Wrist extensor muscle pathology in lateral epicondylitis

Lateral Epicondylalgia and Thoracic Kyphosis: A Study on Young Athletes

OBJECTIVE

The etiology of lateral epicondylalgia (LE) remains unclear, although it has been linked to various factors. Recent theories suggest a potential connection between LE and impairments in the kinetic chain. In our study, we aimed to investigate the association between another factor influencing kinetic chain impairment, specifically an increased angle of thoracic kyphosis, and the presence of initial signs of LE in young athletes.

DESIGN

This study employed an observational, case-control design.

SETTING

The participants underwent examination during a routine preventive checkup conducted by a sports physician at Novi Sad Healthcare Center, Sports Medicine Center.

PARTICIPANTS

One hundred young athletes aged 10 to 15 years were included in the study. Half of the participants reported pain in the lateral aspect of the elbow during maximal hand grip, while the remaining athletes served as controls and did not experience any pain.

ASSESSMENT OF INDEPENDENT VARIABLES

Thoracic kyphosis inclination angles were measured using a digital inclinometer.

MAIN OUTCOME MEASURES

Pain was assessed using the pressure pain threshold at a specific point associated with lateral epicondylalgia, measured by a digital algometer.

RESULTS

Participants exhibiting initial signs of LE displayed significantly different angles of anteroposterior curvatures of the spine compared with the control group. Moreover, the angle of thoracic kyphosis was significantly associated with pain in the lateral aspect of the elbow.

CONCLUSIONS

Our findings confirm an association between initial signs of lateral epicondylalgia and the grade of thoracic kyphosis in young athletes.

Deficits in neuromuscular control of increasing force in patients with chronic lateral epicondylitis

Objective: This study investigated the neuromuscular control of increasing and releasing force in patients with chronic lateral epicondylitis (CLE). Methods: Fifteen patients with CLE (10 males, 5 females, 46.5 ± 6.3 years) and fifteen healthy participants (9 males, 6 females, 45.3 ± 2.5 years) participated in this study. In addition to power grip and maximal voluntary contraction (MVC) of wrist extension, force fluctuation dynamics and characteristics of inter-spike intervals (ISI) of motor units (MUs) with various recruitment thresholds in the extensor carpi radialis brevis (ECRB) and extensor carpi radialis longus (ECRL) during a designated force-tracking task with a trapezoidal target (0%-75%-0% MVC) were assessed. Results: Besides a smaller MVC of wrist extension, the patients exhibited significantly greater task errors (p = 0.007) and force fluctuations (p = 0.001) during force increment than the healthy counterparts. Nevertheless, no force variables significantly differed between groups during force release (p > 0.05). During force increment, the amplitudes of the motor unit action potential of the ECRB and ECRL muscles of the patients were smaller than those of the heathy counterparts (p < 0.001). The patient group also exhibited a higher percentage of motor units (MU) with lower recruitment threshold (<5% MVC) in the ECRL/ECRB muscles and a lower percentage of MU with higher recruitment threshold (>40% MVC) in the ECRB muscle, compared to the healthy group. During force increment, the patient group exhibited a higher rate of decrease in inter-spike intervals (ISIs) of motor units with lower recruitment thresholds (<10% MVC) in the ECRB and ECRL muscles, compared to the control group (p < 0.005). Conclusion: The patients with CLE exhibited more pronounced impairment in increasing force than in releasing force. This impairment in increasing force is attributed to deficits in tendon structure and degenerative changes in the larger motor units of the wrist extensors. To compensate for the neuromuscular deficits, the rate of progressive increase in discharge rate of the remaining smaller motor units (MUs) is enhanced to generate force. Significance: The deficits in neuromuscular control observed in CLE with degenerative changes cannot be fully explained by the experimental pain model, which predicts pain-related inhibition on low-threshold motor units.

Lateral epicondylosis: A literature review to link pathology and tendon function to tissue-level treatment and ergonomic interventions

BACKGROUND

Common treatments for lateral epicondylosis (LE) focus on tissue healing. Ergonomic advice is suggested broadly, but recommendations based on biomechanical motion parameters associated with functional activities are rarely made. This review analyzes the role of body functions and activities in LE and integrates the findings to suggest motion parameters applicable to education and interventions relevant to activities and life roles for patients.

PURPOSE

This study examines LE pathology, tendon and muscle biomechanics, and population exposure outlining potentially hazardous activities and integrates those to provide motion parameters for ergonomic interventions to treat or prevent LE. A disease model is discussed to align treatment approaches to the stage of LE tendinopathy.

STUDY DESIGN

Integrative review METHODS: We conducted in-depth searches using PubMed, Medline, and government websites. All levels of evidence were included, and the framework for behavioral research from the National Institutes of Health was used to synthesize ergonomic research.

RESULTS

The review broadened the diagnosis of LE from a tendon ailment to one affecting the enthesis of the capitellum. It reinforced the continuum of severity to encompass degeneration as well as regeneration. Systematic reviews confirmed the availability of evidence for tissue-based treatments, but evidence of well-defined harm reducing occupational interventions was scattered amongst evidence levels. Integration of biomechanical studies and population information gave insight into types of potentially hazardous activities and provided a theoretical basis for limiting hazardous exposures to wrist extensor tendons by reducing force, compression, and shearing during functional activities.

CONCLUSIONS

These findings may broaden the first treatment approach from a passive, watchful waiting into an active exploration and reduction of at-risk activities and motions. Including the findings into education modules may provide patients with the knowledge to lastingly reduce potentially hazardous motions during their daily activities, and researchers to define parameters of ergonomic interventions.

Tennis elbow

Tennis elbow is the most common cause of lateral-sided elbow pain with a major socioeconomic impact. The etiology of tennis elbow is not completely understood, but there are many different treatment options. This review gives an overview of the current concepts of diagnosis and treatment of tennis elbow and the impact on work participation.

Ultrasound-Guided Interventions in Lateral Epicondylitis

Lateral epicondylitis is a painful condition related to the myotendinous origin of the extensor muscles at the lateral epicondyle of the humerus. Primary treatment typically involves the use of rest, non-steroidal anti-inflammatory drugs (NSAIDs), and physiotherapy. However, in refractory cases where conventional therapy is ineffective, ultrasound-guided injection therapies have become a growing form of treatment. These include needle tenotomy, autologous whole blood injection (AWB), platelet-rich plasma (PRP) injection and steroid injection. The consensus regarding the efficacy of individual approaches of ultrasound-guided treatment is unclear in the literature, and is explored further in this review.When evaluating these injection therapies individually, there are multiple case series describing the efficacy of each intervention in refractory lateral epicondylitis. A systematic review of needle tenotomy demonstrates an improvement in pain symptoms for patients with this condition, but all studies were poorly designed with no placebo or control group. Additionally, for PRP therapy, a systematic review performed in 2013 demonstrated a statistically significant improvement in pain and functionality for refractory lateral epicondylitis. However, these studies were similarly associated with a high risk of bias. Autologous whole blood injection has been evaluated through well-designed studies to show statistically significant reductions in pain with this intervention. But very few studies in total have been completed using AWB for lateral epicondylitis, and therefore no clear conclusions can be drawn at this time. Finally, corticosteroid use overall is unsupported in the evidence both in the short and long term, especially given that this condition is not an inflammatory pathology.

Effectiveness of standardized ultrasound guided percutaneous treatment of lateral epicondylitis with application of autologous blood, dextrose or perforation only on pain: a study protocol for a multi-center, blinded, randomized controlled trial with a 1 year follow up

Background

In the treatment of Lateral Epicondylitis (LE) no single intervention concerning injection therapies has been proven to be the most effective with regard to pain reduction. In this trial 3 injection therapies (perforation with application of autologous blood, perforation with application of dextrose and perforation only) will be compared in a standardized and ultrasound guided way. The objective is to assess the effectiveness of these 3 injection therapies on pain, quality of life and functional recovery. By conducting this study, we hope to make a statement on the effectiveness of injection therapy in the treatment of LE. Hereby, unnecessary treatments can be avoided, a more universal method of treatment can be established and the quality of the treatment can be improved.

Methods/design

A multicenter, randomized controlled trial with a superiority design and 12 months follow-up will be conducted in four Dutch hospitals. One hundred sixty five patients will be recruited in the age of 18 to 65 years, with chronic symptomatic lateral epicondylitis lasting longer than 6 weeks, which have concordant pain during physical examination. Patients will be randomized by block randomization to one of the three treatment arms. The treatment will be blinded for patients and outcome assessors. The following three injection therapies are compared: perforation with application of autologous blood, perforation with application of dextrose and perforation only. Injections will be performed ultrasound guided in a standardized and automated way. The primary endpoint is: pain (change in ‘Visual Analogue Scale’). Secondary endpoints are quality of life and functional recovery. These measurements are collected at baseline, 8 weeks, 5 months and 1 year after treatment.

Discussion

When completed, this trial will provide evidence on the effectiveness of injection therapy in the treatment of lateral epicondylitis on pain, quality of life and functional recovery. In current literature proper comparison of the effectiveness of injectables for LE is questionable, due to the lack of standardization of the treatment. This study will overcome bias due to manually performed injection therapy.

Trial registration

This study is registered in the Trial Register (www.trialregister.nl) of the Dutch Cochrane centre. Trial ID; NTR4569. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4569

Ultrasound-Guided Percutaneous Electrical Nerve Stimulation of the Radial Nerve for a Patient With Lateral Elbow Pain: A Case Report With a 2-Year Follow-up

BACKGROUND

Patients with lateral elbow pain are often diagnosed with lateral epicondylalgia. Lateral elbow pain is often associated with dysfunction of the wrist extensor muscles; however, in some cases, it can also mimic signs and symptoms of radial nerve dysfunction.

CASE DESCRIPTION

In this case report, a 43-year-old man, who was originally referred with a diagnosis of lateral epicondylalgia as a result of playing table tennis and who previously responded favorably to manual therapy and exercise, presented to the clinic for treatment. An exacerbation while participating in a table tennis match resulted in a return of his lateral epicondylalgia symptoms, which did not respond favorably to the same interventions used in his prior course of therapy. Further examination revealed sensitization of the radial nerve, which was treated with 2 sessions of ultrasound-guided percutaneous electrical nerve stimulation and 4 weeks of a low-load, concentric/eccentric exercise program for the wrist extensors.

OUTCOMES

Following this intervention, the patient experienced clinically meaningful improvement in pain intensity (numeric pain-rating scale), function (Patient-Rated Tennis Elbow Evaluation), and related disability (Disabilities of the Arm, Shoulder and Hand questionnaire). The patient progressively exhibited complete resolution of pain and function, which was maintained at 2 years.

DISCUSSION

This case report demonstrates the outcomes of a patient with lateral elbow pain who did not respond to manual therapy and exercise. Once radial nerve trunk sensitivity was identified and the intervention, consisting of ultrasound-guided percutaneous electrical nerve stimulation targeting the radial nerve combined with a low-load exercise program, was applied, a full resolution of pain and function occurred rapidly. Future clinical trials should examine the effect of percutaneous electrical nerve stimulation in the management of nerve-related symptoms associated with musculoskeletal pain conditions.

LEVEL OF EVIDENCE

Therapy, level 5. J Orthop Sports Phys Ther 2019;49(5):347-354. Epub 18 Jan 2019. doi:10.2519/jospt.2019.8570.

Lateral epicondylalgia: A primary nervous system disorder

Lateral epicondylalgia (LE) is the most common chronic painful condition affecting the elbow in the general population. Although major advances have been accomplished in recent years in the understanding of LE, the underlying physiopathology is still a reason for debate. Differences in clinical presentation and evolution of the symptoms among patients, suggest the need for revisiting the current knowledge about subjacent mechanisms that attempt to explain pain and functional loss. Previous models have suggested that the condition is mainly a degenerative tendinopathy, associated with changes in pain pathways and the motor system. The hypothesis of this work is that LE is the clinical manifestation of a primary nervous system disorder, characterized by an abnormal increase in neuronal activity and a subsequent loss of homeostasis, which secondarily affects the musculoskeletal tissues of the elbow-forearm-hand complex. A new model for LE is presented, supported by an in-deep analysis of basic sciences, epidemiological and clinical studies.

Short-Term Effect of Low-Dose, Electromyography-Guided Botulinum Toxin A Injection in the Treatment of Chronic Lateral Epicondylar Tendinopathy: A Randomized, Double-Blinded Study

BACKGROUND

Botulinum toxin A (BoNT-A) is a novel treatment for chronic lateral epicondylar tendinopathy. Preliminary studies have demonstrated promising results; however, confirmation of the effectiveness of BoNT-A treatment and further assessment of its side effects are required. This study investigated the analgesic effects of BoNT-A in the treatment of chronic lateral epicondylar tendinopathy.

METHODS

This was a phase-III, single-center, randomized, double-blinded, placebo-controlled study including 60 patients with chronic lateral epicondylar tendinopathy that had been resistant to treatment for >6 months. Patients received either a 40-IU injection of BoNT-A or saline solution placebo into the extensor carpi radialis brevis (ECRB) muscle, aided by electromyographic (EMG) stimulation. Follow-up was 3 months. The primary assessment criterion was the percentage of patients whose pain was reduced by >50% at 90 days after injection. Secondary outcomes, including pain intensity, pain frequency, interference with quality of life, sick leave taken, maximum grip strength, and side effects, were assessed at days 30 and 90, and the number of participants per group requesting additional therapies at day 90 was recorded.

RESULTS

Twenty-nine patients in the BoNT-A group and 28 patients in the placebo group were included in the day-90 analysis. Fifteen (51.7%) of the patients who were administered BoNT-A and 7 (25%) of the patients who received placebo reported a >50% reduction in initial pain intensity at day 90 (p = 0.005). Pain intensity and the effect on quality of life, measured using visual analog scales, were both significantly lower in the group treated with BoNT-A compared with placebo at day 90 (p < 0.05). The rate of clinically detected transitory paresis of the third finger on extension was 17.2% in the BoNT-A group, with no associated functional impairment.

CONCLUSIONS

BoNT-A at 40 IU injected into the ECRB is an effective treatment for chronic lateral epicondylar tendinopathy that has been otherwise resistant to medical treatment. The rate of paresis of the third finger was low, with no associated functional impairment.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Morphological and physiological differences in the upper trapezius muscle in patients with work-related trapezius myalgia compared to healthy controls: A systematic review

BACKGROUND

Trapezius myalgia is a common musculoskeletal complaint, characterized by pain, stiffness and tightness of the upper trapezius muscle. It is often work-related and caused by prolonged static and repetitive work tasks. It is hypothesized that this leads to various morphological and physiological alterations in muscle tissue but the pathophysiology is poorly understood. These alterations can be investigated by analysing muscle biopsies in order to reveal the underlying cellular mechanisms.

OBJECTIVES

This systematic review aimed at providing a summary of the existing literature regarding morphological and physiological differences between people with work-related trapezius myalgia and healthy controls, obtained by analysing muscle biopsies.

DESIGN

Systematic review.

METHODS

A systematic literature search was performed in following databases: Pubmed, Web of Science and Embase by using different keyword combinations. This systematic review is reported following the PRISMA guidelines.

RESULTS

Generally, low to moderate evidence was found for the absence of differences in muscle morphology in people with trapezius myalgia, compared to healthy controls. However, significant differences were mainly found in comparison with the control group with another occupation than the myalgic group. It can thus be hypothesized that morphological alterations in muscle tissue are related to work load and not to pain. Low to moderate evidence was also found for the absence of differences at the physiological level.

CONCLUSIONS

Based on this systematic review, there are no clear differences in muscle morphology and physiology between subjects with trapezius myalgia and healthy controls.

Muscle Activity during Rapid Wrist Extension in People with Lateral Epicondylalgia

BACKGROUND

Individuals with lateral epicondylalgia (LE) have delayed upper limb reaction time (RT); however, it is unknown if the mechanisms of this dysfunction are related to neural processing or the affected forearm muscles. The aim of this study was to examine the timing of processes that occur before and after forearm muscles are activated during the RT task.

METHODS

Eleven LE (42 ± 11 yr) and 11 healthy controls (42 ± 11 yr) performed rapid wrist extension in response to an audio cue. Intramuscular EMG was obtained from extensor carpi radialis brevis (ECRB), extensor digitorum communis (EDC), extensor carpi ulnaris (ECU), and anconeus. Premotor time (PMT) was the duration from an audio cue to the onset of muscle activity, and motor time (MT) was the onset of muscle activity to the onset of wrist extension. Standard clinical assessments of LE were also performed.

RESULTS

RT was significantly slower (33; 95% CI, 1-66 ms) in the LE group. There were no group differences in PMT and the order of muscle activation. Instead, the MT of ECRB (18; 95% CI, 6-31 ms), EDC (12; 95% CI, 1-23 ms), ECU (28; 95% CI, 9-46 ms), and anconeus (33; 95% CI, 11-56 ms) showed significant delay in LE group. Regression analyses revealed that the duration of LE could predict RT, ECRB, and anconeus PMT, whereas cold pain threshold predicted ECRB MT.

CONCLUSIONS

Delayed RT in LE was predominantly caused by deficits in ECRB and EDC MT. This study provides preliminary evidence that in the people with longer LE symptoms, duration appeared to have faster RT, although confirmation of this finding is required before firm conclusions can be drawn.

The influence of different non-articular proximal forearm orthoses (brace) widths in the wrist extensors muscle activity, range of motion and grip strength in healthy volunteers

PURPOSE

The purpose this study was perform a biomechanical evaluation to compare the influence of commercial models of different non-articular proximal forearm orthoses widths (2.5 cm, 5.5 cm, 7.5 cm and 12.0 cm) in the extensor muscle activation, range of motion and grip strength in healthy subjects.

METHODS

Was analyzed data from extensor carpi radialis, extensor carpi ulnares and extensor digitorum comunis using surface electromyography, simultaneous with a wrist electrogoniometer MiotecTM and a hydraulic dynamometer JamarTM. The sequence of tests with all the commercial orthoses models was randomized. Statistics analyses were performed by linear model with mixed effects.

RESULTS

According to our findings the non-articular proximal forearm orthoses (2.5 cm - narrowest) positioned close to lateral epicondyle provided lesser muscle activation on extensor carpi radialis brevis/longus and extensor digitorum comunis, decreased wrist extension and grip strength during submaximal grip task (p< 0.01).

CONCLUSIONS

A narrow non-articular proximal forearm orthosis positioned close to the lateral epicondyle might decrease the extensor muscle activation and therefore could reduce mechanical stress on its insertion, based on this sample. Clinical studies must be conducted to confirm these findings.

Experienced versus Inexperienced Interexaminer Reliability on Location and Classification of Myofascial Trigger Point Palpation to Diagnose Lateral Epicondylalgia: An Observational Cross-Sectional Study

The purpose was to evaluate the interexaminer reliability of experienced and inexperienced examiners on location and classification of myofascial trigger points (MTrPs) in two epicondylar muscles and the association between the MTrP found and the diagnosis of lateral epicondylalgia (LE). Fifty-two pianists (some suffered LE) voluntarily participated in the study. Three physiotherapists (one inexperienced in myofascial pain) examined, located, and marked MTrPs in the extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC) muscles. Forearms were photographed and analyzed to establish the degree of agreement on MTrPs diagnosis. Data showed 81.73% and 77.88% of agreement on MTrP classification and 85.58% and 72.12% on MTrP location between the expert evaluators for ECRB and EDC, respectively. The agreement on MTrP classification between experienced and inexperienced examiners was 54.81% and 51.92% for ECRB and 50.00% and 55.77% for EDC. Also, agreement on MTrP location was 54.81% and 60.58% for ECRB and 48.08% and 48.08% for EDC. A strong association was found between presence of relevant MTrPs, LE diagnosis, and forearm pain when the examiners were experts. The analysis of location and classification of MTrPs in the epicondylar muscles through physical examination by experienced evaluators is reliable, reproducible, and suitable for diagnosing LE.

Chronic hyperglycemia increases the risk of lateral epicondylitis: the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS)

Background

Although humeral epicondylitis is a common health problem, there have been no reports that describe its prevalence in Japanese general population, and relatively little is known about its etiology and associated risk factors.

Questions/purposes

This study aimed to clarify the prevalence of humeral epicondilitis in Japanese general population, and investigate the associated risk factors using the data from a cross-sectional study of the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS).

Methods

A total of 1,777 participants who participated in health checkups conducted at rural area in Japan in 2010 were enrolled. The prevalence of lateral and medial epicondylitis was investigated. Logistic regression models were performed to examine the relationship between lateral epicondylitis and correlated factors such as occupational status, smoking and alcohol preferences, and medical characteristics.

Results

The overall prevalence of lateral and medial epicondylitis was 2.5 % and 0.3 %, respectively. A shortened version of the disabilities of the arm, shoulder and hand (The QuickDASH) score was significantly higher in subjects with lateral epicondylitis than in those without (15.0 ± 12.7 vs 8.5 ± 11.1). Subjects with definite chronic hyperglycemia (HbA1c ≥ 6.5) showed a 3.37-times higher risk of lateral epicondylitis than those with favorable glycemic control (HbA1c < 5.5) (95 % confidence interval (CI) 1.16–8.56). Age and sex, as well as occupational status, smoking and alcohol preference, and other metabolic factors were not significantly related to higher risk of lateral epicondylitis.

Conclusions

Lateral epicondylitis influences activities of daily living. Chronic hyperglycemia might be one of the risk factor for lateral epicondylitis.

Clinical relevance

Chronic hyperglycemia is significantly associated with lateral epicondylitis.

Influence of volar and dorsal static orthoses in different wrist positions on muscle activation and grip strength in healthy subjects

Introduction

Orthoses are indicated for injuries of the wrist, although there is weak evidence for its influence on extensor muscle activation patterns. The purpose of this study was to compare two designs of volar and dorsal wrist orthoses in several positions, from flexion to extension, by surface electromyography wrist extensor muscle activation and grip strength in healthy subjects.

Methods

We analysed extensor carpi radialis brevis and longus, extensor carpi ulnaris and extensor digitorum comunis muscle activity by surface electromyography. The volunteers performed maximum and submaximum (50%) isometric grips, which were evaluated with a Jamar™ dynamometer using volar and dorsal orthoses with several positions of the wrist (0°, 15° and 30°), both in flexion and extension ( p < 0.05).

Results

Our results showed a significant decrease in extensor muscle activation at 15° and 30° of wrist extension in both volar and dorsal orthoses at 100% and 50% of maximum task. A decrease was also found at rest at 15° of wrist flexion volar orthoses. Decreased grip strength was found at 15° and 30° of wrist flexion in both volar and dorsal orthoses.

Conclusions

Based on the results of this sample, we would suggest, as orthotic prescriptions, 15° or 30° wrist extension orthoses as a supporting therapeutic modality for performance in new studies with lateral epicondylitis in association with low-intensity grip activity; or 15° of wrist flexion volar orthoses for rest, depending on the chronicity of the disease and individual assessment. Future studies with symptomatic patients are needed to confirm these findings.

Mechanical solution for a mechanical problem: Tennis elbow

Lateral epicondylitis is a relatively common clinical problem, easily recognized on palpation of the lateral protuberance on the elbow. Despite the “itis” suffix, it is not an inflammatory process. Therapeutic approaches with topical non-steroidal anti-inflammatory drugs, corticosteroids and anesthetics have limited benefit, as would be expected if inflammation is not involved. Other approaches have included provision of healing cytokines from blood products or stem cells, based on the recognition that this repetitive effort-derived disorder represents injury. Noting calcification/ossification of tendon attachments to the lateral epicondyle (enthesitis), dry needling, radiofrequency, shock wave treatments and surgical approaches have also been pursued. Physiologic approaches, including manipulation, therapeutic ultrasound, phonophoresis, iontophoresis, acupuncture and exposure of the area to low level laser light, has also had limited success. This contrasts with the benefit of a simple mechanical intervention, reducing the stress on the attachment area. This is based on displacement of the stress by use of a thin (3/4-1 inch) band applied just distal to the epicondyle. Thin bands are required, as thick bands (e.g., 2-3 inch wide) simply reduce muscle strength, without significantly reducing stress. This approach appears to be associated with a failure rate less than 1%, assuming the afflicted individual modifies the activity that repeatedly stresses the epicondylar attachments.

FOREARM BAND VERSUS ELBOW TAPING: AS A MANAGEMENT OF LATERAL EPICONDYLITIS

Purpose: There are several treatments available for the management of lateral epicondylitis, but there is a dearth of clinical trials compared to the efficacy of a forearm band over supportive elbow taping technique as an adjunct measure in the management of lateral epicondylitis. Materials and Methods: Totally 45 subjects with the mean age of 30±5 years diagnosed with lateral epicondylitis participated in the study based upon inclusion and exclusion criteria. Subjects were randomly allocated to three groups (n = 15 in each); Group-A (forearm band), Group-B (elbow taping) and Group-C (control), provided with a forearm band, supportive elbow taping technique and as a control group, respectively, although all groups received the conventional physiotherapy in addition to these adjunct measures. The outcome measurements included pain-free grip strength and functional improvement, assessed by using hand-held dynamometer and patient-rated forearm evaluation questionnaire (PRFEQ), respectively. Total duration of study was four weeks. Results: Although all the groups showed improvement with respect to increase in the pain-free grip strength and enhancement of functional independence, however, Group-A has shown the maximum improvement followed by Group-B which in turn proved to be more effective than conventional physiotherapy alone. Conclusion: The application of the forearm band produced a significant increase in the grip strength and function as compared to the elbow taping and control groups. The study implies the potential use of a forearm band in the future in addition to the conventional therapy in the management of patients with lateral epicondylitis.

Natural course in tennis elbow--lateral epicondylitis after all?

Tennis elbow is a common and difficult-to-treat condition largely because of lack of evidence. The natural history is unknown, but the condition is described as self-limiting. The objective of this case report is to describe the natural course of two control participants (pain free), who later developed tennis elbow, patient history, clinical findings, and ultrasound and colour Doppler examination before, during and after a period of tennis elbow.

Shoulder and forearm oxygenation and myoelectric activity in patients with work-related muscle pain and healthy subjects

We tested hypotheses of (a) reduced oxygen usage, oxygen recovery, blood flow and oxygen consumption; and (b) increased muscle activity for patients diagnosed with work-related muscle pain (WRMP) in comparison to healthy controls. Oxygenation was measured with near infrared spectroscopy (NIRS), and muscle activity with EMG for the extensor carpi radialis (ECR) and trapezius descendens (TD) muscles. Eighteen patients with diffuse neck-shoulder-arm pain and 17 controls (matched in age and sex) were equipped with NIRS and EMG probes. After determining an individual's maximum voluntary contraction (MVC) force, short-term (20 s) isometric contractions for the ECR and TD of 10, 30, 50 and 70 % MVC generated ∆StO₂ and StO₂% recovery (Rslope) from NIRS, and RMS%max from EMG signals. In addition, upper arm venous (VO) and arterial (AO) occlusions generated slopes of total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) for the resting ECR as surrogates of blood flow and oxygen consumption, respectively. Mixed model analyses, t tests, and Mann-Whitney test were used to assess differences between groups. There was no significant difference in MVC between groups for either muscle. Also, ∆StO₂%, Rslope for either muscle, and ECR-HbTslope were not different between groups, thus our hypotheses of reduced oxygen use, recovery, and blood flow for patients were not confirmed. However, patients had a significantly lower ECR-HHbslope confirming our hypothesis of reduced consumption. Further, there was no difference in RMS%max during contractions meaning that the hypothesis of increased activity for patients was not confirmed. When taking into account the number of NIRS variables studied, differences we found between our patient group and healthy controls (i.e., in forearm oxygen consumption and shoulder oxygen saturation level) may be considered modest. Overall our findings may have been impacted by the fact that our patients and controls were similar in muscle strength, which is in contrast to previous studies.

Evidence-based soft tissue rheumatology: epicondylitis and hand stenosing tendinopathy

Lateral and medial epicondylitis represent overuse tendinopathies of wrist extensor and wrist flexor muscles, respectively. In lateral epicondylitis, a short-term therapeutic efficacy of glucocorticoid injection and limited evidence on the efficacy of acupuncture has been shown. De Quervain tendinopathy is caused by tendinous impingement by a thickened retinaculum. There is limited evidence on the efficacy of glucocorticoid injection in this condition.Trigger finger usually results from tendon entrapment beneath a thickened A1 flexor pulley. An association with hand tool use and diabetes has been shown in this condition, and there is evidence on the therapeutic efficacy of glucocorticoid injection. No other therapeutic modality has shown efficacy or has been assessed in a placebo-controlled clinical trial in these conditions.It can be concluded that epicondylitis and stenosing tendinopathy are readily diagnosed, and most patients recover with current therapies. However, still unsolved issues preclude a purely evidence-based approach to these entities.

Selective 360° percutaneous extensor carpi radialis brevis tendon release for tennis elbow: an experimental study

OBJECTIVES

The purpose of this study was to define in volunteers and cadavers the positions of structures at risk and the extensor carpi radialis brevis (ECRB) origin limits for sonographically guided percutaneous tendon release in tennis elbow.

METHODS

First, in volunteers, we used Doppler sonography to determine the position (danger zone) of the structures at risk (neurovascular bundle and radial collateral ligament) from the most lateral point of the epicondyle (point of entry). Second, in cadavers, we studied the footprint of the ECRB's origin for finally performing sonographically guided tendon release (1- to 2-mm incision) away from the danger zone. Efficacy was measured in terms of detachment ratios for the ECRB and safety as the absence of neurovascular bundle or radial collateral ligament injuries.

RESULTS

In 10 volunteers (20 elbows), the neurovascular bundle was located 18.1 mm or greater anteromedially from the point of entry. The neurovascular bundle was not in direct contact with the bone. In 13 formaldehyde-embalmed cadaver elbows, the distance between the origin of the ECRB and the radial collateral ligament was 0 mm or greater. The anterior origin of the ECRB did not contact the neurovascular bundle. The maximum attachment limits of the ECRB were at 15, 5, 15, and 16 mm from the point of entry (anterior, posterior, proximal, and distal margins, respectively). Average detachment ratios were excellent for anterior and distal margins and good for posterior and proximal margins, without neurovascular bundle or radial collateral ligament injuries.

CONCLUSIONS

This study determined a danger zone to avoid and an area of probability in which to enclose most of the ECRB's origin for sonographically guided percutaneous tendon release. A 360° ECRB detachment can be performed safely and effectively. Clinically, sonographically guided percutaneous tendon release should selectively target pathologic regions.

Anatomical association between wrist extensor musculature and topographical pain sensitivity maps of the elbow area

OBJECTIVE

High-density topographical sensitivity maps have been developed to visualize nonuniformity deep tissue pain sensitivity in, for example, lateral epicondylitis (LE). The aim of this cadaveric study was to determine the anatomical association between the topographical sensitivity maps over the elbow area and wrist extensor musculature.

METHODS

A topographical pressure sensitivity map consisting of 12 points forming a 3 × 4 matrix: 4 points in the superior part, 4 points in the middle, and 4 points in the lower part around the lateral epicondyle was marker on a 50-year embalmed cadaver. Color marker pins were inserted into each point. Pins were removed during the process of dissection, but the small holes created by their removal assured accurate relocation.

RESULTS

Progressive dissection revealed that points 1 to 4 (superior line) were placed over the musculotendinous junction and belly of the extensor carpi radialis brevis (ECRB) muscle, points 6 to 8 (middle line) were placed over the musculotendinous junction and belly of the extensor digitorum communis muscle, and points 9 to 12 (inferior line) were located over the musculotendinous junction and belly of the extensor carpi ulnaris muscle. It was also observed that the superficial branch of the radial nerve runs between the belly of the ECRB and extensor digitorum communis muscles.

CONCLUSIONS

This study confirmed that anatomical location previously assumed supporting the important wrist extensor muscles, particularly the ECRB, in patients with LE as depicted by pressure pain sensitivity maps. This study also suggests a potential role of the superficial branch of the radial nerve in LE.

Bilateral changes in forearm oxygen consumption at rest and after exercise in patients with unilateral repetitive strain injury: a case-control study

STUDY DESIGN

Case-control study.

OBJECTIVES

To investigate whether oxygen consumption and blood flow at rest and after exercise are lower in the affected arm of patients with repetitive strain injury (RSI) compared to controls, and lower in the healthy nonaffected forearm within patients with unilateral RSI.

BACKGROUND

RSI is considered an upper extremity overuse injury. Despite the local presentation of complaints, RSI may be represented by systemic adaptations. Insight into the pathophysiology of RSI is important to better understand the development of RSI complaints and to develop effective treatment and prevention strategies.

METHODS

Twenty patients with unilateral RSI and 20 gender-matched control subjects participated in this study. Forearm muscle blood flow and oxygen consumption were measured using near-infrared spectroscopy at baseline and immediately after isometric handgrip exercises at 10%, 20%, and 40% of the individual maximal voluntary contraction.

RESULTS

Unilateral RSI resulted in a lower oxygen consumption and blood flow in the affected forearm at baseline and lower oxygen consumption after incremental handgrip exercises compared to controls (P<.05). In addition, exercise-induced blood flow and oxygen consumption in the nonaffected forearm in patients with RSI were similarly reduced.

CONCLUSION

Blood flow and oxygen consumption after exercise are similarly attenuated in the affected and nonaffected arms of patients with unilateral RSI. Our findings suggest that, despite the unilateral character in clinical symptoms, RSI demonstrates systemic adaptations in forearm blood flow and oxygen consumption at rest and after exercise.

Variation of force amplitude and its effects on local fatigue

Trends in industry are leaning toward stereotyped jobs with low workloads. Physical variation is an intervention to reduce fatigue and potentially musculoskeletal disorders in such jobs. Controlled laboratory studies have provided some insight into the effectiveness of physical variation, but very few have been devoted to force variation without muscular rest as a component. This study was undertaken to determine multiple physiological responses to five isometric elbow extension protocols with the same mean amplitude (15% maximum voluntary contraction, MVC), cycle time (6 s), and duty cycle (50 %). Sustained (15 %Sus) and intermittent contractions including zero force (0-30 %Int) differed significantly in 19 of 27 response variables. Contractions varying by half the mean force (7.5-22.5 %Int) led to 8 and 7 measured responses that were significantly different from 0-30 %Int and 15 %Sus, respectively. A sinusoidal condition (0-30 %Sine) resulted in 2 variables that were significantly different from 0-30 %Int, and 16 different from 15 %Sus. Finally, ten response variables suggested that varying forces with 1 % as the lower contraction level was significantly less fatiguing than 15 %Sus, while no responses were significantly different from 0-30 %Int. Sustained contractions led to decreased twitch force 24-h post-exercise, whereas recovery was complete within 60 min after intermittent contractions. This suggests that time-varying force may be a useful intervention to reduce local fatigue in workers performing low-load tasks, and also that rest per se did not seem to cause any extraordinary effects beyond those predictable from the force variation amplitude.

Influence of pain associated with musculoskeletal disorders on grip force timing

STUDY DESIGN

Retrospective repeated-measures design.

INTRODUCTION

Pain is a common symptom associated with musculoskeletal conditions.

PURPOSE

This study examined if pain resulting from a unilateral upper extremity musculoskeletal injury compromises the person's ability to rapidly initiate and release handgrip.

METHODS

Delays in initiating and releasing a handgrip were determined for 28 individuals with "low pain" and 12 individuals with "high pain" in the injured upper extremity. All participants had no pain in the uninjured upper extremity.

RESULTS

The high-pain group was 10% slower in initiating and releasing a grip than the low-pain group, in both injured and uninjured upper extremities, for both maximal and submaximal grips. In addition, delay in grip initiation was, on average, 8% longer for the injured than for the uninjured upper extremity.

CONCLUSIONS

Unilateral musculoskeletal pain appears to delay grip initiation and relaxation bilaterally, perhaps due to a centrally mediated mechanism.

LEVEL OF EVIDENCE

n/a.

Effect of lateral epicondylosis on grip force development

STUDY DESIGN

Case-Control.

INTRODUCTION

Although it is well known that grip strength is adversely affected by lateral epicondylosis (LE), the effect of LE on rapid grip force generation is unclear.

PURPOSE OF THE STUDY

To evaluate the effect of LE on the ability to rapidly generate grip force.

METHODS

Twenty-eight participants with LE (13 unilateral and 15 bilateral LE) and 13 healthy controls participated in this study. A multiaxis profile dynamometer was used to evaluate grip strength and rapid grip force generation. The ability to rapidly produce force is composed of the electromechanical delay and rate of force development. Electromechanical delay is defined as the time between the onset of electrical activity and the onset of muscle force production. The Patient-rated Tennis Elbow Evaluation (PRTEE) questionnaire was used to assess pain and functional disability. Magnetic resonance imaging was used to evaluate tendon degeneration.

RESULTS

LE-injured upper extremities had lower rate of force development (50 lb/sec, confidence interval [CI]: 17, 84) and less grip strength (7.8 lb, CI: 3.3, 12.4) than nonnjured extremities. Participants in the LE group had a longer electromechanical delay (- 59% , CI: 29, 97) than controls. Peak rate of force development had a higher correlation (r = 0.56; p<0.05) with PRTEE function than grip strength (r = 0.47; p<0.05) and electromechanical delay (r = 0.30; p>0.05) for participants with LE. In addition to a reduction in grip strength, those with LE had a reduction in rate of force development and an increase in electromechanical delay.

CONCLUSIONS

Collectively, these changes may contribute to an increase in reaction time, which may affect risk for recurrent symptoms. These findings suggest that therapists may need to address both strength and rapid force development deficits in patients with LE.

LEVEL OF EVIDENCE

3B.

Blood flow to the extensor carpi radialis brevis muscle following adrenaline infusion in patients with lateral epicondylitis

PURPOSE

Based on previous evidence of muscle fiber injury and decreased blood flow in the extensor carpi radialis brevis (ECRB) muscle in lateral epicondylitis (LE), we hypothesized that there would also be an abnormal (vasoconstrictive) vascular response to adrenaline in the ECRB muscle in LE.

METHODS

In a case-control study, we measured skeletal muscle blood flow in 8 patients with LE and in 8 healthy controls in response to a 30-minute intravenous infusion of adrenaline. We used local clearance of technetium-99m in the main portion of the ECRB muscle to calculate muscle blood flow.

RESULTS

In support of the hypothesis, the blood flow response to the adrenaline infusion was markedly different in the 2 study groups. Whereas the continuous decrease in technetium-99m clearance rate over time was interrupted by the adrenaline-induced vasodilatory effect in the control group, we detected no such effect in the patient group.

CONCLUSIONS

In the ECRB muscle in LE, there is a shift in the balance of vasodilatory and vasoconstrictory influences of adrenaline, leading to vasoconstriction during low-dose adrenaline infusion. The adverse adrenaline effect is similar to what was previously observed after minor muscle injury. Whether the vasoregulatory change, by causing relative muscle ischemia, represents the primary etiology in LE or results from muscle injury cannot be determined, but it is likely to contribute to the development and continuation of chronic muscle pain in LE. New ways of thinking about the condition may be required, and pharmacological treatment might be an option to improve the blood supply and avoid further damage to the affected ECRB muscle-tendon unit.

Joint manipulation in the management of lateral epicondylalgia: a clinical commentary

Lateral epicondylalgia or tennis elbow is a prevalent musculoskeletal disorder that is characterized by lateral elbow pain often associated with gripping tasks. The underlying pathology remains to be fully elucidated; however, evidence indicates that the disorder does not involve an inflammatory process but rather impairments of the pain and motor systems as well as morphological changes in the structure of both the extensor carpi radialis brevis muscle and tendon. Although the most efficient management approach remains controversial, there is a growing body of literature reporting the effects and underlying mechanisms of joint manipulation in the management of lateral epicondylalgia. Evidence exists demonstrating that joint manipulation directed at the elbow and wrist as well as at the cervical and thoracic spinal regions results in clinical alterations in pain and the motor system. In addition to presenting this evidence, this paper describes proposed underlying physiological mechanisms of joint manipulation associated with the observed clinical effects. We propose that this information will be useful for the physical therapist in making clinical decisions regarding the selection of treatment technique for the management of patients with lateral epicondylalgia.

Interactive effects of acute experimental pain in trapezius and sored wrist extensor on the electromyography of the forearm muscles during computer work

We investigated the interactive effects of shoulder pain and wrist extensor muscle soreness on surface electromyography (EMG) during computer mouse work. On day one, subjects (N = 12) performed computer work with/without acute muscle pain induced in the trapezius muscle. Subsequently, eccentric exercise was performed to induce delayed onset muscle soreness (DOMS) in wrist extensor muscles. In presence of DOMS on day two, computer work recordings with/without pain were repeated. EMG signals were recorded from the descending part of trapezius bilaterally, flexor carpi ulnaris and extensor carpi radialis brevis. Experimental muscle pain in trapezius led to a decrease in the muscular activity of the wrist extensor (P < 0.02) and decreased the relative rest time in the wrist flexor even in presence of DOMS (P < 0.01). The present result suggests that shoulder pain plays a role in the coordination of wrist flexors and extensors during computer work.

Pressure pain sensitivity mapping in experimentally induced lateral epicondylalgia

PURPOSE

The aim of this study was to apply topographical techniques to investigate changes in pressure pain sensitivity after induction of delayed onset muscle soreness (DOMS) in the elbow region in healthy subjects.

METHODS

Pressure pain thresholds (PPT) were assessed over 12 points forming a 3 x 4 matrix (4 points in the superior part, 4 points in the middle, and 4 points in the lower part around the lateral epicondyle) over the dominant elbow in 13 healthy men, and pressure sensitivity maps were calculated. DOMS, as a model for lateral epicondylalgia (LE), was induced by repetitive high-level eccentric contractions of the wrist extensor muscles. PPT maps were assessed before, immediately after, and 24 h after eccentric exercise (DOMS).

RESULTS

The two-way repeated-measure ANOVA detected significant differences in mean PPT for the measurement points (F = 5.96, P < 0.001), with lower PPT over the points located over the extensor carpi radialis brevis muscle. There was also a significant effect of time (F = 121.3, P < 0.001) but no time x point location interaction (F = 0.7, P = 0.8). PPT were lower 24 h after (P < 0.001) but not immediately after (P > 0.05) eccentric exercise.

CONCLUSIONS

The study provides new key information regarding mechanical pain hyperalgesia in experimentally induced LE. Topographical pressure pain sensitivity maps from the elbow region revealed heterogeneously distributed mechanical sensitivity before and during DOMS. The most sensitive localizations for PPT assessment correspond to the muscle belly of the extensor carpi radialis brevis. Our results support the implication of the extensor carpi radialis brevis muscle in LE.

Forearm posture and grip effects during push and pull tasks

Direction of loading and performance of multiple tasks have been shown to elevate muscle activity in the upper extremity. The purpose of this study was to evaluate the effects of gripping on muscle activity and applied force during pushing and pulling tasks with three forearm postures. Twelve volunteers performed five hand-based tasks in supinated, neutral and pronated forearm postures with the elbow at 90 degrees and upper arm vertical. All tasks were performed with the right (dominant) hand and included hand grip alone, push and pull with and without hand grip. Surface EMG from eight upper extremity muscles, hand grip force, tri-axial push and pull forces and wrist angles were recorded during the 10 s trials. The addition of a pull force to hand grip elevated activity in all forearm muscles (all p < 0.017). During all push with grip tasks, forearm extensor muscle activity tended to increase when compared with grip only while flexor activity tended to decrease. Forearm extensor muscle activity was higher with the forearm pronated compared with neutral and supinated postures during most isolated grip tasks and push or pull with grip tasks (all p < 0.017). When the grip dynamometer was rotated so that the push and pull forces could act to assist in creating grip force, forearm muscle activity generally decreased. These results provide strategies for reducing forearm muscle loading in the workplace. STATEMENT OF RELEVANCE: Tools and tasks designed to take advantage of coupling grip with push or pull actions may be beneficial in reducing stress and injury in the muscles of the forearm. These factors should be considered in assessing the workplace in terms of acute and cumulative loading.

Management of Tennis Elbow with sodium hyaluronate periarticular injections

Objectives

To determine the efficacy and safety of peri-articular hyaluronic acid injections in chronic lateral epicondylosis (tennis elbow).

Design

Prospective randomized clinical trial in primary care sport medicine.

Patients

Three hundred and thirty one consecutive competitive racquette sport athletes with chronic (>3 months) lateral epicondylosis were administered 2 injections (first injection at baseline) into the subcutaneous tissue and muscle 1 cm. from the lateral epicondyle toward the primary point of pain using a two-dimensional fanning technique. A second injection was administered 1 week later.

Outcomes measures

Assessments were done at baseline, days 7, 14, 30, 90 and 356. Efficacy measures included patient's visual analogue scale (VAS) of pain at rest (0-100 mm) and following assessment of grip strength (0-100 mm). Grip strength was determined using a jamar hydraulic hand dynamometer. Other assessments included patients' global assessment of elbow injury (5 point categorical scale; 1 = no disability, 5 = maximal disability), patients' assessment of normal function/activity (5 point categorical scale), patients/physician satisfaction assessment (10 point categorical scale), time to return to pain-free and disability-free sport and adverse events as per WHO definition. Differences between groups were determined using an intent-to-treat ANOVA.

Results

Average age of the study population was 49 years (± 12 years). One hundred and sixty-five patients were randomized to the HA and 166 were randomized to the control groups. The change in VAS pain was -6.7 (± 2.0) for HA vs -1.3 (± 1.5) for control (p < 0.001). The VAS post handgrip was -7.8 (± 1.3) vs +0.3 (± 2.0) (p < 0.001) which corresponded to a significant improvement in grip of 2.6 kg in the HA vs control groups (p < 0.01). Statistically significant improvement in patients' global assessment of elbow injury (p < 0.02), patients' assessment of normal function/activity (p < 0.05) and patients/physician satisfaction assessment (p < 0.05) were also observed favoring the HA group. Time to return to pain-free and disability-free sport was 18 (± 11) days in the HA group but was not achieved in the control group. VAS changes were maintained in the HA group at each followup while those in the control significantly declined from baseline. Assessment of patient and physician satisfaction continued to favor the HA group at subsequent followup.

Conclusion

Peri-articular HA treatment for tennis elbow was significantly better than control in improving pain at rest and after maximal grip testing. Further, HA treatment was highly satisfactory by patients and physicians and resulted in better return to pain free sport compared to control.

Treatment of lateral epicondilitis using three different local injection modalities: a randomized prospective clinical trial

BACKGROUND

To determine the effectiveness of three different local injection modalities in the treatment of lateral epicondilitis.

METHODS

In a prospective randomized study on lateral epicondilitis, 75 patients were divided into three equal groups A, B and C (n = 25) and were treated using three different method of local injection. The patients in group A were treated with local injection of a steroid (1 mL triamcinolone) combined with local anaesthetic (1 mL lidocaine), those in group B were treated with injection of local anaesthetic (1 mL lidocaine) combined with peppering technique and those in group C with local injection of a steroid (1 mL triamcinolone) combined with local anaesthetic (1 mL lidocaine) and peppering technique. The outcome was defined by measuring the elbow pain during the activity using a 10-cm visual analogue scale (VAS) and satisfaction with the treatment using a scoring system based on the criteria of the Verhaar et al. at 3 weeks and 6 months after the injection and compared with the pre-treatment condition.

RESULTS

There were significant (P = 0.006) differences in the successful outcomes between the three groups at 6 months. In group C in which local steroid + peppering injection technique were used; excellent results were obtained in 84% of patients comparing to 36% and 48% for patients in groups A and B, respectively. The successful outcomes were statistically higher in group C comparing to group A (P = 0.002) and group B (P = 0.011). In all groups, there was a significantly lower pain (VAS) at the 3-week and 6-month follow-ups comparing to the pre-treatment condition. VAS measured at 6-month follow-up were significantly lower in group C comparing to other groups (P = 0.002).

CONCLUSION

In the treatment of lateral epicondilitis, combination of corticosteroid injections with peppering is more effective than corticosteroid injections or peppering injections alone and produces better clinical results.

Muscle metabolism and acid-base status during exercise in forearm work-related myalgia measured with31P-MRS

In this study, we examined muscle metabolic and acid-base status during incremental wrist extension exercise in the forearm of individuals with work-related myalgia (WRM). Eighteen women employed in full-time occupations involving repetitive forearm labor were recruited in this cross-sectional study. Nine of these women were diagnosed with WRM, while the other nine had no previous WRM history and were used as age-matched controls (Con). Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) was used to noninvasively monitor the intracellular concentrations of phosphocreatine ([PCr]) and inorganic phosphate ([Pi]) as well as intracellular pH (pHi) status during exercise in WRM and Con. We observed a 38% decreased work capacity in WRM compared with Con [0.18 W (SD 0.03) vs. 0.28 W (SD 0.10); P = 0.007]. Piecewise linear regression of the incremental exercise data revealed that the onset of a faster decrease in pHi(i.e., the pH threshold, pHT) and the onset of a faster increase in log([Pi]/[PCr]) (i.e., the phosphorylation threshold, PT) occurred at a 14% relatively lower power output in WRM [pHT: 45.2% (SD 5.3) vs. 59.0% (SD 4.6), P < 0.001; PT: 44.8% (SD 4.3) vs. 57.8% (SD 3.1), P < 0.001; % of peak power output, Con vs. WRM, respectively]. Monoexponential modeling of the kinetics of [PCr] and pHirecovery following exercise demonstrated a slower ( P = 0.005) time constant (τ) for [PCr] in WRM [113 s (SD 25)] vs. Con [77 s (SD 23)] and a slower ( P = 0.007) τ for pHiin WRM [370 s (SD 178)] vs. Con [179 s (SD 52)]. In conclusion, our results suggest that WRM is associated with an increased reliance on nonoxidative metabolism. Possible mechanisms include a reduction in local muscle blood flow and perfusion, an increased ATP cost of force production, or both.

Impact of repetition number on muscle performance and histological response

Skeletal muscle injury is major concern in sport- and occupation-related fields.

PURPOSE

We investigated the effects of increasing stretch-shortening contraction (SSC) repetition number in vivo and the resulting changes in functional performance and quantitative morphometry in rat skeletal muscle.

METHODS

Functional testing was performed on the ankle dorsiflexor muscles of Sprague-Dawley rats, which were randomly exposed to 30 SSC, 70 SSC, 150 SSC, or 15 isometric contractions of equal duration. Changes in functional performance and muscle morphometry were assessed at 48 h after exposure. Stereology was used to quantify the volume density of degenerative myofibers and normal myofibers in the tibialis anterior muscle from each group, as well as measures of inflammation and swelling and changes in the interstitial space.

RESULTS

At 48 h there was a significant decline in isometric force for the 70- and 150-SSC groups (P < 0.05 and P < 0.05, respectively). Stereological measures indicated significant decreases in the percentage of volume density of normal myofibers in the 70- and 150-SSC groups (P < 0.05). Measures for percentage of volume density of degenerative myofibers and inflammation were increased (P < 0.0001 and P < 0.05, respectively) in the 70- and 150-SSC groups. Moreover, a significant increase in the percentage of volume density of degenerative myofibers in the 150-SSC group compared with the 70-SSC group was observed (P < 0.05).

CONCLUSION

These data strongly suggest that exposure to increasing SSC repetitions results in increased functional decrements and morphometric indices of myofiber degeneration and inflammation, and that there is an apparent threshold (repetition number) at which this occurs.

Prevalence of and referred pain from myofascial trigger points in the forearm muscles in patients with lateral epicondylalgia

OBJECTIVE

Referred pain and pain characteristics evoked from the extensor carpi radialis brevis, extensor carpi radialis longus, extensor digitorum communis, and brachioradialis muscles was investigated in 20 patients with lateral epicondylalgia (LE) and 20-matched controls.

METHODS

Both groups were examined for the presence of myofascial trigger points (TrPs) in a blinded fashion. The quality and location of the evoked referred pain, and the pressure pain threshold (PPT) at the lateral epicondyle on the right upper extremity (symptomatic side in patients, and dominant-side on controls) were recorded. Several lateral elbow pain parameters were also evaluated.

RESULTS

Within the patient group, the elicited referred pain by manual exploration of 13 out of 20 (65%) extensor carpi radialis brevis muscles, 12/20 (70%) extensor carpi radialis longus muscles, 10/20 (50%) brachioradialis muscles, and 5/20 (25%) extensor digitorum communis muscles, shares similar pain patterns as their habitual lateral elbow and forearm pain. The mean number of muscles with TrPs for each patient was 2.9 [95% confidence interval (CI) 1,4] of which 2 (95% CI 1,3) were active, and 0.9 (95% CI 0,2) were latent TrPs. Control participants only had latent TrPs (mean: 0.4; 95% CI 0,2). TrP occurrence between the 2 groups was significantly different for active TrPs (P<0.001), but not for latent TrPs (P>0.05). The referred pain pattern was larger in patients than in controls, with pain referral to the lateral epicondyle (proximally) and to the dorso-lateral aspect of the forearm in the patients, and confined to the dorso-lateral aspect of the forearm in the controls. Patients with LE showed a significant (P<0.001) lower PPT (mean: 2.1 kg/cm; 95% CI 0.8, 4 kg/cm) as compared with controls (mean: 4.5 kg/cm; 95% CI 3, 7 kg/cm). Within the patient group, PPT at the lateral epicondyle was negatively correlated with both the total number of TrPs (rs=-0.63; P=0.003) and the number of active TrPs (rs=-0.5; P=0.02): the greater the number of active TrPs, the lower the PPT at the lateral epicondyle.

DISCUSSION

Our results suggest that in patients with LE, the evoked referred pain and its sensory characteristics shared similar patterns as their habitual elbow and forearm pain, consistent with active TrPs. Lower PPT and larger referred pain patterns suggest that peripheral and central sensitization exists in LE.

The role of physical examinations in studies of musculoskeletal disorders of the elbow

OBJECTIVES

To present data on pain and physical findings from the elbow region, and to discuss the role of diagnostic criteria in epidemiological studies of epicondylitis.

METHODS

From a cohort of computer workers a subgroup of 1369 participants, who reported at least moderate pain in the neck and upper extremities, were invited to a standardised physical examination. Two independent physical examinations were performed-one blinded and one not blinded to the medical history. Information concerning musculoskeletal symptoms was obtained by a baseline questionnaire and a similar questionnaire completed on the day of examination.

RESULTS

349 participants met the authors' criteria for being an arm case and 249 were elbow cases. Among the 1369 participants the prevalence of at least mild palpation tenderness and indirect tenderness at the lateral epicondyle was 5.8%. The occurrence of physical findings increased markedly by level of pain score. Only about one half with physical findings fulfilled the authors' pain criteria for having lateral epicondylitis. A large part with physical findings reported no pain at all in the elbow in any of the two questionnaires, 28% and 22%, respectively. Inter-examiner reliability between blinded and not blinded examination was found to be low (kappa value (0.34-0.40)).

CONCLUSION

Very few with at least moderate pain in the elbow region met common specific criteria for lateral epicondylitis. The occurrence of physical findings increased markedly by level of pain score and the associations were strongest with pain intensity scores given just before the examination. Physical signs were commonly found in subjects with no pain complaints. No further impact was achieved if the physical examination was not blinded to the medical history. Furthermore, the authors propose that pain, clinical signs and disability are studied as separate outcomes, and that the diagnoses of lateral epicondylitis should be used only for cases with classical signs of inflammation reflected by severe pain, which for example conveys some disability.

[Extra-articular elbow arthroscopy.]

Extra-articular elbow arthroscopy has to be considered as the evolution of the elbow surgery to a mini invasive endoscopically assisted surgery developed by the recent advance of the elbow arthroscopy. Various pathologies, such as lateral epicondylitis, ulnar nerve entrapment, distal Biceps tendon rupture, synovial cysts, or olecranon bursitis have been treated arthroscopically. Extra-articular pathologies can be treated through an intra-articular endoscopic approach. The true endoscopic extra-articular technique is proced through a real anatomical space or inside a space of work created de novo by the surgeon. The difficulty of using endoscopy in extra-articular pathologies of the elbow is related to the vasculo-nervous structures sourrounding the articulation wich are directly subject to potential injury. Elbow extra-articular endoscopy must be considered as a difficult and sometimes dangerous procedure reserved to experimented elbow arthroscopic surgeons. Those techniques are yet to demonstrate their superiority in term of results and security compare to the open techniques.