Muscle strain on the radial wrist extensors during motion-simulating stretching exercises for lateral epicondylitis: a cadaveric study

Upper limb position affects pain-free grip strength in individuals with lateral elbow tendinopathy

BACKGROUND AND PURPOSE

Pain-free grip (PFG) force is commonly used to monitor treatment outcomes in lateral elbow tendinopathy (LET); however, it is unclear whether changes in forearm and elbow position affect PFG force values. This study aims to examine the effect of elbow/shoulder and forearm position on non-normalised and normalised PFG force in individuals with unilateral LET.

METHODS

A cohort study including 21 subjects with clinically diagnosed unilateral LET (13 females, mean [SD] age 50 [8] years) performed PFG force (symptomatic arm) and maximal grip (asymptomatic arm) tasks using four upper limb positions: (1) shoulder neutral, elbow flexed (90°), forearm pronated; (2) shoulder neutral, elbow flexed (90°), forearm neutral; (3) shoulder flexed (90°), elbow extended, forearm pronated; and (4) shoulder flexed (90°), elbow extended, forearm neutral. PFG force was normalised to the maximal grip of the asymptomatic side. Repeated-measures analyses of variance were used to compare non-normalised and PFG force normalised to maximal grip between positions.

RESULTS

Both non-normalised and normalised PFG forces were greater in position 2 than position 1, position 3 and position 4 (elbow-by-forearm interaction non-normalised p = 0.002, normalised p = 0.004). There were no differences between positions 1, 3 and 4 for either non-normalised or normalised PFG strength.

DISCUSSION

This study shows that PFG force was higher when performed with forearm neutral supination/pronation, elbow flexion and shoulder neutral than other tested positions, and irrespective of whether PFG force was normalised to the maximal grip force of the contralateral limb. This indicates that arm position should be standardised for comparison.

Evaluating the immediate effect of forearm and wrist orthoses on pain and function in individuals with lateral elbow tendinopathy: A systematic review

BACKGROUND

Lateral elbow tendinopathy is associated with pain during gripping, with forearm/wrist orthoses prescribed for treatment.

OBJECTIVES

To investigate the immediate effects of forearm and/or wrist orthoses on outcome measures of pain and function in individuals with lateral elbow tendinopathy.

DESIGN

Systematic review METHODS: Four electronic databases were searched to identify randomised controlled trials reporting the immediate effects of forearm and/or wrist orthoses on pain and function in individuals with lateral elbow tendinopathy. The quality of evidence was rated from high to very low, using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) for the primary outcomes. Where possible, standardised mean difference (SMD) and 95% confidence intervals were calculated to compare post measures between forearm and/or wrist orthoses and control/placebo conditions.

RESULTS

The search revealed 1965 studies, of which, seven randomised crossover trials were included. Using the GRADE approach there was low quality evidence revealing a significant decrease in pain during contraction (SMD range -0.65 to -0.83) with forearm orthoses compared to a control/placebo condition. Low quality evidence revealed improvements in pain-free grip strength with the use of a forearm orthosis (SMD range 0.24-0.38), but not maximal grip strength (SMD range 0.14-0.15). Low quality evidence revealed a static wrist orthosis did not improve pain-free grip strength (SMD -0.08) or maximal grip strength (SMD -0.22).

CONCLUSION

There is low quality evidence that forearm orthoses can immediately reduce pain during contraction and improve pain-free grip strength but not maximal grip strength in individuals with lateral elbow tendinopathy.

Effect of wrist and finger flexion in relation to strain on the tendon origin of the extensor carpi radialis brevis: A cadaveric study simulating stretching exercises

BACKGROUND

Stretching exercises based on wrist flexion-ulnar deviation with elbow extension, forearm pronation, and additional index or middle finger flexion have been used to stretch the wrist extensors for lateral epicondylitis. The purpose of this study was to quantify the strain on the tendon origin of the extensor carpi radialis brevis in cadaver specimens during these stretching exercises.

METHODS

We used 8 fresh frozen/thawed cadaveric upper extremities. The strain on the extensor carpi radialis brevis tendon origin was measured by the addition of 4 types of traction (no traction, wrist flexion-ulnar deviation, and index or middle finger flexion in combination with wrist flexion-ulnar deviation) in 7 sequential elbow flexion angles during forearm pronation. Two types of varus stress load to the elbow (none, gravity on the forearm) were also applied.

FINDINGS

A significant increase in strain was obtained by wrist traction with 0°, 15° and 30° of elbow flexion (P<0.05). The strain was also significantly increased by adding finger traction (P<0.05) and varus stress load (P<0.05). A maximum strain value of 5.30 (SD 1.73) % was obtained when traction on the middle finger in combination with traction of the wrist was added at 15° elbow flexion with varus stress load.

INTERPRETATION

The present study provides data about the amount of strain on the extensor carpi radialis brevis tendon during stretching exercises of the wrist and finger extensors. The results of this study could be applied to stretching exercises for patients with lateral epicondylitis.

Effect of simultaneous stretching of the wrist and finger extensors for lateral epicondylitis: a gross anatomical study of the tendinous origins of the extensor carpi radialis brevis and extensor digitorum communis

BACKGROUND

Pulling the wrist into flexion with the elbow in extension and forearm in pronation has been used as the stretching technique of wrist extensors for lateral epicondylitis. Simultaneous stretching of the fingers in addition to the wrist flexion has also been applied. However, the mechanism of this simultaneous stretching has not been clarified. This study is designed to clarify the mechanism underlying this simultaneous stretching technique based on the anatomical features of the origins of the extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC).

METHODS

Thirty-nine arms from formalin-embalmed Japanese human specimens were dissected. The features of the origins of the ECRB and EDC were macroscopically observed, and the locations of each origin on the lateral epicondyle were measured.

RESULTS

The ECRB had a long and wide, purely tendinous origin which originated from the anterior slope of the lateral epicondyle. The tendinous origin of the index finger of the EDC (EDC-IF) arose from the posterior aspect of the ECRB tendinous origin, with a coexisting muscular portion observed at the level of the proximal forearm. The middle finger of the EDC (EDC-MF) had a short tendinous origin with an associated muscular portion and originated proximo-laterally to the origin of the ECRB on the lateral epicondyle. In addition, the muscular origin of the EDC-MF arose on the superficial and posterior aspect of the ECRB tendinous origin. In contrast, the ring and little fingers of the EDC originated from the tendinous septum of the extensor digiti minimi and extensor carpi ulnaris, and had no connection with the ECRB tendinous origin.

CONCLUSIONS

On the basis of our anatomical findings, simultaneous stretching of the wrist extensors by wrist, index and middle fingers flexion could provide stretching force to both the tendinous origins of the ECRB and EDC through the EDC-IF and EDC-MF.

Ultrasound-guided percutaneous needle electrolysis in chronic lateral epicondylitis: short-term and long-term results

BACKGROUND

Ultrasound (US)-guided percutaneous needle electrolysis (PNE) is a novel minimally invasive approach which consists of the application of a galvanic current through an acupuncture needle.

OBJECTIVE

To evaluate the clinical and ultrasonographic effectiveness of a multimodal programme (PNE, eccentric exercise (EccEx) and stretching) in the short term for patients with chronic lateral epicondylitis, and to determine whether the clinical outcomes achieved decline over time.

METHODS

A one-way repeated measures study was performed in a clinical setting in 36 patients presenting with lateral epicondylitis. The patients received one session of US-guided PNE per week over 4-6 weeks, associated with a home programme of EccEx and stretching. The main outcome measures were severity of pain, disability (Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire), structural tendon changes (US), hypervascularity and patients' perceptions of overall outcome. Measurements at 6, 26 and 52 weeks follow-up included recurrence rates (increase in severity of pain or disability compared with discharge), perception of overall outcome and success rates.

RESULTS

All outcome measures registered significant improvements between pre-intervention and discharge. Most patients (n=30, 83.3%) rated the overall outcome as 'successful' at 6 weeks. The ultrasonographic findings showed that the hypoechoic regions and hypervascularity of the extensor carpi radialis brevis changed significantly. At 26 and 52 weeks, all participants (n=32) perceived a 'successful' outcome. Recurrence rates were null after discharge and at follow-up at 6, 26 and 52 weeks.

CONCLUSIONS

Symptoms and degenerative structural changes of chronic lateral epicondylitis are reduced after US-guided PNE associated with EccEx and stretching, with encouragingly low recurrences in the mid to long term.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT02085928.

Immediate effects of 2 types of braces on pain and grip strength in people with lateral epicondylalgia: a randomized controlled trial

STUDY DESIGN

Repeated-measures, crossover, double-blinded randomized controlled trial.

OBJECTIVES

To compare the immediate effectiveness of 2 types of counterforce braces in improving pain-free grip strength, pressure pain threshold, and wrist angle during a gripping task in individuals with lateral epicondylalgia.

BACKGROUND

Sports medicine management of lateral epicondylalgia often includes application of a counterforce brace, but the comparative effectiveness of different braces is unclear. The most common brace design consists of a single strap wrapped around the proximal forearm. A variation of this brace is the use of an additional strap that wraps above the elbow, which aims to provide further unloading to the injured tissue.

METHODS

Pain-free grip strength, pressure pain threshold, and wrist angle during a gripping task were measured on 34 participants with a clinical diagnosis of lateral epicondylalgia (mean ± SD age, 47.8 ± 8.5 years). Measurements were made without a brace, as well as immediately before and after the application of 2 types of counterforce braces. Each condition was tested during a separate session, with a minimum of 48 hours between sessions. Analysis-of-variance models were used to test the differences within and between conditions.

RESULTS

Pain-free grip strength (17.2 N; 95% confidence interval: 7.5, 26.8) and pressure pain threshold (42.2 kPa; 95% confidence interval: 16.5, 68.0) significantly improved on the affected side immediately following the intervention conditions as well as the control condition. There was no significant difference between braces or the control condition for any outcome.

CONCLUSION

Both types of counterforce braces had an immediate positive effect in participants with lateral epicondylalgia, without differences between interventions and similar to a no-brace control condition. Therefore, while the use of a brace may be helpful in managing immediate symptoms related to lateral epicondylalgia, the choice of which brace to use may be more a function of patient preference, comfort, and cost. Further research is required to investigate the comparative longer-term and clinical effects of the 2 braces.

TRIAL REGISTRATION

ACTRN12609000354280 ( www.anzctr.org.au).

Strain reduction of the extensor carpi radialis brevis tendon proximal origin following the application of a forearm support band

STUDY DESIGN

Experimental laboratory design.

OBJECTIVES

To measure the strain at the proximal origin of the extensor carpi radialis brevis (ECRB), and to determine the influence of a forearm support band.

BACKGROUND

A forearm support band is often used with the intent to decrease stresses around the origin of the wrist extensors. However, the influence of the location of the band has not been studied.

METHODS AND MEASURES

The forearm support band was applied on 8 cadaver arms (mean +/- SD age, 78.4 +/- 10.3 years) and 2 experimental conditions were performed. First, strain measurements were made without applying tension to the distal ECRB tendon, then strain measurements were made with a traction force of 21.5 N being applied to the distal ECRB tendon. Strain of the proximal origin of the ECRB, 1.0 cm distal from the lateral epicondyle, was recorded using a strain gauge. The band was mounted on the forearm at distances equal to 80%, 70%, 60%, 50%, 40%, 30%, and 20% of the forearm length as measured from the wrist. Testing order was randomized. Tension applied to the band was 19.6 N.

RESULTS

When no tension was applied to the ECRB, there was no statistically significant difference (P>.05) in strain values at the ECRB origin by mounting the band at any of the forearm positions. In the tension condition, the average (SD) strain with no band was 2.40% (1.40%). The average strain value of 0.85% (0.65%), when the band was mounted 80% of the forearm length proximal to the wrist, was statistically smaller than that obtained without the band (P<.05).

CONCLUSIONS

The strain on the ECRB origin was less when the forearm support band was applied 80% proximal from the wrist joint.

LEVEL OF EVIDENCE

Therapy, level 5.