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

Strain measurement of the deep layer of the supraspinatus tendon using fresh frozen cadaver: The influence of shoulder elevation

BACKGROUND

The shoulder is a uniquely complex large joint. Effective and safe physical therapy efforts towards rehabilitating injured and repaired shoulders requires a thorough understanding of shoulder mechanics from both generalized and very specific perspectives. Numerous biomechanical studies have been published on the shoulder. None of the studies, to our knowledge, considered the strain of the deep layers of the supraspinatus tendon for scapular plane elevation.

METHODS

Ten unilateral fresh-frozen human cadaveric specimens were used for the study. Scapular plane angles ranging from -10 to 30 degrees were evaluated for tensile loads, ranging from 0 to 120 Newtons, exerted on the supraspinatus tendon. Strain measurements that specifically targeted the deep layer of the supraspinatus tendon during tensile loading were recorded.

FINDINGS

Strains recorded in the supraspinatus deep layer while increasing tendon force of the supraspinatus were significant for isometric gleno-humeral elevation of 30° and 20°. The response of strain to tendon force was less pronounced for 10° or less of gleno-humeral elevation.

INTERPRETATION

When performing isometric shoulder exercise regimens, rotator cuff forces and both surface and deep tendon strain, relative to scapular positioning, are relevant and should be considered.

Exercise interventions in lateral elbow tendinopathy have better outcomes than passive interventions, but the effects are small: a systematic review and meta-analysis of 2123 subjects in 30 trials

Objective

To evaluate the effectiveness of exercise compared with other conservative interventions in the management of lateral elbow tendinopathy (LET) on pain and function.

Design

Systematic review and meta-analysis.

Methods

We used the Cochrane risk-of-bias tool 2 for randomised controlled trials (RCTs) to assess risk of bias and the Grading of Recommendations Assessment, Development and Evaluation methodology to grade the certainty of evidence. Self-perceived improvement, pain intensity, pain-free grip strength (PFGS) and elbow disability were used as primary outcome measures.

Eligibility criteria

RCTs assessing the effectiveness of exercise alone or as an additive intervention compared with passive interventions, wait-and-see or injections in patients with LET.

Results

30 RCTs (2123 participants, 5 comparator interventions) were identified. Exercise outperformed (low certainty) corticosteroid injections in all outcomes at all time points except short-term pain reduction. Clinically significant differences were found in PFGS at short-term (mean difference (MD): 12.15, (95% CI) 1.69 to 22.6), mid-term (MD: 22.45, 95% CI 3.63 to 41.3) and long-term follow-up (MD: 18, 95% CI 11.17 to 24.84). Statistically significant differences (very low certainty) for exercise compared with wait-and-see were found only in self-perceived improvement at short-term, pain reduction and elbow disability at short-term and long-term follow-up. Substantial heterogeneity in descriptions of equipment, load, duration and frequency of exercise programmes were evident.

Conclusions

Low and very low certainty evidence suggests exercise is effective compared with passive interventions with or without invasive treatment in LET, but the effect is small.

PROSPERO registration number

CRD42018082703.

The effects of counterforce brace on pain in subjects with lateral elbow tendinopathy: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Lateral elbow tendinopathy, also known as "tennis elbow" or "lateral epicondylitis," is a common disease leading to pain in the lateral side of the elbow and disability during hand gripping. A counterforce brace is one of the most conventional treatments. However, its effects on outcomes remain inconclusive.

OBJECTIVES

To investigate the effects of counterforce braces on pain in subjects with lateral elbow tendinopathy. Grip strength was reviewed as a secondary outcome.

STUDY DESIGN

Systematic review and meta-analysis of randomized controlled trials.

METHODS

PubMed, Embase, Scopus, Web of Science, CENTRAL, PEDro, ProQuest, RECAL, and RehabData were searched from January 1, 1995, through June 15, 2019.

RESULTS

Seventeen studies were included with a total of 1145 participants. A small improvement in pain over the short term (standardized mean difference -0.02; 95% confidence interval: -0.85 to 0.80) and a moderate-to-large improvement in pain in subjects 45 years or younger (standardized mean difference -0.86; 95% confidence interval: -2.45 to 0.72) in favor of the brace versus physiotherapy interventions were found. In contrast, over the long-term physiotherapy interventions (standardized mean difference 1.17; 95% confidence interval: -0.00 to 2.34), wrist splint (standardized mean difference 0.35; 95% confidence interval: -0.07 to 0.76), and laser therapy (standardized mean difference 0.58; 95% confidence interval: -0.44 to 1.59) had better effects on pain improvement versus the brace.

CONCLUSION

The results indicated that physiotherapy interventions compared to counterforce braces have better effects, especially over the long-term. However, counterforce braces may have better effects on pain in younger people (<45 years old) over the short term (<6 weeks).

CLINICAL RELEVANCE

The results suggest that counterforce bracing is a reasonable strategy to alleviate pain over the short term. However, the subgroup analysis suggests that factors such as age may have a role in their effectiveness.

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.

The immediate sensorimotor effects of elbow orthoses in patients with lateral elbow tendinopathy: a prospective crossover study

BACKGROUND

Counterforce orthoses are used to manage lateral elbow tendinopathy, and their effectiveness in improving motor function has been documented. Little is known about the impact of bracing on sensory function. The objective of this study was to investigate the immediate effectiveness of 2 counterforce orthoses in improving the sensorimotor abilities of the hand in patients with lateral elbow tendinopathy.

METHODS

In this crossover, randomized controlled trial, elbow proprioception, pain severity, pain-free grip strength, and finger dexterity were measured in 50 participants with a diagnosis of lateral elbow tendinopathy. Outcomes were measured in 3 randomized conditions (no brace, forearm band, or elbow sleeve). Data were analyzed using 1-way repeated-measures analysis of variance for each outcome measure.

RESULTS

Better scores were observed with the forearm band, as compared with no orthosis, for multiple outcomes including joint position reproduction score at 70° of elbow flexion (P = .006), pain (P < .001), grip strength (P = .01), and dexterity (P < .001). The elbow sleeve yielded better scores than no orthosis for the following outcomes: joint position reproduction score at 110° (P < .001), pain (P < .001), and grip strength (P = .012). No statistically significant difference was found between the orthoses' effects on pain reduction and grip strength (P > .05). The forearm band showed better scores on joint position reproduction at 70° compared with the elbow sleeve (P = .006), whereas the elbow sleeve showed better scores at 110° (P < .001).

CONCLUSION

Our results support the mechanisms occurring with the use of either of the described orthotic interventions. Future randomized trials with longer-term outcomes that include sensorimotor mechanisms might enhance our understanding of the comparative effectiveness.

Prospective randomized controlled trial in the treatment of lateral epicondylitis with a new dynamic wrist orthosis

BACKGROUND

In the treatment of lateral epicondylitis (LE), the role of a new dynamic wrist orthosis is unclear.

PATIENTS AND METHODS

Patients suffering from a LE longer than 3 months were multicentrically and prospectively randomized into a physiotherapeutic group (PT group) and in a physiotherapy group plus wrist orthosis (PT + O group). Physiotherapy consisted of daily eccentric strengthening exercises under initial professional supervision. Inclusion criteria were a Placzek score greater than 4. Exclusion criteria were previous surgery, rheumatic arthritis, elbow instability, radicular symptoms, higher-grade extensor tendon rupture, or cervical osteoarthritis. The clinical evaluation was performed after 12 weeks and 12 months. The Patient-Rated Tennis Elbow Evaluation (PRTEE) scale, Placzek Score, the pain rating (VAS), range of motion and the Subjective Elbow Score were evaluated.

RESULTS

Of the initially 61 patients, 31 were followed up after 12 weeks and 22 after 12 months. Twenty-nine patients (43%) were male, the mean age was 46, and 44 patients (66%) had the right elbow involved. At 12 weeks, there was a pain reduction on the VAS in both groups (PT + O: 6.5-3.7 [p = .001]; PT: 4.7-4.1 [p = .468]), albeit it was only significant for the PT + O group. At 12 months, reduction was significant in both groups (PT + O: 1.1 [p = .000]; PT: 1.3 [p = .000]). The painless maximum hand strength in kg improved in both groups significant after 3 and 12 months. The Placzek score was reduced from 8.25 to 3.5 [p = .001] after 12 weeks for the PT + O group and from 8.1 to 3.8 [p = .000] in the PT group, as well as after 12 months in the PT + O group to 0 [p = .000] and in the PT group to 2.0 [p = .000]. The PRTEE improved in both groups after 12 weeks (PT + O: 52.8--31.3 [p = .002]; PT: 48.6-37.6 [p = .185]) and 12 months (PT + O: 16.15 [p = .000]; PT: 16.6 [p = .000]), although the reduction at 12 weeks was not significant for the PT group.

CONCLUSION

The elbow orthosis appears to accelerate the healing process with respect to the PRTEE and pain on the VAS (12 weeks follow-up), although there is an adjustment after 12 months in both groups and a significant improvement of symptoms is achieved in all endpoints.

Measurement of strain and tensile force of the supraspinatus tendon under conditions that simulates low angle isometric elevation of the gleno-humeral joint: Influence of adduction torque and joint positioning

BACKGROUND

Recently, supraspinatus muscle exercise has been reported to treat rotator cuff disease and to recover shoulder function. However, there have been no report on the direct measurement of strain on the supraspinatus tendon during simulated isometric gleno-humeral joint elevation.

METHODS

Ten fresh-frozen shoulder specimens with the rotator cuff complex left intact were used as experimental models. Isometric gleno-humeral joint elevation in a sitting position was reproduced with low angle of step-by-step elevation in the scapular plane and strain was measured on the surface layer of the supraspinatus tendon.

FINDINGS

In isometric conditions, applied tensile force of the supraspinatus tendon increased significantly with increases in adduction torque on the gleno-humeral joint. Significant increases in the strain on the layer were observed by increase in adduction torque, which were recorded in isometric elevation at -10° and 0°, but little increase in the strain was observed at 10° or greater gleno-humeral elevation.

INTERPRETATION

Increased strain on the surface layer of the supraspinatus tendon was observed during isometric gleno-humeral elevation from -10 to 0°. These findings demonstrate a potential risk of inducing overstretching of the supraspinatus tendon during supraspinatus muscle exercise.

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.

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.

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).

Influence of infrapatellar and suprapatellar straps on quadriceps muscle activity and onset timing during the body-weight squat

The use of knee braces for the treatment of patellofemoral pain syndrome (PFPS) is widely documented, yet the mechanism by which such braces alleviate knee pain remains unclear. This study attempted to clarify this issue by simplifying the brace to the level of only straps. The effectiveness of an infrapatellar strap for PFPS remains controversial, and the use of a suprapatellar strap has not yet been studied. Quadriceps muscle activity and onset timing parameters were measured with surface electromyography (EMG) during a body-weight squat in 19 healthy subjects during 4 different knee-strapping conditions (infra, supra, both, and none). No differences in normalized mean or peak EMG activity in any part of the quadriceps were found. The onset timing of the vastus lateralis (VL) was significantly delayed when using an infrapatellar strap (p < 0.05) or both straps (p < 0.05) and marginally delayed when using a suprapatellar strap (p < 0.10) in comparison with the no-strap (control) condition. No differences in the vastus medialis oblique (VMO) onset timing or VMO-VL onset timing difference were found among the strapping conditions, although an improvement in timing was noted with the suprapatellar condition. The results provide novel evidence that the application of an infrapatellar strap, suprapatellar strap, or both straps improves quadriceps muscle timing imbalances by delaying VL onset. Because the largest delay in VL onset occurred when wearing both straps, the combined application of an infrapatellar and suprapatellar strap may be the most beneficial in managing patellofemoral pain. Knee straps, unlike braces, are cost effective, nonrestrictive, and can be universally fitted to any knee and based on the results deserve further study in the patellofemoral pain population.

Effect of distal radius volar plate position on contact pressure between the flexor pollicis longus tendon and the distal plate edge

PURPOSE

Some clinical studies have suggested that distal radius plates placed distal to the watershed line have the potential to impinge on the traversing flexor tendons. However, the validity of this theory remains unclear. The purpose of this study was to evaluate the quantitative effect of volar plate position on flexor pollicis longus (FPL) tendon friction by measuring the contact pressure between the FPL tendon and the distal edge of the locking plate.

METHODS

We used 7 fresh cadaveric upper extremities without wrist osteoarthritis or any deformity. External loads of 1.5 and 3.0 kgf were applied to the FPL tendon to simulate the pinch function of the thumb. A distal radius volar plate was applied to these cadaveric specimens in various positions relative to the watershed line. We measured contact pressure between the distal plate edge and the FPL tendon using a thin flexible pressure sensor and compared it among various positions of the volar plate for wrist extension angles of 0°, 30°, and 60° and ulnar deviation angles of 0° and 20°.

RESULTS

Under the 30° or 60° wrist extension condition, contact pressure significantly increased when the distal plate edge was placed distal to the watershed line, compared with when it was placed proximal to or at the watershed line.

CONCLUSIONS

Our quantitative results support the theory that plates placed distal to the watershed line have the potential to impinge on the traversing FPL tendon, even when a radius fracture heals anatomically.

CLINICAL RELEVANCE

This study clarifies a mechanism of FPL tendon irritation after volar plate fixation for distal radius fractures.

Effect of elbow and forearm position on contact pressure between the extensor origin and the lateral side of the capitellum

PURPOSE

Bone-to-tendon contact in the origin of the common extensor tendons is considered to be one of the causes of lateral epicondylitis. Some factors, including elbow and forearm position, varus stress to the elbow, or contraction of the wrist extensor tendons, are considered to affect this bone-to-tendon contact. However, no studies have evaluated the effect of the elbow and forearm position on bone-tendon interface. The purpose of this study is to evaluate the effect of the position of the elbow and forearm on the contact pressure of the tendinous origin of the common wrist and finger extensors.

METHODS

We used 8 fresh cadaveric upper extremities. Contact pressure between the origin of the common extensor tendons and the lateral side of the capitellum was measured with a pressure sensor and was compared among various conditions, including elbow flexion angle (0°, 30°, 60°, and 90°), forearm rotation position (neutral and 81.5° pronation position), and varus stress load of the elbow (none, gravity on the forearm, and gravity on the forearm +1.96 Nm). Contact pressure was also measured during tension force of the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor digitorum communis by 0, 9.8, and 19.6 N.

RESULTS

Contact pressure was significantly increased with the elbow extension position, forearm pronation position, and varus stress to the elbow under tension of the extensor carpi radialis longus or extensor carpi radialis brevis.

CONCLUSIONS

This study provides data about the amount of contact pressure between bone and tendon at the origin of the common extensor tendons in the elbow. This information may lead to a better understanding of, and better treatment for, lateral epicondylitis.

The immediate effect of orthotic management on grip strength of patients with lateral epicondylosis

STUDY DESIGN

Controlled laboratory study using a randomized crossover design.

OBJECTIVE

To determine the immediate effect of 3 common types of orthoses (2 elbow counterforce orthoses and a wrist splint) on grip strength in individuals with lateral epicondylosis.

BACKGROUND

Lateral epicondylosis is a common cause of pain and upper limb dysfunction. Although the effectiveness of orthoses has been reported, comparisons of effectiveness among orthoses are limited.

METHODS AND MEASURES

Fifty-two subjects with lateral epicondylosis were recruited (20 men, 32 women; mean +/- SD age, 41 +/- 8 years). Maximum and pain-free grip strength were assessed using a digital hand grip dynamometer immediately after the application of each orthosis. The 4 testing conditions included a placebo orthosis as a control condition, an elbow strap orthosis, an elbow sleeve orthosis, and a wrist splint. Data were analyzed using a 1-way analysis of variance for each outcome measure.

RESULTS

Pain-free grip-strength was greater when using the elbow strap or the elbow sleeve orthosis compared to when using the placebo control orthosis or the wrist splint (P<.02), but there was no difference between the elbow sleeve and strap orthoses (P>.05), nor between the wrist splint and placebo orthosis (P>.05). Maximum grip strength was less when using the wrist splint compared to when tested with the elbow sleeve or the elbow strap (P< or =.003). Use of the elbow strap, elbow sleeve, or wrist splint did not change maximum grip strength compared to the control placebo orthosis condition (P>.05). There was also no difference in maximum grip strength between the elbow strap and the elbow sleeve conditions (P>.05).

CONCLUSION

The use of the 2 types of elbow orthoses (strap and sleeve) resulted in an immediate increase in pain-free grip strength. No differences between the 2 orthoses were found, suggesting that either can be used. A wrist splint produced no immediate change in pain-free or maximum grip-strength, indicating that it should not be used as a first-choice orthosis based on those outcome measures.