Modifiers of change in physical functioning in older adults with knee pain: the Observational Arthritis Study in Seniors (OASIS)

Skeletal muscle myostatin mRNA expression is upregulated in aged human adults with excess adiposity but is not associated with insulin resistance and ageing

Myostatin negatively regulates skeletal muscle growth and appears upregulated in human obesity and associated with insulin resistance. However, observations are confounded by ageing, and the mechanisms responsible are unknown. The aim of this study was to delineate between the effects of excess adiposity, insulin resistance and ageing on myostatin mRNA expression in human skeletal muscle and to investigate causative factors using in vitro models. An in vivo cross-sectional analysis of human skeletal muscle was undertaken to isolate effects of excess adiposity and ageing per se on myostatin expression. In vitro studies employed human primary myotubes to investigate the potential involvement of cross-talk between subcutaneous adipose tissue (SAT) and skeletal muscle, and lipid-induced insulin resistance. Skeletal muscle myostatin mRNA expression was greater in aged adults with excess adiposity than age-matched adults with normal adiposity (2.0-fold higher; P < 0.05) and occurred concurrently with altered expression of genes involved in the maintenance of muscle mass but did not differ between younger and aged adults with normal adiposity. Neither chronic exposure to obese SAT secretome nor acute elevation of fatty acid availability (which induced insulin resistance) replicated the obesity-mediated upregulation of myostatin mRNA expression in vitro. In conclusion, skeletal muscle myostatin mRNA expression is uniquely upregulated in aged adults with excess adiposity and insulin resistance but not by ageing alone. This does not appear to be mediated by the SAT secretome or by lipid-induced insulin resistance. Thus, factors intrinsic to skeletal muscle may be responsible for the obesity-mediated upregulation of myostatin, and future work to establish causality is required.

Static posturography as a novel measure of the effects of aging on postural control in dogs

Aging is associated with impairment in postural control in humans. While dogs are a powerful model for the study of aging, the associations between age and postural control in this species have not yet been elucidated. The aims of this work were to establish a reliable protocol to measure center of pressure excursions in standing dogs and to determine age-related changes in postural sway. Data were obtained from 40 healthy adult dogs (Group A) and 28 senior dogs (Group B) during seven trials (within one session of data collection) of quiet standing on a pressure sensitive walkway system. Velocity, acceleration, root mean square, 95% ellipse area, range and frequency revolve were recorded as measures of postural sway. In Group A, reliability was assessed with intraclass correlation, and the effect of morphometric variables was evaluated using linear regression. By means of stepwise linear regression we determined that root mean square overall and acceleration in the craniocaudal direction were the best variables able to discriminate between Group A and Group B. The relationship between these two center-of-pressure (COP) measures and the dogs’ fractional lifespan was examined in both groups and the role of pain and proprioceptive deficits was evaluated in Group B. All measures except for frequency revolve showed good to excellent reliability. Weight, height and length were correlated with most of the measures. Fractional lifespan impacted postural control in Group B but not Group A. Joint pain and its interaction with proprioceptive deficits influence postural sway especially in the acceleration in the craniocaudal direction, while fractional lifespan was most important in the overall COP displacement. In conclusion, our study found that pressure sensitive walkway systems are a reliable tool to evaluate postural sway in dogs; and that postural sway is affected by morphometric parameters and increases with age and joint pain.

Predictors of resilience in older adults with lower limb osteoarthritis and persistent severe pain

BACKGROUND

Resilience refers to the process in which people function well despite adversity. Persistent severe pain may be considered an adversity in people with lower limb osteoarthritis (LLOA). The objectives of this study are: (1) to identify what proportion of older adults with LLOA and persistent severe pain show good functioning; and (2) to explore predictors of resilience.

METHODS

Data from the European Project on OSteoArthritis (EPOSA) were used involving standardized data from six European population-based cohort studies. LLOA is defined as clinical knee and/or hip osteoarthritis. Persistent severe pain is defined as the highest tertile of the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index both at baseline and follow-up. Resilience is defined as good physical, mental or social functioning at follow-up despite having LLOA with persistent severe pain.

RESULTS

In total, 95 (14.9%) out of 638 individuals with LLOA had persistent severe pain. Among these, 10 (11.0%), 54 (57.4%) and 49 (53.8%) had good physical, mental and social functioning, respectively. Only 4 individuals (4.5%) were resilient in all three domains of functioning. Younger age, male sex, higher education, higher mastery, smoking and alcohol use, higher physical activity levels, absence of chronic diseases, and more contacts with friends predicted resilience in one or more domains of functioning.

CONCLUSIONS

Few people with LLOA and persistent severe pain showed good physical functioning and about half showed good mental or social functioning. Predictors of resilience differed between domains, and might provide new insights for treatment.

Relationship of Patellofemoral Osteoarthritis to Changes in Performance-based Physical Function Over 7 Years: The Multicenter Osteoarthritis Study

OBJECTIVE

To determine the relationship of patellofemoral osteoarthritis (PFOA) to changes in performance-based function over 7 years.

METHODS

There were 2666 participants (62.2 ± 8.0 yrs, BMI 30.6 ± 5.9 kg/m2, 60% female) from the Multicenter Osteoarthritis Study with knee radiographs at baseline who completed repeated chair stands and a 20-meter walk test (20MWT) at baseline, 2.5, 5, and 7 years. Generalized linear models assessed the relation of radiographic PFOA and radiographic PFOA with frequent knee pain to longitudinal changes in performance-based function. Analyses were adjusted for age, sex, BMI, tibiofemoral OA, and injury/surgery.

RESULTS

Linear models demonstrated a significant group-by-time interaction for the repeated chair stands (P = 0.04) and the 20MWT (P < 0.0001). Those with radiographic PFOA took 1.01 seconds longer on the repeated chair stands (P = 0.02) and 1.69 seconds longer on the 20MWT (P < 0.0001) at 7 years compared with baseline. When examining the relation of radiographic PFOA with frequent knee pain to performance-based function, there was a significant group-by-time interaction for repeated chair stands (P = 0.05) and the 20MWT (P < 0.0001). Those with radiographic PFOA with frequent knee pain increased their time on the repeated chair stands by 1.12 seconds (P = 0.04) and on the 20MWT by 1.91 seconds (P < 0.0001) over 7 years.

CONCLUSION

Individuals with radiographic PFOA and those with radiographic PFOA with frequent knee pain have worsening of performance-based function over time. This knowledge may present opportunities to plan for early treatment strategies for PFOA to limit functional decline over time.

Musculoskeletal pain in Parkinson's disease: a narrative review

The prevalence of musculoskeletal (MSK) pain in people with Parkinson's disease (PD) is higher than that of age-matched controls. In this review, we outline what is known about MSK pain in PD, focusing on the neck, shoulder, knee, hip and low back. We also compare what is known about MSK pain in PD to what is known in older adults without PD. Finally, we outline areas of for future research related to MSK pain in people with PD.

Changes in body weight and knee pain in adults with knee osteoarthritis 3.5 years after completing diet and exercise interventions

OBJECTIVE

To determine whether long-term diet (D) and exercise (E) interventions, alone or in combination (D+E), have beneficial effects for older adults with knee osteoarthritis 3.5-years after the interventions end.

METHODS

This is a secondary analysis of a subset (N = 94) of the first 184 participants who had successfully completed the Intensive Diet and Exercise in Arthritis (IDEA) trial (N = 399) and who consented to follow-up testing. Participants were older (age ≥ 55 years), overweight and obese adults with radiographic and symptomatic knee osteoarthritis in at least one knee who completed 1.5-year D+E (N=27), D (N=35), or E (N=32) interventions and returned for 5-year follow-up testing an average of 3.5-years later.

RESULTS

During the 3.5-years following the interventions, weight regain in D+E and D was 5.9 kg (7%) and 3.1 kg (4%), respectively, with a 1 kg (1%) weight loss in E. Compared to baseline, weight (D+E, -3.7 kg, P=.0007; D, -5.8 kg, P<.0001; E, -2.9 kg, P=.003) and WOMAC pain (D+E, -1.2, P=.03; D, -1.5, P=.001; E -1.6, P=.0008) were lower in each group at 5-year follow-up. The effect of group assignment at 5-year follow-up was significant for body weight, with D less than E (-3.5 kg, P=.04).

DISCUSSION

Older adults with knee osteoarthritis who completed 1.5-year diet or diet plus exercise interventions experienced partial weight regain 3.5 years later, yet relative to baseline, they preserved statistically significant changes in weight loss and reductions in knee pain.

Cross-sectional and temporal differences in health-related quality of life of people with and without osteoarthritis: a 10-year prospective study

OBJECTIVE

To describe the impact of OA on health-related quality of life (HRQoL) in the forms of health state utilities (HSUs) and health-dimension scores, and to compare the longitudinal changes in HRQoL for people with and without OA, using an Australian population-based longitudinal cohort.

METHODS

Participants of the Tasmanian Older Adult Cohort with data on OA diagnosis and HRQoL were included [interviewed at baseline (n = 1093), 2.5 years (n = 871), 5 years (n = 760) and 10 years (n = 562)]. HRQoL was assessed using the Assessment of Quality of Life four-dimensions and analysed using multivariable linear mixed regressions.

RESULTS

Compared with participants without OA, HSUs for those with OA were 0.07 (95% confidence interval: 0.09, 0.05) units lower on average over 10 years. HSUs for participants with knee and/or hip OA were similar to those with other types of OA at the 2.5 year follow-up and then diverged, with HSUs of the former being up to 0.09 units lower than the latter. Those with OA had lower scores for psychological wellness, independent living and social relationships compared with those without OA. Independent living and social relationships were mainly impacted by knee and/or hip OA, with the effect on the former increasing over time.

CONCLUSION

Interventions to improve HRQoL should be tailored to specific OA types, health dimensions, and times. Support for maintaining psychological wellness should be provided, irrespective of OA type and duration. However, support for maintaining independent living could be more relevant to knee and/or hip OA patients living with the disease for longer.

Knee-related disability was largely influenced by cognitive factors and disturbed body perception in knee osteoarthritis

The aim of this study was to explore the existence of subgroups in a cohort of people with knee osteoarthritis (OA) based upon data from multiple pain-related variables and to profile identified clusters according to levels of pain intensity and knee-related disability. Three hundred and three people with knee OA were recruited. Latent profile analysis was used to confirm the optimal number of knee OA subgroups. Body mass index, radiographic knee OA severity, pain catastrophizing, pain related self-efficacy, and knee specific self-perception, were incorporated into the model. Cluster, demographic and clinical variables were compared between the resulting classes. Four distinct classes were identified. Cluster 1 (28.7%) represented early radiographic OA, and moderate pain intensity, disability and cognitive and perceptual dysfunction. Cluster 2 (18.8%) showed advanced radiographic OA, and moderate pain intensity, disability and cognitive and perceptual dysfunction. Cluster 3 (34.3%) represented various levels of radiographic OA, and the lowest pain intensity, disability and cognitive and perceptual dysfunction. Cluster 4 (18.1%) represented various levels of radiographic OA, the highest disability and cognitive and perceptual dysfunction. Considering cognitive factors and disturbed body perception may help to explain the phenomenon of the discrepancy between the knee-related disability and the severity of radiographic knee OA.

Semixup: In- and Out-of-Manifold Regularization for Deep Semi-Supervised Knee Osteoarthritis Severity Grading From Plain Radiographs

Knee osteoarthritis (OA) is one of the highest disability factors in the world. This musculoskeletal disorder is assessed from clinical symptoms, and typically confirmed via radiographic assessment. This visual assessment done by a radiologist requires experience, and suffers from moderate to high inter-observer variability. The recent literature has shown that deep learning methods can reliably perform the OA severity assessment according to the gold standard Kellgren-Lawrence (KL) grading system. However, these methods require large amounts of labeled data, which are costly to obtain. In this study, we propose the Semixup algorithm, a semi-supervised learning (SSL) approach to leverage unlabeled data. Semixup relies on consistency regularization using in- and out-of-manifold samples, together with interpolated consistency. On an independent test set, our method significantly outperformed other state-of-the-art SSL methods in most cases. Finally, when compared to a well-tuned fully supervised baseline that yielded a balanced accuracy (BA) of 70.9 ± 0.8% on the test set, Semixup had comparable performance - BA of 71 ± 0.8% ( p=0.368 ) while requiring 6 times less labeled data. These results show that our proposed SSL method allows building fully automatic OA severity assessment tools with datasets that are available outside research settings.

The Dunkin Hartley Guinea Pig Is a Model of Primary Osteoarthritis That Also Exhibits Early Onset Myofiber Remodeling That Resembles Human Musculoskeletal Aging

Skeletal muscle dysfunction, articular cartilage degeneration, and bone loss occur essentially in parallel during aging. Mechanisms contributing to this systemic musculoskeletal decline remain incompletely understood, limiting progress toward developing effective therapeutics. Because the progression of human musculoskeletal aging is slow, researchers rely on rodent models to identify mechanisms and test interventions. The Dunkin Hartley guinea pig is an outbred strain that begins developing primary osteoarthritis by 4 months of age with a progression and pathology similar to aging humans. The purpose of this study was to determine if skeletal muscle remodeling during the progression of osteoarthritis in these guinea pigs resembles musculoskeletal aging in humans. We compared Dunkin Hartley guinea pigs to Strain 13 guinea pigs, which develop osteoarthritis much later in the lifespan. We measured myofiber type and size, muscle density, and long-term fractional protein synthesis rates of the gastrocnemius and soleus muscles in 5, 9, and 15-month-old guinea pigs. There was an age-related decline in skeletal muscle density, a greater proportion of smaller myofibers, and a decline in type II concomitant with a rise in type I myofibers in the gastrocnemius muscles from Dunkin Hartley guinea pigs only. These changes were accompanied by age-related declines in myofibrillar and mitochondrial protein synthesis in the gastrocnemius and soleus. Collectively, these findings suggest Dunkin Hartley guinea pigs experience myofiber remodeling alongside the progression of osteoarthritis, consistent with human musculoskeletal aging. Thus, Dunkin Hartley guinea pigs may be a model to advance discovery and therapeutic development for human musculoskeletal aging.

Comparative efficacy of treatments for patients with knee osteoarthritis: a network meta-analysis

Background

Knee osteoarthritis is a common cause of musculoskeletal pain and a leading cause of disability and healthcare economic burden. The optimum treatment for knee osteoarthritis is still inconclusive. A network meta-analysis is required to assess the efficacy and safety of treatments and provide more scientific medical evidence.

Methods

Relevant studies were searched through PubMed, Embase, and Cochrane Library electronic databases from the inception to October 2018. Continuous outcomes such as pain, stiffness, physical function and total scores were expressed as the mean differences with 95% credible interval. Surface under the cumulative ranking curve illustrated the rank probability of each therapy under different outcomes.

Results

Nineteen studies were included in this study, with a total of 2395 patients. For knee pain, platelet-rich plasma (0.691) was ranked at the first place, followed by hyaluronic acid combined with platelet-rich plasma (0.670) and hyaluronic acid (0.402). In terms of stiffness, hyaluronic acid combined with platelet-rich plasma (0.743) enjoyed the highest value, platelet-rich plasma (0.603) was the next and hyaluronic acid (0.386) was the third. As for physical function, the rank was hyaluronic acid combined with platelet-rich plasma (0.772), platelet-rich plasma (0.608) and hyaluronic acid (0.343). For total scores, the order given by surface under the cumulative ranking was hyaluronic acid combined with platelet-rich plasma (0.765), platelet-rich plasma (0.624) and hyaluronic acid (0.37).

Conclusions

Hyaluronic acid combined with platelet-rich plasma showed the best efficacy in improving stiffness, physical function, and total scores, while platelet-rich plasma appeared the best in terms of pain reduction.

MicroRNA‑1 regulates the development of osteoarthritis in a Col2a1‑Cre‑ERT2/GFPfl/fl‑RFP‑miR‑1 mouse model of osteoarthritis through the downregulation of Indian hedgehog expression

The present study assessed the effects of microRNA‑1 (miR‑1) on the development of osteoarthritis using human tissues and a Col2a1‑Cre‑ERT2/GFPfl/fl‑RFP‑miR‑1 mouse model of osteoarthritis. Human cartilage tissues (n=20) were collected for reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), histological analysis and immunohistochemistry experiments. A transgenic mouse model of osteoarthritis was established by subjecting Col2a1‑Cre‑ERT2/GFPfl/fl‑RFP‑miR‑1 transgenic mice to anterior cruciate ligament transection (ACLT). Mice were subjected to radiography and in vivo fluorescence molecular tomography (FMT), while mouse tissues were collected for histological analysis, RT‑qPCR and Safranin O staining. It was found that the miR‑1 level was downregulated, whereas the levels of Indian hedgehog (Ihh), as well as those of its downstream genes were upregulated in human osteoarthritic cartilage. In the transgenic mice, treatment with tamoxifen induced miR‑1, as well as collagen, type II (Col2a1) and Aggrecan (Acan) expression; however, it decreased Ihh, glioma‑associated oncogene homolog (Gli)1, Gli2, Gli3, smoothened homolog (Smo), matrix metalloproteinase (MMP)‑13 and collagen type X (Col10) expression. Safranin O staining revealed cartilage surface damage in the non‑tamoxifen + ACLT group, compared with that in the tamoxifen + ACLT group. Histologically, an intact cartilage surface and less fibrosis were observed in the tamoxifen + ACLT group. Immunohistochemistry revealed that the protein expression of Ihh, Col10, and MMP‑13 was significantly higher in the joint tissues of the non‑tamoxifen + ACLT group than in those of the tamoxifen + ACLT group. However, Col2a1 expression was lower in the joint tissues of the non‑tamoxifen + ACLT group than in those of the tamoxifen + ACLT group. The results of RT‑qPCR and FMT further confirmed these findings. On the whole, the findings of the present study demonstrate that miR‑1 expression protects against osteoarthritis‑induced cartilage damage and gene expression by inhibiting Ihh signaling.

The Association of Diabetes with Knee Pain Severity and Distribution in People with Knee Osteoarthritis using Data from the Osteoarthritis Initiative

Limited research has examined the association between diabetes mellitus (DM) and knee pain in people with osteoarthritis (OA). Therefore, this study aimed at examining the association between DM and knee pain severity, and to explore the association between DM and knee pain distribution (unilateral or bilateral versus no pain) in subjects with knee OA. This is a cross-sectional analysis of the baseline visit of individuals who were enrolled in the Osteoarthritis Initiative. Data of participants with knee OA were used for this analysis (n = 1319), and grouped into subjects with both knee OA and DM (n = 148) or knee OA only without DM (n = 1171). Pain severity was measured using a numeric rating scale from 0 to 10 over the past 7 and 30 days for each knee, and the more symptomatic knee with higher pain severity was chosen for analysis. DM was significantly associated with increased knee pain severity over 7 days (B 0.68; 95% CI 0.25-1.11) and over 30 days (B 0.59; 95% CI 0.17-1.01) after adjustments for all covariates, including age, gender, BMI, race, depression symptoms, composite OA score, use of pain medications, and knee injections. Multinomial regression showed that participants with knee OA and DM had 2.45 (95% CI 1.07-5.61) to 2.55 (95% CI 1.12-5.79) times higher likelihood of having unilateral and bilateral knee pain than those without DM and without knee pain. This study found that DM was associated with higher pain severity and unilateral and bilateral knee pain distribution.

[The clinical status and treatment options for osteoarthritis in patients with frailty]

Aging is an independent risk factor for the development of many diseases and geriatric syndromes. Osteoarthritis (OA), as the most common joint disease in the elderly, can be attributed to age - associated conditions. And the most significant geriatric syndrome, which dramatically affects the management and prognosis of an elderly, is frailty. The review provides current information on the prevalence of OA and frailty, their clinical and prognostic significance, and also shows the mutually aggravating role of these two conditions. The difference between non - and medication management of patients with OA and frailty is emphasized.

Development and validation of risk stratification trees for incident slow gait speed in persons at high risk for knee osteoarthritis

OBJECTIVES

Disability prevention strategies are more achievable before osteoarthritis disease drives impairment. It is critical to identify high-risk groups, for strategy implementation and trial eligibility. An established measure, gait speed is associated with disability and mortality. We sought to develop and validate risk stratification trees for incident slow gait in persons at high risk for knee osteoarthritis, feasible in community and clinical settings.

METHODS

Osteoarthritis Initiative (derivation cohort) and Multicenter Osteoarthritis Study (validation cohort) participants at high risk for knee osteoarthritis were included. Outcome was incident slow gait over up to 10-year follow-up. Derivation cohort classification and regression tree analysis identified predictors from easily assessed variables and developed risk stratification models, then applied to the validation cohort. Logistic regression compared risk group predictive values; area under the receiver operating characteristic curves (AUCs) summarised discrimination ability.

RESULTS

1870 (derivation) and 1279 (validation) persons were included. The most parsimonious tree identified three risk groups, from stratification based on age and WOMAC Function. A 7-risk-group tree also included education, strenuous sport/recreational activity, obesity and depressive symptoms; outcome occurred in 11%, varying 0%-29 % (derivation) and 2%-23 % (validation) depending on risk group. AUCs were comparable in the two cohorts (7-risk-group tree, 0.75, 95% CI 0.72 to 0.78 (derivation); 0.72, 95% CI 0.68 to 0.76 (validation)).

CONCLUSIONS

In persons at high risk for knee osteoarthritis, easily acquired data can be used to identify those at high risk of incident functional impairment. Outcome risk varied greatly depending on tree-based risk group membership. These trees can inform individual awareness of risk for impaired function and define eligibility for prevention trials.

Sarcopenic osteoarthritis: a new entity in geriatric medicine?

PURPOSE

Osteoarthritis, a disease characterized by cartilage degradation, abnormal subchondral bone remodeling and some grade of inflammation, and sarcopenia, a condition of low muscle mass associated with reduced strength and function, are prevalent disorders in older adults. In this review, we examine what is known about the relationship between osteoarthritis and sarcopenia, with particular focus on the older population. We also discuss how osteoarthritis and sarcopenia may interact and affect each other in clinical progression and the potential benefits from developing treatments that address such muscular-skeletal interaction.

METHODS

We searched in Pubmed and Scopus through a combination of search and MESH terms, for osteoarthritis and sarcopenia.

RESULTS

Even if more literature is needed, there is increasing evidence that decline in lower limb muscle strength is associated with knee or hip osteoarthritis in a pathological network of pain, altered joint stability, maladapted postures and defective neuromuscular communication. At the cellular levels, chondrocytes and myoblasts share common pathways, and the close anatomical location of both cell types also suggest the possibility of paracrine communication.

CONCLUSIONS

Sarcopenia and osteoarthritis are significantly intercorrelated and in the near future should be considered as an only entity, as we have recently proposed for sarcopenia and osteoporosis. The treatment of both sarcopenia and osteoarthritis is based on physical exercise and nutritional interventions with the aim of improving cartilage, bone and muscle health. Future studies are needed, particularly to know the exact prevalence of sarcopenia in people with osteoarthritis, its peculiar consequences and the most appropriate treatments.

Carvacrol ameliorates inflammatory response in interleukin 1β-stimulated human chondrocytes

Carvacrol, a monoterpenic phenol present in Origanum vulgare (oregano) and Thymus vulgaris (thyme), possesses anti‑inflammatory effects; however, little is known about the effects and underlying mechanism of carvacrol on chondrocytes in osteoarthritis (OA). The present study aimed to investigate the protective effects of carvacrol against inflammation in interleukin 1β (IL‑1β)‑stimulated human chondrocytes. The results indicated that carvacrol inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) production, and decreased the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX‑2). Carvacrol also suppressed the protein expression levels of matrix metalloproteinase (MMP)‑3 and MMP‑13 in IL‑1β‑stimulated human OA chondrocytes. Furthermore, carvacrol suppressed the activation of nuclear factor (NF)‑κB signaling pathway in IL‑1β‑induced human chondrocytes. In conclusion, the present results demonstrated that carvacrol was able to inhibit IL‑1β‑induced NO and PGE2 production, as well as iNOS, COX‑2 and MMPs expression in human chondrocytes by suppressing the activation of NF‑κB signaling pathway. Thus, carvacrol may have potential therapeutic functions for the treatment of OA.

Cartilage oligomeric protein, matrix metalloproteinase-3, and Coll2-1 as serum biomarkers in knee osteoarthritis: a cross-sectional study

Biochemical markers reflecting joint remodeling in osteoarthritis (OA) are a promising diagnostic tool. The aim of this study was to investigate serum levels of candidate biomarkers in subjects with and without knee OA and assess their correlation with clinical parameters and knee structural damage. 56 patients with primary knee OA and 31 healthy controls participated in this study. Patients were separated into two groups: isolated knee OA and generalized OA. Clinical parameters were obtained by validated self-reported questionnaires and a visual analogue scale. Serum levels of cartilage oligomeric protein (COMP), matrix metalloproteinase-3 (MMP-3), and Coll2-1 were quantified by enzyme-linked immunosorbent assay. Knee structural damage was determined by plain X-ray and 1.5 T magnetic resonance imaging (MRI), using Kellgren-Lawrence (KL) grading scale and Whole-Organ Magnetic Resonance Imaging Score (WORMS), respectively. Compared to controls, patients had significantly higher median serum COMP (985 vs. 625 ng/ml; p < 0.001) and MMP-3 (36.85 vs. 22.10 ng/ml; p = 0.003) levels. Patients with radiographic evidence of KLII/III knee OA had greater median COMP levels than KLI patients (1095 vs. 720 ng/ml; p = 0.001). In the generalized OA group, mean MMP-3 levels were higher than in the isolated knee OA group (30.40 vs. 55.13 ng/ml; p < 0.001). COMP correlated positively with WORMS (r _s = 0.454, p < 0.001) and MMP-3 (r _s = 0.337, p = 0.003). Cut-off values for serum COMP and MMP-3 were determined. We observed higher serum COMP and MMP-3 levels in knee OA patients compared to controls. COMP may reflect knee structural damage, while MMP-3-OA "generalization".

Self-efficacy, pain, and quadriceps capacity at baseline predict changes in mobility performance over 2 years in women with knee osteoarthritis

This study examined the extent to which baseline measures of quadriceps strength, quadriceps power, knee pain and self-efficacy for functional tasks, and their interactions, predicted 2-year changes in mobility performance (walking, stair ascent, stair descent) in women with knee osteoarthritis. We hypothesized that lesser strength, power and self-efficacy, and higher pain at baseline would each be independently associated with reduced mobility over 2 years, and each of pain and self-efficacy would interact with strength and power in predicting 2-year change in stair-climbing performance. This was a longitudinal, observational study of women with clinical knee osteoarthritis. At baseline and follow-up, mobility was assessed with the Six-Minute Walk Test, and stair ascent and descent tasks. Quadriceps strength and power, knee pain, and self-efficacy for functional tasks were also collected at baseline. Multiple linear regression examined the extent to which 2-year changes in mobility performances were predicted by baseline strength, power, pain, and self-efficacy, after adjusting for covariates. Data were analyzed for 37 women with knee osteoarthritis over 2 years. Lower baseline self-efficacy predicted decreased walking (β = 1.783; p = 0.030) and stair ascent (β = -0.054; p < 0.001) performances over 2 years. Higher baseline pain intensity/frequency predicted decreased walking performance (β = 1.526; p = 0.002). Lower quadriceps strength (β = 0.051; p = 0.015) and power (β = 0.022; p = 0.022) interacted with lesser self-efficacy to predict worsening stair ascent performance. Strategies to sustain or improve mobility in women with knee osteoarthritis must focus on controlling pain and boosting self-efficacy. In those with worse self-efficacy, developing knee muscle capacity is an important target.

Knee Extensor Strength and Risk of Structural, Symptomatic, and Functional Decline in Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

To perform a systematic review and meta-analysis on the association between knee extensor strength and the risk of structural, symptomatic, or functional deterioration in individuals with or at risk of knee osteoarthritis (KOA).

METHODS

We systematically identified and methodologically appraised all longitudinal studies (≥1-year followup) reporting an association between knee extensor strength and structural (tibiofemoral, patellofemoral), symptomatic (self-reported, knee replacement), or functional (subjective, objective) decline in individuals with or at risk of radiographic or symptomatic KOA. Results were pooled for each of the above associations using meta-analysis, or if necessary, summarized according to a best-evidence synthesis.

RESULTS

Fifteen studies were included, evaluating >8,000 participants (51% female), with a followup time between 1.5 and 8 years. Meta-analysis revealed that lower knee extensor strength was associated with an increased risk of symptomatic (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] pain: odds ratio [OR] 1.35, 95% confidence interval [95% CI] 1.10-1.67) and functional decline (WOMAC function: OR 1.38, 95% CI 1.00-1.89, and chair-stand task: OR 1.03, 95% CI 1.03-1.04), but not increased risk of radiographic tibiofemoral joint space narrowing (JSN) (OR 1.15, 95% CI 0.84-1.56). No trend in risk was observed for KOA status (present versus absent). Best-evidence synthesis showed inconclusive evidence for lower knee extensor strength being associated with increased risk of patellofemoral deterioration.

CONCLUSION

Meta-analysis showed that lower knee extensor strength is associated with an increased risk of symptomatic and functional deterioration, but not tibiofemoral JSN. The risk of patellofemoral deterioration in the presence of knee extensor strength deficits is inconclusive.

Arthritis and Risk of Cognitive and Functional Impairment in Older Mexican Adults

OBJECTIVE

This study investigated the risk of cognitive and functional impairment in older Mexicans diagnosed with arthritis. Participants included 2,681 Mexicans, aged ≥60 years, enrolled in the Mexican Health and Aging Study cohort.

METHOD

Participants were categorized into arthritis and no arthritis exposure groups. Primary outcome included participants categorized into "cognitively impaired" or "cognitively normal" groups. Secondary outcomes included participants categorized into Normal, Functionally Impaired only, Cognitively Impaired only, or Dementia (both cognitively and functionally impaired) groups. Multivariable logistic and multinomial regression models were used to assess the relationships.

RESULTS

Overall, 16% or 7% were diagnosed with cognitive impairment or dementia. Compared with older Mexicans without arthritis, those who were diagnosed with arthritis had significantly increased risk of functional impairment (adjusted odds ratio [OR] 1.82, 95% confidence interval [CI] = [1.45, 2.29]), but not of dementia.

CONCLUSION

Arthritis is associated with increased risk of functional impairment, but not with dementia after 11 years in older Mexicans.

The Influence of Knee Pain Location on Symptoms, Functional Status, and Knee-related Quality of Life in Older Adults With Chronic Knee Pain: Data From the Osteoarthritis Initiative

OBJECTIVE

To evaluate whether knee pain location can influence symptoms, functional status, and knee-related quality of life in older adults with chronic knee pain.

MATERIALS AND METHODS

A total of 2959 painful knees from the Osteoarthritis Initiative database were analyzed. Trained interviewers recorded patient-reported location of knee pain. Painful knees were divided into 3 groups of patellofemoral only pain, tibiofemoral only pain, and combined pain. Self-reported knee-specific symptoms, functional status, and knee-related quality of life were assessed using the Knee Injury and Osteoarthritis Outcome Score.

RESULTS

The most common knee pain pattern was tibiofemoral only pain (62%), followed by patellofemoral only pain (23%), and combined pain (15%). The combined pain pattern was associated with greater odds of reporting pain, symptoms, sports, or recreational activity limitations and lower knee-related quality of life compared with either isolated knee pain patterns, after adjusting for demographics and radiographic disease severity. Individual item analysis further revealed that patients with combined pain had greater odds of reporting difficulty with daily weight-bearing activities that required knee bending compared with tibiofemoral or patellofemoral only pain patterns. Furthermore, symptoms, functional status, and knee-related quality of life were comparable between patients with patellofemoral and tibiofemoral only pain patterns, after adjusting for demographics and radiographic disease severity.

DISCUSSION

Combined patellofemoral and tibiofemoral pain is associated with poorer clinical presentation compared with isolated knee pain from either location. In addition, patellofemoral pain in isolation may be as important as tibiofemoral pain in causing symptoms and functional limitation in older adults with chronic knee pain.

Blockade of hypoxia-induced CXCR4 with AMD3100 inhibits production of OA-associated catabolic mediators IL-1β and MMP-13

Binding of the chemokine stromal cell-derived factor-1 (SDF-1) to its receptor C-X-C chemokine receptor type 4 (CXCR4) results in receptor activation and the subsequent release of matrix metalloproteinases (MMPs) that contribute to osteoarthritis (OA) cartilage degradation. As hypoxia is a defining feature of the chondrocyte microenvironment, the present study investigated the possible mechanism through which SDF‑1 induces cartilage degradation under hypoxic conditions. To do this, OA chondrocyte cultures and patient tissue explants pretreated with the CXCR4 inhibitor, AMD3100 were incubated with SDF‑1. It was identified that hypoxic conditions significantly elevated the expression of CXCR4 in osteoarthritic chondrocytes relative to normoxic conditions. Furthermore, SDF‑1 elevated MMP‑13 mRNA levels and proteinase activity. It also elevated the mRNA and protein levels of runt‑related transcription factor 2, and induced the release of glycosaminoglycans and the inflammatory cytokine, interleukin‑1β. By contrast, such changes did not occur to an appreciable degree in cells that were pretreated with AMD3100. The results of the present study demonstrate that even under hypoxic conditions, where CXCR4 expression is significantly elevated in chondrocytes, AMD3100 effectively blocks this receptor and protects chondrocytes from OA‑induced catabolism, suggesting that the successful inhibition of CXCR4 may be an effective approach for OA treatment.

Prognosis of Pain and Physical Functioning in Patients With Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically summarize the literature on the course of pain in patients with knee osteoarthritis (OA), prognostic factors that predict deterioration of pain, the course of physical functioning, and prognostic factors that predict deterioration of physical functioning in persons with knee OA.

METHODS

A search was conducted in PubMed, CINAHL, Embase, Psych-INFO, and SPORTDiscus up to January 2014. A meta-analysis and a qualitative data synthesis were performed.

RESULTS

Of the 58 studies included, 39 were of high quality. High heterogeneity across studies (I(2)  >90%) and within study populations (reflected by large SDs of change scores) was found. Therefore, the course of pain and physical functioning was interpreted to be indistinct. We found strong evidence for a number of prognostic factors predicting deterioration in pain (e.g., higher knee pain at baseline, bilateral knee symptoms, and depressive symptoms). We also found strong evidence for a number of prognostic factors predicting deterioration in physical functioning (e.g., worsening in radiographic OA, worsening of knee pain, lower knee extension muscle strength, lower walking speed, and higher comorbidity count).

CONCLUSION

Because of high heterogeneity across studies and within study populations, no conclusions can be drawn with regard to the course of pain and physical functioning. These findings support current research efforts to define subgroups or phenotypes within knee OA populations. Strong evidence was found for knee characteristics, clinical factors, and psychosocial factors as prognostics of deterioration of pain and physical functioning.

Mechanical hyperalgesia and reduced quality of life occur in people with mild knee osteoarthritis pain

OBJECTIVES

This study determined whether individuals with mild knee pain due to osteoarthritis (OA) experience hyperalgesia and central sensitivity by comparing them with age-matched and sex-matched control participants and determined whether these levels are associated with pain intensity. This study also determined whether these individuals experience significantly poorer quality of life than age-matched and sex-matched controls and whether pain and function predict quality of life.

METHODS

Quantitative sensory tests (QSTs), including punctate pain intensity (PPI), pressure pain threshold (PPT), and heat pain threshold, tolerance, and temporal summation, were measured in 75 individuals with mild knee OA pain and 25 age-matched and sex-matched controls. Pain intensity, walking function, and quality of life were also assessed.

RESULTS

Significant differences were found for PPI at all sites, for PPT at the affected knee, and for quality of life. QST measures significantly correlated with pain intensity. Pain, but not function, predicted quality of life.

DISCUSSION

Individuals with mild knee pain due to OA experience mechanical (but not thermal) hyperalgesia that relates to pain intensity. They have a reduced quality of life that is predicted by pain intensity. More aggressive pain management for mild knee OA pain is indicated to improve the quality of life for individuals who are not yet candidates for joint replacement.

Decrease of muscle strength is associated with increase of activity limitations in early knee osteoarthritis: 3-year results from the cohort hip and cohort knee study

OBJECTIVE

To determine whether a decrease in muscle strength over 3 years is associated with an increase in activity limitations in persons with early symptomatic knee osteoarthritis (OA), and to examine whether the longitudinal association between muscle strength and activity limitations is moderated by knee joint proprioception and laxity.

DESIGN

A longitudinal cohort study with 3-year follow-up. Measurements were performed at the second (t0) and fifth (t1) year of the Cohort Hip and Cohort Knee (CHECK) study. Statistical analyses included paired t tests, chi-square tests, and regression analyses. In regression analyses, the association between muscle strength and activity limitations was adjusted for confounders.

SETTING

A rehabilitation and rheumatology center.

PARTICIPANTS

Subjects (N=146) with early symptomatic knee OA from the CHECK study.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Muscle strength, proprioception, and laxity were assessed using specifically designed measurement devices. Self-reported and performance-based activity limitations were measured with the Western Ontario and McMaster Universities Osteoarthritis Index, the Get Up and Go test, the walk test, and the stair-climb test.

RESULTS

A total of 116 women (79.5%) and 30 men (20.5%), with a mean age ± SD of 58.4±4.9 years and a mean body mass index ± SD of 25.5±3.6, were included in the study. Overall, small 3-year changes in muscle strength and activity limitations were observed. At the group level, the average muscle strength increased by 10% (1.0±0.3 to 1.1±0.3Nm/kg) over the 3 years. The 3-year decrease in muscle strength was independently associated with an increase in performance-based activity limitations on all 3 measures (B=-1.12, B=-5.83, and B=-1.25, respectively). Proprioception and laxity did not moderate this association.

CONCLUSIONS

In patients with early knee OA, decreased muscle strength is associated with an increase in activity limitations. Our results are a step toward understanding the role of muscle weakness in the development of activity limitations in knee OA. Further well-designed experimental studies are indicated to establish the causal role of muscle weakness in activity limitations.

Association of knee confidence with pain, knee instability, muscle strength, and dynamic varus-valgus joint motion in knee osteoarthritis

OBJECTIVE

To investigate associations between self-reported knee confidence and pain, self-reported knee instability, muscle strength, and dynamic varus-valgus joint motion during walking.

METHODS

We performed a cross-sectional analysis of baseline data from 100 participants with symptomatic and radiographic medial tibiofemoral compartment osteoarthritis (OA) and varus malalignment recruited for a randomized controlled trial. The extent of knee confidence, assessed using a 5-point Likert scale item from the Knee Injury and Osteoarthritis Outcome Score, was set as the dependent variable in univariable and multivariable ordinal regression, with pain during walking, self-reported knee instability, quadriceps strength, and dynamic varus-valgus joint motion during walking as independent variables.

RESULTS

One percent of the participants were not troubled with lack of knee confidence, 17% were mildly troubled, 50% were moderately troubled, 26% were severely troubled, and 6% were extremely troubled. Significant associations were found between worse knee confidence and higher pain intensity, worse self-reported knee instability, lower quadriceps strength, and greater dynamic varus-valgus joint motion. The multivariable model consisting of the same variables significantly accounted for 24% of the variance in knee confidence (P < 0.001).

CONCLUSION

Worse knee confidence is associated with higher pain, worse self-reported knee instability, lower quadriceps muscle strength, and greater dynamic varus-valgus joint motion during walking. Since previous research has shown that worse knee confidence is predictive of functional decline in knee OA, addressing lack of knee confidence by treating these modifiable impairments could represent a new therapeutic target.

Associations of foot posture and function to lower extremity pain: results from a population-based foot study

OBJECTIVE

Studies have implicated foot posture and foot function as risk factors for lower extremity pain. Empirical population-based evidence for this assertion is lacking; therefore, the purpose of this study was to evaluate cross-sectional associations of foot posture and foot function to lower extremity joint pain in a population-based study of adults.

METHODS

Participants were members of the Framingham Foot Study. Lower extremity joint pain was determined by the response to the National Health and Nutrition Examination Survey-type question, "On most days do you have pain, aching or stiffness in your (hips, knees, ankles, or feet)?" The Modified Arch Index classified participants as having planus, rectus (referent), or cavus foot posture. The Center of Pressure Excursion Index classified participants as having overpronated, normal (referent), or oversupinated foot function. Crude and adjusted (age, sex, and body mass index) logistic regression determined associations of foot posture and function to lower extremity pain.

RESULTS

Participants with planus structure had higher odds of knee (odds ratio [OR] 1.57, 95% confidence interval [95% CI] 1.24-1.99) or ankle (OR 1.47, 95% CI 1.05-2.06) pain, whereas those with a cavus foot structure had increased odds of ankle pain only (OR 7.56, 95% CI 1.99-28.8) and pain at 1 lower extremity site (OR 1.37, 95% CI 1.04-1.80). Associations between foot function and lower extremity joint pain were not statistically significant except for a reduced risk of hip pain in those with an oversupinated foot function (OR 0.69, 95% CI 0.51-0.93).

CONCLUSION

These findings offer a link between foot posture and lower extremity pain, highlighting the need for longitudinal or intervention studies.

The avoidance model in knee and hip osteoarthritis: a systematic review of the evidence

The avoidance model in patients with knee and hip osteoarthritis (OA) hypothesizes that pain and psychological distress lead to avoidance of activities, and thereby to muscle weakness and activity limitations. This paper systematically reviews the scientific evidence for the validity of this avoidance model. A qualitative data synthesis was used to identify levels of evidence. Sixty studies were included. In knee OA, strong evidence was found that avoidance of activities is associated with activity limitations via muscle weakness (mediation by muscle weakness), strong evidence was found for an association between muscle weakness and activity limitations, and weak evidence was found that pain and psychological distress are associated with muscle weakness via avoidance of activities (mediation by avoidance). In hip OA, weak evidence was found for mediation by muscle weakness; and strong evidence was found for an association between muscle weakness and activity limitations. More research is needed on the consecutive associations between pain or psychological distress, avoidance of activities and muscle weakness, and to confirm causal relationships.

The PICO project: aquatic exercise for knee osteoarthritis in overweight and obese individuals

BACKGROUND

Aquatic exercise is recommended by the Osteoarthritis Research Society (OARSI), by the American College of Rheumatology (ACR) and by the European League Against Rheumatism (EULAR) as a nonpharmacological method of controlling the knee osteoarthritis (KOA) symptoms. Moreover, given that weight loss results in a reduction of the load that is exerted upon the knee during daily activities, obesity is also considered to be a modifiable risk factor for the development and or exacerbation of KOA. The implementation of an exercise based weight loss program may, however, itself be limited by the symptoms of KOA. The aquatic program against osteoarthritis (termed "PICO" in Portuguese) prioritizes the control of symptoms and the recovery of functionality, with an attendant increase in the patient's physical activity level and, consequently, metabolic rate. Our laboratory is assessing the effectiveness of 3 months of PICO on the symptoms of KOA, on physical function, on quality of life and on gait. In addition, PICO shall examine the effects of said exercise intervention on inflammatory biomarkers, psychological health, life style and body composition.

METHODS/DESIGN

The trial is a prospective, single-blinded, randomized controlled trial, and involves 50 overweight and obese adults (BMI = 28-43.5 kg/m²; age 40-65 yrs) with radiographic KOA. The participants are randomly allocated into either an educational attention (control) group or an aquatic (exercise program) group. This paper describes the experimental protocol that is used in the PICO project.

DISCUSSION

The PICO program shall provide insight into the effectiveness of an aquatic exercise program in the control of KOA symptoms and in the improvement of the quality of life. As such, they are likely to prove a useful reference to health professionals who intend to implement any kind of therapeutic intervention based around aquatic exercise.

TRIAL REGISTRATION

NCT01832545.

Effects of self-reported osteoarthritis on physical performance: a longitudinal study with a 10-year follow-up

BACKGROUND AND AIMS

Osteoarthritis (OA) of the knee or hip is associated with limitations in activities of daily life. There are only a few long-term studies on how knee or hip OA affects the course of physical performance. The aim of this study was to investigate the effects of knee or hip OA on physical performance during a follow-up period of 10 years.

METHODS

Participants in the Longitudinal Aging Study Amsterdam with self-reported hip or knee OA (N = 155) were prospectively followed for 10 years on 4 occasions from the onset of OA and compared to participants without OA (N = 1004). Physical performance was tested with walk, chair stand and balance tests. Scores for each test were summed to a total performance score (range 0-12), higher scores indicating better performance. Generalized estimating equations were used to analyze differences between participants with and without OA, unadjusted as well as adjusted for confounders.

RESULTS

There was a significant interaction between OA and sex (P = 0.068). Both in men and women, total performance was lower for participants with OA, with greater differences in men. Chair stand and walking performance (P < 0.05), but not balance, were lower in participants with OA. After adjustment for confounders, these associations remained significant in men but not in women. Additional analyses correcting for follow-up duration and attrition showed lower performance scores for men and women with OA.

CONCLUSIONS

OA negatively affected physical performance 3-6 years after it was first reported. Performance in men with OA was more affected than in women.

Unilateral vs bilateral symptomatic knee osteoarthritis: associations between pain intensity and function

OBJECTIVE

The objective of this study was to determine if associations between pain distribution (unilateral vs bilateral) and measures of function (self-report vs performance-based) were influenced by knee pain intensity of the painful knee(s) in persons with moderate to severe symptomatic knee OA.

METHODS

Data from persons in the Osteoarthritis Initiative (OAI) dataset (n = 852) with symptomatic knee OA were studied. Key dependent variables were the WOMAC physical function, Knee Injury and Osteoarthritis Outcome Score (KOOS) quality of life, the repeated chair stand test and the 20-m walk test. In addition to covariates, the independent variables were the presence of unilateral or bilateral OA involvement (either Kellgren and Lawrence grade 3 or 4 or a grade <3) and pain category (mild, moderate or severe).

RESULTS

WOMAC physical function scores consistently showed the strongest association with pain intensity for persons with unilateral vs bilateral knee pain. For example, in persons with unilateral severe knee pain, WOMAC scores averaged 19.9 (S.D. = 12.0) points while persons with bilateral knee pain with at least one knee rated as severe had WOMAC scores ranging from 25.3 to 28.9, depending on pain severity of the contralateral knee. These differences were statistically significant (P < 0.001) as was the test for trend (P = 0.001). Self-report measures generally showed larger effect sizes than performance-based measures.

CONCLUSION

Knee pain intensity influences self-report and performance-based tests differently depending on whether knee pain is unilateral or bilateral. WOMAC scores are most strongly associated with pain intensity in persons with unilateral vs bilateral pain while walking tests are least influenced by pain intensity.

The age-related changes in cartilage and osteoarthritis

Osteoarthritis (OA) is closely associated with aging, but its underlying mechanism is unclear. Recent publications were reviewed to elucidate the connection between aging and OA. With increasing OA incidence, more senior people are facing heavy financial and social burdens. Age-related OA pathogenesis is not well understood. Recently, it has been realized that age-related changes in other tissues besides articular cartilage may also contribute to OA development. Many factors including senescence-related secretory phenotypes, chondrocytes' low reactivity to growth factors, mitochondrial dysfunction and oxidative stress, and abnormal accumulation of advanced glycation end products (AGEs) may all play key roles in the pathogenesis of age-related OA. Lately, epigenetic regulation of gene expression was recognized for its impact on age-related OA pathogenesis. Up to now, few studies have been reported about the role of miRNA and long-noncoding RNA (lncRNA) in age-related OA. Research focusing on this area may provide valuable insights into OA pathogenesis. OA-induced financial and social burdens have become an increasingly severe threat to older population. Age-related changes in noncartilage tissue should be incorporated in the understanding of OA development. Growing attention on oxidative stress and epigenetics will provide more important clues for the better understanding of the age-related OA.

Excess body weight and four-year function outcomes: comparison of African Americans and whites in a prospective study of osteoarthritis

OBJECTIVE

We evaluated whether African Americans in the Osteoarthritis Initiative (OAI) have a greater risk (versus whites) of poor 4-year function outcome within strata defined by sex, body mass index (BMI), and waist circumference.

METHODS

Using Western Ontario and McMaster Universities Osteoarthritis Index function, 20-meter walk, and chair stand performance, poor outcome was defined as moving into a worse function group or remaining in the 2 worst groups over 4 years. Logistic regression was used to evaluate the relationship between racial group and outcome within each stratum, adjusting for age, education, and income, and then further adjusting for BMI, comorbidity, depressive symptoms, physical activity, knee pain, and osteoarthritis (OA) severity.

RESULTS

In 3,695 persons with or at higher risk for knee OA, higher BMI and large waist circumference were each associated with poor outcome. Among women with high BMI and among women with large waist circumference, African Americans were at greater risk for poor outcome by every measure, adjusting for age, education, and income. From fully adjusted models, potential explanatory factors included income, comorbidity, depressive symptoms, pain, and disease severity. Findings were less consistent for men, emerging only for the 20-meter walk or chair stand outcomes, and potentially explained by age and knee pain.

CONCLUSION

Among OAI women with excess body weight, African Americans are at greater risk than whites for poor 4-year outcome. Modifiable factors that may help to explain these findings in the OAI include comorbidity, depressive symptoms, and knee pain. Targeting such factors, while supporting weight loss, may help to lessen the outcome disparity between African American and white women.

Associations for change in physical and psychological factors and treatment response following exercise in knee osteoarthritis: an exploratory study

OBJECTIVE

Understanding how changes in physical and psychological factors following therapeutic exercise are associated with treatment outcome could have important implications for refining rehabilitation programs for knee osteoarthritis (OA). The objective of this study was to examine the association of changes in these factors with changes in pain and function after an exercise program for people with knee OA.

METHODS

In total, 152 people with knee OA completed an exercise program consisting of lower extremity strengthening, stretching, range of motion, balance and agility, and aerobic exercises. The change from baseline to the 2-month followup was calculated for physical and psychological factors, including self-reported knee instability, quadriceps strength, knee and ankle range of motion, lower extremity muscle flexibility, fear of physical activity, anxiety, and depressive symptoms. Treatment response was defined as a minimum of a 20% improvement from baseline in both a numerical knee pain rating scale and the Western Ontario and McMaster Universities Osteoarthritis Index physical function scale. The association of each factor with treatment response was examined with logistic regression mutually adjusted for age, sex, body mass index, radiographic severity, and exercise group.

RESULTS

Change in self-reported knee instability (odds ratio [OR] 1.67 [95% confidence interval (95% CI) 1.13-2.47]) and fear of physical activity (OR 0.93 [95% CI 0.88-1.00]) were the only 2 factors that were significantly associated with treatment response after adjustment for covariates.

CONCLUSION

Improvement in knee instability and fear of physical activity were associated with increased odds of a positive treatment response following therapeutic exercise in subjects with knee OA.

Knee confidence as it relates to physical function outcome in persons with or at high risk of knee osteoarthritis in the osteoarthritis initiative

OBJECTIVE

To evaluate whether low knee confidence at baseline is associated with poor baseline-to-3-year physical function outcome in the Osteoarthritis Initiative.

METHODS

Knee confidence was assessed using an item from the Knee Injury and Osteoarthritis Outcome Score instrument. Physical function was assessed using self-report measures (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] function score and Short Form 12 physical component scale) and performance-based measures (20-meter walk and chair stand test). Poor function outcome was defined as moving into a worse function group or remaining in the 2 worst function groups between baseline and 3 years. Logistic regression was used to evaluate the relationship between baseline knee confidence level and poor baseline-to-3-year function outcome, adjusting for potential confounders.

RESULTS

The sample included 3,975 men and women with or at high risk of developing osteoarthritis of the knee, of whom 37-53% had poor baseline-to-3-year function outcome. For both self-report measures, increasingly worse knee confidence was associated with a greater risk of poor function outcome, and trend tests supported a graded response (e.g., the adjusted odds ratios [95% confidence intervals] for the WOMAC function score for worsening confidence categories were 1.26 [1.07-1.49], 1.43 [1.16-1.77], and 2.05 [1.49-2.82], P for trend <0.0001). Similar associations between confidence and performance-based function outcome were observed, but statistical significance did not persist in adjusted analyses. Factors independently associated with poor function outcome for all 4 outcome measures were depressive symptoms, comorbidity, body mass index, and joint space narrowing.

CONCLUSION

These findings indicate that worse knee confidence at baseline is independently associated with greater risk of poor function outcome by self-report measures, with evidence of a graded response; the relationship with performance measures is not significant in fully adjusted models.

Yoga for osteoarthritis: nursing and research considerations

Osteoarthritis (OA) is a leading cause of pain and disability worldwide. Current treatment guidelines recommend nonpharmacological approaches such as yoga for firstline treatment of OA. Yoga is a promising mind-body practice that includes physical postures, breathing practices, and meditative mental focus. This article presents the current evidence, as well as a proposed conceptual model for future research. Current research on yoga for OA is scant but promising, showing some evidence of reduced pain, sleep disturbance, and disability. The conceptual model described here proposes musculoskeletal effects (strengthening, flexibility, relaxation), reduction of autonomic arousal, and therapeutic cognitive patterns (distraction, mindfulness) as potentially important mechanisms of yoga. This article also describes considerations for patients and health care providers when evaluating the potential usefulness and safety of yoga programs: yoga style, instructor qualifications, and amount of time spent in yoga practice.

ARTICULAR SOUND AND CLINICAL STAGES IN KNEE ARTHROPATHY

Objective: To clarify the pathophysiology of knee arthropathy, articular sound in the knee joint was recorded using an accelerometer, vibroarthrography (VAG), during standing-up and sitting-down movements in patients with osteoarthropathy (OA) of the knees. Methods: VAG signals and angular changes of the knee joint during standing-up and sitting-down movements were recorded in patients with OA, including 17 knees with OA at Kellgren–Lawrence stage I and II, 16 knees with OA at III and IV stages, and 20 knees of age-matched control subjects. Results: The level of VAG signals was greater in knees with a higher stage of OA at 50–99 and 100–149 Hz among the groups (ANOVA with Tukey–Kramer multiple comparisons test, p < 0.01). The VAG signals did not correlate with WOMAC-pain or physical scores. Conclusions: We considered that the increase in VAG signals in these ranges of frequency corresponded with pathological changes of OA, but not self-reported clinical symptoms. This method of VAG can be used by clinicians during interventions to obtain pathological information regarding structural changes of the knee joint.

Prospective study of self-reported pain, radiographic osteoarthritis, sarcopenia progression, and falls risk in community-dwelling older adults

OBJECTIVE

To examine the potential role of self-reported joint pain, stiffness, and dysfunction, and radiographic osteoarthritis (ROA), in sarcopenia progression and falls risk in older adults.

METHODS

Seven hundred nine older adults (50% women, mean ± SD age 62 ± 7 years) were examined at baseline and followup (mean ± SD 2.6 ± 0.4 years). ROA was assessed using the Altman atlas, and pain at 7 anatomic sites was self-reported. Dual x-ray absorptiometry assessed leg lean mass, dynamometry assessed knee extension and whole leg strength, leg muscle quality (LMQ) was calculated as whole leg strength relative to leg lean mass, and the Physiological Profile Assessment assessed falls risk.

RESULTS

In women only, baseline knee pain predicted a greater decline in knee extension strength, whole leg strength, and LMQ, and a greater increase in falls risk. Severe knee pain, stiffness, and dysfunction predicted greater declines in knee extension strength and increases in falls risk (all P < 0.05). Hip pain also predicted a greater decline in knee extension strength (-1.53 kg; 95% confidence interval [95% CI] -2.95, -0.11). No associations were observed between pain and sarcopenia indicators in men. Somewhat surprisingly, higher baseline total knee ROA score predicted a greater increase in mean leg lean mass (0.05 kg; 95% CI 0.02, 0.08) in both sexes. A path analysis demonstrated that knee ROA may contribute to declines in LMQ in women, through increases in pain, stiffness, and dysfunction.

CONCLUSION

Knee and hip pain may directly contribute to the progression of sarcopenia and increased falls risk in older women.

Development of a standardised Occupational Therapy--Driver Off-Road Assessment Battery to assess older and/or functionally impaired drivers

INTRODUCTION

Research has been conducted over several years to develop a new off-road assessment battery referred to as the Occupational Therapy - Driver Off-Road Assessment Battery. This article documents the development of the Battery, and provides preliminary research evidence to support its content and predictive validity.

METHODS

Literature reviews and a focus group with nine driver assessor occupational therapists were undertaken, as well as data collection using the Occupational Therapy - Driver Off-Road Assessment Battery with 246 clients. A Classification and Regression Tree model was constructed to ascertain the predictive validity of the Battery, with fitness-to-drive as the outcome.

RESULTS

Twenty-one physical, 13 sensory and seven assessments of cognition/perception were identified as being reflective of the skills required for driving. Following rating of their psychometric properties, the best assessments were presented to focus group members. The driver assessors supported the inclusion of several assessments and encouraged the development of new assessments. A draft version of the Occupational Therapy - Driver Off-Road Assessment Battery was tested and found to have excellent predictive validity for client on-road performance of 82.6%. The Classification and Regression Tree model showed that client performance on tests included in the Battery should be used together, rather than in isolation, to support fitness-to-drive recommendations.

CONCLUSION

This research identified the most suitable physical, sensory and cognitive assessments to include in the Occupational Therapy - Driver Off-Road Assessment Battery, and provided support for its validity. The development of this standardised battery assists driver assessors to accurately and consistently assess and report the off-road driving capacity of clients.

Feasibility of bone density evaluation using plain digital radiography

OBJECTIVE

For the radiographic evaluation of subchondral bone changes (sclerosis) in osteoarthritis (OA), bone density (BD) is commonly subjectively assessed. BD evaluation using plain digital radiography might be influenced by acquisition and post-processing (PP) settings. Objective of this study was to evaluate the effects of these settings on the measurement of BD using digital radiographs.

METHODS

A bone density standard (BDS) of hydroxyapatite (HA) mimicked a BD range of 1.0-5.75 g/cm(2). Digital radiographs were acquired with variation in acquisition settings, and with clinical and minimal PP. An aluminum step wedge served as an internal reference to express the gray values of the BDS in mm aluminum equivalents (mmAl). The relation (R(2)) between actual BD and BD normalized to the reference wedge was evaluated with linear regression analyses for radiographs with variations in PP and acquisition settings. Precision of BD measurement of the BDS was evaluated for application in clinical practice.

RESULTS

The correlation between actual BD and BD normalized to the reference was improved by changing PP from clinical (R(2)=0.96) to minimal (R(2)=0.98). Higher tube voltage [kilovolt (kV)] improved the correlation further. Even for clinical PP, average standard deviation (SD) was 0.97 mmAl, much smaller than the change of 2.51 mmAl clinically observed in early OA, which implies the feasibility of BD measurements on digital radiographs.

CONCLUSION

Changing PP and acquisition settings in clinical practice can have profound effect on outcome. If done with care, accurate BD measurement is feasible using plain digital radiography.

Prevalence of knee pain and its influence on quality of life and physical function in the Korean elderly population: a community based cross-sectional study

To investigate the prevalence of knee pain and its influence on physical function and quality of life (QOL), we examined 504 community residents of Chuncheon, aged ≥ 50 yr. Demographic information was obtained by questionnaire, and radiographic evaluations consisted of weight-bearing semi-flexed knee anteroposterior radiographs. Self-reported QOL and function were assessed using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index and Short Form 12 (SF-12). Performance-based lower extremity function was assessed using the tests consisting of standing balance, usual walk and chair stands. The prevalence of knee pain was 46.2% (32.2% in men and 58.0% in women) and increased with age in women. After adjustment of confounders including the presence of knee OA, the subjects with knee pain had significantly worse WOMAC function and SF-12 scores compared to subjects without knee pain. Among the subjects with knee pain, women had worse WOMAC and SF-12 scores than men. Subjects with knee pain had worse physical performance score compared to those without knee pain, especially among females. In conclusion, the prevalence of knee pain is high (32.2% in men and 58.0% in women) in this elderly community population in Korea. Independent of knee OA and other confounding factors, subjects with knee pain have more than 5-fold increase in the risk of belonging to the worst lower extremity function compared to subjects without knee pain.

The epidemiology of sarcopenia in community living older adults: what role does lifestyle play?

BACKGROUND: Sarcopenia, the age-related decline in skeletal muscle mass and function, is a relatively poorly understood process which may play an important role in the incidence of physical disability and falls in older adults. Evidence demonstrates that both genetic and environmental factors contribute to increased susceptibility for sarcopenia development, yet some of these factors may represent unavoidable consequences of ageing. METHODS: A review of literature, generally from epidemiological research, was performed to examine the influence that potentially modifiable lifestyle factors (general physical activity, dietary nutrient intake and sun exposure), as well as chronic disease and medication use, may have on sarcopenia progression. RESULTS: The review demonstrated that while physical activity, nutrient intake and sun exposure often decline during ageing, each may have important but differing benefits for the prevention of muscle mass and functional declines in older adults. Conversely, age-related increases in the prevalence of chronic diseases and the subsequent prescription of pharmacotherapy may exacerbate sarcopenia progression. CONCLUSIONS: The prevalence of poor physical activity, diet and sun exposure, as well as chronic disease and medication use, within older adult populations may be modifiable through simple lifestyle and health care interventions. As such, these factors may represent the most effective targets for sarcopenia prevention during the ageing process.

A systematic review of the association between radiographic and clinical osteoarthritis of hip and knee

OBJECTIVE

There is ongoing debate on whether an association between radiographic and clinical osteoarthritis (OA) exists. We hypothesized that the inconsistency in the detection of an association might be caused by different definitions of OA, by different radiographic protocols, and by scoring methods for radiographic damage and symptoms. The goal of this study was to evaluate which methodological criteria are important to detect an association between radiographic and clinical OA of hip and knee.

METHODS

A literature search was performed with the keywords 'OA', 'hip', 'knee', 'radiographic', and 'clinical' and results were screened for relevant studies. Quality criteria for study characteristics and methodology were developed. Studies were classified according to these criteria and the presence of an association between radiographic and clinical OA was scored. The importance of methodological quality and patient characteristics on the presence of an association was evaluated.

RESULTS

The literature search resulted in 39 studies describing an association between radiographic and clinical OA. The frequency of an association between radiographic and clinical OA outcome measures diminished when less quality criteria were fulfilled. Specifically the criterion for standardized outcome measures appeared important in the detection of an association. The association was not influenced by patient characteristics. Only four studies were identified that fulfilled all quality criteria and in these studies an association was found for the knee joint and an inconsistent association was found for the hip joint.

CONCLUSION

Methodological quality criteria are of importance to reveal an association between radiographic and clinical OA.

Relationship between radiological severity and clinical and psychological factors in knee osteoarthritis

This study was designed to investigate the relationship between radiological severity and clinical and psychological factors in patients with knee osteoarthritis (OA). Patients with knee OA (n = 100) were included in the study. Radiographic staging was done using Kellgren-Lawrence (KL) radiological rating scale. Stage 1-2 changes according to KL were grouped as 'early' and stage 3-4 as 'late' radiological OA. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used for self-reported disability. Performance-based functional assessments were measured as time needed to walk 15 m and time needed to climb ten steps. Health-related quality of life was assessed by Nottingham Health Profile (NHP). Beck Depression Inventory (BDI) was used to assess the presence and severity of depression. Social isolation was assessed by a related NHP subscale. Significantly higher scores were found in the late stage group for NHP pain, physical mobility and social isolation subscales and all WOMAC subscales. Mean BDI score was significantly higher (p = 0.001) and performance-based functional score was significantly worse (p < 0.001) in the late stage group compared to the early stage. In logistic regression analysis, NHP social isolation subscore was found to be associated with WOMAC pain subscore (p = 0.013, odds ratio [OR] = 1.163; 95% confidence interval [CI], 1.032-1.309) and radiological severity (p = 0.018, OR = 2.924; 95% CI, 1.198-7.136). Radiological severity is an important indicative factor for pain, disability, depression and social isolation. We believe that assessment of psychological involvement in addition to pain and disability might provide benefit in the management of patients with advanced radiological knee OA.

Does electric stimulation of the vastus medialis muscle influence rehabilitation after total knee replacement?

Patients with knee osteoarthritis present with reduced quadriceps muscle strength, which is partially responsible for impaired function and disability. Although total knee replacement (TKR) is an effective surgical procedure, residual muscle weakness is not usually addressed and may persist for years postoperatively. This article reports the results of a prospective, randomized, controlled trial evaluating the effect of electric muscle stimulation of the vastus medialis on the speed and effort of walking, quality of life, and knee performance in patients undergoing TKR. Seventy patients who underwent TKR were randomly divided into 2 groups. Patients in group A received electric muscle stimulation and standard physiotherapy for 6 weeks, while patients in group B received physiotherapy only. All patients were assessed with both subjective and objective clinical scales preoperatively and at 6, 12, and 52 weeks postoperatively. Patients in group A demonstrated a statistically significant increase in walking speed, Oxford Knee Score, and American Knee Society function score compared to those in group B at 6 weeks (P=.003, .001, and .001, respectively) and at 12 weeks (all P=.001). A statistically significant increase in the SF-36 physical component summary score was observed at 6, 12, and 52 weeks (all P=.001). Three patients found the sensation of the electrical stimulation uncomfortable and abandoned its use. No skin reactions and surgical site infections were observed. Electrical stimulation of the vastus medialis muscle in addition to conventional physiotherapy improves functional recovery and early rehabilitation after TKR.

Phenotypic alterations of neurons that innervate osteoarthritic joints in rats

OBJECTIVE

Pain is a prominent feature of osteoarthritis (OA). To further understand the primary mechanisms of nociception in OA, we studied the expression of the phenotype markers calcitonin gene-related peptide (CGRP), isolectin B4 (IB4), and neurofilament 200 (NF200) in sensory neurons innervating the OA knee joint in rats.

METHODS

OA was induced in rats by intraarticular injection of 2 mg of mono-iodoacetate (MIA) into the knee. Neurons innervating the joint were identified by retrograde labeling with fluorogold in dorsal root ganglia (DRG) and colocalized with neurochemical markers by immunofluorescence. The total number of DRG cells was determined by stereologic methods in Nissl-stained sections.

RESULTS

A 37% decrease in the number of fluorogold-backlabeled cells was observed in rats with OA when compared with control rats, even though no decrease in the total number of cells was observed. However, an increase in the number of medium/large cell bodies and a decrease in the number of the smallest cells were observed, suggesting the occurrence of perikarya hypertrophy. The percentage of CGRP-positive cells increased significantly, predominantly in medium/large cells, suggesting the occurrence of a phenotypic switch. Colocalization of CGRP and NF200 revealed no significant changes in the percentage of double-labeled cells, but an increase in the number of medium/large double-labeled cells was observed. No differences in the expression of either IB4 or NF200 were observed in fluorogold-backlabeled cells.

CONCLUSION

These results indicate that MIA-induced OA causes an up-regulation of CGRP in different subpopulations of primary afferent neurons in DRG due to a phenotypic switch and/or cell hypertrophy which may be functionally relevant in terms of the onset of pain in this pathologic condition.

Brain activity for chronic knee osteoarthritis: dissociating evoked pain from spontaneous pain

Chronic pain is a hallmark of osteoarthritis (OA), yet little is known about its properties and representation in the brain. Here we use fMRI combined with psychophysics to study knee pain in fourteen OA patients and nine healthy controls. Mechanical painful pressure stimuli were applied to the knee in both groups and ratings of evoked pain and related brain activity examined. We observe that psychophysical properties and brain activation patterns of evoked pain are essentially the same between OA patients and healthy subjects, and between worse and better OA knees. In OA patients, stimulus-related brain activity could be distinguished from brain activity associated with spontaneous pain. The former activated brain regions commonly observed for acute painful stimuli in healthy subjects, while the spontaneous pain of OA engaged prefrontal-limbic regions closely corresponding to areas observed for spontaneous pain in other chronic pain conditions, such as chronic back pain and post-herpetic neuralgia. Arthritis-related clinical characteristics of knee OA also mapped to prefrontal-limbic regions. In a subgroup of patients (n=6) we examined brain activity changes for a 2-week, repeat measure, cyclooxygenase-2 inhibitor (valdecoxib) therapy. Treatment decreased spontaneous pain for the worse knee and clinical characteristics of OA, and increased blood and csf levels of the drug which correlated positively with prefrontal-limbic brain activity. These findings indicate dissociation between mechanically induced and spontaneous OA knee pain, the latter engaging brain regions involved in emotional assessment of the self, and challenge the standard clinical view regarding the nature of OA pain.