Aberrations in the control of quadriceps muscle force in patients with knee osteoarthritis

OBJECTIVE: To characterize the distribution of error in knee joint proprioception, quadriceps force accuracy and steadiness, and muscle strength in patients with knee osteoarthritis (OA). Special attention was paid to eccentric strength. METHODS: We compared knee OA patients (n=20: 15 women, 5 men) with age- and sex-matched, symptom-free adults. Knee pain and mobility were assessed with standard tests. Knee joint proprioception was measured with a repositioning test. Quadriceps force accuracy and steadiness were determined during a force target-tracking task. Maximal voluntary quadriceps force was measured during eccentric, isometric, and concentric contractions. RESULTS: OA patients had knee pain, needed 67% more time to complete 4 functional tasks, and produced 82% more proprioception errors (all P < 0.05). About 80% of this error was due to overshooting the target and 68% of the overshooting error occurred at 2 of the 5 least flexed knee joint positions. OA patients had 89% more errors in accurately matching target forces during submaximal quadriceps contractions and in the same tasks, OA patients also produced these forces with 155% more variability (all P < 0.05). OA patients had especially weakened ability to produce maximal voluntary eccentric strength. CONCLUSION: Quadriceps dysfunction in knee OA includes impaired proprioception, especially in the more extended knee joint positions; impaired ability to accurately and steadily control submaximal force; and impaired eccentric strength. These results have implications for designing exercise and rehabilitation programs for patients with knee OA.     

Impact of joint status on contraction steadiness of m. quadriceps femoris in people with severe haemophilia

Impaired contraction steadiness of lower limb muscles affects functional performance and may increase injury risk. We hypothesize that haemophilic arthropathy of the knee and the strength status of quadriceps are relevant factors which compromise a steady contraction. This study addresses the questions if impaired steadiness of the quadriceps is verifiable in people with haemophilia (PWH) and whether a connection between the status of the knee joint and quadriceps strength exists. A total of 157 PWH and 85 controls (C) performed a strength test with a knee extensor device to evaluate their bilateral and unilateral maximal quadriceps strength and steadiness. Isometric steadiness was measured by the coefficient of variation of maximum peak torque (CV‐MVIC in %). For classification of the knee joint status the World Federation of Haemophilia (WFH) score was used. Lower steadiness (higher CV values) was found in PWH compared with C during bilateral [PWH vs. C; 0.63 (0.36/1.13) vs. 0.35 (0.15/0.72), median (Q25/Q75) P < 0.001] and unilateral trials [left leg: 0.70 (0.32/1.64) vs. 0.50 (0.23/1.04), P < 0.05; right leg: 0.68 (0.29/1.51) vs. 0.39 (0.18/0.68), P < 0.001]. PWH with a WFH score difference (≥1) between their extremities showed a less steady contraction in the more affected extremity (P < 0.05). More unsteady contractions have also been found in extremities with lower quadriceps strength compared with the contralateral stronger extremities (P < 0.001), whereby the weaker extremities were associated with a worse joint status (P < 0.001). The results of this study verify an impaired ability to realize a steady contraction of quadriceps in PWH and the influence of joint damage and strength on its manifestation.     

Quadriceps strength,inter‐extremity difference (IED) and joint status in adult persons with severe haemophilia in different age stages

Quadriceps weakness seems to be a hallmark in adult persons with severe haemophilia (PWH). The purpose of this study was to compare PWH and non‐haemophilic controls in different age stages with reference to joint status and quadriceps strength. Further aims were to examine the extent of strength‐specific inter‐extremity‐difference (IED) and the prevalence of abnormal IED (AIED). A total of 106 adults with severe haemophilia (H) and 80 controls (C) had undergone an orthopaedic examination for classification of knee and ankle status using the WFH score. Quadriceps strength was evaluated unilaterally as well as bilaterally with a knee extensor device. Each group was divided into four age‐related subgroups (HA/CA: 18–29, HB/CB: 30–39, HC/CC: 40–49, HD/CD: 50–70; in years). H presented a worse knee and ankle status than C indicated by higher WFH scores (P < 0.01). Regarding the age‐matched subgroups only HB showed higher knee scores than CB (P < 0.05). The ankles were clinically more affected in HB‐HD compared with those in age‐matched controls (P < 0.05). H showed lower quadriceps strength than C (P < 0.05). In addition, all subgroups of H presented lower strength (HA: 10–17, HB: 19–23, HC: 35–36, HD: 53–61; in%, P < 0.05). IED was higher in H than in C [H: 12.0 (5.3/32.2) vs. C: 7.1 (2.9/10.9); Median (quartiles) in%, P < 0.001] and increased with age in H. We discovered an AIED in 35% of H. These findings highlight the importance for the early implementation of preventive and rehabilitative muscle training programmes in the comprehensive treatment of PWH.     

Proprioceptive accuracy in women with early and established knee osteoarthritis and its relation to functional ability, postural control, and muscle strength

The purpose of this study was to identify differences in knee proprioceptive accuracy between subjects with early knee osteoarthritis (OA), established knee OA, and healthy controls. Furthermore, the relation between proprioceptive accuracy on the one hand and functional ability, postural balance, and muscle strength on the other hand was also explored. New MRI-based classification criteria showing evidence of beginning joint degeneration have been used to identify subjects with early knee OA. A total of 45 women with knee OA (early OA, n?=?21; established OA, n?=?24) and 20 healthy female control subjects participated in the study. Proprioceptive accuracy was evaluated using the repositioning error of a knee joint position sense test using a three-dimensional motion analysis system. Subjective and objective functional ability was assessed by the knee injury and osteoarthritis outcome score, the timed “Up & Go” test, and the stair climbing test. The sensory organization test measured postural control. Muscle strength was measured by isokinetic dynamometry. Early OA subjects showed no significant differences in proprioceptive accuracy compared to healthy controls. In contrast, established OA subjects showed a higher repositioning error compared to early OA subjects (+29 %, P?=?0.033) and healthy controls (+25 %, P?=?0.068). Proprioceptive accuracy was not significantly associated with functional ability, postural balance, and muscle strength. Knee joint proprioceptive deficits were observed in established OA but not in early OA, suggesting that impaired proprioception is most likely a consequence of structural degeneration, rather than a risk factor in the pathogenesis of knee OA. Impaired proprioceptive accuracy was not associated with disease-related functionality in knee OA patients. Treatment strategies designed to address proprioceptive deficits may be not effective in prevention of knee OA progression and may have no impact on patients’ functionality. However, this should be confirmed further in well-designed clinical trials.     

Increased synovial fluid visfatin is positively linked to cartilage degradation biomarkers in osteoarthritis

The aim of this study is to investigate visfatin levels in both synovial fluid (SF) and plasma of patients with primary knee osteoarthritis (OA) and its relationship with biomarkers of cartilage degradation in SF. Thirty OA patients, 12 SF control, and 12 plasma control subjects were enrolled in this study. Visfatin levels in both SF and plasma were measured using enzyme-linked immunosorbent assay (ELISA). Degradation biomarkers of collagen II and aggrecan in SF were also measured. The radiographic grading of OA in the knee was performed by the Kellgren-Lawrence (KL) criteria. Compared to controls, OA patients had higher SF visfatin concentration (8.95 ± 2.5 vs. 4.48 ± 2.49 ng/ml, P < 0.001). SF visfatin levels in KL grade 4 were significantly elevated compared with those of KL grade 3 (10.57 ± 2.49 vs. 7.54 ± 1.5 ng/ml, P = 0.001). SF visfatin positively correlated with degradation biomarker of collagen II, CTX-II (r = 0.497, P = 0.005), and degradation biomarker of aggrecan, AGG1 (r = 0.451, P = 0.012) and AGG2 (r = 0.434, P = 0.017). These findings suggest that SF visfatin might involved in cartilage matrix degradation.     

Prospective comparative study between knee alignment-oriented static and dynamic balance exercise in patellofemoral pain syndrome patients with dynamic knee valgus

Exercise therapy has been reported as an effective treatment method for patellofemoral pain syndrome (PFPS). However, there is a lack of studies regarding the effectiveness of balance exercise in the treatment of patients with PFPS. This study aimed to prospectively compare changes in proprioception, neuromuscular control, knee muscle strength, and patient-reported outcomes between patients with PFPS treated with knee alignment-oriented static balance exercise (SBE) and dynamic balance exercise (DBE). The participants were divided into 2 groups: 17 knee alignment-oriented SBE group and 19 knee alignment-oriented DBE group. Proprioception was assessed by dynamic postural stability using postural stabilometry. Neuromuscular control and knee muscle strength were measured for acceleration time and peak torque in quadriceps muscle using an isokinetic device. Patient-reported outcomes were evaluated using a visual analog scale for pain and the Kujala Anterior Knee Pain Scale. There was greater improvement in dynamic postural stability (0.9 ± 0.3 vs 1.2 ± 0.5; 95% confidence interval [CI]: 0, 0.6; Effect size: 0.72; P = .021) and quadriceps AT (40.5 ± 14.3 vs 54.1 ± 16.9; 95% CI: 2.9, 24.2; Effect size: 0.86; P = .014) in the DBE group compared to the SBE group. Knee alignment-oriented DBE can be more effective in improving dynamic postural stability and quadriceps muscle reaction time compared with the knee alignment-oriented SBE in PFPS patients with dynamic knee valgus.     

Is knee joint proprioception worse in the arthritic knee versus the unaffected knee in unilateral knee osteoarthritis?

Objective. Neuromuscular joint protection requires proprioceptive input and motor output. Impairment of proprioception in knee osteoarthritis (OA) may contribute to, and/or result from, the disease. If this impairment was exclusively a local result of OA, a between-knee difference would be expected in patients with unilateral OA (UOA). To explore causal directions, 2 hypotheses were tested: 1) proprioception is worse in UOA patients versus elderly controls; 2) proprioception is worse in the arthritic knee versus the unaffected knee in UOA patients. Methods. Twenty-eight UOA patients (Kellgren-Lawrence grade ⩾2 in 1 knee and <2 in the other knee) and 29 elderly controls were enrolled. The unaffected knee of each UOA patient and both knees of the elderly controls were required to meet symptom, examination, and radiographic criteria. Proprioception (detection threshold of joint displacement after slow, passive, automated knee motion), body mass index, pain, functional status, range of motion, and laxity were measured. Results. UOA patients had worse proprioception than did elderly controls, in either knee. A between-knee difference was not found in UOA patients. Conclusion. Impaired proprioception is not exclusively a local result of disease in knee OA. The relative importance of impaired proprioception in the development and progression of knee OA will require longitudinal study.     

Prevalence and associated factors of knee osteoarthritis in a community-based population in Heilongjiang, Northeast China

Few data exist concerning the prevalence of knee OA and associated factors in Northeast China. This study was undertaken to estimate the prevalence of radiographic and symptomatic knee OA among community residents and to elucidate relevant risk factors. Unmatched case–control study was adopted to study risk factors of knee OA. Radiographic OA was evaluated according to the Kellgren and Lawrence grading scheme. Statistical analyses included tests and logistic model regressions. A total of 1,196 people aged 40–84 years participated in the community-based health survey in Northeast China in 2005. Survey participants completed an interviewer-based questionnaire. The standardized prevalence of symptomatic knee OA was 16.05% and it was significantly higher in women than in men (19.87% vs. 11.91%, = 13.76, P < 0.001). There was also an increased tendency with age in both sex (men:  x ² = 29.67, P _trend < 0.001; women: x ² = 40.26, P _trend < 0.001). The prevalence of symptomatic knee OA was significantly higher than that in Beijing and Shantou, while lower than that in Wuchuan county of inner Mongolia with nonsignificant difference. Logistic regressions revealed that age, sex, BMI, and work status might be risk factors for knee OA in urban residents, whereas age, BMI, and smoking habits might be risk factors in rural dwellers. Symptomatic knee OA is extremely common with preponderance for elderly women and constitutes a major public health problem. The findings will be useful to guide the distribution of future health care resources and preventive strategies.     

Lower bone mineral density of forearm in postmenopausal patients with radiographic hand osteoarthritis

The association between clinical parameters and forearm bone mineral density (BMD) in postmenopausal females with radiographic hand OA has not been determined. We investigated the difference in forearm BMD between radiographic hand OA and non-radiographic hand OA, and also the association between clinical parameters of patients and the level of forearm BMD. A total of 180 postmenopausal patients with hand OA were enrolled in this study. We classified them into two groups according to the Kellgren–Lawrence (K–L) radiological grade, one with radiographic hand OA (K–L grade ≥ 2) and the other with non-radiographic OA (K–L grade < 2) as controls. The number of nodal joints, swollen joints and tender joints were determined in the physical examination, and measures of BMD (g/cm²), Australian Canadian (AUSCAN) OA hand index, grip strength, pinch strength, and visual analogue scale (VAS) were also estimated. Patients with radiographic hand OA had lower distal radius BMD when compared with controls (0.35 ± 0.06 vs. 0.40 ± 0.05, P < 0.001). After adjusting for variables such as age, menopausal duration, number of nodal joints, and AUSCAN function index, the difference in BMD between the two groups was also significantly different (0.35 ± 0.04 vs. 0.38 ± 0.04, P < 0.001). For analysis of risk factors for forearm BMD in hand OA, age and K–L OA grade in total hand OA are considered risk factors, whereas age and menopause duration contribute to the forearm BMD in radiographic hand OA patients (P < 0.001, P = 0.002, respectively). The development of osteoporosis at the distal radius in radiographic hand OA is associated with older age (OR = 1.216, P = 0.002), lower BMI (OR = 0.777, P = 0.004) and lower stiffness in the AUSCAN OA index (OR = 0.505, P = 0.003). This study shows that the BMD levels of the distal radius in patients with radiographic hand OA are significantly lower when compared to those of controls. Forearm BMD levels are positively associated with age and K–L radiological grade in total hand OA, whereas age and menopausal duration are closely related with radiographic hand OA. The presence of osteoporosis in the distal radius in radiographic hand OA may be influenced by age, BMI, and stiffness on the AUSCAN index.     

Balance dysfunction in adults with haemophilia

Summary. The main focus of lower limb physical performance assessment in people with haemophilia (PWH) has usually been on function, muscle strength and joint flexibility. The impact of haemophilic arthropathy on balance and falls risk is relatively under‐explored. The aim of this study was to evaluate balance and related performance in PWH compared with age and gender matched healthy controls. It involved a comprehensive suite of clinical and laboratory measures of static and dynamic balance, mobility, strength, physical activity and falls efficacy completed in 20 PWH (mean age 39.4, 100% male) and 20 controls. Fifty percent of PWH reported falls in the past 12 months. Moderate impairment of balance and related measures were identified in PWH compared with the controls, with an average 35% difference between groups. Significant differences were evident between groups on both clinical and laboratory measures, including measures of dynamic bilateral stance balance [limits of stability measures on the laboratory test, functional reach; (P < 0.001); dynamic single leg balance (Step Test, P < 0.001)], gait and mobility (gait speed, step width and turning measures on the laboratory test, timed up and go test; P < 0.001); muscle strength (timed sit to stand, P = 0.002; quadriceps strength, P < 0.001); and activity level and falls efficacy, (P < 0.004). The dynamic clinical and laboratory measures testing similar domains of balance, gait and mobility had moderate correlations (0.310 < r < 0.531, P < 0.01). Moderate impairments in balance, mobility and related measures were identified in PWH, compared with the control group. Clinicians should include assessments of balance and related measures when reviewing adults with haemophilia.     

Synovial fluid level of adiponectin correlated with levels of aggrecan degradation markers in osteoarthritis

The objective of this study was to investigate adiponectin levels in both plasma and synovial fluid of female patients with knee osteoarthritis (OA) and to analyze the correlation between adiponectin and degradation markers of cartilage matrix in synovial fluid. Thirty female patients with knee OA were enrolled in this study. Levels of adiponectin and degradation markers of cartilage matrix were measured using enzyme-linked immunosorbent assay. Adiponectin level in synovial fluid was significantly lower with respect to paired plasma level (0.93 ± 0.64 vs. 7.50 ± 3.29 μg/ml, P < 0.001). Correlation analysis showed that synovial fluid adiponectin significantly correlated with degradation markers of aggrecan, AGG1 (r = 0.441, P = 0.015) and AGG2 (r = 0.445, P = 0.014), but not significantly correlated with degradation marker of collagen II, CTX-II. These findings suggest that adiponectin might involve in the regulation of the degradation of cartilage matrix in OA.     

Increased level of heme oxygenase-1 in rheumatoid arthritis synovial fluid

We investigated the expression and localization of heme oxygenase-1 (HO-1) in synovial fluid and synovial tissue, and examined the stimulation of HO-1 production in rheumatoid synovial fibroblasts (RASFs). Synovial fluid samples were obtained from knee joints of 20 rheumatoid arthritis (RA) and 20 osteoarthritis (OA) patients, and concentration of HO-1 and matrix metalloproteinase-3 (MMP-3) were measured by enzyme-linked immunosorbent assay (ELISA). Synovial tissues obtained from RA or OA patients during total knee arthroplasty (TKA) were used for immunohistochemical analysis of HO-1. HO-1 production by RASFs in response to various cytokines was examined by ELISA. HO-1 levels in synovial fluid were higher in the RA group than in the OA group with significant difference (P < 0.001), and correlated with serum C-reactive protein (CRP) level (r = 0.80, P < 0.01) in the RA group. Higher levels of HO-1 were seen in the RA-L group (Larsen grade III–V) than in the RA-E (Larsen grade 0-II) group (P < 0.001). There was weak correlation between the levels of HO-1 protein and MMP-3 in synovial fluid in the RA group (r = 0.31, P < 0.01), while no positive correlation was observed in OA. Positive immunoreaction for HO-1 was observed in cells of synovial tissue including synovial fibroblasts and cells in synovial pannus. HO-1 protein levels in cultured media of RASFs were increased by stimulation by interleukin-1β at 6 h and tumor necrosis factor-alpha at 12 h, but suppressed by interferon-gamma at 12 and 24 h. These results indicated that HO-1 expression in synovial tissue might be stimulated by inflammatory cytokines. The correlation of HO-1 concentration in synovial fluid with serum CRP and MMP-3 in joint fluid indicated that HO-1 might be useful as a marker of joint inflammation in RA patients.     

Predictors of disability among Filipinos with knee osteoarthritis

Aims: This study aims to describe the level of disability of Filipino patients with knee osteoarthritis (OA) in relation to common risk factors. Methodology: This is a cross‐sectional analytic study. Patients with knee osteoarthritis diagnosed using the American College of Rheumatology criteria for the classification of knee OA, seen at East Avenue Medical Center, using the Quezon City, Philippines, were entered by convenient sampling. The Western Ontario and McMaster Universities (WOMAC (va) 3.1 Tagalog Version) osteoarthritis index was used. Self‐reported disability was measured by the function subscale of the WOMAC OA index and used as the dependent variable. Independent variables assessed as possible risk factors affecting disability were age, sex, weight, height, body mass index (BMI), education (in years), number of comorbidities present, smoking status (pack years), duration of knee OA, pain and stiffness. Categories of disability were identified as high, moderate and low. Analyses of the data were performed using Statistical Package for the Social Sciences (SPSS) version 13. Results: Eighty‐five subjects were included in the study. The mean disability score was 674.1 ± 318.81 (moderate disability). Chi‐square tests showed that the categories or levels of disability are not significantly dependent on the categorical variables. Significant direct correlations were seen between mean disability and weight (r = 0.260, P = 0.016), pain (r = 0.574, P = 0.000), and stiffness (r = 0.616, P = 0.000). Conclusion: This is the first study analysing the relationship between disability and specific risk factors among Filipino patients with knee OA. Self‐reported disability of knee OA in the population studied was strongly related to pain scores, weight and joint stiffness scores.     

Quadriceps strength and the risk of cartilage loss and symptom progression in knee osteoarthritis

Objective

To determine the effect of quadriceps strength in individuals with knee osteoarthritis (OA) on loss of cartilage at the tibiofemoral and patellofemoral joints (assessed by magnetic resonance imaging [MRI]) and on knee pain and function.

Methods

We studied 265 subjects (154 men and 111 women, mean ± SD age 67 ± 9 years) who met the American College of Rheumatology criteria for symptomatic knee OA and who were participating in a prospective, 30‐month natural history study of knee OA. Quadriceps strength was measured at baseline, isokinetically, during concentric knee extension. MRI of the knee at baseline and at 15 and 30 months was used to assess cartilage loss at the tibiofemoral and patellofemoral joints, with medial and lateral compartments assessed separately. At baseline and at followup visits, knee pain was assessed using a visual analog scale, and physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index.

Results

There was no association between quadriceps strength and cartilage loss at the tibiofemoral joint. Results were similar in malaligned knees. However, greater quadriceps strength was protective against cartilage loss at the lateral compartment of the patellofemoral joint (for highest versus lowest tertile of strength, odds ratio 0.4 [95% confidence interval 0.2, 0.9]). Those with greater quadriceps strength had less knee pain and better physical function over followup (P < 0.001).

Conclusion

Greater quadriceps strength had no influence on cartilage loss at the tibiofemoral joint, including in malaligned knees. We report for the first time that greater quadriceps strength protected against cartilage loss at the lateral compartment of the patellofemoral joint, a finding that requires confirmation. Subjects with greater quadriceps strength also had less knee pain and better physical function over followup.

     

Osteoprotegerin and the receptor activator of NF-kappa B ligand in the serum and synovial fluid. A comparison of patients with longstanding rheumatoid arthritis and osteoarthritis

We examined OPG and soluble RANKL in the serum (sOPG, sRANKL) and synovial fluid (synOPG, synRANKL) in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). OPG and RANKL were measured in 85 patients (44 with RA, 41 patients with OA) in serum and synovial fluid as well. For measuring of OPG and RANKL ELISA tests were used. The results of OPG and RANKL were compared with clinical and radiological scores. We found a negative correlation for OPG and RANKL in synovial fluids: not only for the whole group of patients (P< 0.003, r=–0.32), but also for the subgroups (RA: P<0.04, r=–0.28, OA: P<0.002, r=–0.54). SRANKL and synRANKL were positively correlated in the whole group (P<0.01, r=0.25) and in the OA group (P<0.02, r=0.35); the RA group was showing a trend (P<0.063, r=0.24), however. Serum OPG was lower in RA, synOPG higher in OA. The difference between the two patient groups was only significant for synOPG (P<0.03, r=0.056), but not for sOPG (P<0.09, r=0.19), sRANKL (P<0.43, r=0.85) or synRANKL (P<0.11, r=0.22). The synOPG:synRANKL ratio was significantly correlated with the Larsen score (P<0.004, r=0.38). Synovial OPG is significantly decreased in rheumatoid joints, whereby synovial RANKL is increased. Lower synOPG could reflect a lower protective effect on bone, thus leading to an earlier and more pronounced bone destruction in RA. However, the effect of different mediators for joint destruction in RA and OA seems not to be important to the pathophysiological changes in the joints. The upregulation of serum OPG might be the result of the inflammation; in contrast, an upregulation of RANKL could not be found in the serum of patients with RA and OA.     

Static postural sway, proprioception, and maximal voluntary quadriceps contraction in patients with knee osteoarthritis and normal control subjects

OBJECTIVES: To investigate whether subjects with knee osteoarthritis (OA) have reduced static postural control, knee proprioceptive acuity, and maximal voluntary contraction (MVC) of the quadriceps compared with normal controls, and to determine possible independent predictors of static postural sway. METHODS: 77 subjects with symptomatic and radiographic knee OA (58 women, 19 men; mean age 63.4 years, range 36-82) and 63 controls with asymptomatic and clinically normal knees (45 women, 18 men; mean age 63 years, range 46-85) underwent assessment of static postural sway. 108 subjects (59 patients, 49 controls) also underwent assessment of knee proprioceptive activity and MVC (including calculation of quadriceps activation). In patients with knee OA knee pain, stiffness, and functional disability were assessed using the WOMAC Index. The height (m) and weight (kg) of all subjects was assessed. RESULTS: Compared with controls, patients with knee OA were heavier (mean difference 15.3 kg, p<0.001), had increased postural lateral sway (controls: median 2.3, interquartile (IQ) range 1.8-2.9; patients: median 4.7, IQ range 1.9-4.7, p<0.001), reduced proprioceptive acuity (controls: mean 7.9, 95% CI 6.9 to 8.9; patients: mean 12.0, 95% CI 10.5 to 13.6, p<0.001), weaker quadriceps strength (controls: mean 22.5, 95% CI 19.9 to 24.6; patients: mean 14.7, 95% CI 12.5 to 16.9, p<0.001), and less percentage activation of quadriceps (controls: mean 87.4, 95% CI 80.7 to 94.2; patients: mean 66.0, 95% CI 58.8 to 73.2, p<0.001). The significant predictors of postural sway were knee pain and the ratio of MVC/body weight. CONCLUSIONS: Compared with age and sex matched controls, subjects with symptomatic knee OA have quadriceps weakness, reduced knee proprioception, and increased postural sway. Pain and muscle strength may particularly influence postural sway. The interaction between physiological, structural, and functional abnormalities in knee OA deserves further study.     

Effect of glucosamine or chondroitin sulfate on the osteoarthritis progression: a meta-analysis

The aim of this study was to assess the structural efficacies of daily glucosamine sulfate and chondroitin sulfate in patients with knee osteoarthritis (OA). The authors surveyed randomized controlled studies that examined the effects of long-term daily glucosamine sulfate and chondroitin sulfate on joint space narrowing (JSN) in knee OA patients using the Medline and the Cochrane Controlled Trials Register, and by performing manual searches. Meta-analysis was performed using a fixed effect model because no between-study heterogeneity was evident. Six studies involving 1,502 cases were included in this meta-analysis, which consisted of two studies on glucosamine sulfate and four studies on chondroitin sulfate. Glucosamine sulfate did not show a significant effect versus controls on minimum JSN over the first year of treatment (SMD 0.078, 95% CI −0.116 to −0.273, P = 0.429). However, after 3 years of treatment, glucosamine sulfate revealed a small to moderate protective effect on minimum JSN (SMD 0.432, 95% CI 0.235–0.628, P < 0.001). The same was observed for chondroitin sulfate, which had a small but significant protective effect on minimum JSN after 2 years (SMD 0.261, 95% CI 0.131–0.392, P < 0.001). This meta-analysis of available data shows that glucosamine and chondroitin sulfate may delay radiological progression of OA of the knee after daily administration for over 2 or 3 years.     

Sensorimotor changes and functional performance in patients with knee osteoarthritis

OBJECTIVE—Muscles are essential components of our sensorimotor system that help maintain balance and perform a smooth gait, but it is unclear whether arthritic damage adversely affects muscle sensorimotor function. Quadriceps sensorimotor function in patients with knee osteoarthritis (OA) was investigated, and whether these changes were associated with impairment of functional performance.
METHODS—Quadriceps strength, voluntary activation, and proprioceptive acuity (joint position sense acuity) were assessed in 103 patients with knee OA and compared with 25 healthy control subjects. In addition, their postural stability, objective functional performance (the aggregate time for four activities of daily living), and disabilities (Lequesne index) were also investigated.
RESULTS—Compared with the control subjects, the patients with knee OA had weaker quadriceps (differences between group mean 100N, CI 136, 63N), poorer voluntary activation (20% CI 13, 25%) that was associated with quadriceps weakness, and impaired acuity of knee joint position sense (1.28°, CI 0.84, 1.73°). As a group the patients were more unstable (p=0.0017), disabled (10, CI 7, 11), and had poorer functional performance (19.6 seconds, CI 14.3, 24.9 seconds). The most important predictors of disability were objective functional performance and quadriceps strength.
CONCLUSIONS—In patients with knee OA, articular damage may reduce quadriceps motoneurone excitability, which decreases voluntary quadriceps activation thus contributing to quadriceps weakness, and diminishes proprioceptive acuity. The arthrogenic impairment in quadriceps sensorimotor function and decreased postural stability was associated with reduced functional performance of the patients.

     

Serum and synovial cartilage oligomeric matrix protein (COMP) in patients with rheumatoid arthritis and osteoarthritis

ObjectiveTo measure serum and synovial COMP levels in rheumatoid arthritis (RA) and osteoarthritis (OA) patients and to assess their correlation with clinical, laboratory and ultrasonographic parameters.MethodsTwo groups of patients were included in this study consisting of 32 patients with RA and 10 patients with knee OA. Ultrasonography of knee joints was performed and serum and synovial Cartilage oligomeric matrix protein (COMP) levels were measured using an inhibition ELISA.ResultsThe mean synovial COMP level was significantly higher in RA compared to OA patients (14.3 ± 5.19μg/mL and 9.26 ±2.42 μg/mL respectively, P< 0.01). Amongst RA patients, it was higher in those with erosions. COMP levels were higher in synovial fluid compared to serum levels in both groups (P <0.01). Amongst RA patients, synovial COMP levels showed a significant positive correlation with synovial membrane thickness on ultrasonography (P <0.001), and significant negative correlation with the cartilage thickness (P <0.001). In OA group, synovial and serum COMP level showed significant positive correlation with WOMAC index for the lower limbs (r= 0.64, P < 0.05, and r=0.92, P <0.001 respectively) and a significant negative correlation with cartilage thickness (P <0.001).ConclusionThe synovial COMP and ultrasonographic joint evaluation may be considered as markers of disease activity and cartilage destruction in both RA and OA patients.