Knee osteoarthritis: interpretation variability of radiological signs

Reproducibility assessment of different descriptions of the Kellgren and Lawrence classification for osteoarthritis of the knee

Objective

To assess the inter- and intraobserver reproducibility of the original version and different descriptions of the Kellgren and Lawrence classification used in epidemiological studies for osteoarthritis of the knee.

Methods

The study included 72 patients with osteoarthritis of the knee. Three medical members of the Brazilian Society of Knee Surgery were invited to evaluate the images. An intra- and interobserver analysis was conducted, with an interval of one month. The intraobserver agreement was analyzed using the weighted Cohen's Kappa coefficient. The interobserver agreement was analyzed using the Krippendorff alpha coefficient (α).

Results

The intraobserver assessment indicated conflicting results. In the interobserver analysis, the level of agreement was superficial.

Conclusions

The classification of Kellgren and Lawrence and its variants generated a low reproducibility between observers. The intraobserver analysis showed a lack of uniformity in the use of this classification and its variants, even among experienced observers.

Sensitivity of standing radiographs to detect knee arthritis: a systematic review of Level I studies

PURPOSE

The purpose of this study was to perform a systematic review of the available literature to define the level of quality evidence for determining the sensitivity and specificity of different radiographic views in detecting knee osteoarthritis and to determine the impact of different grading systems on the ability to detect knee osteoarthritis.

METHODS

A systematic review of the literature was conducted to identify studies that evaluated the standing anteroposterior (AP) and 45° posteroanterior (PA) views for tibiofemoral and patellofemoral arthritis and those comparing the use of the Kellgren-Lawrence versus the joint space narrowing (JSN) radiographic grading systems using arthroscopy as the gold standard. A comprehensive search of PubMed, Scopus, CINAHL, the Cochrane Database, Clinicaltrial.gov, and EMBASE was performed using the keywords "osteoarthritis," "knee," "x-ray," "sensitivity," and "arthroscopy."

RESULTS

Six studies were included in the evaluation. The 45° flexion PA view showed a higher sensitivity than the standing AP view for detecting severe arthritis involving either the medial or lateral tibiofemoral compartment. There was no difference in the specificities for the 2 views. The direct comparison of the Kellgren-Lawrence and the JSN radiographic grading systems found no clinical difference between the 2 systems regarding the sensitivities, although the specificity was greater for the JSN system.

CONCLUSIONS

The ability to detect knee osteoarthritis continues to be difficult without using advanced imaging. However, as an inexpensive screening tool, the 45° flexion PA view is more sensitive than the standing AP view to detect severe tibiofemoral osteoarthritis. When evaluating the radiograph for severe osteoarthritis using either the Kellgren-Lawrence or JSN grading system, there is no clinical difference in the sensitivity between the 2 methods; however, the JSN may be more specific for ruling in severe osteoarthritis in the medial compartment.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Comparative analysis between radiographic views for knee osteoarthrosis (bipedal AP versus monopedal AP)

Objective

A comparative analysis by applying the criteria of the original classification Ahlbäck in the anteroposterior (AP) bipedal knee in extension and anteroposterior (AP) monopodal knee in symptomatic knee arthrosis. With this analysis we intend to observe the agreement, any advantage or difference between the incidence and degree of joint involvement between the orthopedic surgeons and radiologists with the referring physician.

Methods

From January 2012 to March 2012, was a prospective study of 60 symptomatic arthrosis knees (60 patients), clinically selected group of outpatient knee and radiographic proposals submitted to the search. Of the 60 patients, 39 were female and 21 male, mean age 64 years (ranging from 50 to 84 years). Of the 60 knees studied, 37 corresponded to the right side and 23 on the left side. Statistical analysis was performed by Kappa statistics, which evaluates the interobserver agreement for qualitative data.

Results

According to the scale of Ahlbäck, there was a significant agreement (p < 0.0001) intra-observer in the classification of knee osteoarthritis among the five evaluators. There was a significant agreement (p < 0.0001) with inter-observer referring physician in the incidence of AP monopodal and AP bipedal for the four raters.

Conclusion

The study found no difference between the incidence in the AP monopodal versus AP bipedal in osteoarthritis of the knee.

Effect of long-term vigorous physical activity on healthy adult knee cartilage

INTRODUCTION

Whether participation in long-term vigorous physical activity affects knee cartilage is unclear and may depend on the state of knee health. We examined the association between vigorous physical activity during a decade and the subsequent changes in knee cartilage among healthy adults. We then examined whether this effect differed in those with and without bone marrow lesions (BMLs), as an indicator of preclinical joint damage.

METHODS

A total of 297 healthy adults age 50-79 yr were recruited. Physical activity was assessed via questionnaire at baseline (1990-1994) and at follow-up (2003-2004), and a score for persistence of vigorous physical activity score was determined. Each subject underwent knee magnetic resonance imaging in 2003-2004 and in 2006-2007. Cartilage volume, defects, and BMLs were measured using validated methods.

RESULTS

Persistent participation in vigorous physical activity was associated with worsening of medial knee cartilage defects (odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.0-2.3). In the subgroup with BMLs, but not in those without BML, persistent vigorous physical activity was associated with a significant worsening of medial knee cartilage defects (OR = 3.4, 95% CI = 1.0-16.5) and a trend toward an increased rate of loss of medial knee cartilage volume (21.6 mm·yr, 95% CI = -0.4 to 43.6).

CONCLUSIONS

In knees with BMLs, persistent participation in vigorous physical activity was associated with adverse cartilage changes in the medial compartment. This suggests that the long-term effects of vigorous physical activity may depend on the preexisting health of the joint.

Different thresholds for detecting osteophytes and joint space narrowing exist between the site investigators and the centralized reader in a multicenter knee osteoarthritis study--data from the Osteoarthritis Initiative

OBJECTIVE

To evaluate how the reading of knee radiographs by site investigators differs from that by an expert musculoskeletal radiologist who trained and validated them in a multicenter knee osteoarthritis (OA) study.

MATERIALS AND METHODS

A subset of participants from the Osteoarthritis Initiative progression cohort was studied. Osteophytes and joint space narrowing (JSN) were evaluated using Kellgren-Lawrence (KL) and Osteoarthritis Research Society International (OARSI) grading. Radiographs were read by site investigators, who received training and validation of their competence by an expert musculoskeletal radiologist. Radiographs were re-read by this radiologist, who acted as a central reader. For KL and OARSI grading of osteophytes, discrepancies between two readings were adjudicated by another expert reader.

RESULTS

Radiographs from 96 subjects (49 women) and 192 knees (138 KL grade ≥ 2) were included. The site reading showed moderate agreement for KL grading overall (kappa = 0.52) and for KL ≥ 2 (i.e., radiographic diagnosis of "definite OA"; kappa = 0.41). For OARSI grading, the site reading showed substantial agreement for lateral and medial JSN (kappa = 0.65 and 0.71), but only fair agreement for osteophytes (kappa = 0.37). For KL grading, the adjudicator's reading showed substantial agreement with the centralized reading (kappa = 0.62), but only slight agreement with the site reading (kappa = 0.10).

CONCLUSION

Site investigators over-graded osteophytes compared to the central reader and the adjudicator. Different thresholds for scoring of JSN exist even between experts. Our results suggest that research studies using radiographic grading of OA should use a centralized reader for all grading.

Comparison of MRI-based assessment systems for osteoarthritic knees: the irregularity index system and WORMS

PURPOSE

Several MRI-based evaluation systems for osteoarthritis (OA) of the knee have been developed. Among them the whole-organ magnetic resonance imaging score (WORMS), which evaluates the status of the entire knee joint, appears to be representative. We developed an irregularity index system to measure irregularities of the contours of the femoral condyle on MRI. Only the contour of the condyle was assessed by the irregularity index, whereas several items comprising the knee joint were taken into account by WORMS. This study compared the irregularity index and WORMS in terms of their correlations with clinical scores.

METHODS

Thirty-one medial-type OA knees were studied. Kellgren-Lawrence grading was used for X-ray grading: 8 were grade II, 11 were grade III, and 12 were grade IV. Japanese Orthopaedic Association scores and Japanese knee osteoarthritis measure scores were used for clinical assessments. We determined the correlations between MRI-based assessment scores and clinical scores.

RESULTS

Both the irregularity index and WORMS exhibited positive correlations with these clinical scores. The irregularity index was associated with bone cysts of the medial compartment and menisci in the articular features of WORMS.

CONCLUSIONS

These MRI-based methods are useful for evaluating OA severity. However, the irregularity index may have advantages over WORMS because of its semi-automatic features.

Imaging of knee osteoarthritis

New imaging modalities are broadening the possibilities in osteoarthritis (OA) research, and are offering new insights to help better understand the pathogenesis of this disease. Although knee radiographs are widely employed in epidemiological and clinical studies to assess structural pathology, joint radiographs provide limited outcome measures in knee OA, and other more valid, reliable and sensitive imaging modalities are now available. In particular, magnetic resonance imaging can directly visualize articular cartilage and other joint structures, such as bone and soft tissue, that are now recognized as part of the disease process. This chapter will examine imaging modalities in the assessment of knee OA, and the impact of these on our understanding of the pathogenesis of this disease.

Whole-Organ Arthroscopic Knee Score (WOAKS)

Background

To describe a semi-quantitative score for multi-feature, whole-organ evaluation of the knee in osteoarthritis based on the results of arthroscopic evaluation.

Methods

This was a study of 1,199 patients who were suffering from knee pain for over 3 months (range 3 to 48 months) and had undergone arthroscopy. The mean age of patients was 49.8 (range 17 to 85) years old. Cartilage lesions were graded according to the ICRS protocol (grade 0 to 4 and for osteophytes "grade 5"). Meniscus lesions were classified regarding to the extent of resection which was needed (grade 0: intact meniscus, grade 1: partial meniscectomy, grade 2: subtotal meniscectomy, and grade 3: total meniscectomy). The whole grade of cartilage lesions was calculated as the sum of ICRS grades in all joint surfaces (bearing and non-bearing margin). The whole grade of meniscus lesions was calculated as the sum of the points for medial and lateral meniscus surgery. The Whole-Organ Arthroscopic Knee Score (WOAKS) was the sum of the cartilage and meniscus score.

Results

The mean knee osteoarthritis outcome score (KOOS) of all patients was 67.3 ± 26.0 (range 21 to 128) points. The WOAKS was significantly associated (p = 0.001) with patient age (R = 0.399), the subjective complaints (R = 0.630) in KOOS, and the radiological grade of OA (R = 0.731).

Conclusion

The good correlation between the WOAKS and the subjective complaints as well as the radiological grade of OA suggests that the score can be used as an instrument for description of the "whole organ" knee. This score may be useful for clinical or epidemiological studies in the future.

Osteophytosis, subchondral bone sclerosis, joint effusion and soft tissue thickening in canine experimental stifle osteoarthritis: comparison between 1.5 T magnetic resonance imaging and computed radiography

OBJECTIVE

To compare use of 1.5 T magnetic resonance imaging (MRI) and computed radiography (CR) for morphologic and temporal evaluation of osteophytosis, subchondral sclerosis, joint effusion, and synovial thickening in experimentally induced canine stifle osteoarthritis (OA).

STUDY DESIGN

Prospective study.

ANIMALS

Dogs (n=8).

METHODS

CR (mediolateral and caudocranial projections) and MRI (dorsal 3D T1-weighted gradient echo, sagittal 3D SPGR and T2-weighted fast spin echo with fat saturation) were performed at baseline (n=8) and at week 4 (n=5), week 8 (n=8), and week 26 (n=5) after cranial cruciate ligament transection. Osteophytosis, subchondral bone sclerosis, and joint effusion were scored on CR and MRI, and synovial thickening on MRI.

RESULTS

MRI was more sensitive than CR for detection of osteophytosis and could better discriminate joint effusion from soft tissue thickening, although scores for these variables strongly correlated between modalities (rho=0.94 [osteophytosis] and 0.80 [effusion]; P<.001). Scores for subchondral bone sclerosis also correlated (rho=0.54, P<.004), although this variable may have been over interpreted on CR. Joint effusion and synovial thickening peaked at week 8, before partially regressing at week 26. Conversely, osteophytosis and sclerosis progressed semi-linearly over 26 weeks.

CONCLUSION

MRI is more sensitive than radiography in assessing onset and progression of osteophytosis in canine experimental stifle OA and provides enhanced discrimination between joint effusion and synovial thickening.

CLINICAL RELEVANCE

MRI is as a more powerful imaging modality that should be increasingly used in animals to assess the joint related effects of disease-modifying OA drugs.

Effect of physical activity on articular knee joint structures in community-based adults

OBJECTIVE

It is unclear whether physical activity that is beneficial for the cardiovascular system is detrimental to knee structures. We examined the association between intensity, frequency, and duration of physical activity and knee structures in a community-based population.

METHODS

A total of 297 healthy adults ages 50-79 years with no history of knee injury or disease were recruited from an existing study on healthy aging. Each subject underwent knee magnetic resonance imaging (MRI) to measure tibial cartilage volume, tibiofemoral cartilage defects, and bone marrow lesions. Physical activity and anthropometric data were obtained via questionnaire during 1990-1994 and 2003-2004.

RESULTS

Tibial cartilage volume increased with frequency (P = 0.01) and duration (P = 0.001) of vigorous activity (activity leading to diaphoresis or dyspnea) reported 10 years previously, as well as recent vigorous activity in the 7 days prior to MRI (P = 0.05). Recent weight-bearing vigorous activity increased with tibial cartilage volume (P = 0.02) and was inversely associated with cartilage defects (P = 0.02). A reduced risk of bone marrow lesions was associated with regular walking (P = 0.04).

CONCLUSION

Vigorous physical activity appears to have a beneficial effect on knee articular cartilage in healthy, community-based adults with no history of knee injury or disease. Regular walking reduces the risk of bone marrow lesions in the knee. This study provides further support for a beneficial effect of physical activity for diseases associated with aging and suggests that exercise that is good for the heart is also good for the knees.

Separation of healthy and early osteoarthritis by automatic quantification of cartilage homogeneity

OBJECTIVE

Cartilage loss as determined either by magnetic resonance imaging (MRI) or by joint space narrowing in X-rays is the result of cartilage erosion. However, metabolic processes within the cartilage that later result in cartilage loss may be a more accurate assessment method for early changes. Early biological processes of cartilage destruction are among other things, a combination of proteoglycan turnover, as a result of altered charge distributions, and local alterations in water content (edema). As water distribution is detectable by MRI, the aim of this study was to investigate cartilage homogeneity visualized by MRI related to water distribution, as a potential very early marker for early detection of knee osteoarthritis (OA).

DESIGN

One hundred and fourteen right and left knees from 71 subjects aged 22-79 years were scanned using a Turbo 3D T(1) sequence on a 0.18T MRI Esaote scanner. The medial compartment of the tibial cartilage sheet was segmented using a fully automatic voxel classification scheme based on supervised learning. From the segmented cartilage sheet, homogeneity was quantified by measuring entropy from the distribution of signal intensities inside the compartment. For each knee an X-ray was acquired and the knees were categorized by the Kellgren and Lawrence (KL) index and the joint space width (JSW) was measured. The P-values for separating the groups by each of JSW, cartilage volume, cartilage mean intensity, and cartilage homogeneity were calculated using the unpaired t-test.

RESULTS

The P-value for separating the group diagnosed as KL 0 from the group being KL 1 based on JSW, volume and mean signal intensity the values were P=0.9, P=0.4 and P=0.0009, respectively. In contrast, the P-value for homogeneity was P=0.0004. The precision of the measures assessed, as a test-retest root mean square coefficient of variation (RMS-CV%) was 3.9% for JSW, 7.4% for volume, 3.9% for mean signal intensity and 3.0% for homogeneity quantification.

CONCLUSION

These data demonstrate that the distribution of components of the articular matrix precedes erosion, as measured by cartilage homogeneity related to water concentration. We show that homogeneity was able to separate early OA from healthy individuals in contrast to traditional volume and JSW quantifications. These data suggest that cartilage homogeneity quantification may be able to quantify early biochemical changes in articular cartilage prior to cartilage loss and thereby provide better identification of patients for OA trials who may respond better to medicinal intervention of some treatments. In addition, this study supports the feasibility of using low-field MRI in clinical studies.

Automatic morphometric cartilage quantification in the medial tibial plateau from MRI for osteoarthritis grading

OBJECTIVE

To evaluate whether a novel, fully automatic, morphometric cartilage quantification framework is suitable for assessing level of knee osteoarthritis (OA) in clinical trials.

METHOD

The population was designed with a normal population and groups with varying degree of OA of both sexes and at ages from 21 to 78. Posterior-anterior X-rays were acquired in semi-flexed, load-bearing position. The radiographic signs of OA were evaluated based on the Kellgren and Lawrence score (KL) and the joint space width (JSW) was measured. Turbo 3D T1 magnetic resonance imaging (MRI) scans were acquired with resolution 0.7x0.7x0.8mm(3) from a 0.18T scanner. The morphometric cartilage quantification from MRI resulted in volume, surface area, thickness and surface curvature for the medial tibial cartilage compartment. These quantifications were evaluated against JSW with respect to precision and ability to separate healthy subjects from OA subjects.

RESULTS

The automatic, morphometric cartilage quantifications allowed fairly precise measurements with scan-rescan coefficient of variations (CVs) in the range from 3.4% to 6.3%. All quantifications, including JSW, allowed separation of the groups of healthy and OA subjects. However, for separation of the healthy from the borderline cases (KL 0 vs KL 1), only the Cartilage Curvature quantification allowed statistically significant separation (P<0.01).

CONCLUSION

The novel morphometric framework shows promise for use in clinical trials. The ability of the Cartilage Curvature quantification to detect the early stages of OA and the effectiveness of the focal thickness Q10 measure are particularly noteworthy. Furthermore, these results may indirectly support that low-field MRI may be a low-cost option for clinical trials.

Irregularity of medial femoral condyle on MR imaging serves as a possible indicator of objective severity of medial-type osteoarthritic knee-a pilot study

Irregularly described contour of the femur and the tibia on magnetic resonance (MR) imaging is commonly seen in osteoarthritic (OA) knees. The aim of this study is to examine the relationship between irregularity of contour of medial femoral condyle (tentatively named I-index) and severity of OA. Twenty-six medial-type OA knees with a mean age of 63.8 were studied. All patients had undergone MR imaging to measure the I-index using image analysis software, and its relationship to Lysholm score was examined. The I-index negatively correlated with Lysholm score (r = -0.55, p < 0.01). The I-index for each Kellgren and Lawrence grade was significantly different. We have concluded that the I-index is a potent indicator to objectively describe the severity of OA especially for the advanced stage OA.

Comparison of proprioceptive functions between computerized proprioception facilitation exercise and closed kinetic chain exercise in patients with knee osteoarthritis

AIM

The aim of this study was to compare proprioceptive function between computerized proprioception facilitation exercise (CPFE) and closed kinetic chain exercise (CKCE) for knee osteoarthritis.

DESIGN

Randomized-controlled.

SETTING

Kinesiology laboratory.

PATIENTS

Eighty-one patients with bilateral knee osteoarthritis were randomly assigned to CPFE, CKCE, and control groups.

INTERVENTION

Both exercise groups underwent an 8-week program of three sessions per week. The control group received no training. The CPFE program included a 20-min computer game to be played by the trained foot of the subject. CKCE included 10 sets of 10 repetitions of repeated knee extension and flexion with resistance of 10-25% of body weight.

MAIN OUTCOME MEASURES

Absolute reposition error, functional score, walking speed, and knee muscle strength were assessed with an electrogoniometer, the physical function subscale of Western Ontario and McMaster Osteoarthritis Index, a CASIO stopwatch, and a Cybex 6000 dynamometer before and after the 8-week period.

RESULTS

The results of this study showed that both CPFE and CKCE were effective in improving joint position sense, functional score, walking speed, and muscle strength. Furthermore, CKCE showed greater effect in increasing knee extensor torque in patients with knee osteoarthritis.

CONCLUSION

Clinical effects of CPFE were the same as those of CKCE except for knee extensor torque. The increase in knee extensor torque in CPFE patients was not as great as that seen in CKCE patients.

Cartilage volume quantification via Live Wire segmentation

RATIONALE AND OBJECTIVES

A reduction in cartilage volume is characteristic of osteoarthritis and hence there exists a need for an accurate and reproducible method to measure in vivo cartilage volume. Quantification of cartilage volume from magnetic resonance (MR) images requires a segmentation technique such as the user-driven "Live Wire" strategy that can reliably delineate object volumes in a time-efficient manner. In the present work, the accuracy and reproducibility of the Live Wire method for the quantification of cartilage volume in MR images is evaluated.

MATERIALS AND METHODS

The accuracy of the Live Wire method was assessed by comparing the MR-based volume measurement of a patellar cartilage-shaped phantom versus data calculated via water displacement. The inter- and intra-operator reproducibility of the technique was evaluated from Live Wire segmentation of the patellar cartilage volume from fat-suppressed 3-dimensional spoiled-gradient-echo images of five healthy human volunteers performed by three operators. To provide data for analysis of inter-scan reproducibility, the human scans were repeated five times with the aid of a leg-restraining jig to minimize repositioning error.

RESULTS

The volume of the patellar cartilage-shaped phantom measured via Live Wire segmentation of MR images was within 97.8% of its true volume. The average inter- and intra-operator coefficients of variation of three operators were 3.0% and 0.4%, respectively. The average inter-scan coefficient of variation of five repeated scans of each volunteer was 2.7%.

CONCLUSION

The data suggest that the Live Wire strategy is an accurate, reproducible, and efficient technique to measure cartilage volume in vivo in a feasible amount of operator time.