vendex and Arthritis--Rheumatoid

Neuromuscular electrical stimulation (NMES) is a viable intervention for improving impaired muscle function in individuals with rheumatoid arthritis (RA). However, there is limited evidence about the dose-response relationship between NMES and muscle function in these individuals.. The objectives of this study were to investigate the dose-response relationship between NMES and muscle function in individuals with RA and to establish the minimal NMES training intensity for promoting improvements.. This study was a secondary analysis of data obtained before and after an NMES intervention in a randomized study.. The study took place at a research clinic. Only adults diagnosed with RA were included. The intervention consisted of 36 NMES treatment sessions for the quadriceps muscles over 16 weeks. Muscle function was measured before and after the intervention; quadriceps cross-sectional area and muscle quality were assessed using computed tomography, and strength was measured with an isokinetic dynamometer. NMES training intensity was calculated as a percentage by dividing NMES-elicited quadriceps muscle torque by the maximum voluntary isometric contraction. Improvements in muscle function were calculated using paired-sample t tests. The dose-response relationship was determined using curve estimation regression statistics. The minimum NMES training intensity was defined as that sufficient to significantly improve all muscle function measures.. Twenty-four people (48 legs) participated (75% women; mean [SD] age = 58 [8] years; mean body mass index = 32 [7] kg/m2). Quadriceps cross-sectional area, muscle quality, and strength improved after the intervention. Associations between NMES training intensity and muscle quality (r2 = 0.20) and strength (r2 = 0.23) were statistically significant, but that between NMES training intensity and muscle cross-sectional area was not (r2 = 0.02). The minimum NMES training intensity necessary to improve all measures of muscle function ranged from 11% to 20% of the maximum voluntary isometric contraction.. The relatively small sample size was a limitation.. The minimum NMES training intensity for significant gains in muscle function was ∼15%. Higher NMES intensities may promote better muscle quality and strength in individuals with RA.

Topics: Arthritis, Rheumatoid; Body Mass Index; Electric Stimulation Therapy; Female; Humans; Isometric Contraction; Male; Middle Aged; Muscle Strength; Muscle Weakness; Muscle, Skeletal; Muscular Atrophy; Quadriceps Muscle; Regression Analysis; Sample Size; Torque

The purpose of this study is to present midterm results of NexGen LPS (Zimmer, Warsaw) rotating platform total knee arthroplasty. A prospective consecutive series of 50 primary rotating platform total knee replacements in 43 patients were clinically and radiographically evaluated at a mean follow-up of 46.4 (range 30-78) months. There were 12 men (30%) and 31 women (70%) with an average age of 72.3 years (range 55-85). All implants were cruciate-substituting and cemented. Patients were assessed using the Knee Society Clinical Rating System and the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. Pre-operatively, the mean knee score was 50.7 points (SD 15.1) and the mean function score was 40.5 points (SD 22.7). Post-operatively the mean knee score was 91.6 (SD 6.5) and the mean function score was 85.9 (SD 17.4). No sign of component loosening or osteolysis could be identified. The NexGen LPS rotating platform total knee replacement design provided excellent mid-term clinical and radiographical results.

Topics: Aged; Aged, 80 and over; Arthritis, Rheumatoid; Arthroplasty, Replacement, Knee; Equipment Design; Female; Follow-Up Studies; Humans; Male; Middle Aged; Osteoarthritis, Knee; Prospective Studies; Radiography; Recovery of Function; Severity of Illness Index; Shear Strength; Torque; Treatment Outcome

Rheumatoid arthritis frequently results in functional impairment. This study investigated the effect of a specific exercise regimen on function.. A randomized controlled assessor-blinded (N = 36) compared the effect of knee extensor and flexor muscle training on pain, the timed up and go (TUG) test and the Health Assessment Questionnaire in subjects with non-acute rheumatoid arthritis.. Knee extensor and flexor muscle training increased isokinetic torques at speeds of 60 degrees/sec-1 and 120 degrees/sec-1 as measured by an isokinetic dynamometer (p = 0.02-0.003). The experimental group experienced a reduction in pain (p = 0.03), an improvement in TUG time (p = 0.01) and in function as measured by the Health Assessment Questionnaire (p = 0.04).. Specific knee muscle training can be administered safely in people with non-acute rheumatoid arthritis, and may produce functional benefits.

Topics: Activities of Daily Living; Analysis of Variance; Arthritis, Rheumatoid; Biomechanical Phenomena; Disability Evaluation; Exercise Therapy; Female; Humans; Knee Joint; Male; Middle Aged; Movement; Muscle Contraction; Pain Measurement; Torque

The overexpression of tumor necrosis factor (TNF)-α leads to systemic as well as local loss of bone and cartilage and is also an important regulator during fracture healing. In this study, we investigate how TNF-α inhibition using a targeted monoclonal antibody affects fracture healing in a TNF-α driven animal model of human rheumatoid arthritis (RA) and elucidate the question whether enduring the anti TNF-α therapy after trauma is beneficial or not.. A standardized femur fracture was applied to wild type and human TNF-α transgenic mice (hTNFtg mice), which develop an RA-like chronic polyarthritis. hTNFtg animals were treated with anti-TNF antibody (Infliximab) during the fracture repair. Untreated animals served as controls. Fracture healing was evaluated after 14 and 28 days of treatment by clinical assessment, biomechanical testing and histomorphometry.. High levels of TNF-α influence fracture healing negatively, lead to reduced cartilage and more soft tissue in the callus as well as decreased biomechanical bone stability. Blocking TNF-α in hTNFtg mice lead to similar biomechanical and histomorphometrical properties as in wild type.. High levels of TNF-α during chronic inflammation have a negative impact on fracture healing. Our data suggest that TNF-α inhibition by an anti-TNF antibody does not interfere with fracture healing.

Topics: Animals; Antibodies, Monoclonal; Arthritis; Arthritis, Rheumatoid; Bone Nails; Bony Callus; Disease Models, Animal; Female; Femoral Fractures; Fracture Fixation, Internal; Fracture Healing; Humans; Inflammation; Infliximab; Mice; Mice, Transgenic; Stress, Mechanical; Torque; Tumor Necrosis Factor-alpha; Weight-Bearing

We describe 5 cases of failure of the locking mechanism of the polyethylene insert and tibial base-plate in one design of constrained condylar knee prosthesis due to disengagement of the locking screw. Loosening of the screw is believed to occur because of a counterclockwise torque created by the axial rotation of the femur on the tibia that occurs as the knee extends during gait. This torque is transmitted via the highly rotationally constrained femoral housing and tibial post to the locking screw. These failures suggest that an alternative locking mechanism should be considered for this prosthesis.

Topics: Adult; Aged; Arthritis, Rheumatoid; Arthroplasty, Replacement, Knee; Female; Femur; Humans; Knee Joint; Knee Prosthesis; Male; Middle Aged; Polyethylene; Prosthesis Design; Prosthesis Failure; Radiography; Reoperation; Tibia; Torque; Treatment Outcome

Although glucocorticoids are frequently prescribed for the symptomatic management of inflammatory disorders such as rheumatoid arthritis, extended glucocorticoid exposure is the leading cause of physician-induced osteoporosis and leaves patients at a high risk of fracture. To study the biochemical effects of glucocorticoid exposure and how they might affect biomechanical properties of the bone, Raman spectra were acquired from ex vivo tibiae of glucocorticoid- and placebo-treated wild-type mice and a transgenic mouse model of rheumatoid arthritis. Statistically significant spectral differences were observed due to both treatment regimen and mouse genotype. These differences are attributed to changes in the overall bone mineral composition, as well as the degree of phosphate mineralization in tibial cortical bone. In addition, partial least squares regression was used to generate a Raman-based prediction of each tibia's biomechanical strength as quantified by a torsion test. The Raman-based predictions were as accurate as those produced by microcomputed tomography derived parameters, and more accurate than the clinically-used parameter of bone mineral density. These results suggest that Raman spectroscopy could be a valuable tool for monitoring bone biochemistry in studies of bone diseases such as osteoporosis, including tests of drugs being developed to combat these diseases.

Topics: Analysis of Variance; Animals; Arthritis, Rheumatoid; Biomechanical Phenomena; Disease Models, Animal; Glucocorticoids; Least-Squares Analysis; Mice; Osteoporosis; Prednisolone; Reproducibility of Results; Spectrum Analysis, Raman; Tibia; Torque; X-Ray Microtomography

In clinically diagnosed rheumatoid arthritis (RA), studies were conducted to investigate the reflex and passive tissue contribution to measured increases in joint stiffness in the resting upper limb and during constant contractions of an attached muscle. The tonic stretch reflex was induced by a servo-controlled sinusoidal stretch perturbation of the metacarpophalangeal joint of RA patients, and age- and sex-matched controls. The resulting reflexes and mechanical changes in the RA affected joint were explored. Surface electromyographic (EMG) measurements were obtained from first dorsal interosseus muscle. Reflex gain (EMG/joint angle amplitude ratio), phase difference (reflex delay after stretch), coherence square (proportion of EMG variance accounted for by joint angle changes), joint mechanical gain (torque-joint angle amplitude ratio) and mechanical phase difference (torque response delay after stretch) were determined. RA patients showed decreased reflex gain that was partly due to coexistent severe muscle weakness, as determined from maximum voluntary contraction and grip pressure estimates. The decreased reflex gain was most evident at high stretch frequency suggesting a disproportionate loss of the large diameter afferent response and also increased reflex delay in the patients. These changes ensemble suggest significant loss of neural drive to the motor unit population. Patients also showed increased joint stiffness (measured as torque gain) in the contracting muscle, but there was no evidence of reflex activity or increased stiffness at rest. This suggests that the increased joint stiffness in RA was due to changes in the mechanical properties of the active muscle-joint system rather than changes in reflex properties.

Topics: Adult; Arthritis, Rheumatoid; Biomechanical Phenomena; Electromyography; Female; Fingers; Humans; Joints; Male; Metacarpophalangeal Joint; Middle Aged; Motor Neurons; Muscle Contraction; Muscle Strength; Muscle Weakness; Muscle, Skeletal; Nerve Fibers, Myelinated; Range of Motion, Articular; Reflex, Stretch; Torque

The use of Souter-Strathclyde total elbow prostheses is a well-studied replacement therapy for reconstruction of the elbow, but loosening of the humeral component is still of concern at long-term follow-up. In this study we looked at the effect of humeral component size and bone mineral density with respect to the bone size, torsional stiffness and torque to failure in cadaveric bones. Fourteen cadaveric humeri were available for testing purposes and four different humeral component size categories were used. First, we calculated the bone quality using dual-energy X-ray absorptiometry (DEXA). The torsional stiffness of the prosthetic humeri was measured during two mechanical tests: Firstly, the applied torque was recorded during a torsion fatigue test. The change of torsional stiffness between the tenth and last cycle was calculated. Secondly, a simple torsion test was performed and the torque to failure was recorded. No significant differences in outcome were seen between sizes of humeral components, even after correction for the bone size. Torsional stiffness and torque to failure were significantly correlated with bone mineral density and not with component size. In conclusion, bone quality seems to be a major eminent factor in the fixation of the humeral component in elbow replacement surgery.

Topics: Aged; Aged, 80 and over; Arthritis, Rheumatoid; Arthroplasty, Replacement; Bone Density; Cadaver; Elbow Joint; Elbow Prosthesis; Equipment Failure Analysis; Female; Humans; Humerus; Joint Prosthesis; Male; Middle Aged; Prosthesis Design; Radiography; Range of Motion, Articular; Stress, Mechanical; Torque

The aim of the study was to present a method enabling a reduction of the number of measurements when quantifying isokinetic muscle strength (IMS), and to describe an expression for IMS which is independent of measuring conditions. IMS is a measure of muscle strength used to categorise patients and to assess changes over time. IMS measurements involve one or several measures of peak torque at different chosen angular velocities. Comparisons between studies are difficult and an expression of IMS independent of measuring conditions is needed. Thirty-six women with rheumatoid arthritis were followed for 1 year. IMS was measured on five occasions on both knees at seven angular velocities, giving 10 sets of peak-torque data for each patient. The log[peak-torque]-angular-velocity diagram showed a linear relationship. From this, the peak-torque value at the chosen angular velocity of 30 degrees/s (IMS30) was estimated for each test and the uncertainties involved were quantified. IMS30 is a reliable parameter when comparing effort between knees, visits and patients, and may be based on three sets of data only. IMS may be expressed by a single value, IMS30, representing the fitted line in a log[peak-torque]-angular-velocity diagram. The regression line may be fitted by three or more angular velocities. In principle, IMS30 is independent of the chosen angular velocity, which makes it possible to use an estimated value as IMS30 to compare results, studies and centres in between.

Topics: Arthritis, Rheumatoid; Cohort Studies; Female; Follow-Up Studies; Humans; Isometric Contraction; Knee Joint; Methods; Muscle Contraction; Muscle, Skeletal; Prospective Studies; Reproducibility of Results; Torque