint fluid, T2*-weighted imaging increases detection of superficial lesions. J. Magn. Reson. Imaging 1999;10:178-182.

Occult osteochondral lesions after anterior cruciate ligament rupture. Six-year magnetic resonance imaging follow-up study

Twenty-three patients with acute anterior cruciate ligament injuries, normal radiographs, and occult osteochondral lesions revealed by magnetic resonance imaging were reviewed 6 years after initial injury and anterior cruciate ligament hamstring autograft reconstruction. Each patient completed the Mohtadi Quality of Life outcome measure for anterior cruciate ligament deficiency, underwent clinical examination, and had a repeat magnetic resonance imaging scan. The index and follow-up magnetic resonance imaging scans were compared with respect to cartilage thinning and marrow signal. A significant number of patients had evidence of cartilage thinning adjacent to the site of the initial osteochondral lesion. Marrow signal changes persisted in 15 (65%) of the patients. Clinical comparison of patients with normal cartilage with those who had cartilage thinning revealed similar results on both KT-1000 arthrometry and on the Mohtadi outcome measure. This suggests that the initial injury resulted in irreversible changes in the knee. Injuries causing marrow signal changes may result in an alteration in the load-bearing properties of subchondral bone, which in turn allow for changes in the overlying cartilage. Further follow-up will determine the clinical significance of changes detected by magnetic resonance imaging.

Recommendations for the diagnosis of traumatic meniscal injuries in athletes

It has always been difficult to develop a method of correctly evaluating knee injuries and, in turn, to devise the appropriate rehabilitation programme. Flawless diagnosis of meniscal injury is necessary, considering the diverse consequences of this injury for patients, and even more so in relation to athletes, bearing in mind the intensified physical demands on their bodies. There is no doubt that an accurate and concise clinical evaluation of patients with injuries to the knee is the basis for an exact diagnosis and successful treatment. The use of noninvasive methods, such as magnetic resonance imaging, in addition to clinical evaluation is recommended because of their high accuracy and negative predictive value. The use of invasive methods, such as arthroscopic operations, should be restricted to treatment, and not be used for diagnosis.

Open meniscal repair: clinical and magnetic resonance imaging findings after twelve years

The purpose of this study was to document the longterm clinical, radiographic, and magnetic resonance imaging results after open meniscal repair. Twenty-two patients, with 23 open meniscal repairs, were evaluated after a mean follow-up of 12.9 years using patient history, physical examination, KT-1000 arthrometer testing, the "Orthopaedische Arbeitsgemeinschaft Knie" knee evaluation scheme, Tegner activity score, weightbearing radiographs, and magnetic resonance imaging. Two of the 22 patients had retears and both occurred in unstable knees. Radiographs revealed no degenerative changes in 17 of the 23 compartments. Grade III and IV signal alterations were present on magnetic resonance imaging scans in more than 50% of the repaired menisci. We concluded that the longterm survival rate of repaired menisci was 91%, and that magnetic resonance imaging is unsuitable for diagnosis of the healing process of a repaired meniscus.

Current status of imaging procedures in the diagnosis, prognosis and monitoring of osteoarthritis

X-ray, magnetic resonance imaging (MRI) and arthroscopy are the methods most widely used to assess the status of osteoarthritic joints. How do these methods compare? As diagnostic tools, what is the relative sensitivity of X-ray versus MRI, arthroscopy versus MRI and arthroscopy versus X-ray? Which imaging modalities can be used for predicting progression? Scintigraphy and MRI can assess the degree of cellular activity in the tissues of a joint, which may help in prognosis. Are the methods proven and are they reliable? Recommendations for clinical trials in knee osteoarthritis, state it is essential that reproducible radiographs are obtained for reliable assessment of progression. Two radiographic views of the knee have been proposed; which provides the more reliable assessment, the knee in extension or semi-flexed? Compared with standard radiography, does microfocal radiography make a difference to patient numbers required for drug trials?

The diagnosis of meniscal tears in athletes. A comparison of clinical and magnetic resonance imaging investigations

This study evaluated the predictability of clinical examination alone in comparison with magnetic resonance imaging in the diagnosis of meniscal tears in competitive athletes. Ninety-three competitive athletes were prospectively investigated between 1992 and 1995. A total of 57 athletes were operated on based on clinical examination alone, and the 36 remaining athletes had magnetic resonance imaging before surgery. The correct diagnosis of a meniscal lesion was made on clinical examination alone in 83 athletes (89%) and on magnetic resonance imaging the correct diagnosis was also made in 89% of 36 athletes. The overall values for the clinical investigation of the medial and lateral menisci combined were 94.5%, 91.5%, 99%, 96.5%, 87% for accuracy, positive predictive value, negative predictive value, sensitivity, and specificity, respectively. The overall values for magnetic resonance imaging of the medial and lateral menisci combined were 95.5%, 96.5%, 91.5%, 98%, 85.5% for accuracy, positive predictive value, negative predictive value, sensitivity, and specificity, respectively.

Analysis of three-dimensional computerized representations of articular cartilage lesions

RATIONALE AND OBJECTIVES

The authors assess the accuracy of three-dimensional (3D) computer representations based on magnetic resonance images of articular cartilage lesions, using actual cartilage lesions as reference standards.

METHODS

Grade 2 and grade 3 articular lesions were created on articular surfaces of five porcine knee joints. The knees were then imaged using 3D fat-suppressed SPGR acquisition at four different slice thicknesses. Magnetic resonance imaging data sets were transferred to a computer workstation for image processing and 3D reconstruction. Lesion dimensions (length, width, and depth) based on the 3D reconstructed image were compared with the dimensions measured using actual lesions.

RESULTS

The average percent error of lesion length, width, and depth based on the 3D images ranged from approximately 8% to 12% when using the thinnest magnetic resonance slice thickness (0.7 mm).

CONCLUSIONS

Three-dimensional reconstructed images derived from thin-slice magnetic resonance imaging can provide reasonable representations of true articular cartilage lesion dimensions.

Influence of magnetic resonance imaging on indications for arthroscopy of the knee

In a prospective study, magnetic resonance imaging was performed before arthroscopy for all patients (n = 121) with a meniscal tear (n = 125). Criteria of the study were stable cruciate and collateral ligaments, absence of pathologic radiographic findings, and absence of prior surgical interventions of the involved knee joint. In 43 knees (34%), the clinical diagnosis of a meniscal tear was discarded because of the results of the magnetic resonance imaging examination. Synovitis was diagnosed in 16 patients (13%), articular cartilage damage in 10 patients (8%), bone bruise injuries in 10 patients (8%), osteochondritis dissecans in 3 patients (2%), disruption of the inner layer of the medial collateral ligament in 3 patients (2%), and osteonecrosis in 1 patient. The use of magnetic resonance imaging in establishing diagnosis of disorders of the knee joint altered treatment in a significant proportion of patients. Magnetic resonance imaging should be done before arthroscopy of the knee in all cases in which the clinical diagnosis has been reduced to a suspected meniscus injury.

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.