The Effect of Pulsed Electromagnetic Fields on Back Pain in Polo Ponies Evaluated by Pressure Algometry and Flexion Testing—A Randomized, Double-blind, Placebo-controlled Trial

A prospective, randomised, controlled, double blinded, cross-over study on the effect of a single session of pulsed electromagnetic field therapy on signs of hip osteoarthritis in dogs

BACKGROUND

Canine coxofemoral joint osteoarthritis is a common, painful and debilitating condition. The objective of this study was to evaluate if any measurable changes in pain or lameness occurred in this patient group immediately after a single treatment with pulsed electromagnetic field therapy. Eight dogs with coxofemoral joint osteoarthritis presenting with signs of pain and lameness were prospectively recruited to this randomised, controlled, double blinded, cross-over study. Subjects attended the research facility on two occasions for one active and one placebo treatment with pulsed electromagnetic field therapy. The immediate effect of one pulsed electromagnetic field therapy treatment on pain and lameness was measured subjectively with the Helsinki Chronic Pain Index and Visual Analogue Scale and objectively using a pressure sensitive walkway.

RESULTS

A statistically significant difference (P = 0.03) for change in stride length in the affected limb was recorded for subjects between the active and placebo treatments with pulsed electromagnetic field therapy. Within the active treatment results, there was a statistically significant change in the measurement for reach (P = 0.04) and stride length (P = 0.047) which got shorter in the affected limb post treatment. For the subjective outcome measures, there was no statistically significant difference between the active and placebo treatments for the evening of the treatment day or the next morning from pre-treatment values. Within the placebo treatment results a statistically significant change (improvement) was detected in Visual Analogue Score (P = 0.03) between pre-treatment and the next morning values.

CONCLUSIONS

The findings of this study do not show demonstrable improvement in owner assessed pain levels or temporospatial performance in dogs with coxofemoral joint osteoarthritis immediately after a single application of pulsed electromagnetic field therapy.

A Systematic Review of Complementary and Alternative Veterinary Medicine in Sport and Companion Animals: Electrotherapy

Electrotherapy modalities are currently used in the treatment of animals, but the evidence base supporting their use has not yet been systematically reviewed. Cochrane guidelines, as adapted by the Swedish Agency for Health Technology Assessment and Assessment of Social Services, were followed for this systematic review. A literature search regarding all currently known electrotherapy modalities applied to horses, dogs, and cats was conducted for the years 1980-2020 using three databases: CABI, PubMed, and Web of Science Core Collection. Of the 5385 references found, 41 articles were included in the review: 13 papers on pulsed electromagnetic field therapy (PEMFT), 7 on neural electrical muscle stimulation (NEMS), 5 on transcutaneous electrical nerve stimulation (TENS), 4 on static magnets, 3 on interference, 2 each on percutaneous electrical neural stimulation (PENS), bioelectricity, and diathermy, and 1 each on micro-pulsed stimulation, capacitive coupled electrical stimulation, and microwave therapy. The literature per modality was limited in quantity (mean 3.7 papers). Half of the articles were assessed to have a high risk of bias (20 high, 7 moderate, and 14 low). The existing literature used a spectrum of indications and treatment parameters, which makes comparisons and drawing conclusions to support the use of these modalities in clinical practice challenging. The current scientific evidence is not sufficient to support the clinical effects of electrotherapies for any clinical indication in horses, dogs or cats. The selected suggestive results warrant further high-quality research on PEMFT, NEMS, TENS, and PENS.

Equine Rehabilitation: A Scoping Review of the Literature

Simple Summary

When a horse is diagnosed with a locomotor disorder, the veterinarian treats the specific injury to restore the horse to soundness. Even after the injury has healed, however, the horse may not be fully functional due to persistent limitations in movement or strength in specific areas of the body. As in people, rehabilitation seeks to optimize function and reduce any existing disability using a variety of methods including manual therapy, the use of physical and mechanical agents, and specialized exercise regimes. This study has reviewed the scientific literature with the goal of identifying which types of physical therapy have been described in horses over the past 20 years. The most frequently reported techniques were exercise, electrotherapy, and hydrotherapy but there are relatively few publications describing details of their use and outcomes in clinical cases. This study reviews the methodology and outcomes of rehabilitation in clinical cases. The results highlight the paucity of clinically-based reports on the practical applications of equine rehabilitation and physical therapy.

Abstract

Injuries to the locomotor system are a common problem in athletic horses. Veterinarians address these injuries using appropriate medical, surgical, and pharmacological treatments. During or after recovery from the initial injury, horses may be treated for functional locomotor deficits using specific rehabilitation techniques aimed at restoring full athletic performance. This study reviews the literature to identify which rehabilitative techniques have been used most frequently in horses over the past 20 years, the protocols that were used, and the outcomes of the treatments in naturally occurring injuries and diseases. Publications were identified using keyword selection (Equine Athlete OR Equine OR Horse) AND (Rehabilitation OR Physiotherapy OR Physical Therapy). After removing duplicates and screening papers for suitability, 49 manuscripts were included in the study. The majority of publications that met the inclusion criteria were narrative reviews (49%) in which the authors cited the relatively small number of published evidence-based studies supplemented by personal experience. Observational/descriptive studies were also popular (35%). Randomized control trials accounted for only 10%. The most frequently reported rehabilitation techniques were exercise, electrotherapy, and hydrotherapy. The findings highlight the need for further information regarding type of intervention, parameterization, and outcomes of equine rehabilitation in clinical practice.

Pressure Algometry for the Detection of Mechanical Nociceptive Thresholds in Horses

Simple Summary

It is difficult to measure pain in horses. As animals are not able to verbalize what they feel, we are left with trying to interpret the different signs that they display when they are in pain. Many of these signs are vague (e.g., not eating their food), but some are more readily identified if the animal moves away or lifts their leg when pressure is applied to a sensitive area. Pressure algometry is a tool used to detect responses to applied mechanical stimuli within painful and nonpainful tissues. Pressure algometry has been used in many different studies, but there is no consensus on how to synthesize this information to better diagnose and treat pain in horses. The purpose of this study was to summarize the results of these studies. Based on that review, we conclude that there is good evidence that pressure algometry is a reliable and objective method to measure pain responses. This information will help to improve the diagnosis and treatment of pain in horses.

Abstract

The clinical assessment of pain is subjective; therefore, variations exist between practitioners in their ability to identify and localize pain. Due to differing interpretations of the signs or severity of pain equine practitioners may assign varying levels of clinical significance and treatment options. There is a critical need to develop better tools to qualify and quantify pain in horses. Palpation is the most common method to detect local tenderness or sensitivity. To quantify this applied pressure, pressure algometry has been used to gradually apply pressure over specified landmarks until an avoidance response is noted, which is defined as the mechanical nociceptive threshold (MNT). Numerous studies have used pressure algometry in different applications to measure MNTs in horses. There is an acute need to establish normative values within different body regions and to develop standardized methods of testing MNTs to better guide practitioners in the diagnosis and treatment of pain. The aim of this systematic review was to summarize the evidence for the use of pressure algometry in horses. There is good evidence that pressure algometry is a repeatable, semi-objective method that can be used in a wide array of clinical and research applications to assess MNTs in horses.

Algometry to measure pain threshold in the horse's back - An in vivo and in vitro study

Background

The aim of this study was to provide information on algometric transmission of pressure through the dorsal thoracolumbar tissues of the equine back. Using a commercially available algometer, measurements were carried out with six different tips (hemispheric and cylindrical surfaces, contact areas 0.5 cm², 1 cm², and 2 cm²). In nine live horses the threshold of pressure that lead to any reaction was documented. In postmortem specimens of five euthanized horses the transmission of algometer pressure onto a pressure sensor placed underneath the dorsal thoracolumbar tissues at the level of the ribs or the transverse lumbar processes respectively was measured.

Results

Algometer tips with a contact area of 1 cm² led to widely similar results irrespective of the surface shape; these measurements also had the lowest variance. Contact areas of 0.5 cm² resulted in a lower pressure threshold, and those of 2 cm² resulted in a higher pressure threshold. The hemispheric shape of the contact area resulted in a higher pressure threshold, than the cylindrical contact area.

Compared to the thoracic region, a significantly higher pressure threshold was found in the lumbar region in the live horses. This result corresponds to the increased tissue thickness in the lumbar region compared to the thoracic region, also documented as less pressure transmission in the lumbar region on the in vitro specimens.

Conclusions

Algometry is an easily practicable and well tolerated method to quantify pain but it is important to consider the many factors influencing the results obtained.