Radiographic Grading Of Knee Osteoarthritis Research Articles

Study of Relationship between Bone Mineral Density in Ipsilateral Proximal Femur and Severity of Osteoarthritis of Knee.

Introduction:Osteoarthritis (OA) of the knee is the most common rheumatic disease that is characterized by degradation of articular cartilage, subchondral bone alteration, meniscal degeneration, synovial inflammatory response, and overgrowth of bone and cartilage. In severe OA, the reduced mobility caused by pain can increase bone loss and reduction of bone mineral density leading to osteoporosis.Objective:To examine the possible relationship between severity of osteoarthritis (OA) and bone mineral density (BMD) by evaluating the bone mineral density in ipsilateral proximal femur and radiographic grading of knee OA in the Indian population.Methods:In this cross-sectional observational study, 100 subjects diagnosed with OA knee using ACR criteria were enrolled. Severity of OA knee was assessed using Kellgren-Lawrence scale (1 to 4) on weight-bearing radiographs. The BMD, T-score, and Z-score of the ipsilateral proximal femur was measured by dual-energy X-ray absorptiometry. Pearson’s correlation coefficient was used to test the association of severity of OA knee with BMD.Results:Among 100 subjects, there were 51 females and 49 males with mean age 59.94 ± 6.67. Maximum patients were with K-L grade 2 (42%) followed by grade 3 (30%) and grade 4 (22%). There was statistically significant (p < 0.0001) association between BMD and severity of OA knee. BMD decreased as the K-L grade of OA knee increased from 1 to 4. Similar statistically significant association was observed in T-score and Z-score.Conclusion:The study concluded that BMD of ipsilateral proximal femur decreases with severity of OA knee. These data support the fact that the two conditions may be related to each other and primary care physicians must look for these two conditions in coexistence. Primary prevention of either of the two conditions should be advised, if the other condition coexists in the same patient.

Serum Calprotectin as a Blood-Based Biomarker for Monitoring Knee Osteoarthritis at Early but Not Late Stages.

The identification of early-stage osteoarthritis (OA) is crucial for the deceleration of its progression; however, no reliable biomarker is available for this purpose. The current study aimed to determine the role of serum calprotectin in the detection of early-stage knee OA. In a case-control study, serum samples were collected from 84 patients with primary bilateral knee OA and 52 healthy controls. The radiographic grading of knee OA was performed using the Kellgren-Lawrence classification system. Serum concentrations of calprotectin were measured using an enzyme-linked immunosorbent assay. The mean serum calprotectin level was 2908 ± 2516 ng/mL in OA patients and 901 ± 875 ng/mL in healthy control subjects (P < 0.001). Mean serum calprotectin levels were significantly higher in the lower stages of OA: 3740 ± 2728 ng/mL in OA grade I, 3100 ± 2084 ng/mL in OA grade II, 2246 ± 1418 ng/mL in OA grade III, and 2035 ± 765 ng/mL in OA grade IV (P = 0.047). Serum calprotectin levels were significantly higher in patients with a disease duration <42 months compared with those with a disease duration >42 months (P = 0.043). Serum calprotectin level increases significantly in the early stages of OA and shows a reverse association with disease severity. Therefore, it could be suggested as a promising blood-based marker for early-stage knee OA.

Can We Predict Severity of Osteoarthritis of Knees and Compartmental Involvement Based on a Set of Predefined Clinical Questions in Patients of Knee Pain?

We investigated whether the severity of Osteoarthritis (OA) knees can be predicted based on a set of predefined clinical questions (PCQs) about activities of daily living (ADL). We studied the association of demographic factors and advanced radiographic OA (KL 3 and 4) and the relationship between various physical activities and radiographic involvement of knee joint compartments based on PCQs. Demographic data, radiographic grading of knee OA and PCQs score, were obtained prospectively. Patients' responses to PCQs were marked as scores-that were predefined and graded according to the severity of knee pain. Radiographic knee OA grades were dichotomized and patients were classified as either negative (KL grade 1, 2) or positive (KL grade 3, 4). Multivariate logistic regression was performed to obtain the adjusted odds for total PCQs score in relation with positive radiographic OA considering confounders like age, gender and BMI in the model. Log odds score (LOS) were obtained and ROC analysis was performed on scores to obtain the cut-off value for the screening of knee OA in patients of knee pain. Age and BMI were significantly negatively correlated with PCQs score (r = - 0.473; P < 0.0001 and r = - 0.136; P = 0.046). PCQs scores were significantly lower in females (P = 0.031). Total PCQs score had corresponding OR of 0.901 (P = 0.002) towards knee OA after adjusting for age, gender and BMI. Multivariate model-based LOS resulted in a cut-off of 1.315, which had a sensitivity of 85.5%, specificity of 66.7% and PPV of 92.7%. Severity of knee OA can be predicted based on PCQs. PCQs can predict severity of knee OA and patellofemoral or medial tibiofemoral compartment without radiographs. LOS based on demographics and total PCQs score can be developed as a screening tool for advanced knee OA.

Association of leg muscle symmetry with knee osteoarthritis.

This study aimed to evaluate the relationship of leg muscle symmetry to the prevalence, radiographic grade, and symptoms of knee osteoarthritis (OA). We conducted a cross-sectional study using data from the Korean National Health and Nutrition Examination Survey (KNHANES), collected in 2010 and 2011. Men and women aged 60years or older were included. Leg muscle mass was measured using dual-energy X-ray absorptiometry, and the muscle asymmetry index was defined as ∣(left leg muscle mass)/(left and right leg muscle mass) × 100 - 50∣. Statistical analyses were performed to examine the relationships between the muscle asymmetry index and the radiographic grade and knee symptoms. A total of 2548 subjects were included in the analysis. The muscle asymmetry index was positively associated with radiographic knee OA grade and knee pain, especially in men. Men with knee OA and the highest quartile of muscle asymmetry index were 3.3 times more likely to have knee pain compared with those in the lowest quartile. When subjects were divided into four groups by body mass index (BMI) and muscle asymmetry index, subjects with asymmetric obese and men with asymmetric normal BMI had worse grade of radiographic knee OA. Leg muscle asymmetry in men, irrespective of obesity, was associated with significantly higher grade of radiographic knee OA and prevalent knee pain. Longitudinal studies will be needed to determine the cause-and-effect relationship and to determine whether the higher or lower mass, beyond the asymmetry, is associated with radiographic severity or symptomatic knee OA.Key Points•Leg muscle asymmetry was related to prevalence and radiographic severity of knee OA, especially in men.•Leg muscle asymmetry was associated with knee pain.•Those with both leg muscle asymmetry and obesity showed higher prevalence of knee pain and worse radiographic knee OA.

Characteristics of individual thigh muscles including cross-sectional area and adipose tissue content measured by magnetic resonance imaging in knee osteoarthritis: a cross-sectional study.

This study aimed to identify the parameters related to the area and adipose tissue content of thigh muscles that are associated with radiographic knee osteoarthritis grade. Fifty patients (mean age ± standard deviation, 73.0 ± 4.5years) were divided into early osteoarthritis (n = 23) and established osteoarthritis (n = 27) groups based on Kellgren-Lawrence classification. The femorotibial angle was measured from anteroposterior radiographs of the lower limbs. Individual thigh muscle and adipose tissue areas were analyzed using axial T1-weighted magnetic resonance imaging. After intergroup comparison, logistic regression analysis was performed to determine independent parameters associated with established osteoarthritis. Moreover, correlation coefficients were assessed between the left-right differences of osteoarthritis grade and parameters. Established osteoarthritis exhibited a significantly greater femorotibial angle and increased adipose tissue content in the subcutaneous, intermuscle, and intramuscle of the adductor, vastus lateralis, vastus intermedius, as well as a lower vastus medialis area, in comparison to early osteoarthritis. A greater femorotibial angle, increased intermuscular adipose tissue, and a lower vastus medialis area to knee extensor ratio were significantly independently associated with established osteoarthritis (odds ratio 3.2, 1.8, and 2.0, respectively). The left-right differences of femorotibial angle and vastus medialis area were significantly correlated with osteoarthritis grade, whereas adipose tissue content had no significant correlations with osteoarthritis grade. Greater femorotibial angle and lower vastus medialis area were related with higher osteoarthritis grade. Greater intermuscular adipose tissue content was associated with established osteoarthritis; however, in the left-right differences, adipose tissue content was not related with osteoarthritis grade.

Factors associated with knee pain in 5148 women aged 50 years and older: A population-based study.

ObjectiveThis study was performed to investigate the factors associated with the level of knee pain in a nationally representative sample of noninstitutionalized women aged 50 years or older.MethodsWomen aged 50 years or older were selected and included in the data analyses from the Korean National Health and Nutrition Examination Surveys (2010–2013). Those having malignant diseases or using osteoarthritis medication were excluded. Significant factors associated with the level of knee pain were analyzed using multivariate regression analysis.ResultsA total of 5148 women (average age, 62.9 years; standard deviation, 9.3 years) were included. For women without knee osteoarthritis, level of hip pain (p<0.001), presence of back pain (p<0.001), age (p<0.001), and body mass index (BMI) (p<0.001) were found to be significant factors associated with the level of knee pain. For women with knee osteoarthritis, the radiographic grade of knee osteoarthritis (p<0.001), presence of back pain (p<0.001), level of hip pain (p<0.001), presence of depressive symptoms (p<0.001), and BMI (p = 0.026) were the factors significantly associated with the level of knee pain.ConclusionsWomen without knee osteoarthritis tended to report increasing knee pain with increasing age. BMI is considered a significant controllable factor in knee pain in women regardless of the presence of radiographic knee osteoarthritis. The presence of depressive symptoms may aggravate knee pain in women with knee osteoarthritis. Attention needs to be focused on concomitant musculoskeletal problems such as lumbar spinal and hip diseases in women with knee pain.

Nottingham health profile assessment of health-related quality of life in primary knee osteoarthritis patients: Relation to clinical features and radiologic score

Aim of the workTo evaluate the Nottingham Health Profile (NHP) assessment of health-related quality of life (HRQoL) in primary knee osteoarthritis (KOA) patients and to determine its relationships with clinical and radiological measures. Patients and methodsThis study included 50 primary KOA patients and 25 matched healthy controls. All were assessed by NHP-HRQoL, visual analog scale (VAS) for pain in rest and activity, 15-m walk test for physical performance and knee joint range of motion (ROM). Radiographic grading of KOA was scored using Kellgren–Lawrence (K-L) score. ResultsThe 50 KOA patients were 33 (66%) females and 17 (34%) males with mean age of 43.3 ± 8.6 years and BMI of 32.2 ± 3.7. The VAS at rest was 2.6 ± 2.1, during motion was 6.2 ± 2.1, the 15-m test 22.6 ± 3.6 s, ROM active flexion 122.9 ± 10.8 and in passive flexion 132.1 ± 11.1. All NPH subscales (physical mobility, pain, energy level, sleep and emotional reaction) except social isolation showed significantly higher scores in KOA patients compared to controls and tended to be higher in females. There were significant correlations between NHP subscales with age, VAS-rest, VAS-activity, knee flexion and degree of incomplete extension, walk test, also with K-L score. ConclusionThe NPH-HRQoL is affected in Egyptian patients with primary KOA and may be used as a measure to reflect pain, physical performance and radiographic severity. Physical mobility, pain, sleep, energy, and emotional reactions items were obviously reported except social isolation domain attributed to different cultures and morals of eastern communities.

Relationship between Radiographic Grading of Knee Osteoarthritis and Functional Limitation in Elderly Patients

Relationship between Radiographic Grading of Knee Osteoarthritis and Functional Limitation in Elderly Patients

Serum levels of the bone turnover markers dickkopf-1, osteoprotegerin, and TNF-α in knee osteoarthritis patients.

Knee osteoarthritis (KOA) is a common degenerative joint disease causing pain, stiffness, reduced motion, swelling, crepitus, and disability. Several inflammatory markers and cartilage degradation products can be used as biomarkers in OA. The key factors of bone metabolism in normal joint bone, dickkopf-1 (DKK1) and osteoprotegerin (OPG), interact with Wnt signaling pathway, balancing between bone absorption and bone reconstruction. TNF-α is a key inducer of DKK-1, which belongs to the family of proteins involved in joint remodeling. The present study compared the serum levels of DKK1, TNF-α, and OPG in patients with KOA and healthy controls to analyze the interrelationship and the severity of joint destruction. One hundred forty-eight patients with KOA and 101 healthy controls were enrolled in this study. Anteroposterior knee radiographs determined the severity of the disease in the affected knee. The radiographic grading of KOA was performed by the Kellgren-Lawrence criteria. Serum levels of DKK-1, TNF-α, and OPG were estimated using the multiplex particle-based flow cytometry. Higher serum levels of OPG and TNF-α were observed in KOA than the controls; KOA patients showed a lower serum level of DKK-1, whereas the serum levels of DKK1 correlated with the progression of KOA. The serum levels of TNF-α, OPG, and DKK-1 correlated with incident KOA. In the ROC curve analysis, DKK1 levels showed 78.6% sensitivity and 40% specificity, TNF-α levels showed 74.1% sensitivity and 76.0% specificity, and OPG showed 88.1% sensitivity and 81% specificity in predicting severe KOA. In the univariate and multivariate analyses, TNF-α and OPG emerged as independent predictors of severe KOA. This study, for the first time, combined TNF-α, DKK1, and OPG as valuable biological markers in predicting the severity of KOA radiographically in the clinic. This study also supported the inflammation-induced DKK1 and OPG in OA pathogenesis.

Association of mechanical factors with medial knee osteoarthritis: Across-sectional study from Matsudai Knee Osteoarthritis Survey.

Knee osteoarthritis (OA) is a multifactorial disease that is affected by mechanical factors. The aim of present study was to investigate the association between multiple mechanical factors and medial knee OA in a large epidemiological cohort. Six hundred and ninety-nine subjects (323 males and 376 females), participating in the Matsudai Knee Osteoarthritis Survey 2010, were included. Twelve mechanical factors were selected and their association with the radiographic grade of knee OA, the Western Ontario and McMaster University Index (WOMAC) pain score, and the WOMAC function score was evaluated. A logistic regression analysis identified varus thrust to be associated with the radiographic grade of knee OA in males (OR: 1.876, 95% CI: 1.332-2.663) and females (2.61, 1.922-3.542), the WOMAC pain score in males (1.997, 1.463-2.672), and the WOMAC function score in females (1.449, 1.12-1.874). Quadriceps muscle strength was associated with the radiographic OA grade in males (0.605, 0.399-0.917) and females (0.636, 0.469-0.863), the WOMAC pain score in females (0.537, 0.445-0.789), and the WOMAC function score in males (0.581, 0.44-0.766). The knee flexion angle was also associated with the radiographic OA grade in males (0.344, 0.19-0.621) and females (0.121, 0.022-0.653), and the WOMAC pain score in males (0.287, 0.156-0.53) and females (0.537, 0.336-0.859). Obesity was associated with the radiographic OA grade in males (1.543, 1.041-2.287) and females (1.589, 1.176-2.146), the WOMAC pain score in female (2.017, 1.517-2.68). Femolo-tibial angle had no significant association with the radiographic knee OA grade or with the WOMAC pain and function scores. Among patients with medial knee OA, dynamic mechanical factors, such as varus thrust, quadriceps muscle strength, and range of motion were more likely to be associated with the radiographic grade of knee OA and to be the WOMAC pain and function scores, compared to static mechanical factors.

Association of mechanical factors with medial knee osteoarthritis: A cross-sectional study from Matsudai Knee Osteoarthritis Survey

Abstract Background Knee osteoarthritis (OA) is a multifactorial disease that is affected by mechanical factors. The aim of present study was to investigate the association between multiple mechanical factors and medial knee OA in a large epidemiological cohort. Methods Six hundred and ninety-nine subjects (323 males and 376 females), participating in the Matsudai Knee Osteoarthritis Survey 2010, were included. Twelve mechanical factors were selected and their association with the radiographic grade of knee OA, the Western Ontario and McMaster University Index (WOMAC) pain score, and the WOMAC function score was evaluated. Results A logistic regression analysis identified varus thrust to be associated with the radiographic grade of knee OA in males (OR: 1.876, 95% CI: 1.332–2.663) and females (2.61, 1.922–3.542), the WOMAC pain score in males (1.997, 1.463–2.672), and the WOMAC function score in females (1.449, 1.12–1.874). Quadriceps muscle strength was associated with the radiographic OA grade in males (0.605, 0.399–0.917) and females (0.636, 0.469–0.863), the WOMAC pain score in females (0.537, 0.445–0.789), and the WOMAC function score in males (0.581, 0.44–0.766). The knee flexion angle was also associated with the radiographic OA grade in males (0.344, 0.19–0.621) and females (0.121, 0.022–0.653), and the WOMAC pain score in males (0.287, 0.156–0.53) and females (0.537, 0.336–0.859). Obesity was associated with the radiographic OA grade in males (1.543, 1.041–2.287) and females (1.589, 1.176–2.146), the WOMAC pain score in female (2.017, 1.517–2.68). Femolo-tibial angle had no significant association with the radiographic knee OA grade or with the WOMAC pain and function scores. Conclusion Among patients with medial knee OA, dynamic mechanical factors, such as varus thrust, quadriceps muscle strength, and range of motion were more likely to be associated with the radiographic grade of knee OA and to be the WOMAC pain and function scores, compared to static mechanical factors.

Serum and synovial fluid levels of CCL18 are correlated with radiographic grading of knee osteoarthritis.

BackgroundChemokines are involved in the pathogenesis of osteoarthritis (OA). CCL18, a member of the chemokines family, is observed in synovial fluid (SF) of OA patients. The aim of this study was to determine the association between CCL18 levels in serum and SF with radiographic knee OA.Material/MethodsThis study was conducted in a population of 308 patients with knee OA. The radiological knee OA was graded by the Kellgren-Lawrence grading system.ResultsSerum levels of CCL18 in knee OA patients were markedly higher than those in healthy controls. Serum and SF levels of CCL18 increased with the severity of KL grades and were correlated with disease severity.ConclusionsThe CCL18 levels in serum and SF are correlated with the severity of OA.

Levels of neuropeptide Y in synovial fluid relate to pain in patients with knee osteoarthritis

The precise etiology of knee osteoarthritis (KOA) pain remains highly controversial and there is no known effective treatment. Due to the known and suggested effects of neuropeptide Y (NPY) on pain, we have sought to investigate the relationship between the concentration of NPY in synovial fluid of knee, pain of KOA, and structural severity of KOA. One hundred KOA patients and twenty healthy participants (control group) were recruited. The pain and the radiographic grade of KOA were assessed separately by Hideo Watanabe’s pain score and Tomihisa Koshino’s scoring system. Synovial fluid of knee from all participants was collected with arthrocentesis. Radioimmunoassay was used to examine the concentration of NPY in synovial fluid of knee. Concentrations of NPY in synovial fluid were significantly higher in KOA patients (124.7 ± 33.4 pg/mL) compared with controls (64.8 ± 26.3 pg/mL) (p = 0.0297). According to Hideo Watanabe’s pain score, 100 KOA patients were divided into 5 subgroups: no pain (n = 12), mild pain (n = 25), moderate pain (n = 37), strong pain (n = 19) and severe pain (n = 7). Within the KOA group, significantly higher concentrations of NPY were found in each subgroup as pain intensified (no pain 81.4 ± 11.7 pg/mL, mild pain 99.1 ± 23.2 pg/mL, moderate pain 119.9 ± 31.5 pg/mL, strong pain 171.2 ± 37.3 pg/mL and severe pain 197.3 ± 41.9 pg/mL). Meanwhile, according to Tomihisa Koshino’s scoring system, 100 KOA patients were divided into 3 subgroups: early stage (n = 30), middle stage (n = 53), advanced stage (n = 17). Concentrations of NPY in middle and advanced stage groups of KOA patients were significant higher than early stage group of KOA patients (early stage 96.4 ± 27.1 pg/mL, middle stage 153.3 ± 16.9 pg/mL, advanced stage 149.5 ± 36.7 pg/mL) (p = 0.0163, p = 0.0352). Concentrations of NPY in advanced stage group of KOA patients has no significant difference compare with middle stage group of KOA patients (p = 0. 2175). This study demonstrated the presence and variation of concentrations of NPY in the KOA joint fluid, suggesting a role for NPY as a putative regulator of pain transmission and perception in KOA pain.

Levels of neuropeptide Y in synovial fluid relate to pain in patients with knee osteoarthritis.

BackgroundThe precise etiology of knee osteoarthritis (KOA) pain remains highly controversial and there is no known effective treatment. Due to the known and suggested effects of neuropeptide Y (NPY) on pain, we have sought to investigate the relationship between the concentration of NPY in synovial fluid of knee, pain of KOA, and structural severity of KOA.MethodsOne hundred KOA patients and twenty healthy participants (control group) were recruited. The pain and the radiographic grade of KOA were assessed separately by Hideo Watanabe’s pain score and Tomihisa Koshino’s scoring system. Synovial fluid of knee from all participants was collected with arthrocentesis. Radioimmunoassay was used to examine the concentration of NPY in synovial fluid of knee.ResultsConcentrations of NPY in synovial fluid were significantly higher in KOA patients (124.7 ± 33.4 pg/mL) compared with controls (64.8 ± 26.3 pg/mL) (p = 0.0297). According to Hideo Watanabe’s pain score, 100 KOA patients were divided into 5 subgroups: no pain (n = 12), mild pain (n = 25), moderate pain (n = 37), strong pain (n = 19) and severe pain (n = 7). Within the KOA group, significantly higher concentrations of NPY were found in each subgroup as pain intensified (no pain 81.4 ± 11.7 pg/mL, mild pain 99.1 ± 23.2 pg/mL, moderate pain 119.9 ± 31.5 pg/mL, strong pain 171.2 ± 37.3 pg/mL and severe pain 197.3 ± 41.9 pg/mL). Meanwhile, according to Tomihisa Koshino’s scoring system, 100 KOA patients were divided into 3 subgroups: early stage (n = 30), middle stage (n = 53), advanced stage (n = 17). Concentrations of NPY in middle and advanced stage groups of KOA patients were significant higher than early stage group of KOA patients (early stage 96.4 ± 27.1 pg/mL, middle stage 153.3 ± 16.9 pg/mL, advanced stage 149.5 ± 36.7 pg/mL) (p = 0.0163, p = 0.0352). Concentrations of NPY in advanced stage group of KOA patients has no significant difference compare with middle stage group of KOA patients (p = 0. 2175).ConclusionsThis study demonstrated the presence and variation of concentrations of NPY in the KOA joint fluid, suggesting a role for NPY as a putative regulator of pain transmission and perception in KOA pain.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-319) contains supplementary material, which is available to authorized users.

Plasma and synovial osteopontin levels, are they associated with disease severity of primary knee osteoarthritis in Egyptian patients?

Aim of the workThe aim of this study was to examine osteopontin (OPN) levels in both plasma and synovial fluid of patients with primary knee osteoarthritis (OA) and to investigate their relationship with severity of the disease. Patients and methodsFifty patients with primary knee OA were compared to twenty-five apparently healthy controls. OPN levels in plasma and synovial fluid were measured using enzyme-linked immunosorbent assay. Severity of knee pain was assessed by the Western Ontario and McMaster Universities osteoarthritis index. Radiographic grading of knee OA was performed by Kellgren–Lawrence criteria. Magnetic resonance imaging (MRI) was also performed on painful knees. ResultsPlasma OPN was higher in patients (159.65±28.56ng/ml) than controls (90.45±23.63ng/ml). OPN in plasma and synovial fluid was correlated with severity of knee pain (r=0.878, r=0.795, P<0.001). Cartilage loss, marginal osteophytes and subchondral bone cyst were the commonest MRI findings in knee OA. MRI detected also patients with early knee OA that were not detected by plain radiography. ConclusionOPN serves as a biochemical marker of disease severity in knee OA. It also could be predictive to the progression of disease.

SAT0330 Sclerostin concentrations in plasma and synovial fluid inversely correlate with disease severity in knee osteoarthritis

BackgroundOsteoarthritis (OA) is characterized by the progressive destruction of articular cartilage with joint space narrowing and osteophyte formation (1). Although the etiology and pathogenesis of OA remain poorly understood, recent...

Proteomic analysis of synovial fluid: insight into the pathogenesis of knee osteoarthritis

We conducted a proteomic analysis of synovial fluid (SF) to identify differentially expressed proteins and analyse their correlation with osteoarthritis (OA) severity. Our primary purpose was to gain insight into the pathogenesis of OA. SF samples were acquired from 12 knee OA patients and 12 non-OA controls (ten had a meniscus injury, two had a discoid meniscus and all exhibited intact articular cartilage) and sequentially subjected to two-dimensional electrophoresis (2-DE). The radiographic grading of knee OA was performed using the Kellgren-Lawrence criteria. Differentially expressed proteins were identified by matrix-assisted laser desorption/ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Proteins of interest identified from SF were detected using an enzyme-linked immunosorbent assay (ELISA). A total of 31 protein spots showed significant differences (p < 0.05) between the sample groups; 25 of the 31 spots (80.6 %) were identified as proteins of interest. Among them 20 corresponded to up-regulation and five to down-regulation in OA samples. HLA-DR was one of the proteins up-regulated, which was confirmed by ELISA. These observations have implications in delineating the protein expression underlying the pathogenesis of OA and facilitate further elucidation of molecular mechanisms involved in disease progression. Substantial alterations of the protein profile in SF may be associated with OA severity.

Associations of serum leptin concentration with gender, fat mass, interleukins, and growth factors in patients with osteoarthritis of the knee

Aging, obesity, and female gender are risk factors for osteoarthritis (OA) of the knee. Basic research has suggested that leptin may play an important role in the pathological process of OA, and that interleukins (ILs) and growth factors may be related to this process. The objective of the present clinical study was to examine the possible correlations between the serum leptin concentration and gender, fat mass, and the IL and growth factor levels in synovial fluid among patients with knee OA. Forty-four patients with knee OA and hydrarthrosis (age: 50-88 yr) were recruited in our outpatient clinic. Plain radiographs of the knee were taken, and blood and synovial fluid of the knee joint were collected. The serum leptin concentration was significantly higher in women than in men. A simple linear regression analysis showed that body weight, body mass index, and total fat mass, but not age, height, radiographic grade of knee OA, lean body mass, or the levels of IL-6, transforming growth factor-beta (TGF-beta), or insulin-like growth factor-1 (IGF-1) in synovial fluid were significantly correlated with the serum leptin concentration. A multiple regression analysis showed that among gender and the three above-mentioned significant factors, only gender and total fat mass were significantly associated with the serum leptin concentration. These results suggested that the serum leptin concentration was higher in women than in men and that it was related only to an increased total fat mass in patients with knee OA. However, the present clinical study failed to show a significant correlation between the serum leptin concentration and the IL or growth factor levels in synovial fluid.

Physical Function and Properties of Quadriceps Femoris Muscle in Men With Knee Osteoarthritis

Liikavainio T, Lyytinen T, Tyrväinen E, Sipilä S, Arokoski JP. Physical function and properties of quadriceps femoris muscle in men with knee osteoarthritis. Objectives To examine the objective physical function of the lower extremities, to measure the properties of quadriceps femoris muscle (QFM), and to assess subjective disabilities in men with knee osteoarthritis (OA) and to compare the results with those obtained from age- and sex-matched control subjects. Design Cross-sectional study. Setting Rehabilitation clinic in a university hospital. Participants Male volunteers (n=54) (age range, 50–69y) with knee OA and randomly selected healthy, age- and sex-matched control subjects (n=53). Interventions Not applicable. Main Outcome Measures Physical function evaluated with a test battery including the QFM composition measurement, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the RAND 36-Item Short-Form Health Survey, version 1.0. Results Knee OA patients had 13% to 26% poorer ( P range, .050–.001) physical function and muscle strength compared with the controls. There were also significant differences in QFM composition. WOMAC ( P range, .050–.001) and muscle strength ( P<.001) associated with physical function tests, but subjective pain correlated with neither physical function nor muscle strength in knee OA patients. The radiographic knee OA grade did not have any significant effect on physical function, but passive knee motion, knee extension strength, and WOMAC were related to the severity of the disease ( P<.05). Conclusions The patients with knee OA exhibited impaired physical function and muscle strength and QFM composition compared with healthy controls. The severity of radiographic knee OA clearly had adverse effects on functional ability at the later stages of the disease. The results highlight the effect of QFM strength on physical function as well as the importance of patient's subjective and objective physical function when deciding on knee OA treatment policy.

Epidemiology of osteoarthritis of the knee in a rural Japanese population

To investigate the prevalence and risk factors of idiopathic osteoarthritis of the knee in a rural Japanese population, we studied 1547 subjects between the ages of 54 and 79 years who participated in the third Matsudai Knee Osteoarthritis Survey. Data were collected by questionnaire, physical examination, and anteroposterior standing radiographs of both knees. Eighty-four individuals with possible secondary osteoarthritis were excluded from the study. Radiographs were graded from 0 to 4 according to a modified Kellgren and Lawrence scale. Osteoarthritis was defined as being present in a knee if radiographic grades of 2 or higher were detected. Measurement of the femorotibial angle reflected the alignment of the lower extremity. The prevalence of radiographic osteoarthritis of the knee increased with age, and was significantly higher in women than in men (29.7% vs. 10.9%, respectively). However, the prevalence of symptomatic knees with radiographic osteoarthritis (grade 2 or higher) was not significantly different between females and males (35.6% vs. 26.5%, respectively). The femorotibial angle increased with the severity of knee osteoarthritis. Almost all of the knees with radiographic osteoarthritis exhibited a varus deformity due to the loss of cartilage in the medial tibiofemoral compartment. The body mass index increased significantly with each higher radiographic grade of knee osteoarthritis in women, but not in men.