Electrical impedance of the torso is associated with the pressure pain threshold on myofascial trigger points in patients with chronic neck pain: A cross-sectional study

BACKGROUND

Myofascial trigger points are dysfunctional structures present in skeletal muscles and are related to sensory, motor, and autonomic changes. Despite scientific advances in recent decades in the measurement of musculoskeletal pain, evaluation of this clinical phenomenon is supported with instruments that, although valid and reliable, have a considerable degree of subjectivity.

OBJECTIVE

To correlate electrical impedance of the upper limbs and torso with pain intensity, functional capacity, catastrophizing, pressure pain threshold, and skin temperature on myofascial trigger points in the upper trapezius muscle of patients with neck pain.

METHODS

A single-blind cross-sectional study. Twenty-eight volunteers of both genders were included in the study, were aged 18-45 years, and had chronic neck pain and myofascial trigger points in the upper trapezius. The volunteers were assessed using the Numeric Rating Scale, the Neck Disability Index, the Pain-Related Self-Statement Scale, algometry, infrared thermography, and electrical bioimpedance.

RESULTS

The following significant results were observed: a negative association between the pressure pain threshold on myofascial trigger point in the right upper trapezius and electrical impedance of the torso at 5 kHz (rs=-0.392, p= 0.032), 50 kHz (rs=-0.406, p= 0.026), 250 kHz (rs=-0.388, p= 0.034), and to the frequency 500 kHz (rs=-0.444, p= 0.014).

CONCLUSION

Electrical impedance of the torso is associated with the pressure pain threshold of myofascial trigger points on the upper trapezius of individuals with neck pain. Thus, individuals with a lower pressure pain threshold have higher electrical impedance values of the torso and vice versa.

Reliability of skin impedance in subjects with chronic neck pain

BACKGROUND

Skin impedance is a biological signal that has been employed in the measurement of pain. However, there are few scientific data on skin impedance, with a great variety of assessment methods and controversial results.

OBJECTIVE

To examine the intra- and inter-rater reliability of skin impedance measurement in individuals with chronic neck pain.

METHODS

This is a blind cross-sectional study. Thirty individuals of both genders, aged between 18 and 45 years and with chronic neck pain were included in the study. Two examiners assessed skin impedance of the upper and lower limbs and torso at two intervals separated by one week. For statistical analysis, we used the intraclass correlation coefficient (ICC2,3) to determine the intra- and inter-rater reliability of skin impedance, with its respective confidence interval of 95%, standard error of measurement (SEM) and minimum detectable change (MDC).

RESULTS

The intra-rater reliability was considered substantial to excellent, with ICC values ranging between 0.843 and 0.978, SEM between 0.58 and 15.26 Ω, and MDC between 1.61 and 42.31 Ω. The inter-rater reliability was moderate to excellent, with ICC values ranging between 0.761 and 0.997, SEM ranging between 0.22 and 16.72 Ω, and MDC ranging between 0.63 and 46.35 Ω.

CONCLUSION

The measurement of skin impedance of the upper and lower limbs and torso in individuals with chronic neck pain has acceptable reliability values when considered at different times and by different examiners.

Comparison of various SYSADOA for the osteoarthritis treatment: an experimental study in rabbits

BACKGROUND

Osteoarthritis is thought to be the most prevalent chronic and disabling joint disease in animals and humans and its treatment is a major orthopaedic challenge because there is no ideal drug treatment to preserve joint structure and function, as well as to ameliorate the symptomatology of the disease. The aim of the present study was to assess, using histology, histomorphometry and micro-CT, the effects of the treatment with several drugs of the SYSADOA group and a bisphosphonate in a model of early osteoarthritis, comparing all the results obtained.

METHODS

Osteoarthritis was surgically induced by anterior cruciate ligament transection and partial meniscectomy on one knee of 56 rabbits; treatment was started three weeks after surgery and lasted 8 weeks; at the end of this period, the animals were sacrificed. Animals were divided into seven groups (8 animals each), one for each regimen of treatment (glucosamine sulfate, chondroitin sulfate, hyaluronic acid, diacerein, risedronate and a combination of risedronate and glucosamine) and one for the control (placebo-treated) group. Following sacrifice, femoral osteochondral cylinders and synovial membrane samples were obtained for their evaluation by qualitative and quantitative histology and micro-CT.

RESULTS

The model induced osteoarthritic changes in the knee joints and none of the treatments showed a significantly better efficacy over the others. Regarding cartilage thickness and volume, all the treatments achieved scores halfway between control groups, without statistical differences. Regarding the synovial membrane, diacerein and risedronate showed the best anti-inflammatory profile, whereas glucosamine and chondroitin did not present any effect standing the hyaluronic acid results between the others. Regarding the subchondral bone, there were no differences in thickness or volume, but risedronate, diacerein and hyaluronic acid seemed to have considerably modified the orientation of the trabecular lattice.

CONCLUSIONS

Out of the different drugs evaluated in the study for OA treatment, diacerein and risedronate showed, in all the parameters measured, a better profile of effectiveness; hyaluronic acid ameliorated cartilage swelling and promoted bone formation, but with a poor synovial effect; and finally, chondroitin and glucosamine sulfate prevented cartilage swelling in a similar way to the others, but had no effect on cartilage surface, synovial membrane or subchondral bone.

Effects of glucosamine and risedronate alone or in combination in an experimental rabbit model of osteoarthritis

Background

The osteoarthritis (OA) treatment in humans and in animals is a major orthopaedic challenge because there is not an ideal drug for preserving the joint structure and function. The aim of this study was to assess the effects of the treatment with oral glucosamine and risedronate alone or in combination on articular cartilage, synovial membrane and subchondral bone in an experimental rabbit model of OA. Osteoarthritis was surgically induced on one knee of 32 New Zealand White rabbits using the contralateral as healthy controls. Three weeks later treatments were started and lasted 8 weeks. Animal were divided in four groups of oral treatment: the first group received only saline, the second 21.5 mg/kg/day of glucosamine sulfate, the third 0.07 mg/kg/day of risedronate; and the fourth group both drugs simultaneously at the same dosages. Following sacrifice femurs were removed and osteochondral cylinders and synovial membrane were obtained for its histological and micro-CT evaluation.

Results

Sample analysis revealed that the model induced osteoarthritic changes in operated knees. OA placebo group showed a significant increase in cartilage thickness respect to the control and inflammatory changes in synovial membrane; whereas subchondral bone structure and volumetric bone mineral density remained unchanged. All the treated animals showed an improvement of the cartilage swelling independent of the drug used. Treatment with glucosamine alone seemed to have no effect in the progression of cartilage pathology while risedronate treatment had better results in superficial fibrillation and in resolving the inflammatory changes of the tissues, as well as modifying the orientation of trabecular lattice. The combination of both compounds seemed to have additive effects showing better results than those treated with only one drug.

Conclusions

The results of this animal study suggested that glucosamine sulfate and risedronate treatment alone or in combination may be able to stop cartilage swelling. The risedronate treatment could partially stop the fibrillation and the inflammation of synovial membrane as well as modify the orientation of trabeculae in healthy and in osteoarthritic knees.

Are bisphosphonates effective in the treatment of osteoarthritis pain? A meta-analysis and systematic review

OBJECTIVE

Osteoarthritis (OA) is the most common form of arthritis worldwide. Pain and reduced function are the main symptoms in this prevalent disease. There are currently no treatments for OA that modify disease progression; therefore analgesic drugs and joint replacement for larger joints are the standard of care. In light of several recent studies reporting the use of bisphosphonates for OA treatment, our work aimed to evaluate published literature to assess the effectiveness of bisphosphonates in OA treatment.

METHODS

Literature databases were searched from inception to the 30th June 2012 for clinical trials of bisphosphonates to treat OA pain. Data was appraised and levels of evidence determined qualitatively using best evidence synthesis from the Cochrane Collaboration. The two largest studies were conducted with risedronate in the treatment of knee OA, for which meta-analyses were performed for pain and functional outcomes.

RESULTS

Our searches found 13/297 eligible studies, which included a total of 3832 participants. The trials recruited participants with OA of the hand (n=1), knee (n=8), knee and spine (n=3), or hip (n=1). Our meta-analysis of the two largest knee studies using risedronate 15 mg showed odds ratios favouring placebo interventions for the Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain (1.73), WOMAC function (2.03), and WOMAC stiffness (1.82). However, 8 trials (61.5%) reported that bisphosphonates improve pain assessed by VAS scores and 2 (38.5%) reported significant improvement in WOMAC pain scores compared to control groups.

CONCLUSIONS

There is limited evidence that bisphosphonates are effective in the treatment of OA pain. Limitations of the studies we analysed included the differences in duration of bisphosphonate use, the dose and route of administration and the lack of long-term data on OA joint structure modification post-bisphosphonate therapy. Future more targeted studies are required to appreciate the value of bisphosphonates in treating osteoarthritis pain.

TRIAL REGISTRATION

PROSPERO Register CRD42012002541.

Comparison of the effects of elcatonin and risedronate on back and knee pain by electroalgometry using fall of skin impedance and quality of life assessment using SF-36

Back and knee pain is a widespread health problem and a serious threat to the quality of life (QOL) in middle-aged and older adults, as it frequently accompanies osteoporosis and osteoarthritis. In order to compare the effects of elcatonin and risedronate on such pain, 20 units of elcatonin was intramuscularly injected to 18 patients, and 5 mg of risedronate was orally administered daily to 20 others with similar backgrounds. Exercise-induced pain was analyzed by measuring the fall of skin impedance by electroalgometry (EAM), and subjective pain was recorded by a visual rating system (VRS) on a scale of 0 (no pain) to 100 (unbearable pain). In patients treated with elcatonin, the mean EAM-estimated pain was significantly reduced after 4, 5 and 6 months of treatment, and the VRS score after 3, 5 and 6 months, indicating a significant analgesic effect. In the risedronate group, however, improvement was less remarkable. Two-way analysis of variance using pain as a dependent variable and treatment group and time as independent variables revealed a significantly greater effect of elcatonin over risedronate on both the EAM and VRS scores, and the influence of treatment time on pain was indistinguishable between the two treatment groups. Effect of exercise load on pain was less on knee load than knee and spine load and spine load, but indistinguishable between the two groups. Changes in QOL were evaluated by the SF-36 system. Norm-based scoring showed significant improvements in 3 of 4 categories for elcatonin and in 2 of 4 for risedronate, suggesting comparable effects on the physical aspects of QOL, whereas responses to emotionally and socially directed questions indicated significant improvements in all 4 categories for risedronate, but none for elcatonin, suggesting a more physical than emotional component in elcatonin effects compared to risedronate.

Analgesic effect of raloxifene on back and knee pain in postmenopausal women with osteoporosis and/or osteoarthritis

To assess the effect of raloxifene on bone and joint pain, 24 postmenopausal women with back or knee pain or both were randomly divided into two groups, based on the chronological sequence of consultation, to be treated with 60 mg raloxifene and 1 microg alfacalcidol (RA)/day (group RA) or 1 microg alfacalcidol alone (A)/day (group A), respectively, for 6 months. Pain following knee loading (KL) by standing up from a chair and bending the knee by squatting, knee and spine loading (KSL) by walking horizontally and ascending and descending stairs, and spine loading (SL) by lying down supine on a bed and leaving the bed to stand was evaluated by electroalgometry (EAM), based on measurement of the fall of skin impedance, and a visual rating scale (VRS), recording subjective pain on a scale of 0-100 between no pain and unbearable pain. The two groups showed no significant difference as to age, indices of mineral metabolism, back and knee pain, and bone status. RA gave a significantly greater analgesic effect than A by both EAM (P = 0.0158) and VRS (P = 0.0268) on overall comparison of the mean response to all modalities of exercise loading. Paired comparison between pretreatment and posttreatment indicated a significant effect of RA by both EAM (P = 0.0045) and VRS (P = 0.0017), but not that of A. The analgesic effect was more clearly noted on combined knee-spine loading (KSL) and spine loading (SL) than simple knee loading (KL). Monthly comparison of the analgesic effect indicated a significantly better analgesic effect in the fifth month by VRS. RA effect greater than A was more evident by EAM than VRS and during months 3-6 than during 1-2 months, suggesting a slowly progressive effect of RA. Pain evaluation by EAM and VRS mostly gave parallel results, except for a few occasions such as knee loading and spine loading by sitting up and leaving a bed, when EAM detected a positive effect but VRS failed to do so. RA appeared to be more effective on bone and joint pain than A in postmenopausal women according to both EAM and VRS measurements.