Quadriceps muscle strength and its relationship to radiographic knee osteoarthritis in Japanese elderly

Correlation Between Coronal Position Sequence of Lumbar and WOMAC Score in Knee Osteoarthritis (KOA) in Standard Standing Position

INTRODUCTION

Sagittal sequences of the spine have been shown to correlate with knee osteoarthritis (KOA), but coronal sequences and KOA have never been studied before. The study required patients to use a standard standing posture and aimed to explore the relationship between coronal position of lumbar spine and WOMAC score in KOA.

METHODS

This is a cross-sectional observational study. Data on a total of 268 patients with KOA were collected. Patients were photographed in a standard standing position and lumbar-sacrum offset distance (L-SOD) and lumbar-knee offset distance (ΔL-KOD) were calculated. Patients were then divided into different groups according to different critical values and differences were compared.

RESULTS

In the L-SOD of L1-3, WOMAC function (P = 0.021, P = 0.032, P = 0.001) and total score (P = 0.039, P = 0.034, P < 0.001) were different. In the L-SOD of L3-4, WOMAC pain score were different (P = 0.001, P = 0.032). At a cutoff of 13 mm, ΔL-KOD of L1-2 showed significant differences in pain part (P = 0.025, P = 0.039) and total score (P = 0.036, P = 0.050). There were significant differences in pain (P = 0.023, P = 0.027, P = 0.022), function (P = 0.048, P = 0.038, P = 0.047), and total score (P = 0.030, P = 0.027, P = 0.029) of L3-5. In the 18-mm cutoff group, only L1 and L2 have differences in the pain part (P = 0.050, P = 0.038).

CONCLUSION

Coronal balance of the lumbar spine is associated with knee pain and function. The pelvis plays an important role in maintaining the coronal balance. Both the lumbar spine and the knee joint should be considered when developing the surgical strategy.

Accuracy of a portable lower-limb muscle strength measuring device with a training function

[Purpose] Quadriceps muscle strength is essential for daily living activities. Therefore, we developed a compact and simple lower limb muscle strength measuring device (LocomoScan [LCS]). This study aimed to compare LCS with other instruments to analyze its simplicity, reproducibility, and accuracy. [Participants and Methods] One hundred and four healthy university students (56 males and 48 females) were included in the study. The knee extension force was measured using LCS, and the knee extension torque was measured using other devices (Cybex). In addition, lower leg muscle mass was measured using a body composition meter. The reproducibility of LCS and the correlation between the knee extension torque and lower leg muscle mass were evaluated. [Results] The measurement reproducibility of LCS was significantly higher. The knee extension force confirmed the proportional relative reliability of Cybex with knee extension torque. A relationship between knee extension force and lower limb muscle mass was also observed, indicating that muscle mass cannot be estimated as muscle strength. [Conclusion] The high reproducibility of the knee extension force measurement using LCS demonstrates its potential as a portable alternative instrument for muscle strength measurement in clinical practice. Therefore, LCS device is a simple and effective tool for assessing muscle strength.

Assessment of lower limb muscle strength can predict fall risk in patients with chronic liver disease

Falls are caused by a combination of factors, including loss of lower limb muscle strength (LMS), and associated with declined performance status (PS). Age-related sarcopenia is generally associated with decreased muscle mass and strength of lower limb muscle but without a noticeable loss of those of upper limb or trunk muscle. However, no reports have focused on falls or LMS in chronic liver disease (CLD) patients. This study is the first to analyze the risk factors for falls in patients with CLD, focusing on LMS measurement using the Locomoscan. This study enrolled 315 CLD patients whose LMS was measured. The patients who experienced falls more than 1 year ago or during the observation period were classified as those who experienced falls. We found that risk factors for falls were PS1/2 and decreased LMS (< 0.32 N/kg). The group with sarcopenia had a higher frequency of decreased LMS (54 vs. 26%, p = 0.001) and falls (24 vs. 4.4%, p < 0.001) compared to the non-sarcopenia group. This study found that decreased LMS was an independent risk factor for falls. Assessment of LMS may be used as a better marker associated with the risk of falls in patients with CLD.

A Randomized, Double-Blind, Controlled Trial Assessing If Medium-Chain Triglycerides in Combination with Moderate-Intensity Exercise Increase Muscle Strength in Healthy Middle-Aged and Older Adults

An adequate nutritional intake is recommended for the prevention of physical frailty and sarcopenia. In particular, medium-chain fatty acids (MCFAs) are reportedly important for muscle strength in nursing home residents. However, the effects of MCFAs on healthy adults at risk for frailty remain unknown. Hence, a randomized, placebo-controlled study was conducted to investigate the effects of 12 weeks of medium-chain triglycerides (MCTs) intake and walking on muscle mass and function in healthy, sedentary, middle-aged and older adults with a low body mass index. Three MCT intake groups with different amounts of octanoic and decanoic acid intake were compared with a control group. After 12 weeks, knee extension strength increased in all groups, with the increases in all MCT intake groups being significantly higher than those in the control group (p < 0.05). Grip strength significantly increased from baseline in the MCT 6 g/day intake group (p < 0.05). The combination of aerobic exercise and MCT intake may be effective in preventing decline in muscle strength and promoting increase in muscle strength as they can improve muscle energy production, thereby contributing to the maintenance of good health for middle-aged and older adults at high risk for frailty and sarcopenia.

Comparative Efficacy of Intra-Articular Injection, Physical Therapy, and Combined Treatments on Pain, Function, and Sarcopenia Indices in Knee Osteoarthritis: A Network Meta-Analysis of Randomized Controlled Trials

Knee osteoarthritis (KOA) is associated with a high risk of sarcopenia. Both intra-articular injections (IAIs) and physical therapy (PT) exert benefits in KOA. This network meta-analysis (NMA) study aimed to identify comparative efficacy among the combined treatments (IAI+PT) in patients with KOA. Seven electronic databases were systematically searched from inception until January 2023 for randomized controlled trials (RCTs) reporting the effects of IAI+PT vs. IAI or PT alone in patients with KOA. All RCTs which had treatment arms of IAI agents (autologous conditioned serum, botulinum neurotoxin type A, corticosteroids, dextrose prolotherapy (DxTP), hyaluronic acid, mesenchymal stem cells (MSC), ozone, platelet-rich plasma, plasma rich in growth factor, and stromal vascular fraction of adipose tissue) in combination with PT (exercise therapy, physical agent modalities (electrotherapy, shockwave therapy, thermal therapy), and physical activity training) were included in this NMA. A control arm receiving placebo IAI or usual care, without any other IAI or PT, was used as the reference group. The selected RCTs were analyzed through a frequentist method of NMA. The main outcomes included pain, global function (GF), and walking capability (WC). Meta-regression analyses were performed to explore potential moderators of the treatment efficacy. We included 80 RCTs (6934 patients) for analyses. Among the ten identified IAI+PT regimens, DxTP plus PT was the most optimal treatment for pain reduction (standard mean difference (SMD) = -2.54) and global function restoration (SMD = 2.28), whereas MSC plus PT was the most effective for enhancing WC recovery (SMD = 2.54). More severe KOA was associated with greater changes in pain (β = -2.52) and WC (β = 2.16) scores. Combined IAI+PT treatments afford more benefits than do their corresponding monotherapies in patients with KOA; however, treatment efficacy is moderated by disease severity.

Effect of equipping an unloader knee orthosis with vibrators on pain, function, stiffness, and knee adduction moment in people with knee osteoarthritis: A pilot randomized trial

BACKGROUND

Wearing unloader knee orthoses for the long term may have a side effect on knee adduction moment (KAM).

RESEARCH QUESTION

This study sought to determine whether equipping an unloader knee orthosis with vibrators improves its effectiveness in pain, stiffness, function, and reducing the KAM.

METHODS

The authors performed a clinical evaluation with the Western Ontario and McMaster Universities (WOMAC) questionnaire and instrumented gait analyses on 14 participants with medial compartment knee osteoarthritis in two testing sessions: before wearing the orthosis and after 6 weeks of use.

RESULTS AND SIGNIFICANCE

Wearing both orthoses for 6 weeks significantly improved (p < 0.05) pain, stiffness, and function compared to the baseline assessment. There was a significantly greater reduction in the first peak KAM (p = 0.016) and KAM impulse (p = 0.008) in the vibratory unloader knee orthosis than in the conventional knee orthosis in the second session. Equipping the unloader knee orthosis with vibrators can improve its effectiveness in reducing the KAM and can prevent the side effects of its use. Furthermore, equipping the unloader knee orthosis with the vibrators did not interfere with its effectiveness on pain, stiffness, and function.

The coronal inclination of the medial tibial plateau affects coronal gait kinematics for varus osteoarthritic knees

PURPOSE

This study aims to (1) measure the kinematics of lower extremity alignment and the bony position relative to the ground during walking, focusing on the coronal plane, and (2) determine the correlation between the kinematics and coronal inclination of the medial tibial plateau (coronal inclination) for healthy and varus knee osteoarthritis (OA).

METHODS

In this study, 43 women (non-OA, 9 knees; early OA, 13 knees; advanced OA, 21 knees; mean age 58 ± 17 years) were examined. The knee phenotypes in varus knee OA were varied. Three-dimensional (3D) knee kinematics were calculated in gait analysis by combining the motion capture system and the 3D lower extremity alignment assessment system via biplanar long-leg X-rays, applying the 3D-2D registration technique. The main parameters were the kinematics of the bony axes relative to the ground in the coronal plane during the stance phase of the gait. The differences in overall kinematics were assessed using repeated measures ANOVA with Tukey's post hoc test. The association between kinematic parameters and coronal inclination was evaluated by multiple linear regression after univariate analysis.

RESULTS

The tibia tilted laterally during the loading response, and a plateau area subsequently appeared until the terminal stance phase, whereas the femur slowly tilted laterally until the terminal stance phase. The dynamic alignment showed a relatively large varus angular change during the loading response in all groups. The trend of motion was similar among all groups (p = n.s.), although to varying degrees. The coronal inclination was the more dominant factor than the Kellgren-Lawrence (K-L) grades (β =  - 0.423, p = 0.005) when the change in dynamic alignment was determined.

CONCLUSIONS

The TAA plateau area after the loading response implies that the tibial articular surface may become horizontal. The femur slowly tilted laterally until the terminal stance phase in response to the tibial motion. Consequently, the dynamic alignment showed a varus angular change, in which coronal MCT was more involved than K-L grades.

Asymmetries and relationships between muscle strength, proprioception, biomechanics, and postural stability in patients with unilateral knee osteoarthritis

Background: The pathological mechanism of knee osteoarthritis (KOA) is unknown. KOA degeneration may be associated with changes in muscle strength, proprioception, biomechanics, and postural stability.

Objective: This study aimed to assess asymmetries in muscle strength, proprioception, biomechanics, and postural stability of bilateral lower limbs in patients with unilateral KOA and healthy controls and analyze correlations between KOA and these parameters.

Methods: A total of 50 patients with unilateral KOA (age range: 50-70) and 50 healthy subjects were recruited as study participants (age range: 50-70). Muscle strength, proprioception, femorotibial angle (FTA), femoral condylar–tibial plateau angle (FCTP), average trajectory error (ATE), and center of pressure (COP) sways areas were accessed in study participants, and the correlation between these variables was investigated.

Results: In patients with unilateral KOA, lower limb muscle strength was significantly lower on the symptomatic side than on the asymptomatic side (p < 0.01), while the proprioception (degree error), FTA, FCTP, and ATE were substantially higher compared to the asymptomatic side (p < 0.01). However, no significant difference was observed in the healthy controls (p > 0.05). Patients with unilateral KOA had lower muscle strength than healthy controls (p < 0.05), but their proprioception (degree error: the difference between the target and reproduction angles), ATE, and COP sway areas were higher (p < 0.05). Muscle strength was found to be negatively correlated with ATE and COP sways areas (p < 0.05), whereas proprioception (degree error) was positively correlated with ATE and COP sways areas (p < 0.05) in all study participants. However, no correlation was found between FTA, FCTP, and ATE, COP sways areas in patients with unilateral KOA (p > 0.05).

Conclusion: In patients with unilateral KOA, muscle strength, proprioception, biomechanics, and postural stability of bilateral limbs are asymmetrical in unilateral KOA patients. Muscle strength, proprioception, and postural stability are significantly associated variables, and changes in these variables should be considered in KOA prevention and rehabilitation.

Association between Daily Physical Activity and Locomotive Syndrome in Community-Dwelling Japanese Older Adults: A Cross-Sectional Study

This study aimed to evaluate the association between locomotive syndrome (LS) and daily physical activity (PA) in community-dwelling older adults. This cross-sectional study included 80 healthy Japanese older adults (40 men and 40 women; age: 60-79 years). Habitual daily PA was evaluated using a triaxial wrist accelerometer. Participants were divided into two groups based on the results of the two-step test, stand-up test, and 25-question geriatric locomotive function scale. Binomial logistic regression analysis was conducted to examine the statistical relationships between daily PA and category of LS, adjusting for age from adjusted odds ratio (adjusted OR) with the 95 percent confidence intervals (95%CI) and bootstrap 95%CI. The mean step count and time spent on moderate to vigorous physical activity (MVPA) were significantly higher among non-LS participants than among LS participants in women, but not in men. Logistic regression analyses indicated that spending longer than 28 min/day on MVPA was significantly associated with a lower likelihood of LS relative to short time category under 28 min/day in women (adjusted OR = 0.12, 95%CI = 0.02-0.59, bootstrap 95%CI = 0.01-0.43), but not in men. This study suggests that in community-dwelling older women, those with higher MVPA had lower odds of LS, and daily MVPA was associated with LS, but not in men. Therefore, the associations between LS and daily physical activity were partly dependent on sex differences.

A Strong Correlation Between the Severity of Flatfoot and Symptoms of Knee Osteoarthritis in 95 Patients

Objective

The purpose of this study is to assess the association between the presence and severity of flatfoot and symptoms of knee OA.

Methods

95 participants with knee OA were recruited from a patient cohort at a regional hospital. Symptoms of knee OA, including knee degeneration, femorotibial alignment, pain, stiffness and dysfunction were assessed using the Kellgren-Lawrence (K-L) grading system, femoral-tibial angle (FTA), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Participants were divided into groups with flatfoot (mild, moderate and severe) and without flatfoot based on the Clarke's angle. Linear regression and ordinal logistic regression were used for statistical analysis, as appropriate.

Results

Having flatfoot was associated with a significantly increased risk of having a higher K-L grade (OR: 20.03; 95% CI, 5.88, 68.27; p < 0.001), smaller FTA (Beta: −2.96; 95% CI, −4.41, −1.50; p < 0.001), higher pain score (Beta: 0.47; 95% CI, 0.24, 0.69; p < 0.001) and greater loss of function (Beta: 0.25; 95% CI, 0.02, 0.48; p = 0.03). Severe grades of flat feet were associated with a higher K-L grade (OR: 0.19; 95% CI, 0.08, 0.44; p < 0.001), smaller FTA (Beta: 1.51; 95% CI, 0.66, 2.35; p = 0.001), higher pain score (Beta: −0.25; 95% CI, −0.39, −0.11; p = 0.001), greater stiffness (Beta: −0.24; 95% CI, −0.38, −0.09; p = 0.002) and greater loss of function (Beta: −0.27; 95% CI, −0.41, −0.14; p < 0.001).

Conclusion

The results indicated that the severity of flattening is significantly associated with symptoms of knee OA. For the conservative management of knee OA, both flatfoot and its severity should be carefully considered.

Is there a relationship between hand grip strength and knee osteoarthritis in terms of radiological and functional findings in female patients?

Objectives

The aim of this study was to assess the presence of the relationship between hand grip strength (HGS) and radiological and functional signs of knee osteoarthritis (KOA).

Patients and methods

Between March 2019 and January 2020, a total of 64 female patients (mean age: 63.4±8.8 years; range, 50 to 80 years) with bilateral chronic knee pain who were diagnosed with KOA using radiological and clinical findings according to the 2019 American College of Rheumatology guidelines were included in the study. Patient demographics, body mass index (BMI) values, and hand dominance were recorded. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Lower Extremity Functional Scale (LEFS) were used for the assessment of KOA functionality. The Kellgren-Lawrence (KL) grading system was used for the radiological assessment of KOA. Electronic dynamometer was used for HGS measurement and values were normalized according to BMI results.

Results

In the assessment of relationship between HGS and functionality of KOA, a negative, moderate correlation was found between the WOMAC and HGS-Dominant (D) (r=0.312, p<0.05) and HGS-Non-Dominant (ND) (r=0.391, p<0.01). In addition, a positive, moderate correlation was found between the LEFS and HGS-D (r=0.344, p<0.01) and HGS-ND (r=0.371, p<0.01). There was a weak, negative correlation between the HGS-ND, KL-D (r=0.256, p<0.05) and KL-ND (r=0.283, p<0.05), while no significant correlation was found between the HGS-D and KL.

Conclusion

Our study results show that HGS-ND is associated with KOA radiologically and functionally. The HGS should be added in the WOMAC and LEFS scales in the functional assessment of KOA and new scales including HGS assessment should be developed.

Association of isometric quadriceps strength with stride and knee kinematics during gait in community dwelling adults with normal knee or early radiographic knee osteoarthritis

BACKGROUND

Identifying indicators of early knee osteoarthritis is important for preventing the onset and/or progression of the disease. Although low quadriceps strength and changes in stride and knee kinematics during gait have been suggested as possible indicators, their relevance and relationships have not been fully examined. This study aimed to analyze the association of quadriceps strength with stride and knee kinematics during gait in adults with normal knee or early knee osteoarthritis.

METHODS

A total of 881 knees from 474 community dwelling adults (238 males and 236 females) were included. Radiographic images of the knee in standing position were obtained, and grading of knee osteoarthritis was classified. Isometric quadriceps strength was measured using a force detector device. Three-dimensional knee kinematics during gait was obtained by a motion capture system. Sex-based difference of quadriceps strength, stride and knee kinematics during gait was evaluated by multiple comparison among grades by sex and multiple regression of quadriceps strength was analyzed by stride and knee kinematics during gait.

FINDINGS

Stride length and quadriceps strength were significantly reduced with higher grade in both sexes, and changes in knee kinematics during gait differed by sex from early knee osteoarthritis. Quadriceps strength in both sexes was significantly correlated with changes in stride length and knee kinematics during gait.

INTERPRETATION

Improving quadriceps strength in early knee osteoarthritis was related with maintaining gait ability and restraining abnormal knee kinematics during gait. This may help to develop clinical approaches to prevent the onset and/or progression of knee osteoarthritis.

Empirical study of the 30-s chair-stand test as an indicator for musculoskeletal disorder risk of sedentary behaviour in Japanese office workers: a cross-sectional empirical study

Objectives

Sedentary behaviour among office workers and the risk of adverse health outcomes are public health problems. However, risk indicators for these outcomes require invasive biochemical examination. A proactive screening tool using a non-invasive, easy-to-use method is required to assess the risk focused on musculoskeletal health for primary prevention. However, middle-aged adults have insufficient awareness of musculoskeletal disorders. This study examined to determine whether the 30-s chair-stand test (CS-30) can be used as a proactive screening index for musculoskeletal disorder risk of sedentary behaviour in office workers.

Design

Cross-sectional study using self-administered questionnaires and physical measurements.

Setting

Four workplaces located in a metropolitan area of Japan.

Participants

431 Japanese office workers aged 20–64 years. 406 valid sets of results remained (valid response rate: 94.2%).

Primary and secondary outcome measures

Musculoskeletal function was measured using the CS-30, quadriceps muscle strength. Receiver operating characteristic curve analysis was used to determine the sensitivity, specificity and optimal cut-off value for the CS-30. The risk of future incidence of musculoskeletal disorders was calculated using current quadriceps muscle strength.

Results

In total participants, 47.0% were male and the mean sitting time in work duration was 455.6 min/day (SD=111.2 min). The mean lower limb quadriceps muscle strength was 444.8 N (SD=131.3 N). For the optimum cut-off value of 23 on the CS-30 for all participants, sensitivity was 0.809 and specificity was 0.231. For men, the optimum cut-off was 25, with a sensitivity of 0.855 and a specificity 0.172. For women, the optimum cut-off was 21, with a sensitivity of 0.854 and a specificity 0.275.

Conclusions

Sensitivity was high, but specificity was insufficient. The CS-30 may be a potential proactive screening index for musculoskeletal disorder risk of sedentary behaviour, in combination with other indicators.

In vivo Measurement of Knee Extensor Muscle Function in Mice

Skeletal muscle plasticity in response to countless conditions and stimuli mediates concurrent functional adaptation, both negative and positive. In the clinic and the research laboratory, maximal muscular strength is widely measured longitudinally in humans, with knee extensor musculature the most reported functional outcome. Pathology of the knee extensor muscle complex is well documented in aging, orthopedic injury, disease, and disuse; knee extensor strength is closely related to functional capacity and injury risk, underscoring the importance of reliable measurement of knee extensor strength. Repeatable, in vivo assessment of knee extensor strength in pre-clinical rodent studies offers valuable functional endpoints for studies exploring osteoarthritis or knee injury. We report an in vivo and non-invasive protocol to repeatedly measure isometric peak tetanic torque of the knee extensors in mice across time. We demonstrate consistency using this novel method to measure knee extensor strength with repeated assessment in multiple mice producing similar results.

Comparative trial of the effects of continuous locomotion training provided at pharmacies: a pilot study

Background

While the world’s population is growing older, healthy life expectancy is not increasing. The Japanese Orthopedic Association proposed the concept of ‘locomotive syndrome,’ manifested as a decline in mobility functions, and introduced a short test battery for assessing the risk of this syndrome. The test battery includes the ‘stand-up test,’ ‘two-step test,’ and ‘25-question Geriatric Locomotive Function Scale’ (25-question GLFS). The purpose of locomotion training is to improve and sustain standing and gait functions. However, the place where locomotion training can be provided and followed up has not been decided upon. Therefore, a study was conducted to explore the effect of locomotive syndrome improvement by continuous locomotion training provided at community pharmacies. The objective of this study was to evaluate the effect of pharmacists’ instructions and follow-up on the compliance and effectiveness of locomotion training.

Methods

The inclusion criteria were 1) age ≥ 65 years and 2) decline in mobility functions. Guidance on how to perform locomotion training was provided by a pharmacist at the pharmacy. The participants performed locomotion training at home. They were tested and instructed at the pharmacy once a month for 3 months. The main outcome measures were test battery results and the percentage of number of days participants who were able to do the training at home.

Results

Eleven participants were analysed. The minimum implementation percentage was 78%. Improvements were observed in 25-question GLFS, muscle strength, and standing time on one leg. Three participants no longer showed a noticeable decline in mobility function.

Conclusion

Continuous locomotion training provided at pharmacies could contribute to locomotive syndrome prevention.

Trial registration

This study was registered with the University hospital Medical Information Network Clinical Trials Registry (UMIN-CTR; identification No. UMIN000027963. Registered 28 June 2017).

Cortical thickness of the tibial diaphysis reveals age- and sex-related characteristics between non-obese healthy young and elderly subjects depending on the tibial regions

PURPOSE

This study aimed to evaluate the age- and sex-related characteristics in cortical thickness of the tibial diaphysis between non-obese healthy young and elderly subjects as reference data.

METHODS

The study investigated 31 young subjects (12 men and 19 women; mean age, 25 ± 8 years) and 54 elderly subjects (29 men and 25 women; mean age, 70 ± 6 years). Three-dimensional estimated cortical thickness of the tibial diaphysis was automatically calculated for 5000-9000 measurement points using the high-resolution cortical thickness measurement from clinical computed tomography data. In 12 assessment regions created by combining three heights (proximal, central, and distal diaphysis) and four areas of the axial plane at 90° (medial, anterior, lateral, and posterior areas) in the tibial coordinate system, the standardized thickness was assessed using the tibial length.

RESULTS

As structural characteristics, there were no differences in the medial and lateral thicknesses, while the anterior thickness was greater than the posterior thickness in all groups. The sex-related difference was not shown. As an age-related difference, elderly subjects showed greater or lesser cortical thickness than the young subjects, depending on the regions of the tibia.

CONCLUSIONS

Cortical thickness was different depending on sex, age, and regions in the tibia. The results of this study are of clinical relevance as reference points to clarify the causes of various pathological conditions for diseases.

LEVEL OF EVIDENCE

Level 3.

Association of knee osteoarthritis grade with one-leg standing balance and quadriceps strength in male independent ambulators aged ≥80 years

BACKGROUND

One-leg standing (OLS) balance is an important predictor of falls in people of advanced age. In this population, muscle weakness and knee osteoarthritis also contribute to falls and resultant fractures and thereby affect mortality rates. The Kellgren-Lawrence (KL) classification is widely used in the radiographic evaluation of knee osteoarthritis. This study was performed to evaluate OLS balance and the quadriceps strength (QS) for each KL grade and to clarify the impact of the knee osteoarthritis grade on OLS balance and QS.

HYPOTHESIS

OLS balance shows results compatible with those of previous reports when independent walking is possible because of maintenance of QS regardless of the OA grade.

METHODS

This single-center prospective cross-sectional study included data on 106 male orthopedic patients (106 knees) aged ≥80 years who could walk independently. OLS balance with eyes open was assessed using the patient's preferred leg. A handheld dynamometer was used to measure QS. The ratio of muscle strength to body weight (QS/BW ratio) was used to evaluate outcomes. Weight-bearing standing knee radiographs were evaluated using the KL classification. OLS balance and the QS/BW ratio were evaluated for each KL grade, and the correlations of the KL grade with OLS balance and the QS/BW ratio were assessed simultaneously.

RESULTS

For each KL grade, the number of participants (n), median OLS balance (seconds), and QS/BW ratio (N/kg) were as follows: grade I: 24, 12, and 4.9; grade II: 51, 14, and 5.2; grade III: 22, 14, and 4.9; and grade IV: 9, 26, and 5.7, respectively. There were no significant differences in either OLS balance or the QS/BW ratio among the four grades.

CONCLUSIONS

Participants exhibited good OLS balance and QS/BW ratio regardless of their KL grade. This study demonstrated an absence of correlations of the KL grade with OLS balance and the QS/BW ratio, as was previously reported for the KL grade and pain.

LEVEL OF EVIDENCE

Level II prospective study.

Knee kinematics of severe medial knee osteoarthritis showed tibial posterior translation and external rotation: a cross-sectional study

BACKGROUND

Knee osteoarthritis (OA) gradually reduces knee function and limits activities of daily living with age. However, the progression of abnormal kinematics of the knee in knee OA is unclear.

AIMS

This study aimed to clarify the relationship between stage of knee OA and abnormal knee kinematics and to identify a strategy for prevention of knee OA.

METHODS

A total of 112 knees of 99 patients (45 men/54 women; 55.9 ± 18.2 years), comprising 28 (27/1) in Kellgren-Lawrence grade 0, 18 (8/10) in grade 1, 27 (2/25) in grade 2, 28 (6/22) in grade 3, and 11 (3/8) in grade 4, were enrolled in this cross-sectional study. In vivo knee kinematics was obtained using a three-dimensional-to-two-dimensional registration technique utilizing CT-based bone models and lateral fluoroscopy during knee extension-flexion in an upright sitting position and squatting.

RESULTS

The external rotation angle of the tibia relative to the femur was greater in grade 3/4 knees than in grade 0/1 knees and tibial posterior translation was greater in grade 3/4 knees than in grade 0-2 knees.

DISCUSSION

Age-related changes in muscle activity and joint instability are considered to be the cause of these abnormal kinematics.

CONCLUSIONS

As the stage of knee OA progresses, there was a tendency toward increasing tibial external rotation and tibial posterior translation during knee extension-flexion in sitting position and squatting. Prevention of the progress of the abnormal knee kinematics may prevent the progression of the knee OA.

Examination of the changes in lower extremities related to progression of adult spinal deformity: a longitudinal study of over 22 years

This longitudinal observational study investigated the relationship between changes in spinal sagittal alignment and changes in lower extremity coronal alignment. A total of 58 female volunteers who visited our institution at least twice during the 1992 to 1997 and 2015 to 2019 periods were investigated. We reviewed whole-spine radiographs and lower extremity radiographs and measured standard spinal sagittal parameters including pelvic incidence [PI], lumbar lordosis [LL], pelvic tilt [PT], sacral slope [SS] and sagittal vertical axis [SVA], and coronal lower extremity parameters including femorotibial angle (FTA), hip–knee–ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA) and mechanical lateral distal tibial angle (mLDTA). Lumbar spondylosis and knee osteoarthritis were assessed using the Kellgren–Lawrence (KL) grading system at baseline and at final follow-up. We investigated the correlation between changes in spinal sagittal alignment and lower extremity alignment and changes in lumbar spondylosis. The mean age [standard deviation (SD)] was 48.3 (6.3) years at first visit and 70.2 (6.3) years at final follow-up. There was a correlation between changes in PI-LL and FTA (R = 0.449, P < 0.001) and between PI-LL and HKA (R = 0.412, P = 0.001). There was a correlation between changes in lumbar spondylosis at L3/4 (R = 0.383, P = 0.004) and L4/5 (R = 0.333, P = 0.012) and the knee joints. Changes in lumbar spondylosis at L3/4 and L4/5 were related to changes in KOA. Successful management of ASD must include evaluation of the state of lower extremity alignment, not only in the sagittal phase, but also the coronal phase.

Comparison of quadriceps setting strength and knee extension strength tests to evaluate lower limb muscle strength based on health-related physical fitness values in elderly people

OBJECTIVE

Conventionally, knee extension strength is often used as the indicator for lower limb muscle strength; however, several recent studies have also used quadriceps setting strength. This study aimed to investigate and compare the association of quadriceps setting and knee extension strength with health-related physical fitness.

METHODS

We evaluated quadriceps setting strength and isometric knee extension strength in 75 elderly subjects (mean age, 76.8±5.3 years) to determine their lower limb muscle strength. Health-related physical fitness was evaluated using the physical fitness test advocated by the Ministry of Education and Culture, Sports, Science and Technology in Japan. The test consists of the following components: grip strength, sit-up, sit and reach, one leg standing with eyes open, 10 m obstacle walk and 6 min walk.

RESULTS

When adjusted for age, sex and body mass index, quadriceps setting strength was significantly correlated with grip strength, number of sit-ups, sit and reach distance, 10 m obstacle walking time and 6 min walking distance. In contrast, knee extension strength was associated only with grip strength and number of sit-ups.

CONCLUSION

More health-related physical fitness parameters with quadriceps setting strength than knee extension strength. Quadriceps setting strength may be superior to knee extension strength as a predictor of health-related physical fitness.

Reference Values and Correlations for Multiple Physical Performance Measures: A Cross-Sectional Study among Independently Mobile Older Men in Japan

Purpose: Japan is one of few countries with a male life expectancy over 80 years. The gap between the healthy life span and the total life expectancy is large, highlighting the importance of maintaining physical performance. The present study aims to establish reference values for multiple physical performance measures among high-functioning oldest-old Japanese men and to investigate the correlations among these measurements to understand how these variables are related. Methods: This study was conducted with 120 Japanese males aged 80 years or older who were able to walk independently. Seven measures of physical performance were assessed: handgrip strength, quadriceps strength, static balance ability (one-legged stance), dynamic balance ability (Functional Reach Test; FRT), walking ability (5-m walking time test), combined movement ability (Timed Up & Go test), and bone quality. Cognitive function was also measured (Mini-Mental State Examination; MMSE). Results: Specific reference values are reported for each physical performance measurement explored in this study. Only six participants were classified as cognitively impaired, and 16 had mild cognitive impairment. There were significant correlations of varying levels among all of the measures of physical performance. Age was significantly correlated with all performance measures except FRT, and there was no correlation between age and MMSE. MMSE was weakly correlated with FRT and unrelated to the other performance measures. Conclusions: The reference ranges can be used by older men who have not yet reached 80 years and their health care providers as physical performance targets to facilitate the maintenance of independent mobility in later life.

Simplified Measurement of Maximum Strength After Knee Surgery: Application-Based Knee-Training Device Compared to Isokinetic Testing

Context

Isokinetic testing is used as a standard tool in measuring strength in professional athletes. It is often used to evaluate improvement during rehabilitation. The disadvantages of isokinetic testing include its costs, the fact that it is not portable, and its risk of injury, which makes it not suitable for early postoperative rehabilitation.

Hypothesis

The aim of this study was to investigate the relationship between the results of the isokinetic testing and the measurements of an application-based knee-training device.

Study Design

Exploratory diagnostic study.

Methods

In this monocentric study, 100 subjects performed an isokinetic maximum strength examination and an assessment on the application-based knee-training device in a randomized order. The isokinetic testing was based on the Swiss Olympic protocol with 3 sets of 5 repetitions of maximum strength testing for flexion and extension. The subjects consisted of 50 healthy professional athletes and 50 healthy recreational athletes, half male and half female, between the ages of 18 to 30 years old.

Results

No medical or technical issues were reported. The analysis of the relationship between application-based knee-training device and extension showed a Pearson correlation coefficient of r=0.667 for the left knee and r=0.604 for the right knee. For flexion, the Pearson correlation coefficient was r=0.640 for the left side and r=0.673 for the right side. When strength measured by the application-based knee-training device was adjusted for height and weight of the subjects, the Pearson correlation was even stronger (extension left: r=0.727, right: r=0.689; flexion left: r=0.641, right: r=0.711).

Conclusion

The study shows a moderate to high correlation between isokinetic testing and the application-based knee-training device. These results suggest that the application-based knee-training device is effective for early strength rehabilitation without the risk of injury.

Knee Osteoarthritis Grade does not Correlate with Quadriceps Muscle Strength or Bone Properties of the Calcaneus in Men Aged 80 Years or More who Can Walk independently

Purpose: Muscle weakness and bone deterioration in the elderly are related to falls and fractures, resulting in decreased mobility. Knee osteoarthritis also may contribute to falls and fractures and thereby affect mortality rates. The Kellgren–Lawrence (KL) classification is widely used in the radiographic evaluation of knee osteoarthritis. Aims: This study aimed to evaluate the quadriceps strength and bone properties of the calcaneus for each KL grade, and to clarify the impact of knee osteoarthritis grade on quadriceps strength and bone properties. Methods: This prospective cross-sectional study included data on 108 male patients (213 knees), aged ≥80 years, who could walk independently. A handheld dynamometer was used to measure quadriceps strength. Bone properties were evaluated using broadband ultrasound attenuation with a portable bone densitometer. Weight-bearing standing knee radiographs were evaluated using KL classification. Quadriceps strength and bone properties were evaluated for each KL grade and the correlations between the grade and quadriceps strength and bone properties were assessed simultaneously. Results: The numbers of participants in KL grades I–IV were 46, 102, 45, and 20, respectively. There were no differences among grades for either quadriceps strength or bone properties. Conclusions: Participants exhibited good quadriceps strength and bone properties regardless of their KL grade. Relatively high mechanical loading of muscle and bone incurred while walking independently, likely explaining this result. Clinically, this study demonstrated the absence of correlations between KL grade and quadriceps strength and bone properties, as was previously reported in studies showing the absence of a correlation between KL grade and pain.

Hip abductor muscle weakness and slowed turning motion in people with knee osteoarthritis

Laser range sensor-based timed up and go (laser-TUG) test can evaluate performance in TUG subtasks (sit-to-walk [STW], walking a short distance, and turning). This study aimed to test the hypothesis that weaker hip abductor muscle strength is more significantly associated with slowed turning speed than with the other TUG subtasks (STW and straight walking) after controlling for quadriceps muscle strength in patients with knee osteoarthritis (OA). Community-dwelling participants with knee OA (Kellgren and Lawrence [K&L] grade ≥ 1; mean age, 68.6 years; 70.3% women) underwent laser-TUG. Spatiotemporal gait parameters in TUG and the TUG subtasks were evaluated as outcome measures. The isometric muscle strength of the hip abductor and quadriceps was measured using a hand-held dynamometer. Multiple linear regression analysis was performed to examine the relationship between muscle strength as an independent variable and spatiotemporal parameters as dependent variables. The relative importance of hip abductor muscle strength was determined using the percentages of unique variance. Participants with weaker hip abductor muscle strength demonstrated 0.094 m/s slower turning speed after adjustment for covariates including quadriceps muscle strength. The unique variance explained by hip abductor muscle strength in turning speed was 2.1%. However, no significant relationships were confirmed between weak hip abductor muscle strength and the time to perform TUG and the straight walking (forward and return) phase. These findings indicate that turning motion may be more sensitive to aggravated hip abductor muscle weakness and may show better response to hip muscle strengthening exercises. Longitudinal studies are warranted to elucidate this issue.

Reduction in Thigh Muscle Strength Occurs Concurrently but Does Not Seem to Precede Incident Knee Pain in Women: Data From the Osteoarthritis Initiative Cohort

OBJECTIVE

The aim of the study was to investigate whether muscle strength declines before or concurrent with incident knee pain in subjects with and without radiographic knee osteoarthritis.

DESIGN

Osteoarthritis initiative participants with incident knee pain (occurrence of infrequent/frequent knee pain during the past 12 mos at two consecutive follow-up time points (either years Y3 + Y4 or Y4 + Y5) were compared with controls (no incident knee pain) with 2-yr changes in knee extensor strength during BL➔Y2 (before) and Y2➔Y4 (concurrent).

RESULTS

Two hundred two knees (49% women, 40% radiographic knee osteoarthritis) displayed incident pain, and 439 did not (46% women, 23% radiographic knee osteoarthritis). Women with radiographic knee osteoarthritis displayed a significantly greater (P = 0.04) reduction in knee extensor strength concurrent with incident pain compared with controls (mean = -17.6 N vs. +4.5 N), but men did not. A similar trend was observed in women without radiographic knee osteoarthritis, but this was not statistically significant (P = 0.08). There was no significant relationship with change in extensor strength before incident pain (P ≥ 0.43).

CONCLUSIONS

These results suggest that in women, incident knee pain is accompanied by a concurrent reduction in knee extensor strength, whereas loss in strength does not precede incident knee pain. The findings encourage interventional studies that attempt to attenuate a decline in extensor strength once knee symptoms occur.

Evaluation of a Cost-Effective Novel Diagnostic Method for Lumbar Herniated Disc with Knee-Osteoarthritis: A Randomized Sample Study

The aim of this study was to determine a cost-effective diagnostic method for lumbar herniated disc with knee osteoarthritis (LHD-KOA) based on aberrant outcome measures, levels of biomarkers, and examination of the lower-extremity. Data were separately analyzed for each cohort suffering with LHD-KOA (n=108; 59.82±7.15years) and without LHD-KOA (n=108; 58.81±7.61years), and findings were confirmed with radiological images. The aberrant-leg-features (bilateral: knee gaps between the short head of biceps femoris and the surface of the bed, diameters of calves and thighs, angles of straight leg raising, knee-flexion and -extension in a supine position) and biochemical parameters (Interleukin-10, Tumor necrosis factor-alpha, C-reactive protein, creatine kinase-muscle, and Aldolase-A), and outcome measures, Western Ontario and McMaster Universities osteoarthritis index (WOMAC), knee-injury osteoarthritis outcomes scale (KOOS), Oswestry disability index (ODI), and body mass index (BMI)for participants with and without LHD-KOA were evaluated with appropriate techniques. All the subjects underwent standardized physical examination and completed a questionnaire. The risk ratios and mean± standard deviations of biomarkers, anatomical features, and outcome measures of the experimental subjects were highly significant compared to controls (p<0.0001). Results suggest that monitoring the studied aberrant outcome measures, biomarkers, and lower-anatomical features may be a cost-effective diagnostic tool for LHD-KOA. Further research is recommended for an alternative treatment protocol for LHD-KOA.

Trunk movement asymmetry associated with pain, disability, and quadriceps strength asymmetry in individuals with knee osteoarthritis: a cross-sectional study

OBJECTIVE

This study examined 1) the clinical relevance of trunk movement asymmetry, which was evaluated using a trunk-mounted inertial measurement unit (IMU), and 2) the relationship between trunk movement asymmetry and lower limb muscle strength asymmetry in individuals with knee osteoarthritis (OA).

DESIGN

One-hundred-thirty-one participants (mean age, 74.2 years; 71.8% female; Kellgren and Lawrence [K&L] grade ≥1) underwent gait analysis at their preferred pace for IMU-based measurement of trunk movement asymmetry (harmonic ratio [HR] and improved HR). The isometric strength of quadriceps and hip abductors was evaluated using a hand-held dynamometer. Pain and disability level were evaluated using a validated self-reported questionnaire. Multiple regression analyses with covariate adjustment were performed to examine the relationship between trunk movement asymmetry (independent variable) and pain, disability level, or muscle strength asymmetry (dependent variables).

RESULTS

Individuals with severe knee OA (K&L grade ≥3) had increased trunk movement asymmetry in the medio-lateral axis compared to those with a K&L grade of 1. Increased trunk movement asymmetry was associated with a greater knee pain and disability. The increased trunk movement asymmetry was significantly associated with an increase in the asymmetry of quadriceps strength, but not with asymmetry in the strength of hip abductor.

CONCLUSION

Our findings indicate that increased medio-lateral trunk movement asymmetry may be an indicator of impairment, rather than adaptation, in individuals with knee OA. This preliminary finding warrants validation by future study. Paying close attention to medio-lateral trunk movement asymmetry may be key to our understanding of OA-related pain and disability.

Evaluation of the association between locomotive syndrome and metabolic syndrome

BACKGROUND

Locomotive syndrome (LS) includes disorders of the musculoskeletal system and is a high-risk condition that requires nursing care. We included an examination of locomotive function in specific health checkups to investigate the relationship between LS risk and the muscle strengths. The purpose of this study was to determine the distribution of LS and the relationship between LS and metabolic syndrome (MetS).

METHODS

Among 2695 participants who undertook a specific health checkup, 790 received a locomotive examination (302 men and 488 women; mean age, 65.9 years). Data for MetS components were measured in the specific health checkup. Data about the locomotive examination were obtained from five tests: the two-step test, stand-up test, 25-question Geriatric Locomotive Function Scale, and measurement of lower limb muscular strength and grip strength.

RESULTS

The MetS components did not differ according to LS risk level in men. In women, body weight, body mass index, and abdominal circumference were significantly lower in the non-LS group than in the LS risk level 1 or 2 groups. The ratio of lower limb muscular strength to body weight differed significantly between all risk groups in men and women. In women, lower limb muscular strength was significantly higher in those at risk of both LS and MetS (double-risk group) than in the LS-only group. In women, the ratio of lower limb muscular strength to body weight was significantly lower in the double-risk group than in the LS-only group.

CONCLUSIONS

Adding a locomotive examination to the specific health checkup may be useful for identifying people at risk of LS or MetS. The prevalence rates of LS and MetS correlate positively in women. The ratio of lower limb muscular strength to body weight might be a better index of locomotor dysfunction than lower limb muscular strength alone.

Influence of the severity of knee osteoarthritis on the association between leg muscle mass and quadriceps strength: the SPSS-OK study

Quadriceps strength is important for maintaining functional movement in patients with knee osteoarthritis (OA). We aimed to examine whether knee OA severity weakened the magnitude of the associations between leg muscle mass, quadriceps strength, and functional movement. Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe study (SPSS-OK) was a single-center cross-sectional study. We recruited 611 patients with knee OA. Leg muscle mass was determined by bioimpedance and used as a proxy for quadriceps muscle mass. Quadriceps strength and indices of functional movement (assessed by the functional activities category of the new Knee Society Score questionnaire [KSS] and the Timed Up and Go [TUG] test) were measured. Knee OA severity was determined by the Kellgren-Lawrence radiographic grade. A series of general linear models was fitted with adjustment for confounding variables. The increase in quadriceps strength per leg associated with a 1-kg increase in leg mass per leg was 7.29 Nm, 5.43 Nm, and 3.77 Nm among patients with knee OA grade 1/2, 3, and 4, respectively (P for interaction = 0.003). A 1-Nm increase in quadriceps strength per leg was associated with both a 0.14 point increase in KSS movement score and a 0.05 s decrease in TUG, regardless of knee OA severity (P for interaction 0.430 and 0.323). Severe knee OA may reduce efficiency in the exertion of quadriceps strength by leg muscle mass even when the amount of muscle mass remains unchanged.

Quadriceps muscle weakness is related to increased risk of radiographic knee OA but not its progression in both women and men: the Matsudai Knee Osteoarthritis Survey

PURPOSE

The purpose of this study was to investigate the causal relationship between quadriceps muscle strength and radiographic knee osteoarthritis (OA) in a longitudinal study.

METHODS

The present study included 976 knees from 488 subjects who participated in both the 5th (2007) and 7th (2013) surveys of the Matsudai Knee Osteoarthritis Survey. Bilateral quadriceps strengths of each subject were measured using the quadriceps training machine (QTM-05F, Alcare Co., Ltd., Tokyo, Japan). Additionally, weight-bearing standing knee radiographs were obtained, and knee OA was graded according to the Kellgren-Lawrence classification system. The relationships between quadriceps strength and the incidence and progression of radiographic knee OA were assessed using multiple logistic regression analysis.

RESULTS

After adjusting for age and body mass index (BMI), both female and male knees in the lowest quantile of quadriceps strength had higher risk of the incidence of radiographic knee OA compared with the highest quantile of quadriceps strength (women: OR 2.414, 95% CI 1.098-5.311; men: OR 2.774, 95% CI 1.053-7.309). In contrast, after adjusting for age, BMI and femorotibial angle, both female and male knees in the lowest quantile compared with the highest quantile of quadriceps strength did not differ in risk of the progression of radiographic knee OA (women: OR 1.040, 95% CI 0.386-2.802; men: OR 2.814, 95% CI 0.532-14.898).

CONCLUSION

Quadriceps muscle weakness was related to increased risk of the incidence of radiographic knee OA, but not its progression, in both women and men. Therefore, the clinically important finding of this study is that, in both women and men, maintaining higher quadriceps muscle strength may be one of the most effective prevention methods for incident radiographic knee OA.

LEVEL OF EVIDENCE

II.

Development of a questionnaire survey to evaluate lower limb function of patients with knee osteoarthritis

This study aimed to develop a self-questionnaire index relevant to lower limb functional assessment reflecting clinical symptoms and activity restrictions associated with activities of daily living (ADL) for patients with knee osteoarthritis. This cross-sectional study enrolled patients with knee osteoarthritis (Kellgren/Lawrence grade ≥ 1). Participants evaluated clinical symptoms and activity restrictions using self-reported questionnaires. Radiographic evaluation, knee joint range of motion (ROM), and lower limb muscle strength were assessed. Associations between clinical symptoms, activity restrictions, and knee and hip joint function were evaluated using multiple and logistic regression analysis. Overall, 142 participants were included in the final analysis. Patients with knee pain while rising from a chair had lower knee and hip extension strength (knee extension β = - 0.28; 95% confidence interval (CI), - 0.41 to - 0.14; P < 0.0001; hip extension β = - 0.26; 95% CI, - 0.42 to - 0.08; P = 0.0034), and restricted knee extension ROM (odds ratio [OR] = 2.17; 95% CI, 1.02-4.63; P = 0.041). Patients with knee pain during stair climbing, turning or who were unable to stand on one leg without external support had reduced hip abduction muscle strength (β = - 0.17; 95% CI, - 0.27 to - 0.07; P = 0.0008). Patients with knee pain while rising from a chair or stepping showed more severe knee joint degeneration on radiographic evaluation (OR = 3.26; 95% CI, 1.11-10.91; P = 0.03). The self-questionnaire index reflected clinical symptoms and activity restrictions associated with ADL and was significantly associated with lower limb function in individuals with knee osteoarthritis.

Age-related erosion of obstacle avoidance reflexes evoked with electrical stimulation of tibial nerve during walking

In young healthy adults, characteristic obstacle avoidance reflexes have been demonstrated in response to electrical stimulation of cutaneous afferents of the foot during walking. It is unknown whether there is an age-related erosion of this obstacle avoidance reflex evoked with stimulation to the tibial nerve innervating the sole of the foot. The purpose of this study was to identify age-dependent differences in obstacle avoidance reflexes evoked with electrical stimulation of the tibial nerve at the ankle during walking in healthy young and older (70 yr and older) adults with no history of falls. Toe clearance, ankle and knee joint displacement and angular velocity, and electromyograms (EMG) of the tibialis anterior, medial gastrocnemius, biceps femoris, and vastus lateralis were measured. A significant erosion of kinematic and EMG obstacle avoidance reflexes was seen in the older adults compared with the young. Specifically, during swing phase, there was reduced toe clearance, ankle dorsiflexion, and knee flexion angular displacement in older adults compared with the young as well as changes in muscle activation. These degraded reflexes were superimposed on altered kinematics seen during unperturbed walking in the older adults including reduced toe clearance and knee flexion and increased ankle dorsiflexion compared with the young. Notably, during mid-swing the toe clearance was reduced in the older adults compared with the young by 2 cm overall, resulting from a combination of 1-cm reduced reflex response in the older adults superimposed on 1-cm less toe clearance during unperturbed walking. Together, these age-related differences could represent the prodromal phase of fall risk. NEW & NOTEWORTHY This study demonstrated age-dependent erosion of obstacle avoidance reflexes evoked with electrical stimulation of the tibial nerve at the ankle during walking. There was significant reduction in toe clearance, ankle dorsiflexion, and knee flexion reflexes as well as changes in muscle activation during swing phase in older adults with no history of falls compared with the young. These degraded reflexes, superimposed on altered kinematics seen during unperturbed walking, likely represent the prodromal phase of fall risk.

Age-related reduction of trunk muscle torque and prevalence of trunk sarcopenia in community-dwelling elderly: Validity of a portable trunk muscle torque measurement instrument and its application to a large sample cohort study

Trunk muscle weakness and imbalance are risk factors for postural instability, low back pain, and poor postoperative outcomes. The association between trunk muscle strength and aging is poorly understood, and establishing normal reference values is difficult. We aimed to establish the validity of a novel portable trunk muscle torque measurement instrument (PTMI). We then estimated reference data for healthy young adults and elucidated age-related weakness in trunk muscle strength. Twenty-four university students were enrolled to validate values for PTMI, and 816 volunteers from the general population who were recruited to the Iwaki Health Promotion Project were included to estimate reference data for trunk muscle strength. Trunk flexion and extension torque were measured with PTMI and KinCom, and interclass correlation coefficients (ICC) were estimated to evaluate the reliability of PTMI values. Furthermore, from the young adult reference, the age-related reduction in trunk muscle torque and the prevalence of sarcopenia among age-sex groups were estimated. The ICC in flexion and extension torque were 0.807 (p<0.001) and 0.789 (p<0.001), respectively. The prevalence of sarcopenia increased with age, and the prevalence due to flexion torque was double that of extension torque. Flexion torque decreased significantly after 60 years of age, and extension torque decreased after 70 years of age. In males over age 80, trunk muscle torque decreased to 49.1% in flexion and 63.5% in extension. In females over age 80, trunk muscle torque decreased to 60.7% in flexion and 68.4% in extension. The validity of PTMI was confirmed by correlation with KinCom. PTMI produced reference data for healthy young adults, and demonstrated age-related reduction in trunk muscle torque. Trunk sarcopenia progressed with aging, and the loss of flexion torque began earlier than extension torque. At age 80, trunk muscle torque had decreased 60% compared with healthy young adults.

Influence of Obstructive Sleep Apnea in the Functional Aspects of Patients With Osteoarthritis

STUDY OBJECTIVES

It has been demonstrated in recent studies that obstructive sleep apnea (OSA) is the most prevalent sleep disorder in patients with osteoarthritis (OA), and thus the current study aimed to investigate the influence of OSA on knee extensor torque, pain, stiffness, and physical function in men with low-grade knee OA.

METHODS

The study included 60 male volunteers, aged 40 to 70 years, allocated into four groups: Group 1 (G1) Control (n = 15): without OA and without OSA; Group 2 (G2) (n = 15): with OA and without OSA; Group 3 (G3) (n = 15): without OA and with OSA; and Group 4 (G4) (n = 15) with OA and with OSA. All volunteers were examined using knee radiographs and polysomnography, responded to the Western Ontario McMaster Osteoarthritis Index (WOMAC) questionnaire, and completed a test on an isokinetic dynamometer to evaluate peak isometric knee extensor torque, both concentric and eccentric (90°/s and 180°/s).

RESULTS

Regarding the data from the WOMAC questionnaire (for pain, stiffness, and physical function), it was observed that G4 showed higher values compared to G1 or G3. For the concentric isometric and isokinetic peak knee extensor torque, lower values were observed in G4 compared to G1 or G3.

CONCLUSIONS

Patients who have knee OA in the early grades, when associated with OSA, have higher changes of the peak extensor torque, pain, stiffness, and physical function, compared with patients who did not have OSA.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov, Identifier: NCT01422967, Title: Changes Of Sleep on the Sensoriomotor and Cytokine In Patients With Osteoarthritis, URL: https://clinicaltrials.gov/ct2/show/NCT01422967.

Quadriceps strength impairment in the mid- to long-term follow-up period after total knee arthroplasty

PURPOSE

Quadriceps strength impairment after total knee arthroplasty (TKA) continues to be a concern. However, most studies of quadriceps strength have short-term follow-up periods. Whether quadriceps strength impairment occurs in the long-term follow-up period after TKA remains unclear. The purpose of this study was to compare the quadriceps strength between posterior cruciate ligament-retaining (CR) and substituting (PS) design mobile-bearing TKA (1) in the same patients after an average of 10 years and (2) between TKA patients and age-matched controls.

METHODS

A prospective, quasi-randomized design was used. Thirty-four patients (68 knees) who underwent bilateral TKA (CR on one side and PS on the other) were followed for a minimum of 5 years, and 35 age-matched controls (70 knees) were evaluated. A handheld dynamometer was used to measure quadriceps isometric strength. For each patient, the maximum value of three trials was used. The ratio of muscle strength to body weight (MS/BW ratio; N/kg) was used to evaluate outcomes.

RESULTS

The median MS/BW ratio was 3.3 (range 1.4-10.5) for CR 3.4 (range 0.9-9.3) for PS, and 4.6 (range 0.4-8.8) for controls. The MS/BW ratio did not differ between prosthesis designs, but was significantly smaller in both CR (p = 0.020) and PS (p = 0.024) than in controls.

CONCLUSIONS

Posterior cruciate ligament-retaining TKA does not confer a substantial advantage an average of 10 years postoperatively. In addition, quadriceps strength, as measured using a hand-held dynamometer, was significantly lower in both TKA patient groups than in age-matched controls. Clinically, the results of this study indicate that quadriceps-strengthening exercises should be continued in the long term after TKA.

LEVEL OF EVIDENCE

II.

Association between body weight and proximal tibial bone mineral density after bilateral total knee arthroplasty

BACKGROUND

Proximal tibial bone mineral density (BMD) has been studied for its potential impact on subsidence and loosening of the tibial component after total knee arthroplasty (TKA). However, no known studies of proximal tibial BMD after TKA have evaluated the effect of major impact factors such as body weight (BW), muscle strength, and level of activity. We aim to determine whether factors such as level of activity, quadriceps strength, BW, gender, age, and prosthetic design affect proximal tibial BMD over the mid- to long-term following TKA.

METHODS

We evaluated 36 patients (72 knees) who were undergoing bilateral TKA performed by a single surgeon. Median follow up time was 115months (range, 60-211months) for a minimum of five years. We measured BMD in the proximal tibia and used a hand-held dynamometer to measure quadriceps isometric strength, recording the maximum value of three measurements for each patient.

RESULTS

Univariate analyses using Spearman's correlation coefficient for continuous variables revealed a weak negative correlation between age and BMD (r=-0.316, P=0.007) and a moderate positive correlation between BW and BMD (r=0.430, P<0.001). However, no significant correlations were found between the other factors above and BMD for continuous and discrete variables. Based on multivariate analyses, only BW had a significant effect on BMD (β=0.342, P=0.003).

CONCLUSIONS

BW is the most impact factor on the proximal tibial BMD after mid- to long-term follow up TKA. Therefore, the management of BW may contribute to prevention of decline of tibial BMD for TKA patients owing to aging.

Comparison of lower leg muscle strength and grip strength for diagnosing slower gait speed in the elderly

Objectives

Sarcopenia, decreased muscle volume and muscle weakness in the elderly is a serious risk of various adverse outcomes. Current diagnostic procedure for sarcopenia includes gait speed, grip strength, and percentage of skeletal muscle volume. However, lower leg muscle strength decreases much faster than grasp power, and we have evaluated the usefulness of its measurement using a recently developed instrument (Locomoscan).

Methods

Forty-three institutionalized elderly subjects were evaluated for their anthropometrical parameters, body composition, grasp and lower leg muscle strength, and gait speed. They were categorized into 2 groups; gait speed equal to or higher than 0.8 m/s and that below 0.8 m/s.

Results

Leg muscle strength per body weight was significantly greater in those with their gait speed equal to or higher than 0.8 m/s, whereas there was no significant difference in other parameters. Receiver operator characteristics analysis has shown that leg muscle alone significantly predicted the greater gait speed.

Conclusions

Lower leg muscle strength can be useful for predicting gait speed.

Quadriceps muscle strength reference value as index for functional deterioration of locomotive organs: Data from 3617 men and women in Japan

BACKGROUND

Quadriceps muscle strength reference value of normal individuals in Japan is necessary to quantitatively evaluate functional deterioration of locomotive organs. Therefore, we established a reference value by using the Locomo Scan, a new device that measures knee extension muscle strength.

METHODS

We measured knee extension muscle strength with the Locomo Scan in 3617 individuals (1692 men, 1925 women, 20-89 years; mean age. 50.7 years) by implementing our own 49 measurement events in 20 prefectures.

RESULTS

The means of maximum knee extension muscle strength for men (women) in each age group were as follows: 20s, 546 (475) N; 30s. 552 (475) N; 40s, 534 (450) N; 50s, 507 (442) N; 60s, 471 (405) N; 70s, 385 (340) N; and 80s, 359 (267) N. No significant differences were found from the 20s to 40s age groups, but older groups had significantly decreased knee extension muscle strength with age for both sexes.

CONCLUSIONS

We established reference values for quadriceps muscle strength with the Locomo Scan as an index for functional deterioration of locomotive organs based on a large-scale sample.

Are there different factors affecting walking speed and gait cycle variability between men and women in community-dwelling older adults?

BACKGROUND

Few studies have examined the relationships between walking speed and gait cycle variability, and muscle strength and postural stability, with a focus on gender differences.

AIM

The aim of this study was to examine whether there are different factors affecting walking speed and gait cycle variability between men and women in community-dwelling older adults.

METHODS

The subjects comprised 712 community-dwelling older adults (252 men, 460 women, aged 68.7 ± 4.8 years). Walking speed and coefficient of variation (CV) of step time at a comfortable walking pace were measured. The maximal isometric strength of six lower limb muscles and postural stability were evaluated. Stepwise regression analysis was performed, using lower limb muscle strength and postural stability as independent variables, to investigate the association with walking speed or CV.

RESULTS

For older men, age, body mass index (BMI) and quadriceps setting (QS) strength were significant and independent determinants of walking speed. No variables were identified as significant determinants of CV. For older women, BMI and hip flexion, hip abduction, QS muscle strength were significant determinants of walking speed. Only hip abduction strength was a significant determinant of CV.

DISCUSSION

The results of this study suggest that QS strength is related to walking speed in both men and women, whereas hip flexion and abduction muscle strength are related to walking speed, and hip abduction muscle strength is related to gait cycle variability in older women.

CONCLUSION

Gender differences exist in factors affecting walking speed and gait cycle variability in community-dwelling older adults.

Associations between serum 25-hydroxyvitamin D3 level and skeletal muscle mass and lower limb muscle strength in Japanese middle-aged subjects

Objectives

One of the important risk factors of falling is decreased muscle mass and muscle strength. Recently, there has been an increasing concern on the role of vitamin D in muscle strength and physical activity. Aim of our study is to examine the relationships between vitamin D status and muscle mass and muscle strength in middle-aged healthy adults.

Methods

Subjects were 40 healthy volunteers aged 42.0 ± 10.6 years old. Evaluation was made for serum vitamin D₃ metabolites including 25-hydroxyvitamin D₃ [25(OH)D₃] and 24,25-dihydroxyvitamin D₃ [24,25(OH)₂D₃] concentrations, lower limb muscle strength, and dietary intake by food frequency questionnaire. Body composition was measured by dual-energy X-ray absorptiometry (DXA), and appendicular skeletal mass index (ASMI) was calculated as skeletal muscle mass/squared height.

Results

70% of the subjects had vitamin D insufficiency/deficiency (serum total 25(OH)D < 20 ng/mL), and female subjects had significantly lower serum total 25(OH)D level compared with males. Vitamin D insufficiency/deficiency group had significantly higher body fat, lower SMI and muscle strength, probably reflecting higher percentage of female subjects. Serum vitamin D₃ metabolites levels were significantly correlated with whole and site-specific ASMI, and lower limb muscle strength, except for the correlation between serum 24,25(OH)₂D₃ concentration and lower limb muscle strength. In addition, serum 25(OH)D₃ level was a positive significant predictor for both ASMI and lower limb muscle strength, while serum 24,25(OH)₂D₃ level was not their significant predictor.

Conclusions

Serum 25(OH)D₃ level was significantly correlated with both skeletal muscle mass and lower limb muscle strength.

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

BACKGROUND

Knee osteoarthritis (OA) is a multifactorial disease that is affected by mechanical factors. The aim of present study was to investigate the association between multiple mechanical factors and medial knee OA in a large epidemiological cohort.

METHODS

Six hundred and ninety-nine subjects (323 males and 376 females), participating in the Matsudai Knee Osteoarthritis Survey 2010, were included. Twelve mechanical factors were selected and their association with the radiographic grade of knee OA, the Western Ontario and McMaster University Index (WOMAC) pain score, and the WOMAC function score was evaluated.

RESULTS

A logistic regression analysis identified varus thrust to be associated with the radiographic grade of knee OA in males (OR: 1.876, 95% CI: 1.332-2.663) and females (2.61, 1.922-3.542), the WOMAC pain score in males (1.997, 1.463-2.672), and the WOMAC function score in females (1.449, 1.12-1.874). Quadriceps muscle strength was associated with the radiographic OA grade in males (0.605, 0.399-0.917) and females (0.636, 0.469-0.863), the WOMAC pain score in females (0.537, 0.445-0.789), and the WOMAC function score in males (0.581, 0.44-0.766). The knee flexion angle was also associated with the radiographic OA grade in males (0.344, 0.19-0.621) and females (0.121, 0.022-0.653), and the WOMAC pain score in males (0.287, 0.156-0.53) and females (0.537, 0.336-0.859). Obesity was associated with the radiographic OA grade in males (1.543, 1.041-2.287) and females (1.589, 1.176-2.146), the WOMAC pain score in female (2.017, 1.517-2.68). Femolo-tibial angle had no significant association with the radiographic knee OA grade or with the WOMAC pain and function scores.

CONCLUSION

Among patients with medial knee OA, dynamic mechanical factors, such as varus thrust, quadriceps muscle strength, and range of motion were more likely to be associated with the radiographic grade of knee OA and to be the WOMAC pain and function scores, compared to static mechanical factors.

Lumbar spondylosis, lumbar spinal stenosis, knee pain, back muscle strength are associated with the locomotive syndrome: Rural population study in Japan

OBJECTIVES

To comprehensively investigate the clinical and physical factors associating with locomotive syndrome (Loc-S); the locomotorium-disability for daily life.

METHODS

647 volunteers participated (247 males, 400 females, Age: 58.4 ± 11.0, BMI: 22.5 ± 3.3). Three self-assessment questionnaires were administered: 1) "25-question Geriatric Locomotive Function Scale" (GFLS-25) for evaluating Loc-S (GLFS-25 ≥ 16 defined as Loc-S); 2) "diagnostic support tool for LSS" (LSS-DST) for evaluating the prevalence of lumbar spinal stenosis (LSS); 3) Knee injury and Osteoarthritis Outcome Score (KOOS). Plain radiographs of the bilateral knees and lumbar spine were evaluated, and the severity of lumbar spondylosis (LS) and knee osteoarthritis (KOA) defined by Kellgren-Lawrence grade. Bone status was evaluated by using the osteo-sono assessment index (OSI) at the calcaneus. Isometric muscle strength of trunk and leg (Nm/kg, both extension and flexion) were evaluated. Linear regression analysis was performed to elucidate the factors concerned with GFLS-25 including age, sex, and BMI.

RESULTS

Thirty-nine subjects (6.0%, 13 males, 26 females) were defined as having Loc-S. Single regression model showed that age, height, BMI, skeletal muscle mass, OSI, LSS, KOOS, the severity of LS and KOA, and trunk- and leg-muscle strength were correlated with the degree of GLFS-25. Stepwise multiple regression model showed that sex, height, LSS, KOOS, the severity of LS, and back muscle strength were significantly correlated with that of GLFS-25.

CONCLUSION

In this cross-sectional study, pain status associated with LSS and knee joint, structural severity for LS, and back muscle strength primarily affected the degree of GFLS-25. For managing Loc-S, we must pay more intensive attention to these factors.

The Knee injury and Osteoarthritis Outcome Score reflects the severity of knee osteoarthritis better than the revised Knee Society Score in a general Japanese population

PURPOSE

The purposes of this study were to examine population-based reference data for sex- and age-related differences between the 2011 revised Knee Society Score (KSS2011) and the Knee injury and Osteoarthritis Outcome Score (KOOS), to assess the correlation between those scores and radiographic knee osteoarthritis (OA), and to validate the use of the scores in a general Japanese population.

METHODS

This cross-sectional study included 963 volunteers (368 males, 595 females; mean age: 54.7years). Participants were classified into five subgroups by age: under 40, 40s, 50s, 60s, and over 70years old. The KSS2011 and KOOS were determined using self-administered questionnaires. Weight-bearing radiographs of the bilateral knee were taken and graded according to the Kellgren-Lawrence (KL) scale. The mean KSS2011 and KOOS were compared among age groups. Correlations between the severity of knee OA and each score were assessed using multiple regression analysis.

RESULTS

The overall KSS2011 tended to gradually decrease with age. Most subscales of the KSS2011 did not show sex-related differences. Similarly, the overall KOOS and all its subscales steadily decreased by approximately 20 points per decade with age. Most subscales of the KOOS were significantly decreased in females over 50. The KL grade was significantly related to both the overall KOOS (β=-0.42, p<0.001) and KSS2011 (β=-0.13, p=0.001), though the correlation to the KOOS was stronger.

CONCLUSION

The overall KSS2011 and KOOS appear to decrease with age. In this population, the KOOS reflects the severity of knee OA better than the KSS2011.

Quadriceps muscle strength, radiographic knee osteoarthritis and knee pain: the ROAD study

Background

The objective of this study was to clarify the association of quadriceps muscle strength with knee pain using a large-scale, population-based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study.

Methods

From the 2566 subjects at the third visit of the ROAD study, the present study analyzed 2152 subjects who completed radiographic examinations and measurements of muscle strength and mass (690 men and 1462 women; mean age, 71.6 ± 12.2 years). Knee pain was assessed by an experienced orthopedist. Knee osteoarthritis (OA) was defined according to Kellgren-Lawrence (KL) grade. Quadriceps muscle strength and muscle mass at the lower limbs were measured by the Quadriceps Training Machine (QTM-05F, Alcare Co., Ltd. Tokyo, Japan) and the Body Composition Analyzer MC-190 (Tanita Corp., Tokyo, Japan), respectively.

Results

Quadriceps muscle strength and weight bearing index (WBI: quadriceps muscle strength by weight) were significantly associated with knee pain after adjustment for age and body mass index, whereas grip strength and muscle mass at the lower limbs were not. The significant association of quadriceps muscle strength with knee pain was independent of radiographic knee OA.

Conclusion

The present cross-sectional study showed an independent association of quadriceps muscle strength with knee pain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-015-0737-5) contains supplementary material, which is available to authorized users.

Knee extensor muscle weakness is a risk factor for development of knee osteoarthritis. A systematic review and meta-analysis

The objective of this study was to perform a systematic review and meta-analysis on the association between knee extensor muscle weakness and the risk of developing knee osteoarthritis. A systematic review and meta-analysis was conducted with literature searches in Medline, SPORTDiscus, EMBASE, CINAHL, and AMED. Eligible studies had to include participants with no radiographic or symptomatic knee osteoarthritis at baseline; have a follow-up time of a minimum of 2 years, and include a measure of knee extensor muscle strength. Hierarchies for extracting data on knee osteoarthritis and knee extensor muscle strength were defined prior to data extraction. Meta-analysis was applied on the basis of the odds ratios (ORs) of developing symptomatic knee osteoarthritis or radiographic knee osteoarthritis in subjects with knee extensor muscle weakness. ORs for knee osteoarthritis and 95% confidence intervals (CI) were estimated and combined using a random effects model. Twelve studies were eligible for inclusion in the meta-analysis after the initial searches. Five cohort studies with a follow-up time between 2.5 and 14 years, and a total number of 5707 participants (3553 males and 2154 females), were finally included. The meta-analysis showed an overall increased risk of developing symptomatic knee osteoarthritis in participants with knee extensor muscle weakness (OR 1.65 95% CI 1.23, 2.21; I(2) = 50.5%). This systematic review and meta-analysis showed that knee extensor muscle weakness was associated with an increased risk of developing knee osteoarthritis in both men and women.

The hallmarks of osteoarthritis and the potential to develop personalised disease-modifying pharmacological therapeutics

Osteoarthritis (OA) is an age-related condition and the leading cause of pain, disability and shortening of adult working life in the UK. The incidence of OA increases with age, with 25% of the over 50s population having OA of the knee. Despite promising preclinical data covering various molecule classes, there is regrettably at present no approved disease-modifying OA drugs (DMOADs). With the advent of next generation sequencing technologies, other therapeutic areas, in particular oncology, have experienced a paradigm shift towards defining disease by its molecular composition. This paradigm shift has enabled high resolution patient stratification and supported the emergence of personalised or precision medicines. In this review we evaluate the potential for the development of OA therapeutics to undergo a similar paradigm shift given that OA is increasingly being recognised as a heterogeneous disease affecting multiple joint tissues. We highlight the evidence for the role of these tissues in OA pathology as different "hallmarks" of OA biology and review the opportunities to identify and develop targeted disease-modifying pharmacological therapeutics. Finally, we consider whether it is feasible to expect the emergence of personalised disease-modifying medicines for patients with OA and how this might be achieved.

The relationship between radiological severity and functional status in patients with knee osteoarthritis

In this study, we aimed to explore the relationship between radiological findings and functional status in patients with knee osteoarthritis (OA). In this study, 117 female patients diagnosed with knee osteoarthritis according to the ACR criteria were included. Antero-posterior knee radiographs of the patients were graded according to Kellgren-Lawrence, and functional capacity was evaluated with WOMAC and Lequesne indexes. Quadriceps and hamstring muscle strengths were also concentrically measured using an isokinetic dynamometer, five repetitions at 90°/s and 20 repetitions at 180°/s. In this study, a significant relationship was determined between the age, weight, praying period, and pain period of the patients with the radiological findings. No significant relationship was determined between the functional capacity of knee and muscle strength and the radiological findings. However, left hamstring functioning capacity was found as lower in the group with the radiological findings. The radiological findings in knee OA are not associated with decrease in knee muscle strength and functional capacity. Clinical symptoms such as pain, decrease in range of motion, etc. in knee OA may be responsible for decrease in knee muscle strength and functional capacity.