Quantitative MR imaging evaluation of chondropathy in osteoarthritic knees

Short tau inversion recovery and proton density-weighted fat suppressed sequences for the evaluation of osteoarthritis of the knee with a 1.0 T dedicated extremity MRI: development of a time-efficient sequence protocol

Aim of this study was to develop a time-efficient sequence protocol for a 1.0 T dedicated MR system to be used for whole-organ scoring of osteoarthritis (OA). Thirty-four knees were examined using a protocol that included fat suppressed fast spin echo proton density weighted sequences (PDFS) in three planes plus a coronal STIR sequence. Two radiologists scored each knee by consensus for five OA features. In separate sessions, all knees were scored using three different combinations of sequences: (1) all four sequences (reference protocol, 16 min 31 s scanning time), (2) three PDFS sequences without STIR ("No STIR", 12 min 25 s scanning time) and (3) sagittal and axial PDFS sequences plus a coronal STIR sequence ("No PDFS", 11 min 49 s scanning time). Agreement of the readings using both subsets of sequences compared to the reference protocol was evaluated using weighted kappa statistics. kappa-coefficients showed good or excellent agreement for both sequence subsets in comparison to the reference protocol for all assessed features. kappa-coefficients for No PDFS/No STIR: bone marrow abnormalities (0.74/0.67), subarticular cysts (0.84/0.63), marginal osteophytes (0.77/0.71), menisci (0.75/0.79), tibial cartilage (0.71/0.78). Optimization of sequence protocols consisting of three sequences results in time savings and cost efficiency in imaging of knee OA without loss of information over a more time consuming protocol.

Association of prevalent and incident knee cartilage defects with loss of tibial and patellar cartilage: A longitudinal study

OBJECTIVE

To describe the association between prevalent and incident knee cartilage defects and loss of knee cartilage in male and female adults.

METHODS

A convenience sample of 325 subjects (mean age 45 years; age range 26-61 years) was evaluated at baseline and approximately 2 years later. Knee cartilage volume, cartilage defect scores (0-4 scale), and joint surface area were determined using T1-weighted fat-suppression magnetic resonance imaging techniques. Height, weight, and radiographic evidence of osteoarthritis were measured by standard protocols.

RESULTS

Multivariable analysis revealed that baseline cartilage defect scores at the medial tibia, lateral tibia, and patella had a dose-response association with the annual rate of change in knee cartilage volume at the corresponding site (beta = -1.3% to -1.2% per grade; P < 0.05 for all comparisons). In addition, an increase in knee cartilage defect score (change of > or =1) was associated with higher rates of knee cartilage volume loss at all sites (beta = -1.9% to -1.7% per year; P < 0.01 for all comparisons). Furthermore, a decrease in the knee cartilage defect score (change of less than or equal to -1) was associated with an increase in knee cartilage volume at all sites (beta = 1.0% to 2.7% per year; P < 0.05 for all comparisons).

CONCLUSION

Prevalent knee cartilage defects are predictive of compartment-specific cartilage loss over 2 years. Both increases and decreases in knee cartilage defects are associated with changes in knee cartilage volume, which implies a potential for reversal of knee cartilage loss.

Association of cartilage defects with loss of knee cartilage in healthy, middle-age adults: A prospective study

OBJECTIVE

The significance of asymptomatic knee cartilage defects in healthy individuals is not known. The aim of this study was to examine the association between cartilage defects in the knee and cartilage volume both cross-sectionally and longitudinally in healthy, middle-age adults.

METHODS

Eighty-six healthy men and women (mean +/- SD age 53.8 +/- 8.8 years) underwent T1-weighted fat-suppressed magnetic resonance imaging of their dominant knees at baseline and at the 2-year followup visit. Knee cartilage volume was measured. Cartilage defects were scored according to a grading system (0-4) and as present (a defect score of > or = 2) or absent in the medial and lateral tibiofemoral compartments.

RESULTS

Cartilage defects in the medial and lateral tibiofemoral compartments were very common (in 61% and 43% of subjects, respectively). Those with cartilage defects had a 25% reduction in medial tibial cartilage volume, a 15% reduction in lateral tibial cartilage volume, and a 19% reduction in total femoral cartilage volume relative to those with no cartilage defects in cross-sectional analyses (all P < 0.05). In the medial tibiofemoral compartment, the annual loss of tibial cartilage in those with cartilage defects was 2.5% (95% confidence interval [95% CI] 2.2%, 3.1%) compared with an annual loss of tibial cartilage of 1.3% (95% CI 0.5%, 2.0%) in those with no defects (P = 0.028), independent of other known risk factors for osteoarthritis (OA).

CONCLUSION

These data suggest that the presence of asymptomatic, non-full-thickness medial tibiofemoral cartilage defects identifies healthy individuals most likely to lose knee cartilage in the absence of radiographic knee OA. Thus, interventions aimed at reducing or reversing cartilage defects may reduce the risk of subsequent knee OA.

Meniscal tear and extrusion are strongly associated with progression of symptomatic knee osteoarthritis as assessed by quantitative magnetic resonance imaging

BACKGROUND

The relation between knee meniscal structural damage and cartilage degradation is plausible but not yet clearly proven.

OBJECTIVES

To quantitate the cartilage volume changes in knee osteoarthritis using magnetic resonance imaging (MRI), and determine whether meniscal alteration predicts cartilage volume loss over time.

METHODS

32 patients meeting ACR criteria for symptomatic knee osteoarthritis were studied. MRI knee acquisitions were done every six months for two years. The cartilage volumes of different knee regions were measured. Three indices of structural change in the medial and lateral menisci were evaluated--degeneration, tear, and extrusion--using a semiquantitative scale.

RESULTS

24 patients (75%) had mild to moderate or severe meniscal damage (tear or extrusion) at baseline. A highly significant difference in global cartilage volume loss was observed between severe medial meniscal tear and absence of tear (mean (SD), -10.1 (2.1)% v -5.1 (2.4)%, p = 0.002). An even greater difference was found between the medial meniscal changes and medial compartment cartilage volume loss (-14.3 (3.0)% in the presence of severe tear v -6.3 (2.7)% in the absence of tear; p<0.0001). Similarly, a major difference was found between the presence of a medial meniscal extrusion and loss of medial compartment cartilage volume (-15.4 (4.1)% in the presence of extrusion v -4.5 (1.7)% with no extrusion; p<0.001).

CONCLUSIONS

Meniscal tear and extrusion appear to be associated with progression of symptomatic knee osteoarthritis.

Quantitative magnetic resonance imaging evaluation of knee osteoarthritis progression over two years and correlation with clinical symptoms and radiologic changes

OBJECTIVE

To evaluate the change in osteoarthritic (OA) knee cartilage volume over a two-year period with the use of magnetic resonance imaging (MRI) and to correlate the MRI changes with radiologic changes.

METHODS

Thirty-two patients with symptomatic knee OA underwent MRI of the knee at baseline and at 6, 12, 18, and 24 months. Loss of cartilage volumes were computed and contrasted with changes in clinical variables for OA and with standardized semiflexed knee radiographs at baseline at 1 and 2 years.

RESULTS

Progression of cartilage loss at all followup points was statistically significant (P < 0.0001), with a mean +/- SD of 3.8 +/- 5.1% for global cartilage loss and 4.3 +/- 6.5% for medial compartment cartilage loss at 6 months, 3.6 +/- 5.1% and 4.2 +/- 7.5% at 12 months, and 6.1 +/- 7.2% and 7.6 +/- 8.6% at 24 months. Discriminant function analysis identified 2 groups of patients, those who progressed slowly (<2% of global cartilage loss; n = 21) and those who progressed rapidly (>15% of global cartilage loss; n = 11) over the 2 years of study. At baseline, there was a greater proportion of women (P = 0.001), a lower range of motion (P = 0.01), a greater circumference and higher level of pain (P = 0.05) and stiffness in the study knee, and a higher body mass index in the fast progressor group compared with the slow progressor group. No statistical correlation between loss of cartilage volume and radiographic changes was seen.

CONCLUSION

Quantitative MRI can measure the progression of knee OA precisely and can help to identify patients with rapidly progressing disease. These findings indicate that MRI could be helpful in assessing the effects of treatment with structure-modifying agents in OA.

Whole-Organ Magnetic Resonance Imaging Score (WORMS) of the knee in osteoarthritis

OBJECTIVES

To describe a semi-quantitative scoring method for multi-feature, whole-organ evaluation of the knee in osteoarthritis (OA) based on magnetic resonance imaging (MRI) findings. To determine the inter-observer agreement of this scoring method. To examine associations among the features included in the scoring method.

METHODS

Nineteen knees of 19 patients with knee OA were imaged with MRI using conventional pulse sequences and a clinical 1.5 T MRI system. Images were independently analyzed by two musculoskeletal radiologists using a whole-organ MRI scoring method (WORMS) that incorporated 14 features: articular cartilage integrity, subarticular bone marrow abnormality, subarticular cysts, subarticular bone attrition, marginal osteophytes, medial and lateral meniscal integrity, anterior and posterior cruciate ligament integrity, medial and lateral collateral ligament integrity, synovitis/effusion, intraarticular loose bodies, and periarticular cysts/bursitis. Intraclass correlation coefficients (ICC) were determined for each feature as a measure of inter-observer agreement. Associations among the scores for different features were expressed as Spearman Rho.

RESULTS

All knees showed structural abnormalities with MRI. Cartilage loss and osteophytes were the most prevalent features (98% and 92%, respectively). One of the least common features was ligament abnormality (8%). Inter-observer agreement for WORMS scores was high (most ICC values were >0.80). The individual features showed strong inter-associations.

CONCLUSION

The WORMS method described in this report provides multi-feature, whole-organ assessment of the knee in OA using conventional MR images, and shows high inter-observer agreement among trained readers. This method may be useful in epidemiological studies and clinical trials of OA.

Early radiographic osteoarthritis is associated with substantial changes in cartilage volume and tibial bone surface area in both males and females

OBJECTIVE

To describe the association between early radiographic osteoarthritis of the knee (ROA), knee cartilage volume and tibial bone surface area.

METHODS

Cross-sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61). Articular cartilage volume, bone area and volume were determined at the patella, medial tibial and lateral tibial compartments by processing images acquired in the sagittal plane using T1-weighted fat saturation MRI. ROA was assessed with a standing semiflexed radiograph and the OARSI atlas for joint space narrowing and osteophytosis. Both radiographs and MRIs were performed in the right knee and read by different observers.

RESULTS

ROA (predominantly grade 1) was present in 17% of subjects of which medial joint space narrowing was most common (14%) followed by medial osteophytes (6%). Grade one medial joint space narrowing was associated with substantial reductions in cartilage volume at both the medial and lateral tibial and patellar sites within the knee (adjusted mean difference 11-13%, all P<0.001) while grade one osteophytosis was associated with substantial increases in both lateral and medial tibial joint surface area (adjusted mean difference 10-16%, all P<0.001). In contrast, osteophytosis was not associated with a significant change in cartilage volume and joint space narrowing was not associated with a significant change in tibial bone area (all P>0.05).

CONCLUSIONS

Early medial compartment ROA is associated with substantial reductions in cartilage volume and increases in bone area. These large changes, when combined with similar measurement error for MRI and radiographs, suggest that MRI may be superior at detecting and hence understanding early osteoarthritis of the knee in humans.

Treatment of osteoarthritic cartilage lesions with osteochondral autograft transplantation

Twenty-two osteochondral autograft transplantations were performed on two types of knees: those with isolated (group 1) and multiple (group 2) degenerative cartilage lesions. At minimum 24-month follow-up, group 1 had significantly better pain relief and function than group 2 based on the Western Ontario and McMaster Universities Osteoarthritis Index and pain scores (10-point visual analog scale). Osteochondral autograft transplantation may be effective in treating knees with isolated degenerative cartilage lesions but appears contraindicated in those with multiple lesions.

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.

The significance of quality of life in health care

This paper compares a traditional biomedical model with an outcomes model for evaluating health care. The traditional model emphasizes diagnosis and disease-specific outcomes. In contrast, the outcomes model emphasizes life expectancy and health-related quality of life. Although the models are similar, they lead to different conclusions with regard to some interventions. For some conditions, diagnosis and treatment may reduce the impact of a particular disease without extending life expectancy or improving quality of life. Older individuals with multiple co-morbidities may not benefit from treatments for a particular disease if competing health problems threaten life or reduce quality of life. In preventive medicine, diagnosis of disease is made more difficult because of ambiguity, uncertainty, lead-time bias, and length bias. In some circumstances, successful diagnosis and treatment may actually reduce life expectancy or overall life quality. Example applications of the outcomes model from clinical policy analysis, individual decision making and shared decision-making are offered. The outcomes model has received little attention in dental health care but may have parallels to applications in other areas of medicine.

Measurement accuracy of focal cartilage defects from MRI and correlation of MRI graded lesions with histology: a preliminary study

OBJECTIVES

Although accurate spatial measurement of cartilage thickness from MRI is possible, no studies have assessed the accuracy of measuring cartilage defect dimensions from MRI. In addition, current MR grading scales for assessing cartilage lesions have limited categories, and little is known about how well these scales correlate with histological assessment of the lesion. The objective of this preliminary study is to address both these issues.

METHODS

We performed two experiments on four cadaver knee joints from elderly donors: Experiment 1 assessed the accuracy of measuring controlled defects in cartilage, and Experiment 2 compared MRI grading (Noyes scale) of natural cartilage lesions to histological grading (Mankin scale) of the sectioned cartilage tissue. MRI was performed on 1.5 T clinical scanner (fat-suppressed 3D-SPGR at TR/TE/alpha=55/13.5/45 and 256 x 256 matrix).

RESULTS

The mean difference between defect diameters measured and introduced was less than 0.1mm, which was statistically insignificant (P=0.754). Defect depth was less accurate at >0.4mm, significantly under predicting actual defect depth (P=0.004). Correlation between Noyes grading scores and Mankin grading scores of natural lesions was moderately high (r=0.7) and statistically significant (P=0.001).

CONCLUSIONS

Three-dimensional mapping of cartilage thickness shows great promise for the accurate measurement of focal cartilage defects, though improvement is needed. The Noyes grading scale is consistent with histological Mankin grading of cartilage lesions, though enhancement of MR grading scales is needed, and warranted, based on the signal intensity information available from clinical MRI. Integration of these two analyses-focal defect measurement and signal intensity analysis-could potentially result in a valuable clinical tool for early osteoarthritis diagnosis and longitudinal tracking.

Magnetic resonance-detected subchondral bone marrow and cartilage defect characteristics associated with pain and X-ray-defined knee osteoarthritis

OBJECTIVE

To assess whether the presence of subchondral bone marrow abnormalities (bone marrow edema (BME)) and cartilage defects, determined by magnetic resonance imaging (MRI), would explain the difference between painful osteoarthritis of the knee (OAK) compared with painless OAK or pain without OAK.

METHOD

Four groups of women (30 per group), aged 35-55 years, were recruited from the southeast Michigan Osteoarthritis cohort (group 1: painful OAK; group 2: painless OAK; group 3: knee pain without OAK; and group 4: no OAK or knee pain). OAK was defined by a Kellgren-Lawrence score of 2 or greater, while pain was based on self-report. BME and cartilage defects were identified from MRI.

RESULTS

BME lesions were identified in 56% of all knees. BME lesions were four times (95% CI=1.7, 8.7) more likely to occur in the painless OAK group as compared with the group with pain, but no OAK. BME lesions >1cm were more frequent (OR=5.0; 95% CI=1.4, 10.5) in the painful OAK group than all other groups. While the frequency of BME lesions was similar in the painless OAK and painful OAK groups, there were more lesions, >1cm, in the painful OAK group. About 75% of all knees had evidence of some cartilage defect, of which 35% were full-thickness defects. Full-thickness cartilage defects occurred frequently in painful OAK. One-third of knees with full-thickness defects and 47% of knees with cartilage defects involving bone had BME >1cm. Women with radiographic OA, full-thickness articular cartilage defects, and adjacent subchondral cortical bone defects were significantly more likely to have painful OAK than other groups (OR=3.2; 95% CI=1.3, 7.6).

CONCLUSION

The finding on MRI of subchondral BME cannot satisfactorily explain the presence or absence of knee pain. However, women with BME and full-thickness articular cartilage defects accompanied by adjacent subchondral cortical bone defects were significantly more likely to have painful OAK than painless OAK.

Reliability of a quantification imaging system using magnetic resonance images to measure cartilage thickness and volume in human normal and osteoarthritic knees

OBJECTIVE

The aim of this study was to evaluate the reliability of a software tool that assesses knee cartilage volumes using magnetic resonance (MR) images. The objectives were to assess measurement reliability by: (1) determining the differences between readings of the same image made by the same reader 2 weeks apart (test-retest reliability), (2) determining the differences between the readings of the same image made by different readers (between-reader agreement), and (3) determining the differences between the cartilage volume readings obtained from two MR images of the same knee image acquired a few hours apart (patient positioning reliability).

METHODS

Forty-eight MR examinations of the knee from normal subjects, patients with different stages of symptomatic knee osteoarthritis (OA), and a subset of duplicate images were independently and blindly quantified by three readers using the imaging system. The following cartilage areas were analyzed to compute volumes: global cartilage, medial and lateral compartments, and medial and lateral femoral condyles.

RESULTS

Between-reader agreement of measurements was excellent, as shown by intra-class correlation (ICC) coefficients ranging from 0.958 to 0.997 for global cartilage (P<0.0001), 0.974 to 0.998 for the compartments (P<0.0001), and 0.943 to 0.999 for the condyles(P<0.0001). Test-retest reliability of within-reader data was also excellent, with Pearson correlation coefficients ranging from 0.978 to 0.999 (P<0.0001). Patient positioning reliability was also excellent, with Pearson correlation coefficients ranging from 0.978 to 0.999 (P<0.0001).

CONCLUSIONS

The results of this study establish the reliability of this MR imaging system. Test-retest reliability, between-reader agreement, and patient positioning reliability were all extremely high. This study represents a first step in the overall validation of an imaging system designed to follow progression of human knee OA.

Assessment of progression in knee osteoarthritis: results of a 1 year study comparing arthroscopy and MRI

OBJECTIVE

The objectives of this study were to determine the sensitivity to change of magnetic resonance imaging (MRI) quantification of chondropathy after 1 year in osteoarthritis of the medial tibiofemoral compartment and to assess the predictive value of subchondral bone marrow edema and bone abnormalities on progression of chondropathy.

DESIGN

Twenty patients with symptomatic knee osteoarthritis of the medial compartment underwent a prospective, longitudinal study. All patients were evaluated the same day at entry and after 1 year by plain weight-bearing radiographs, MRI with a three-dimensional gradient-echo sequence, using a 0.2-T dedicated MR unit, and arthroscopy. The medial tibiofemoral chondropathy was quantified blindly with MRI and arthroscopy using the French Society of Arthroscopy (SFA) score. Presence of subchondral bone marrow edema and bone abnormalities on initial MRI was recorded in order to evaluate their influence on both unchanged and worsened chondropathy after 1 year.

RESULTS

After 1 year, no statistically significant changes were observed with plain radiographs and arthroscopy. At variance, a statistically significant worsening of chondropathy was found with MRI using the SFA-MR score (P=0.01). SFA-MR score was the most responsive outcome. Absence of subchondral bone abnormalities and bone marrow edema on initial MR assessment predicted absence of worsening of chondropathy after 1 year.

CONCLUSION

MRI appears promising for evaluating progression of knee osteoarthritis.

Arthroscopic evaluation of potential structure-modifying drug in osteoarthritis of the knee. A multicenter, randomized, double-blind comparison of tenidap sodium vs piroxicam

OBJECTIVE

To test the hypothesis that tenidap has a structure-modifying effect in human knee osteoarthritis.

DESIGN

STUDY

multicenter, prospective, randomized, double blind, 1 year duration.

PATIENTS

primary painful knee osteoarthritis (ACR criteria) of the medial tibiofemoral compartment, medial joint space width > or =2mm, at least 10% of one cartilage surface of the medial compartment affected by superficial fibrillation or worse at baseline arthroscopy. STUDY MEDICATION: once daily dosage of either tenidap 40 mg, tenidap 120 mg or piroxicam 20mg. STUDY ENDPOINTS: bilateral extended weight-bearing X-rays and knee arthroscopy under local anaesthesia were done at entry and after 1 year. Joint space width was measured in millimeters at the narrowest point of the medial compartment. Chondropathy was scored by using reader's overall assessment (VAS score, 100mm) and Société Française d'Arthroscopie (SFA) score (0-100).

RESULTS

Patients (665) were randomized and 494 completed the study. After 1 year, intra-group radiological changes and radiological difference between both tenidap groups and the piroxicam group did not reach statistical significance. The intra-group arthroscopic deterioration of chondropathy was low, but statistically significant in the three study groups. However, there was no statistically significant difference between both tenidap groups and the piroxicam group.

CONCLUSIONS

This study failed to demonstrate any difference between the treatment arms with regard to the structural progression of medial knee osteoarthritis as measured by radiography and arthroscopy. Arthroscopy did, however, appears to be more sensitive in detecting disease progression than the weight-bearing radiographs with fully extended knees. This study shows that it is possible to complete a large international trial using arthroscopy as an outcome measure of articular cartilage.

Reproducibility and reliability of the outerbridge classification for grading chondral lesions of the knee arthroscopically

BACKGROUND

Few studies have investigated the accuracy and reproducibility of the Outerbridge classification system for classification of chondral damage in the knee.

HYPOTHESIS

Arthroscopically assigned Outerbridge grades are accurate, reliable, and reproducible.

STUDY DESIGN

Cadaver study.

METHODS

Six cadaveric knees underwent diagnostic arthroscopy, which was videotaped. An arthrotomy was then performed and the arthroscopically identified lesions were measured with calipers. Nine orthopaedic surgeons reviewed each video and graded each chondral lesion two separate times. Accuracy of observations was calculated based on the percentage of agreement between the grades determined during arthroscopy and arthrotomy.

RESULTS

The overall accuracy was 68% but varied by location. The kappa coefficient between the two scores was 0.602; the arthroscopy grade was higher than the arthrotomy grade 63% of the time. The intraobserver and interobserver kappa coefficients were 0.80 and 0.52, respectively. The mean interobserver kappa between the two physicians in practice 5 years or more was 0.72, compared with 0.50 for physicians in practice less than 5 years.

CONCLUSIONS

The Outerbridge classification was moderately accurate when used to grade chondral lesions arthroscopically.

CLINICAL RELEVANCE

Orthopaedic surgeons can accurately grade chondral lesions of the knee with the Outerbridge classification, regardless of their level of experience.

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.

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.

Chondral injuries

Chondral injures are present in up to 10 to 12% of all individuals. When symptomatic, chondral lesions manifest in knee pain, swelling, and loss of function. Cartilage loss may be partial or complete, and it may affect one or multiple locations. The natural history of untreated lesions most likely results in increased disability and progression of cartilage loss. Lesions are classified according to location, depth, and size. Nonsurgical treatment modalities include oral medications, injections, bracing, or physical therapy. Surgical treatment ranges from arthroscopic debridement to implantation of autologous chondrocytes beneath a periosteal patch covering the lesion. The patient's symptoms, age, activity level, and lesion characteristics must be considered and matched with a suitable procedure.

3-Foot standing AP versus 45 degrees PA radiograph for osteoarthritis of the knee

OBJECTIVE

Flexion and erect standing radiographs were evaluated in the current study to compare their sensitivity in detecting articular cartilage wear.

DESIGN

Prospective cohort study.

SETTING

A tertiary care hospital outpatient orthopedic clinic.

PATIENTS

All patients with osteoarthritis of the knee ages 40 to 75 scheduled for arthroscopic debridement between March 1995 and November 1997 were considered for the current study.

INTERVENTION

Radiographs were obtained 1 week preoperatively in both the 3-foot standing anteroposterior (AP) and a 45 degrees posteroanterior (PA) flexion weight-bearing projection. Joint space height was measured with a ruler in millimeters at the narrowest point of each compartment. All radiographs were assessed by two independent observers who were blinded to the arthroscopic findings and clinical symptoms of the subjects.

MAIN OUTCOME MEASURES

Prediction accuracy of each radiograph for severe Grade IV articular cartilage wear in tibio-femoral compartments.

RESULTS

One hundred fifty-two patients with a mean (+/- SD) age of 60.5+/-8.5 years were enrolled in the study. Fifty-one percent were female. Twelve patients were categorized as having severe lateral compartment articular chondropathy (Grade IV) at the time of arthroscopy. The lateral joint space height averaged 1.0+/-1.7 mm SD on the 45 degrees PA radiograph compared with 2.7+/-1.1 mm SD on the 3-foot standing AP view. Using a cutoff of 2 mm or less, the 45 degrees PA view was much more sensitive (83% versus 42%) at correctly detecting the most severe chondropathy. Forty-one patients were classified with severe Grade IV medial compartment chondropathy at arthroscopy. There was little difference in the average joint space height measured by the 45 degrees PA view (1.4+/-1.4 mm SD) or the 3-foot standing AP view (1.9+/-1.6 mm SD). A number of cutoff measures were evaluated, but no significant advantage could be found for either view in evaluating the medial compartment severity.

CONCLUSIONS

The bilateral 45 degrees PA is superior for detecting lateral compartment wear but offers no advantage on the medial side. This view should be considered as the screening radiograph of choice in evaluating osteoarthritis of the knee.

Update on outcome assessment in rheumatic disorders

Outcome assessment in rheumatic disorders is getting more and more attention. A series of Outcome Measures in Rheumatology (OMERACT) conferences has provided a good impulse for further research in the field. In this chapter we will review the results of the last OMERACT 4 conference in detail. This conference was focused on longitudinal/observational studies, rheumatoid arthritis (response criteria and imaging), and core sets for ankylosing spondylitis and systemic lupus erythematosus. Moreover, an overview of recent literature on measures of disease activity, quality of life measures, and imaging is presented. For the various rheumatic disorders, several new instruments and/or further validation steps are described.