Isokinetic evaluation of knee extensor/flexor muscle strength in patients with hypermobility syndrome

Benign joint hypermobility syndrome (BJHS) is a syndrome with musculoskeletal pain originating from the increased laxity of the joints and the ligaments. The study was to compare the isokinetic strength of knee extensor/flexor muscles of BJHS patients with healthy controls. Forty patients diagnosed as having BJHS with Brighton criteria and 45 years of age, height and weight-matched healthy controls were recruited for the study. Isokinetic testing was performed with isokinetic dynamometry of Biodex System 3Pro and measurements were recorded at knee extension/flexion pattern concentrically at 60, 180, and 240°/s angular velocities. The study group was also evaluated for functional impairment and pain by HAQ and VAS respectively. Knee extensor muscle strength was significantly lower in the patient group compared with the controls. It was hypothesized that the muscle weakness in the study group was related to lengthening of the quadriceps muscle and pain-related inactivity as well as joint instability and proprioception defect.     

Knee extensor and knee flexor strength: cross-sectional area ratios in young and elderly men.

The relationships between isometric and isokinetic-concentric knee extensor and knee flexor strength, and quadriceps and hamstring cross-sectional area (CSA) were determined in young (n = 13, M = 24.5y) and elderly (n = 12, M = 70.7y) men. Quadriceps and hamstring CSA was determined by computed tomography. Knee extensor and flexor strength at 0 degree/s and 120 degree/s was determined on a Kin-Com isokinetic dynamometer. Compared to the young men, elderly men had significantly smaller quadriceps muscles and were weaker (22-32%) in knee flexion and knee extension at both angular velocities. Strength:CSA ratios were similar at 0 degree/s, but elderly men had decreased ratios for both extensors and flexors at 120 degree/s. Correlations of knee extensor and flexor strength with muscle CSA were significant at both velocities in elderly men, but not at either velocity for the knee flexors in young men. The decrease in isometric strength in elderly men can be accounted for by their decrease in muscle CSA, but their decrease in isokinetic-concentric strength was greater than their loss of CSA. Further study is required to determine the reason for this nonproportional loss of isokinetic-concentric strength.     

Meta-analysis on the association between knee extensor strength and structural changes of knee osteoarthritis

This study aimed to perform a meta-analysis to evaluate whether knee extensor (KE) strength weakness was associated with increased structural worsening in knee osteoarthritis (KOA) including joint space narrowing (JSN) and cartilage loss. PubMed, Embase, Scopus, ScienceDirect, Web of Science, and Cochrane library were searched from their inception to May 2020, to identify eligible studies. Odds ratios (ORs) accompanied by 95% confidence intervals (CIs) were calculated for the relationship between KE strength and outcomes. Totally eleven longitudinal studies were included. The pooled crude OR indicated no significant association between KE strength weakness and KOA progression of JSN (OR: 1.13, 95% CI: 0.90, 1.42), and this result duplicated after confounders were adjusted (OR: 1.10, 95% CI: 0.87, 1.39). Subgroup analysis showed the association remained non-significant in sex-specific outcomes and subsets of neutral and malaligned knees, but there was a trend toward increased risk of JSN progression in female knees with low strength (OR: 1.24, 95% CI: 0.87, 1.76, I² = 82%). The pooled crude OR showed that KE strength weakness was associated with increased risk of cartilage loss (OR:1.43, 95% CI: 1.05, 1.95). After adjustment, we found a non-significant trend that low KE strength could increase the risk of cartilage loss (OR: 1.25, 95% CI: 0.95, 1.64), and this trend was separately observed in tibiofemoral or patellofemoral compartments. This meta-analysis suggested that KE strength weakness was not significantly associated with an increased risk of radiographic structural KOA progression in patients with KOA or known risk factors for KOA. However, there was a trend that women with weaker KE strength displayed a higher risk of JSN worsening and that KE strength weakness had an association with an increased risk of cartilage damage.

Effects of age and gender on toe flexor muscle strength

BACKGROUND: Toe flexor muscle strength determines the anterior limit of the functional base of support, thereby affecting a standing individual's maximum forward reach or lean capacity. We developed a method for measuring toe flexor muscle strength in order to test the null hypotheses that it is neither affected by age nor gender. METHODS: Gender-balanced groups of 20 healthy young adults (YA) (average age 22.8 years) and 20 healthy older adults (OA) (average age 73.2 years) participated in the study. Toe flexor isometric muscle strength, calculated as the maximum volitional moment developed simultaneously in the sagittal plane by the toe flexor muscles about a reference axis through the first metatarsophalangeal joint, was measured in three trials while subjects reached forward as far as possible while standing on a force plate. RESULTS: Significant age (p <.005) and gender (p <.0005) differences were found in maximum toe flexor muscle strength. OA were 28.9% less strong than the YA [mean (SD) 13.5 (5.7) Nm and 19.0 (6.8) Nm, respectively]. The men developed 39.1% greater strength than the women [20.2 (7.1) Nm and 12.3 (3.7) Nm, respectively]. However, when normalized by body size (body weight x height), the gender difference in strength no longer reached statistical significance. Across all subjects, the anterior limit of the functional base of support was significantly correlated with toe flexor strength (coefficient of determination: 0.84). CONCLUSIONS: Toe flexor muscle strength decreased significantly with age. This decrement underlies the known age-related reduction in the functional base of support.     

The effect of local heat and cold packs on the skin temperature at the knee joint

Using the infrared radiometer KT 41, skin temperature of the knee joint was measured in 5 healthy persons on five different points. With the same method skin temperature of knee joints was estimated after hot mud packs of 20 minutes duration and cold packs with frozen bags of 30 minutes duration. The highest temperatures were estimated near the popliteal space, the lowest temperatures on the patella. During 24 hours, a distinct periodical course of skin temperature could be observed. After the hot pack skin temperature of the treated joint significantly rose; after 1 hour the average temperature before heat application was reached again. After cold application with deeply frozen bags, skin temperature dropped drastically and remained colder than pretreatment temperature for almost 5 hours. Heat application did not influence skin temperature of untreated contralateral knee but during cold application also the temperature of untreated knee slightly decreased. Considering the correlation between skin temperature and intraarticular temperature of joints, the effect of local heating and cooling seems to be more intense than supposed and confirms the therapeutic benefit of heat and cold in rheumatology.     

Associations of knee extensor strength and standing balance with physical function in knee osteoarthritis

Objective

Knee extensor strength is an important correlate of physical function in patients with knee osteoarthritis; however, it remains unclear whether standing balance is also a correlate. The purpose of this study was to evaluate the cross‐sectional associations of knee extensor strength, standing balance, and their interaction with physical function.

Methods

One hundred four older adults with end‐stage knee osteoarthritis awaiting a total knee replacement (mean ± SD age 67 ± 8 years) participated. Isometric knee extensor strength was measured using an isokinetic dynamometer. Standing balance performance was measured by the center of pressure displacement during quiet standing on a balance board. Physical function was measured by the self‐report Short Form 36 (SF‐36) questionnaire and by the 10‐meter fast‐pace gait speed test.

Results

After adjustment for demographic and knee pain variables, we detected significant knee strength by standing balance interaction terms for both SF‐36 physical function and fast‐pace gait speed. Interrogation of the interaction revealed that standing balance in the anteroposterior plane was positively related to physical function among patients with lower knee extensor strength. Conversely, among patients with higher knee extensor strength, the standing balance–physical function associations were, or tended to be, negative.

Conclusion

These findings suggest that although standing balance was related to physical function in patients with knee osteoarthritis, this relationship was complex and dependent on knee extensor strength level. These results are of importance in developing intervention strategies and refining theoretical models, but they call for further study.     

Aging-related changes in knee flexor muscle strength and cross-sectional area

Weakening muscle strength around the knee tends to render it vulnerable to aging-related damage. This study aimed to examine the association between knee flexor muscle strength and its cross-sectional area (CSA). We also evaluated aging-related changes in flexor muscle strength and CSA. We retrospectively analyzed 252 patients with acute-onset knee pain (<1 month) between September 2006 and August 2009 in accordance with the Strengthening the Reporting of Observational studies in Epidemiology statement. The CSA of each knee flexor muscle (biceps femoris, sartorius, gracilis, semitendinosus (ST), and semimembranosus (SM)) was measured on magnetic resonance imaging axial images at the suprapatellar level. We evaluated flexor muscle strength (peak torque in N.m) using a Cybex dynamometer at 60°/second and 180°/second and its correlation with CSA. In total, 252 patients (mean age, 34.5 years; range, 11 to 66 years; 184 men and 68 women) were included in this study. No significant intergroup differences in demographic data such as sex or body mass index were found. Mean CSA was 605.4 mm² for the SM, 444.7 mm² for the biceps femoris, 282 mm² for the sartorius, 55.4 mm² for the ST, and 34.1 mm² for the gracilis. Mean peak torques were 67.4 N.m and 52.7 N.m at 60°/second and 180°/second, respectively. CSA was positively correlated with flexion strengths of 60°/second (R = 0.363, P < .001) and 180°/second (R = 0.354, P < .001). Muscle strength was associated with CSA in all muscles but the gracilis (R = 0.056, P = .375). Flexion strength decreased significantly with aging from the thirties. Total CSA decreased with aging (r = −0.247, P < .001). The CSA of the biceps femoris, sartorius, SM, and ST decreased significantly, whereas that of the gracilis tended to decrease non-significantly with aging. Flexor muscle strength was associated with total muscle CSA on magnetic resonance imaging and the CSA of every muscle except the gracilis. Flexion strength decreased significantly with aging after the twenties, while total CSA decreased significantly with aging. The CSA of all flexor muscles decreased significantly with aging, whereas that of the gracilis decreased only slightly.     

Assessment of extensor and flexor strength in the individual gonarthrotic patient: Interpretation of performance changes

Summary The intra-session and inter-session reproducibility of knee extensor and flexor strength measurements were examined in 21 gonarthrotic subjects (ten women and eleven men). Using the Cybex 6000 dynamometer, isokinetic peak torque and total work at 30 and 120 degrees/second and isometric peak torque were measured three times on separate days within two weeks by the same examiner. The reproducibility of walking and stair climbing time measurements was also assessed. The concept of critical difference (i.e. the difference between two measurements which would be statistically significant when applied to a reference group in steady state) for the interpretation of muscle strength data obtained by monitoring individual patients is presented.Individual coefficients of variation (CV) were calculated for each muscle strength variable. Depending on the velocity and on whether peak torque or total work were measured, the median CV of intra-session and inter-session extensor strength measurements ranged from 1.5–4.9% and 7.4–10.1%, respectively. CVs for flexor strength measurements were significantly higher. Substantial variability of within subject variances were found, e.g. the 80% central range of CVs for extensor toruqe at 30 degrees/second was 2.5–29.5% (inter-session). Calculated from CVs, critical differences for inter-session measurements exceeded 30% for all muscle strength variables. Median CVs for walking and stair-climbing time were 7.0% and 4.9%, respectively.In conclusion, the large CVs and corresponding critical differences may be a major limitation in the use of muscle strength measurements in the individual gonarthrotic patient.     

Relationship of intermuscular fat volume in the thigh with knee extensor strength and physical performance in women at risk of or with knee osteoarthritis

Objective

To determine the extent to which thigh intermuscular fat (IMF) and quadriceps muscle (QM) volumes explained variance in knee extensor strength and physical performance in women with radiographic knee osteoarthritis (ROA) and without.

Methods

Baseline data from 125 women (age ≥50 years) in the Osteoarthritis Initiative study, with or at risk of knee ROA were included. Knee extensor strength was measured using a fixed force transducer, normalized to body mass (N/kg). Physical performance was the time required for 5 repeated chair stands (seconds). The IMF and QM volumes, normalized to height (cm³/meter), were yielded from analyses of T1‐weighted axial magnetic resonance images of the midthigh. Mean IMF and QM volumes, extensor strength, and physical performance were compared between women with and without ROA, controlling for age. Hierarchical multiple regressions determined whether IMF and QM volumes were related to strength and performance after controlling for age, ROA status (yes/no), alignment, and pain.

Results

Compared to subjects with ROA, the subjects without ROA were stronger and performed chair stands faster (P < 0.05). After adjusting for age, those subjects without ROA had less mean ± SD IMF (61.1 ± 20.3 cm³/meter) compared to mean ± SD ROA (72.0 ± 25.0 cm³/meter; P < 0.05). In the entire sample, 21.1% of variance in knee extensor strength was explained by alignment, pain, and IMF. A model explaining 13.4% of variance in physical performance included OA status and IMF. QM volume was unrelated to strength and physical performance.

Conclusion

IMF volume explained a small amount of variance in knee extensor strength and physical performance among women with or at risk of knee ROA.     

Taiji training improves knee extensor strength and force control in older adults

The purpose of this study was to examine the effects of Taiji training on knee extensor strength and force control in older individuals. Twenty-six healthy older adults (71.9 +/- 1.8 years) participated in the study. Sixteen of the older adults (70.2 +/- 1.8 years) underwent Taiji training for 20 weeks (experimental group), whereas the other 10 (74.6 +/- 1.2 years) served as the control group. For both groups, strength and force control of the knee extensors was assessed twice with an isokinetic dynamometer. Strength was assessed with a maximum voluntary isometric contraction (MVC). Force control was measured as the standard deviation (SD) and coefficient of variation (CV) of force during a constant isometric knee extension task at 2%, 30%, 60%, and 90% MVC. For the experimental group, MVC significantly increased (19.5 +/- 4.9%) and the CV of force decreased (18.9 +/- 3.3%) following Taiji training. Improvements in the CV of force were primarily due to decreases in the SD of force (R(2) =.86) rather than increases in strength (R(2) =.12). Furthermore, decreases in SD of force were independent of improvements in strength. For the control group, strength, SD, and CV of force were not different for the 2 tests. The overall findings suggest that Taiji training improves knee extensor strength and force control in older adults.     

Effects of strength training and detraining on knee extensor strength,muscle volume and muscle quality in elderly women

Strength training seems to be an interesting approach to counteract decreases that affect knee extensor strength, muscle mass and muscle quality (force per unit of muscle mass) associated with ageing. However, there is no consensus regarding the changes in muscle mass and their contribution to strength during periods of training and detraining in the elderly. Therefore, this study aimed at verifying the behaviour of knee extensor muscle strength, muscle volume and muscle quality in elderly women in response to a 12-week strength training programme followed by a similar period of detraining. Statistical analysis showed no effect of time on muscle quality. However, strength and muscle volume increased from baseline to post-training (33 and 26 %, respectively). After detraining, the knee extensor strength remained 12 % superior to the baseline values, while the gains in muscle mass were almost completely lost. In conclusion, strength gains and losses due to strength training and detraining, respectively, could not be exclusively associated with muscle mass increases. Training-induced strength gains were partially maintained after 3 months of detraining in elderly subjects.     

Effect of physical exercise and age on knee joint position sense

This study aimed to test the hypotheses that knee position sense declines with age and that regular exercise can attenuate that decline. This cross-sectional study encompassed 69 older and 60 young adults divided in four groups (exercised-old, N = 31; non-exercised-old, N = 38; exercised-young, N = 35; non-exercised-young, N = 25) according to chronological age and exercise practice in the past year. Knee position sense was measured by open kinetic chain technique and active positioning and is reported as the absolute and relative angular error. Knee angles were determined by computer analysis of videotape images using the Ariel Performance Analysis System. Compared to their non-exercised counterparts, exercised-young and -old showed lower absolute and relative angular errors. The absolute (1.62 ± 0.71°) and relative errors (0.02 ± 1.65°) for exercised-young were lower than all other groups (p < 0.001). The absolute and relative errors of exercised-old (4.27 ± 2.49° and 5.51 ± 3.42°) were similar to non-exercised-young (4.74 ± 2.67° and 4.18 ± 3.40°). The non-exercised-old exhibited higher absolute (9.35 ± 4.34°) and relative errors (9.73 ± 5.15°) than all other groups (p < 0.001). The present data indicates that age has deleterious effects on knee position sense although regular exercise can attenuate that age-related decline.     

The effect of joint aspiration and corticosteroid injections in osteoarthritis of the knee

Aim: To evaluate the benefits of knee joint aspiration and injection in knee osteoarthritis (OA). Methods: A retrospective, pilot study involved 110 patients with knee OA from a dedicated OA clinic in a Melbourne tertiary hospital from 2007 to 2009. Only those who had completed two Multiple Attribute Prioritization Tool (MAPT) questionnaires within 6 months of the initial review were included. The MAPT was designed to help prioritise patients on orthopedic waiting lists. Three groups were analyzed: patients who had no corticosteroid injection or aspiration, patients who received corticosteroid injections, and patients who received both joint aspiration with corticosteroid injections. Results: Patients who had both joint aspiration and injection reported an improvement in pain compared with those who had no injection (56.3%vs. 32.2%, P = 0.03). Those who had joint injections also did better than those without injection (62.7%vs. 32.2%, P = 0.001). Reduced analgesia use was noted in 12.5% of patients with aspiration and injection compared with 1.7% with no injection or aspiration (P = 0.03). Improved walking distance was noted in 22.4% of patients who had injections compared with 8.5% of patients with no injections (P = 0.03). No significant differences in MAPT scores among the different treatment groups were noted. Conclusion: This pilot study appears to show a beneficial trend in giving corticosteroid injections and to aspirate the knee in OA patients. Further studies are needed to address the mechanical benefits, quadriceps strengthening and pain reduction with knee aspiration, as well as the effects that different volumes of fluid may have on knee mechanics and symptoms.     

Age-related declines in knee extensor strength and physical performance in healthy Hispanic and Caucasian women

Hispanic women may undergo greater age-related reductions in physical functional capacity compared with Caucasian women. If so, a greater rate of decline in muscle strength with age could contribute. We tested this hypothesis in 82 healthy sedentary Caucasian (n = 37) and Hispanic (n = 45) adult women aged 21-78 years of similar socioeconomic status. Absolute one-repetition maximum (1-RM) strength of the knee extensors (KE) declined with advancing age in the Caucasian (r = -.55, p < .01) and Hispanic (r = -.45, p < .01) women; the rates of decline were similar in the two groups (-7% to 8% x decade(-1), p = .60). KE strength normalized for thigh fat-free mass (FFM) also declined with age in the Caucasian (r = .52, p < .01) and Hispanic (r = -.41, p < .01) women, the rates of decline being similar (-6% to 7% x decade(-1), p = .66). For all functional performance tasks (10-m walk, stair ascent, stair descent, and chair stand), performance time increased with advancing age (mean of four tasks vs age: Caucasian, r = .64, p < .01; Hispanic, r = .56, p < .01). Absolute and normalized KE 1-RM were inversely related to the mean time for the four performance tasks (r = -.34 to -.58, all p < .01). Normalized KE 1-RM was the best independent predictor of the age-related decline in task performance in both groups. These cross-sectional findings do not support the hypothesis that Hispanic ethnicity per se is associated with a greater decline in KE strength and performance tasks associated with KE strength in healthy women.     

The effect of a corticosteroid on the absorption of 131I-albumin from rabbit knee joint

The disappearance rate of 131I-albumin from the knee joint in six rabbits was measured before and after intraarticular injection of 7.5 mg triamcinolonhexacetonide (Lederspan). A significant decrease in the synovial permeability was demonstrated after injection of triamcinolonhexacetonide (average 64 percent). It is concluded that this demonstrates that corticosteroids have a direct effect on the synovial membrane, which may be an important mechanism whereby they exert their therapeutic effect upon joints.     

Isometric strength and steadiness adaptations of the knee extensor muscles to level and downhill treadmill walking in older adults

An ageing related decline in muscle strength and steadiness decreases quality of life and increases the risk for falls. Downhill treadmill walking (DTW) may enhance muscle strength and steadiness in older adults. Eighteen healthy older adults (age: 67 ± 4, body mass: 75 ± 14 kg) completed 12-weeks of level treadmill walking (LTW, 0 %, n = 8) or DTW (?10 %, n = 10) (30 min, 3 days per week) at a self-selected walking speed (re-adjusted in week 4 and 8). Maximal voluntary isometric force (MVIF) and electromyography (EMG) of the m. quadriceps femoris (QF) were measured at baseline, 4, 8 and 12 weeks. Steadiness of submaximal (5, 10 and 20 % MVIF) isometric contractions (i.e. coefficient of variation of the force signal) and EMG of QF were measured at baseline and 12 weeks. Baseline MVIF of LTW (340 ± 112 N) and DTW (368 ± 128 N) increased equally by 14 ± 6 and 5 ± 6 % (p < 0.05). Steadiness at 5 %MVIF improved following 12 weeks of LTW (baseline: 0.04 ± 0.01; 12 weeks: 0.03 ± 0.01) and DTW (baseline: 0.04 ± 0.02; 12 weeks: 0.03 ± 0.01 (p < 0.05). EMG root mean square of m. vastus lateralis during MVIF increased by 38 % following 12 weeks of LTW only (p < 0.05). The potential implications for an exercise modality, such as DTW, with a lower oxygen demand, to improve muscle strength could serve as a rehabilitative countermeasure for older adults.     

The strength of age effect on tooth loss and periodontal condition in Korean elderly

Aging is a well-known risk factor associated with oral diseases. The aim of this cross-sectional study was to compare tooth loss and periodontal health between the relatively young elderly (65-74 years) and the old elderly (≥75 years) and to investigate the strength of the age effect on oral health status in the Korean elderly. Study population 65 years of age or older were selected from the participants of the Korean National Oral Health Survey (2006) (n = 1193). Oral examination was conducted by eight dentists trained in the World Health Organization (WHO) recommended examination procedure. The chi-square test, multiple regression analyses and multinomial logistic regression analyses were performed using SAS 9.1.3. The oral health status including decayed, missing, and filled teeth (DMFT), missing teeth, and residual teeth significantly differed between the young elderly and the old elderly (p < 0.01). Moreover, the regression coefficients of tooth loss linearly increased across different age groups (5-year intervals, starting at age 65 years) (p < 0.05). However, the odds ratios of periodontal health did not significantly differ across 5-year interval age groups. The findings that age and the number of missing teeth are significantly and linearly related could contribute to the development of oral health care and promotion programs for the elderly tailored to their own age.     

Amyloid deposits in the knee joint at autopsy.

Joint capsule, meniscus, and cartilage from the patella and medial femoral condyle from 30 non-selected autopsies have been investigated for amyloid deposits with light and electron microscopy. Both right and left knee joints from 28 of the 30 autopsy specimens contained amyloid deposits (93%). The amyloid characteristically showed green dichroism in polarised light after staining with alkaline Congo red. The ultrastructural features were also characteristic of amyloid. Amyloid in capsule tissue was found in a subsynovial location, as well as deeper in the capsule tissue, while in the cartilage amyloid was localised along the surface. The meniscus tissue, in particular, contained heavy deposits of amyloid--mainly along the inner margin. Osteoarthritic changes, with fibrillation of the cartilage, were significantly related to amyloid deposition. No pathogenetic correlation between the osteoarthritic changes and amyloid deposition could be shown in the present investigation.