Electrophysiologic basis of dynamic extensor splinting

Efficacy of extension wrist hand orthosis on pain, grip strength and electromyographic activities in lateral epicondylitis: A randomized single-blind clinical trial

BACKGROUND

Lateral epicondylitis (LE) is one of the most common work-related complications characterized by pain, decreased grip strength and dysfunction of upper limb. Although conservative management such as physiotherapy and orthosis is reported as first line of treatment, sufficient evidence to decide their effectiveness is lacking and remains controversial.

PURPOSE

The current study evaluated and compared the efficacy of a custom-made extension wrist hand orthosis adjunct to usual physiotherapy and therapeutics alone for subjects with LE.

STUDY DESIGN

Prospective randomized single-blinded clinical trial.

METHODS

62 subjects with LE were selected as samples using convenience method in this experimental study. They were randomly divided into two groups: usual physiotherapy only and its combination with orthosis. Pain and grip strength were measured using Visual Analog Scale and Jamar hydraulic digital hand dynamometer. Muscle activity of extensor carpi radialis brevis during hand gripping was measured using surface electro-myographic by PowerLab electromyography (AD Instruments, Castle Hill, Australia). Data analysis and comparison were performed for baseline and post-intervention (12weeks).

RESULTS

After 12weeks of treatment, there were significant differences in mean scores of pain (1.22 ± 0.51, p = 0.001), maximum voluntary grip strength (5.82 ± 7.84, p = 0.04), and extensor carpi radialis brevis muscle activation (0.082 ± 0.094, p = 0.02) between the therapeutics alone group and the therapeutics plus orthosis group. Compared to therapeutics alone, those getting a combination of physiotherapy and orthosis had greater treatment efficacy (p < 0.05).

CONCLUSIONS

Both postintervention (12-week) treatments could affect pain scores, grip strength, and extensor muscle activation. Custom-made extension wrist hand orthosis adjunct to usual physiotherapy is more effective than therapeutics alone in subjects with LE. Therefore, the use of wrist orthosis adjunct to physiotherapy should be recommended in rehabilitation settings for LE.

Are the outcomes of relative motion extension orthoses non-inferior and cost-effective compared with dynamic extension orthoses for management of zones V-VI finger extensor tendon repairs: A randomized controlled trial

INTRODUCTION

There is no comparative evidence for relative motion extension (RME) orthosis with dynamic wrist-hand-finger-orthosis (WHFO) management of zones V-VI extensor tendon repairs.

PURPOSE OF THE STUDY

To determine if RME with wrist-hand-orthosis (RME plus) is noninferior to dynamic WHFO for these zones in clinical outcomes.

STUDY DESIGN

Randomized controlled non-inferiority trial.

METHODS

Skilled hand therapists managed 37 participants (95% male; mean age 39 years, SD 18) with repaired zones V-VI extensor tendons randomized to RME plus (n = 19) or dynamic WHFO (n = 18). The primary outcome of percentage of total active motion (%TAM) and secondary outcomes of satisfaction, function, and quality of life were measured at week-6 and -12 postoperatively; percentage grip strength (%Grip), complication rates, and cost data at week-12. Following the intention-to-treat principle non-inferiority was assessed using linear regression analysis (5% significance) and adjusted for injury complexity factors with an analysis of costs performed.

RESULTS

RME plus was noninferior for %TAM at week-6 (adjusted estimates 2.5; 95% CI -9.0 to 14.0), %TAM at week-12 (0.3; -6.8 to 7.5), therapy satisfaction at week-6 and -12, and orthosis satisfaction, QuickDASH, and %Grip at week-12. Per protocol analysis yielded 2 tendon ruptures in the RME plus orthoses and 1 in the dynamic WHFO. There were no differences in health system and societal cost, or quality-adjusted life years.

DISCUSSION

RME plus orthosis wearers had greater injury complexity than those in dynamic WHFOs, with overall rupture rate for both groups comparatively more than reported by others; however, percentage %TAM was comparable. The number of participants needed was underestimated, so risk of chance findings should be considered.

CONCLUSIONS

RME plus management of finger zones V-VI extensor tendon repairs is non-inferior to dynamic WHFO in %TAM, therapy and orthotic satisfaction, QuickDASH, and %Grip. Major costs associated with this injury are related to lost work time.

The optimal orthosis and motion protocol for extensor tendon injury in zones IV-VIII: A systematic review

STUDY DESIGN

Systematic review INTRODUCTION: There exist numerous combinations of orthoses and motion protocols for the treatment of proximal extensor tendon injuries.

PURPOSE

The purpose of this study was to determine the optimal combination of motion protocol and orthotic treatment for the rehabilitation of proximal extensor tendon injuries (zones IV-VIII).

METHODS

A systematic review of English language randomized clinical trials and cohort studies investigating extensor tendon rehabilitation from 1960 to 2016 was conducted in MEDLINE, Embase, Cochrane, CINAHL, PEDro, and OTseeker. Outcomes of total active motion, grip strength, return to work, patient attrition, and patient-reported outcomes were compared.

RESULTS

Eleven studies of predominantly average quality (1, low; 8, average; and 2, high) were included in the final review. Results were difficult to compare due to differences in reporting. Early total active motion and final grip strength were greater with dynamic extension orthoses (191°-214°; 35-38 kg/89% contralateral side) and relative motion orthoses (205°-236°; 85%-95% contralateral side) compared to static orthoses (79°-202°; 23-34 kg/59% contralateral side). Four studies excluded patients who did not follow up, and loss to follow-up was 12%-33% in the other studies. Patient-reported outcomes were not comparable, as they were only included in 3 studies, and each used a different assessment tool.

CONCLUSION

Average quality evidence supports the use of early active motion (EAM) as the superior motion protocol, but optimal orthosis to deliver EAM could not be determined. Prospective research should focus on patient-reported outcomes and the design of orthoses that facilitate the use of the EAM.

LEVEL OF EVIDENCE

2a.

Outcomes of digital zone IV and V and thumb zone TI to TIV extensor tendon repairs using a running interlocking horizontal mattress technique

PURPOSE

Biomechanical evidence has demonstrated that the running interlocking horizontal mattress (RIHM) repair for extensor tendon lacerations is significantly stronger, with higher ultimate load to failure and less tendon shortening compared with other techniques. We investigated the efficacy and safety of primary extensor tendon repair using the RIHM repair technique in the fingers followed by the immediate controlled active motion protocol, and in the thumb followed by a dynamic extension protocol.

METHODS

We conducted a retrospective review of all patients undergoing extensor tendon repair from August 2009 to April 2012 by single surgeon in an academic hand surgery practice. The inclusion criteria were simple extensor tendon lacerations in digital zones IV and V and thumb zones TI to TIV and primary repair performed using the RIHM technique. We included 8 consecutive patients with 9 tendon lacerations (3 in the thumb). One patient underwent a concomitant dorsal hand rotation flap for soft tissue coverage. We used a 3-0 nonabsorbable braided suture to perform a running simple suture in 1 direction to obtain a tension-free tenorrhaphy, followed by an RIHM corset-type suture using the same continuous strand in the opposite direction. Average time to surgery was 10 days (range, 3-33 d). Mean follow-up was 15 weeks (range, 10-26 wk). We applied the immediate controlled active motion protocol to all injuries except those in the thumb, where we used a dynamic extension protocol instead.

RESULTS

Using the criteria of Miller, all 9 tendon repairs achieved excellent or good results. There were no tendon ruptures or extensor lags. No patients required secondary surgery for tenolysis or joint release. No wound complications occurred.

CONCLUSIONS

The RIHM technique for primary extensor tendon repairs in zone IV and V and T1 to TIV is safe, allows for immediate controlled active motion in the fingers and an immediate dynamic extension protocol in the thumb, and achieves good to excellent functional outcomes. These clinical outcomes support prior biomechanical data.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Managing the injured tendon: current concepts

Despite advances in understanding of the mechanical aspects of tendon management with improved suture technique and early stress application with postoperative therapy, clinical results remain inconsistent after repair, especially within the synovial regions. Complementary research to enhance the intrinsic pathway of healing, suppress the extrinsic pathway of healing, and manipulate frictional resistance to tendon gliding is now the focus of current basic science research on tendons. In the future, application of these new biologic therapies may increase the "safety zone" (or tolerance for load and excursion without dysfunctional gapping) as therapists apply stress to healing tendons and may alter future rehabilitation protocols by allowing greater angles of motion (and thus tendon excursion), increased external load, and decreased time in protective orthoses (splints). However, at this time, the stronger repair techniques and the application of controlled stress remain the best and most well-supported intervention after tendon injury and repair in the recovery of functional tendon excursion and joint range of motion. The hand therapist's role in this process remains a critical component contributing to satisfactory outcomes.

A biomechanical study of extensor tendon repair methods: introduction to the running-interlocking horizontal mattress extensor tendon repair technique

PURPOSE

Extensor tendon injuries are common; however, relatively few studies have evaluated extensor tendon repair methods. The purpose of this study was to investigate the properties of the running-interlocking horizontal mattress repair method with regard to tendon shortening, stiffness, strength, and time needed to perform the repair, compared with the modified Bunnell method and the augmented Becker method.

METHODS

Twenty-four extensor tendons from 8 fresh-frozen cadaveric hands were harvested from zone 6. The harvested tendons were randomly assigned into 1 of 3 repair groups: augmented Becker, modified Bunnell, and running-interlocking horizontal mattress repair methods. The running-interlocking horizontal mattress repair combines a running suture with an interlocking horizontal mattress suture. Each repaired tendon was measured for length before and after repair and tested for stiffness, ultimate load to failure, and time required to perform the repair.

RESULTS

The running-interlocking horizontal mattress repair was significantly stiffer (8,506 N/m) than the augmented Becker (5,971 N/m) and the modified Bunnell (6,719 N/m) repairs. The running-interlocking horizontal mattress repair resulted in significantly less shortening (1.7 mm) than the augmented Becker (6.2 mm) and modified Bunnell (6.3 mm) repairs. The running-interlocking horizontal mattress repair took significantly less time to perform without a significant difference in the ultimate load to failure (running-interlocking horizontal mattress repair, 51 N; augmented Becker, 53 N; modified Bunnell, 48 N).

CONCLUSIONS

The running-interlocking horizontal mattress repair is significantly stiffer and faster to perform than either the augmented Becker or the modified Bunnell repairs, and it results in less shortening than either of these methods. The running-interlocking horizontal mattress repair should be strong enough to withstand some early motion.

Outcome of early active mobilization after extensor tendon repair

BACKGROUND

Traditionally the repaired extensor tendons have been treated postoperatively in static splints for several weeks, leading to formation of adhesions and prolonged rehabilitation. Early mobilization using dynamic splints is common, but associated with many shortcomings. We attempted to study the results of early active mobilization, using a simple static splint, and easy-to-follow rehabilitation plan.

MATERIALS AND METHODS

In a prospective study 26 cases of cut extensor tendons in Zone V to VIII were treated with primary or delayed primary repair. Following this, early active mobilization was undertaken, using an easy-to-follow rehabilitation plan. The results were assessed according to the criteria of Dargan at six weeks and one year.

RESULTS

All the 26 patients were followed up for one year. 20 out of 26 patients were below 30 years of age, involving the dominant hand more commonly (16 patients, 62%). Agriculture instruments were the most common mode of injury (13 patients, 50%). The common site for injury was extensor zone VI (42%, n = 11).

CONCLUSION

Rehabilitation done for repaired extensor tendon injuries by active mobilization plan using a simple static splint has shown good results.

A dynamic extensor brace reduces electromyographic activity of wrist extensor muscles in patients with lateral epicondylalgia

STUDY DESIGN

Semiexperimental study.

OBJECTIVE

To investigate the effect of an external wrist extension force on extensor muscle activity during hand gripping in patients with lateral epicondylalgia.

BACKGROUND

Lateral epicondylalgia or "tennis elbow" is a common, often disabling ailment affecting millions of people. An optimal treatment strategy remains to be identified. The use of an external wrist extension force may reduce the extensor muscle activity during gripping in these patients.

METHODS

Muscle activity of the extensor carpi radialis brevis (ECRB), extensor digitorum communis (EDC), and extensor carpi radialis longus (ECRL) was measured using surface EMG. Subjects gripped at an intensity of 10%, 20%, and 30% of the maximum voluntary contraction (MVC) force with and without the dynamic extensor brace and with and without an applied external wrist extension force of 1%, 2%, and 3% of MVC.

RESULTS

At all levels of MVC gripping, the EMG signal of the ECRB and EDC were significantly lower for gripping with than without brace. An extension force of 3% of the MVC force significantly reduced the EMG signal of all muscles in almost all measurement conditions.

CONCLUSIONS

The results of this study indicate that the dynamic extensor brace as well as the external extension force significantly reduced the EMG signal of the wrist extensor muscles during gripping in patients with lateral epicondylalgia. Based on these results, the dynamic extensor brace could be a promising new intervention for lateral epicondylalgia.

New perspectives on extensor tendon repair and implications for rehabilitation

This article reviews the available biomechanical and clinical studies on extensor tendon repair and postoperative management. Immobilization has been a foundation for the postoperative treatment of these injuries, with good or excellent results ranging between 54% and 95%. However, clinical outcomes have consistently improved when utilizing rehabilitation involving either dynamically assisted or active motion, with good or excellent results achieved in at least 90% of cases. In addition, available biomechanical studies concerning finger extension strength, tendon repair strength, tendon shortening, resultant loss of motion, and gliding capability have validated controlled motion as biomechanically sound utilizing contemporary repair techniques.

The efficacy of splinting for lateral epicondylitis: a systematic review

To determine the efficacy of using splinting as a treatment for lateral epicondylitis (LE), a systematic review of the literature was conducted on Medline, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, PEDro, and Cochrane databases using pertinent key words and phrases. Hand searches of article references were also used to ensure that as many relevant articles as possible were identified. Searches were limited to articles published in English. Articles that did not involve splinting (or terminology derivative thereof) as treatment intervention for LE were excluded. From 98 potential articles, 58 were considered strong inclusion candidates. These articles were copied and further triaged according to predefined criteria, resulting in 22 articles that were numbered randomly and blinded. Three reviewers appraised these articles, eliminating 11 of the articles because they did not meet essential criteria of randomization, control group, and/or inferential statistical analysis. Using MacDermid quality scores, the 11 remaining articles were rated by three reviewers. Consensus between the three reviewers was achieved for all quality scores for all 11 articles included in the review. Adjusted quality scores ranged from 44.5 to 16.5 with a mean of 26.3 points. For accurate comparison and consistency of terminology, splints described in the included articles were first classified according to the ASHT Splint Classification, expanded and refined version, and next according to their inherent material properties. Six splints in five classification categories were identified. Discussion of the results from the 11 included studies was organized according to splint category and further separated into strength, pain, and load applied sections. This review identified one Sackett level 1b study and ten Sackett level 2b studies that offer early positive, but not conclusive, support for the effectiveness of splinting lateral epicondylitis. None of the reviewed studies received a perfect quality score, and the wide range of quality scores attests to the fact that considerable improvement of future studies is essential.

The application of an external wrist extension force reduces electromyographic activity of wrist extensor muscles during gripping

STUDY DESIGN

Experimental repeated-measures study.

OBJECTIVE

To investigate the effect of different extension forces applied to the palm of the hand on electromyographic (EMG) activity of the wrist extensor muscles during hand gripping.

BACKGROUND

Lateral epicondylitis is usually caused by repetitive wrist extension that leads to an overuse injury. The current theory is that the process of lateral epicondylitis begins with an overuse injury that leads to microtearing of the extensor carpi radialis brevis muscle and occasionally the extensor digitorum communis muscle. Use of an external wrist extension force might reduce muscle activity during gripping.

METHODS

Muscle activity was measured using surface EMG while subjects gripped at an intensity of 10%, 20%, and 30% of the maximum voluntary contraction force without, and with, an applied external wrist extension force of 1%, 2%, and 3% of maximum voluntary contraction.

RESULTS

Applying an extension force to the palm of the hand reduced EMG activity of the extensor muscles at the same strength generation during hand gripping. The muscles with the most significant reduction in EMG level, the extensor carpi radialis brevis and extensor digitorum communis, are those muscles that are most often involved with lateral epicondylitis.

CONCLUSIONS

This study shows that an external extension force reduces EMG activity of the wrist extensor muscles during gripping in healthy volunteers. As the extension force increased, a greater reduction in muscle activity was noted.

Dynamic splinting after extensor tendon repair in zones V to VII

This retrospective study evaluates a dynamic active motion protocol for extensor tendon repairs in zones V to VII. Fifty-eight patients with 87 extensor tendon injuries were examined. Using Geldmacher's and Kleinert and Verdan's evaluation systems, the results were graded as "excellent" and "good" in more than 94%, and as "satisfactory" in the remainder. The need for secondary tenolysis was low (6%), and no other surgical complication occurred.

Splinting programmes for tendon injuries

It is beyond doubt that splinting programmes have often been an integral and important part of the rehabilitation process in tendon injuries. Over the past three decades, hand splints for tendon injuries of various designs and different mobilisation programmes have been developed in the hope of pursuing better clinical and functional outcome for patients. In this paper, the development of different splinting programmes in flexor and extensor tendon injuries and the current practice in some acute hospitals in Hong Kong were discussed.

Early protected motion after extensor tendon repair

Thirty hands with 50 extensor tendon lacerations, excluding mallet finger injuries, were examined. They were treated with surgical repair followed by immediate motion which included a dynamic splinting and tendon mobilization program. The average follow-up period was 7 months (range, 8 weeks to 2 years). Forty-five of the 50 tendons regained full range of motion (average total active motion, 262 degrees) within an average time of 9 weeks; the remaining 5 tendons had extension lags of < or = 10 degrees. All patients regained at least 93% of their predicted normal strength within 9 to 12 weeks and returned to their previous level of activity in an average of 10 weeks. These results, which include complex lacerations, are an improvement from previously published data. This is probably due to the addition of a tendon mobilization program to dynamic splinting following extensor tendon repair.

The effect of use of a wrist orthosis during functional activities on surface electromyography of the wrist extensors in normal subjects

Wrist orthoses are advocated for patients with lateral epicondylitis on the assumption that use of the orthosis decreases muscle activity of the wrist extensors during activities. The purpose of this study was to compare the amount of electrical activity, root mean square (RMS) calculated from surface EMG recorded over the wrist extensors, during activities when applying four conditions of wrist orthoses: dorsal; volar; semicircular; and no orthosis. Thirteen normal subjects (mean age 27.7 years) performed three lifting and two gripping tasks, repeated on three consecutive days under four orthotic conditions. Measured were RMS and maximum voluntary grip strength. Repeated measures ANOVA's indicated a significant decrease of RMS using the semicircular design during lifting (p < .0005). Grip strength decreased significantly using all three orthotic designs, but RMS recorded during gripping did not. It was concluded that application of a wrist orthosis reduces electrical activity of the wrist extensors less than anticipated and only during lifting.

Extensor Tendon Injuries in the Hand

Until recently, extensor tendon injuries were often discounted as an important hand problem. However, studies have shown that not all extensor lacerations fare well and that loss of flexion can be problematic. Newer postoperative protocols emphasizing tendon gliding have improved results, and better repair techniques and postoperative rehabilitation regimens are under investigation. This article reviews the evaluation of acute open and closed extensor tendon injuries, their conservative and surgical treatment, and postoperative rehabilitation options.

Activity of the extrinsic finger flexors during mobilization in the Kleinert splint

This study investigated the activity of the extrinsic finger flexor muscles during active extension in the Kleinert splint. Electromyographic data on the activity of the profundus and superficialis flexor muscles in 10 healthy subjects were recorded with use of fine needle electrodes. The subjects exercised in the original Kleinert splint as well as in several modifications of the splint, which varied with respect to (1) wrist position, (2) position in which extension of the metacarpophalangeal joint was blocked, (3) number of fingers dynamically splinted, (4) nature of the spring mechanism, (5) amount of resistance, and (6) use of a palmar pulley. Persistent flexor muscle activity during active extension was observed in the majority of subjects. This coactivity was more often observed for the superficialis muscle than for the profundus muscle. The least amount of coactivity was found when extension was least resisted. This study does not support the concept that the flexor muscles relax during resisted extension in the Kleinert splint.

The application of force to the healing tendon

This paper redefines the term "active motion" in postoperative tendon management programs as "minimal active muscle-tendon tension" (MAMTT), and reports a study of internal forces applied to a repaired tendon with MAMTT, with specific guidelines for joint angle and external load application, that allows a repeatable and reliable technique for the application of active stress to a healing tendon repaired with some currently available popular suture techniques. A comparative analysis of the reported tensile strengths of 28 different repair techniques comparing methods of study with conversion of newtons to grams provides the therapist easy access to a workable equation for force application being less than the tensile strength of any specific repair. The "active" hold position or MAMTT for the digital flexor system is calculated mathematically, with drag eliminated, and joint angle position of 45 degrees wrist extension, metacarpophalangeal joint flexion of 83 degrees, proximal interphalangeal joint flexion of 75 degrees, and distal interphalangeal joint flexion of 40 degrees, and an external load applied at the fingertip of 50 grams. In this position, the internal force on the flexor digitorum profundus is 41 grams, and that on the flexor digitorum superficialis is 605 grams. These forces dramatically increase as joint angles become greater, creating forces that exceed the tensile strengths of most repairs. Internal forces along the extensor system are calculated mathematically at approximately 300 grams when the wrist is positioned at 20 degrees of flexion, and the digital joints at a position of 0 degrees of extension in an active hold position. Postoperative management of the repaired flexor or extensor tendon with immediate active motion described as MAMTT is supported by a clinical review of 165 tendons treated with this technique.

[Protected early mobilization using Levame's device after primary repair of the extensor tendons of the hand. Apropos of a series of 88 cases]

Seventy patients with 88 lesions of the hand extensor apparatus were treated by primary repair followed by post-operative mobilisation with a dynamic steel blade splint (Levame). Results were good or very good in 97.7% of cases and moderate in 2.3% of cases for this series of simple lesions from zones 3 to 6. Prognostic factors influencing final result and wrist position during splint are discussed, the authors leave the wrist free for lesions in zone 3 and 4. Early mobilisation is the best treatment for tendinous lesions and a review of the literature confirms the validity of the author's choice. In spite of its biomechanical deficiencies, this simple technique may be used for non-disciplined patients and by non-specialized physiotherapists. For simple lesions of extensor tendons, the Levame splint may be considered as a real dynamic protective splint.

Biomechanical characteristics of extensor tendon suture techniques

Despite their ease of exposure, extensor tendons can be difficult to handle and suture well. Compared with flexor repair, little is known about the various factors that affect the suturing of extensor tendons. The present study was designed to investigate several biomechanical parameters involved in extensor repair. All techniques studied shortened the tendon considerably and produced significant losses of flexion at the metacarpophalangeal and proximal interphalangeal joints. In addition, repairs achieved with all suture techniques were considerably weaker than those achieved when comparable techniques were used on flexor tendons. However, the Kleinert modification of the Bunnell technique provided the strongest sutures in extensor tendons, produced no gapping, caused the least worrisome loss of metacarpophalangeal and proximal interphalangeal flexion, and best approximated the results found in an idealized tendon-shortening model.