An investigation of the asymptomatic limb in unilateral lateral epicondylalgia

© 2015 by the American College of Sports Medicine.Introduction Musculoskeletal ultrasound (MSUS) imaging is used to investigate features of tendinosis. Recent studies have reported tendon pathology not only in the symptomatic tendon but also in the contralateral asymptomatic tendon of animals and humans with unilateral Achilles tendinopathy. This study assessed the symptomatic and contralateral asymptomatic tendon in unilateral lateral epicondylalgia (LE) for features of tendinosis and compared with a pain-free control. Methods Twenty-nine participants with clinically diagnosed unilateral LE and 32 pain-free controls (matched for age, sex, and arm dominance) underwent a blinded bilateral MSUS examination of the common extensor tendon using a standardized protocol. Grayscale features, including tendon thickening, hypoechoic region, fibrillar disruption and calcification, as well as neovascularity, were scored using separate ordinal scales. Tendon thickness and hypoechoic volume were also measured. Results The contralateral asymptomatic tendon did not differ from the tendons of the pain-free controls. The symptomatic tendon of participants with LE revealed a significantly greater score for the following: tendon thickening (mean difference, 0.76 (95% confidence interval, 0.22-1.30)), hypoechoic changes (0.58 (0.05-1.11)), fibrillar disruption (0.97 (0.52-1.42)), and neovascularity (1.53 (0.9-2.2)) than controls. Hypoechoic volume was greater in the symptomatic arm (33.0 mm3 (8.4-57.6)), than that in the controls. Discussion Unlike Achilles tendinopathy, MSUS examination did not reveal features of tendinosis in the contralateral asymptomatic limb beyond those present in tendons of pain-free controls

Sensory and motor deficits exist on the non-injured side of patients with unilateral tendon pain and disability - Implications for central nervous system involvement: A systematic review with meta-analysis

Introduction: Tendinopathy manifests as activityrelated tendon pain with associated motor and sensory impairments. Tendon tissue changes in animals present in injured as well as contralateral non-injured tendon. This review investigated evidence for bilateral sensory and motor system involvement in unilateral tendinopathy in humans.Methods: A comprehensive search of electronic databases, and reference lists using keywords relating to bilateral outcomes in unilateral tendinopathy was undertaken. Study quality was rated with the Epidemiological Appraisal Instrument and meta-analyses carried out where appropriate. Analysis focused on comparison of measures in the non-symptomatic side of patients against pain-free controls.Results: The search revealed 5791 studies, of which 20 were included (117 detailed reviews, 25 met criteria). There were 17 studies of lateral epicondylalgia (LE) and one each for patellar, Achilles and rotator cuff tendinopathy. Studies of LE were available for metaanalysis revealing the following weighted pooled mean deficits: pressure pain thresholds (-144.3 kPa; 95% CI -169.2 to -119.2 p>0.001), heat pain thresholds (-1.2°C; 95% CI -2.1 to -0.2, p>0.001), cold pain thresholds (3.1°C; 95% CI 1.8 to 4.4, p>0.001) and reaction time (37.8 ms; 95% CI 24.8 to 50.7, p>0.001).Discussion: Deficits in sensory and motor systems present bilaterally in unilateral tendinopathy. This implies potential central nervous system involvement. This indicates that rehabilitation should consider the contralateral side of patients. Research of unilateral tendinopathy needs to consider comparison against painfree controls in addition to the contralateral side to gain a complete understanding of sensory and motor features

Forearm muscle activity is modified bilaterally in unilateral lateral epicondylalgia: A case-control study

Lateral epicondylalgia (LE) is associated with a reduced wrist extensor muscle activity and altered biomechanics. This study compared the coordination between forearm muscles during gripping in individuals with LE and pain-free controls. Intramuscular electrodes recorded myoelectric activity from extensor carpi radialis brevis/longus (ECRB/ECRL), extensor digitorum communis (EDC), flexor digitorum superficialis/profundus (FDS/FDP), and flexor carpi radialis (FCR), bilaterally, in 15 participants with unilateral LE and 15 pain-free controls. Participants performed a gripping task at 20% maximum force in four arm positions. The contribution of each muscle was expressed as a proportion of the summed electromyography of all muscles. In individuals with LE, ECRB contributed less to total electromyography in the symptomatic arm but not the asymptomatic arm than pain-free controls. The contribution of EDC and FDP to total electromyography was greater in both the symptomatic and asymptomatic arm of the LE group, than pain-free controls. No other differences were observed between groups. Subtle differences in muscle activation were present with differing arm positions. These findings indicate forearm muscle activity is modified in LE. It is unknown whether this is cause or effect. Changes in the asymptomatic side may imply involvement of central mechanisms. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Lt

Stretching the evidence behind tennis elbow: mobile app user guide

Tennis elbow (TE), formally known as lateral epicondylalgia, is a musculoskeletal condition associated with pain over the lateral elbow and histological changes of the common extensor tendon. Numerous treatments are advocated for this condition, with recent developments in the use of mobile technology now added to the list

Forearm muscle activity in lateral epicondylalgia: A systematic review with quantitative analysis

BACKGROUND: Lateral epicondylalgia (LE) refers to pain at the lateral elbow and is associated with sensory and motor impairments that may impact on neuromuscular control and coordination. OBJECTIVE: This review aimed to systematically identify and analyse the literature related to the comparison of neuromuscular control of forearm muscles between individuals with and without LE. METHODS: A comprehensive search of electronic databases and reference lists using keywords relating to neuromuscular control and LE was undertaken. Studies that investigated electromyography (EMG) measures of forearm muscles in individuals with symptoms of LE were included if the study involved comparison with pain-free controls. The Epidemiological Appraisal Instrument was used to assess study quality. Data extracted from each study were used to calculate the standardised mean difference and 95 % confidence intervals to investigate differences between groups. RESULTS: The search revealed a total of 1920 studies, of which seven were included from 44 that underwent detailed review. Due to differences in outcome measures and tasks assessed, meta-analysis was not possible. The seven included studies used 60 different EMG outcomes, of which 16 (27 %) revealed significant differences between groups. Two were properties of motor unit potentials during wrist extension. Four were measures of increased time between recruitment of wrist extensor muscles and onset of grip force. Seven were measures of amplitude of EMG during tennis strokes. Three were measures of motor cortex organisation. CONCLUSION: Features of neuromuscular control differ between individuals with LE and pain-free controls. This implies potential central nervous system involvement and indicates that rehabilitation may be enhanced by consideration of neuromuscular control in addition to other treatments

Isometric exercise above but not below an individual’s pain threshold influences pain perception in people With lateral epicondylalgia

OBJECTIVE: To examine the acute effects of isometric exercise of different intensities on pain perception in individuals with chronic lateral epicondylalgia. METHODS: Participants performed three experimental tasks completed in a randomised order on separate days: control (no exercise) and isometric wrist extension (10 x 15 sec) at load 20% below (infra-threshold) and 20% above (supra-threshold) an individual’s pain threshold. Self-reported pain intensity (11-point numeric rating scales (NRS)), pressure pain threshold and pain free grip were assessed by a blinded examiner before, immediately after and 30min after task performance. Correlation between pain ratings and clinical variables, including pain and disability and kinesiophobia was performed. RESULTS: 24 individuals with unilateral lateral epicondylalgia of median 3-month duration participated. Pain intensity during contraction was significantly higher during supra-threshold exercise than infra-threshold exercise (Mean difference in NRS 1.0, 95%CI 0.4, 1.5, p = 0.002). Pain intensity during supra-threshold exercise was significantly correlated with pain and disability (R=0.435; p=0.034) and kinesiophobia (R=0.556, p=0.005). Pain intensity was significantly higher immediately after performance of supra-threshold exercise, compared to infra-threshold exercise (p=0.01) and control (p<0.001) conditions, while infra-threshold exercise and control conditions were comparable. Thirty minutes later, pain levels remained significantly higher for supra-threshold exercise compared to infra-threshold exercise (p=0.043). Pressure pain threshold and pain free grip showed no significant effects of time, condition, or time by condition (p>0.05). DISCUSSION: Individuals with lateral epicondylalgia demonstrated increased pain intensity following an acute bout of isometric exercise performed at an intensity above, but not below, their individual pain threshold. Further investigation is needed to determine whether measurement of an individual’s exercise induced pain threshold may be important in reducing symptom flares associated with exercise

Unsupervised isometric exercise versus wait-and-see for lateral elbow tendinopathy

Purpose This study aimed to investigate the effect of unsupervised isometric exercise compared with a wait-and-see approach on pain, disability, global improvement, and pain-free grip strength in individuals with lateral elbow tendinopathy. Methods Forty participants with unilateral lateral elbow tendinopathy of at least 6 wk duration were randomized to either wait-and-see (n = 19) or a single supervised instruction session by a physiotherapist, followed by an 8-wk unsupervised daily program of progressive isometric exercise (n = 21). Primary outcomes were Patient-Rated Tennis Elbow Evaluation, global rating of change on a six-point scale (dichotomized to success and no success) and pain-free grip strength at 8 wk. Secondary outcomes were resting and worst pain on an 11-point numerical rating scale, and thermal and pressure pain thresholds as a measure of pain sensitivity. Results Thirty-nine (98%) participants completed 8-wk measurements. The exercise group had lower Patient-Rated Tennis Elbow Evaluation scores compared with wait-and-see at 8 wk (standardized mean difference [SMD],-0.92; 95% confidence interval [CI],-1.58 to-0.26). No group differences were found for success on global rating of change (29% exercise vs 26% wait-and-see (risk difference, 2.3%; 95% CI,-24.5 to 29.1)), or pain-free grip strength (SMD,-0.33; 95% CI,-0.97 to 0.30). No differences were observed for all secondary outcomes except for worst pain, which was moderately lower in the exercise group (SMD,-0.80; 95% CI,-1.45 to-0.14). Conclusions Unsupervised isometric exercise was effective in improving pain and disability, but not perceived rating of change and pain-free grip strength when compared with wait-and-see at 8 wk. With only one of the three primary outcomes being significantly different after isometric exercises, it is doubtful if this form of exercise is efficacious as a sole treatment. © Lippincott Williams & Wilkins

Diagnostic ultrasound imaging for lateral epicondylalgia: A case-control study

Copyright © 2014 by the American College of Sports Medicine.Introduction: Lateral epicondylalgia (LE) is clinically diagnosed as pain over the lateral elbow that is provoked by gripping. Usually, LE responds well to conservative intervention; however, those who fail such treatment require further evaluation, including musculoskeletal ultrasound. Previous studies of musculoskeletal ultrasound have methodological flaws, such as lack of assessor blinding and failure to control for participant age, sex, and arm dominance. The purpose of this study was to assess the diagnostic use of blinded ultrasound imaging in people with clinically diagnosed LE compared with that in a control group matched for age, sex, and arm dominance.Methods: Participants (30 with LE and 30 controls) underwent clinical examination as the criterion standard test. Unilateral LE was defined as pain over the lateral epicondyle, which was provoked by palpation, resisted wrist and finger extension, and gripping. Controls without symptoms were matched for age, sex, and arm dominance. Ultrasound investigations were performed by two sonographers using a standardized protocol. Grayscale images were assessed for signs of tendon pathology and rated on a four-point ordinal scale. Power Doppler was used to assess neovascularity and rated on a five-point ordinal scale.Results: The combination of grayscale and power Doppler imaging revealed an overall sensitivity of 90% and specificity of 47%. The positive and negative likelihood ratios for combined grayscale and power Doppler imaging were 1.69 and 0.21, respectively.Conclusions: Although ultrasound imaging helps confirm the absence of LE, when findings are negative for tendinopathic changes, the high prevalence of tendinopathic changes in pain-free controls challenges the specificity of the measure. The validity of ultrasound imaging to confirm tendon pathology in clinically diagnosed LE requires further study with strong methodology

Is synergistic organisation of muscle coordination altered in people with lateral epicondylalgia?: a case-control study

BACKGROUND: Lateral epicondylalgia is a common musculoskeletal disorder and is associated with deficits in the motor system including painful grip. This study compared coordination of forearm muscles (muscle synergies) during repeated gripping between individuals with and without lateral epicondylalgia. METHODS: Twelve participants with lateral epicondylalgia and 14 controls performed 15 cyclical repetitions of sub-maximal (20% maximum grip force of asymptomatic arm), pain free dynamic gripping in four arm positions: shoulder neutral with elbow flexed to 90° and shoulder flexed to 90° with elbow extended both with forearm pronated and neutral. Muscle activity was recorded from extensor carpi radialis brevis/longus, extensor digitorum, flexor digitorum superficialis/profundus, and flexor carpi radialis, with intramuscular electrodes. Muscle synergies were extracted using non-negative matrix factorisation. FINDINGS: Analysis of each position and participant, demonstrated that two muscle synergies accounted for >97% of the variance for both groups. Between-group differences were identified after electromyography patterns of the control group were used to reconstruct the patterns of the lateral epicondylalgia group. A greater variance accounted for was identified for the controls than lateral epicondylalgia (p=0.009). This difference might be explained by an additional burst of flexor digitorum superficialis electromyography during grip release in many lateral epicondylalgia participants. INTERPRETATION: These data provide evidence of some differences in synergistic organisation of activation of forearm muscles between individuals with and without lateral epicondylalgia. Due to study design it is not possible to elucidate whether changes in the coordination of muscle activity during gripping are associated with the cause or effect of lateral epicondylalgia

A comparison of fine wire insertion techniques for deep finger flexor muscle electromyography

Introduction: Intramuscular electromyography electrodes targeting flexor digitorum profundus (FDP) are inserted via the anterior or medial aspect of the forearm. These two methods pose different risks to neurovascular structures which overly FDP. This study aimed to compare the insertion depth and consider advantages and limitations of two different techniques to insert intramuscular electrodes into FDP. Methods: Using ultrasound imaging, neurovascular structures were identified along the path of FDP electrode insertion at the junction of the proximal and middle third of the ulna, bilaterally, in ten healthy individuals. Insertion depth was compared between the anterior and medial approaches for the mid muscle belly and targeted insertion to the index finger fascicle of FDP. Results: In our sample the ulnar artery was superficial to the FDP muscle when viewed anteriorly and was beyond the furthest border of FDP when viewed medially. Compared to the anterior approach, the medial insertion depth was 1.5 cm (95%CI 1.4–1.7, p < 0.001) less to the mid-belly of FDP and 0.6 cm (95%CI 0.4–0.7, p < 0.001) less to the index finger fascicle of FDP. Discussion: The medial approach involves less depth and lower risk for perforation of neurovascular structures when inserting intramuscular electrodes into the FDP muscle. © 2018 Elsevier Lt