Knee extensor muscle weakness is a risk factor for the development of knee osteoarthritis: an updated systematic review and meta-analysis including 46 819 men and women

ObjectiveTo update a systematic review on the association between knee extensor muscle weakness and the risk of incident knee osteoarthritis in women and men.DesignSystematic review and meta-analysis.Data sourcesSystematic searches in PubMed, EMBASE, SPORTDiscus, CINAHL, AMED and CENTRAL in May 2021.Eligible criteria for selecting studiesLongitudinal studies with at least 2 years follow-up including baseline measure of knee extensor muscle strength, and follow-up measure of symptomatic or radiographic knee osteoarthritis. Studies including participants with known knee osteoarthritis at baseline were excluded. Risk of bias assessment was conducted using six criteria for study validity and bias. Grading of Recommendations Assessments, Development and Evaluation assessed overall quality of evidence. Meta-analysis estimated the OR for the association between knee extensor muscle weakness and incident knee osteoarthritis.ResultsWe included 11 studies with 46 819 participants. Low quality evidence indicated that knee extensor muscle weakness increased the odds of symptomatic knee osteoarthritis in women (OR 1.85, 95% CI 1.29 to 2.64) and in adult men (OR 1.43, 95% CI 1.14 to 1.78), and for radiographic knee osteoarthritis in women: OR 1.43 (95% CI 1.19 to 1.71) and in men: OR 1.39 (95% CI 1.07 to 1.82). No associations were identified for knee injured populations except for radiographic osteoarthritis in men.DiscussionThere is low quality evidence that knee extensor muscle weakness is associated with incident symptomatic and radiographic knee osteoarthritis in women and men. Optimising knee extensor muscle strength may help to prevent knee osteoarthritis.PROSPERO registration numberCRD42020214976.

Prevalence of frailty and associated factors among community-dwelling older adults after total hip arthroplasty

Objective: To evaluate the prevalence of frailty and associated factors among community-dwelling older adults who have undergone total hip arthroplasty (THA). Materials and methods: This study, which employed a cross-sectional, observational design, was conducted between April and November 2020. The participants were older adults (⩾65 years) who had undergone primary THA at the study hospital. Based on Fried’s modified phenotype, frailty was stratified into 3 degrees according to the presence of 3 or more of the following components: weight loss, weakness, exhaustion, low activity level, and slow walking speed. Multinomial logistic regression was used to analyse the associations of frailty with its potential risk factors. Results: The data of 518 participants were analysed. The overall prevalence of frailty and prefrailty was 11.4% and 51.0%, respectively. The multinomial logistic regression analysis showed that calf circumference (odds ratio [OR] 0.716, 95% confidence interval [CI], 0.611–0.839; p < 0.001), fall history (OR 2.435, 95% CI, 1.114–5.322; p = 0.026), hip abductor muscle strength (OR 0.962, 95% CI, 0.938–0.987; p = 0.003), knee extensor muscle strength (OR 0.980, 95% CI, 0.964–0.996; p = 0.013), and Timed Up and Go test (TUG) performance (OR 1.802, 95% CI, 1.458–2.228; p < 0.001) were associated with frailty. Conclusions: Frailty was highly prevalent in community-dwelling older adults after THA. Further, its potential associations with calf circumference, hip abductor and knee extensor muscle strength, TUG performance, and fall history highlight the significance of these factors for interventions.

Physical and Mental Functions of Cardiovascular Disease Patients Decrease during the State of Emergency Initiated by the COVID-19 Pandemic in Japan

Background and Objective: We aimed to examine the differences in life-space mobility and quality of life (QoL) of patients with cardiovascular disease (CVD) between the pre- and post-nationwide state of emergency initiated by the Coronavirus disease 2019 (COVID-19) pandemic in Japan and to show the factors associated with the decrease in life-space mobility and QoL in these patients. Methods: We undertook a longitudinal study of 20 of 51 consecutive CVD patients with coronary artery disease (CAD) who met the study criteria. We used the Life-Space Assessment (LSA) tool to evaluate Life-space mobility and assessed QoL with the five-level EuroQoL five-dimensional questionnaire (EQ-5D-5L) in Japanese. Results: The LSA scores and EQ-5D-5L QoL score decreased significantly from the pre- to post-nationwide state of emergency in Japan (p < 0.01). ΔLSA was significantly positively associated with body mass index and significantly negatively associated with knee extensor muscle strength and pre-LSA score (p < 0.05). There were no significant relationships between ΔLSA and ΔEQ-5D-5L QoL scores and between ΔEQ-5D-5L QoL scores and patient characteristics. Conclusion: The policies promoted to address the state of emergency in Japan might affect life-space mobility and QoL of CAD patients. Moreover, CAD patients in Japan who were not obese and maintained their physical function and activity tended to refrain from activity during the period between the pre- and post-nationwide state of emergency. Clarification of the effects of the COVID-19 pandemic on the relationship between living space motility and QoL in CAD patients will require further study.

Association of low back pain with muscle weakness, decreased mobility function, and malnutrition in older women: A cross-sectional study

Background Low back pain (LBP) and decreased mobility function are common problem among older people. Muscle weakness has been reported as a risk factor for these conditions, and exercise therapy can improve them. We created a novel exercise device that also measures abdominal trunk muscle strength. Malnutrition has also emerged as a major problem among older people. Muscle is a direct key linking decreased mobility function and malnutrition. This study aimed to examine the associations of LBP with not only decreased physical function and muscle weakness but also nutritional status of older people. Methods We examined the associations of LBP with muscle weakness, decreased mobility function (locomotive syndrome [LS]), and malnutrition among older women. The study included 101 female patients aged 60 years or older scheduled to undergo surgery for degenerative lower extremity diseases. Preoperatively, physical tests including abdominal trunk muscle strength assessment using the device and laboratory tests were conducted. Subjects with LBP (numerical rating scale ≥2; range, 0–4) during the preceding month were allocated to the LBP group (n = 36). Other subjects were allocated to the non-LBP group (n = 65). Results The LBP group had lower abdominal trunk and knee extensor muscle strength, lower serum albumin, and hemoglobin levels as blood biomarkers associated with malnutrition risk, and higher LS test scores than the non-LBP group. A multivariate analysis showed that abdominal trunk muscle weakness and advanced LS were associated with LBP. LBP intensity was negatively correlated with abdominal trunk and knee extensor muscle strength and positively correlated with the LS test score. The serum hemoglobin level was negatively correlated with the LS test score. Conclusion Abdominal trunk muscle weakness and decreased mobility function were associated with LBP among older women.

Relationship between Serum Vitamin D and Leg Strength in Older Adults with Pre-Dialysis Chronic Kidney Disease: A Preliminary Study

Active vitamin D (calcitriol, or 1.25 (OH) 2 D) is associated with muscle weakness, falls, and fracture in community-dwelling older people. This study aimed to investigate the relationship between a serum active vitamin D level and lower extremity muscle strength in elderly patients with pre-dialysis chronic kidney disease (CKD). This cross-sectional study included 231 patients with CKD treated conservatively as outpatients. We analyzed patient background factors, including age, sex, body mass index (BMI), intact parathyroid hormone (PTH), phosphorus, calcium, albumin, serum calcitriol level as an indicator of active vitamin D, and estimated glomerular filtration rate (eGFR) collected from medical records. As an index of lower extremity muscle strength, the isometric knee extension muscle strength-to-weight ratio (kgf/kg) was calculated. The mean patient age was 75.9 ± 6.1 years (68.8% male), and the BMI was 24.1 ± 3.8 kg/m2. A significant correlation was observed between knee extensor muscle strength and serum calcitriol level (r = 0.32, p < 0.01), age (r = –0.30, p < 0.01), BMI (r = −0.31, p < 0.01), intact PTH (r = −0.22, p < 0.01), phosphorus (r = −0.29, p < 0.01), albumin (r = −0.28, p < 0.01), and eGFR (r = 0.25, p < 0.01). Multiple regression analysis showed calcitriol to be significantly associated with knee extensor muscle strength (β: 0.14, 95% confidence interval: 0–0.002, p = 0.04) after adjustment for covariates. These results suggest that the serum active vitamin D level is associated with lower extremity muscle strength in older adults with pre-dialysis CKD. It is necessary to verify whether vitamin D supplementation increases lower extremity muscle strength in pre-dialysis CKD patients.