LATERAL EPICONDYLITIS
is eccentric exercise an effective treatment for lateral epicondylitis? A systematic review
- Mark G Boocock, AUT University, 90 Akoranga Drive, North Shore, Auckland 1142, New Zealand. Email: mark.boocock@aut.ac.nz
Abstract
Objective: To establish the effectiveness of eccentric exercise as a treatment intervention for lateral epicondylitis.
Data sources: ProQuest, Medline via EBSCO, AMED, Scopus, Web of Science, CINAHL.
Review methods: A systematic review was undertaken to identify randomized and controlled clinical trials incorporating eccentric exercise as a treatment for patients diagnosed with lateral epicondylitis. Studies were included if: they incorporated eccentric exercise, either in isolation or as part of a multimodal treatment protocol; they assessed at least one functional or disability outcome measure; and the patients had undergone diagnostic testing. The methodological quality of each study was assessed using the Modified Cochrane Musculoskeletal Injuries Group score sheet.
Results: Twelve studies met the inclusion criteria. Three were deemed ‘high’ quality, seven were ‘medium’ quality, and two were ‘low’ quality. Eight of the studies were randomized trials investigating a total of 334 subjects. Following treatment, all groups inclusive of eccentric exercise reported decreased pain and improved function and grip strength from baseline. Seven studies reported improvements in pain, function, and/or grip strength for therapy treatments inclusive of eccentric exercise when compared with those excluding eccentric exercise. Only one low-quality study investigated the isolated effects of eccentric exercise for treating lateral epicondylitis and found no significant improvements in pain when compared with other treatments.
Conclusion: The majority of consistent findings support the inclusion of eccentric exercise as part of a multimodal therapy programme for improved outcomes in patients with lateral epicondylitis.
- Exercise programme
- eccentric exercise
- tennis elbow
- lateral epicondylitis
- rehabilitation
- systematic review
Introduction
Lateral epicondylitis is a disabling musculoskeletal condition leading to pain and/or tenderness around the elbow.1 It is estimated to affect up to 3% of the population and have significant personal, psychosocial, and economic consequences.1,2 Many treatment options have been proposed for the rehabilitation of patients with lateral epicondylitis, the effectiveness of which are largely unknown. These include exercise, massage, manipulation, taping, acupuncture, orthotic devices, ultrasound, activity modification, and rest.3⇓⇓–6 Identifying an effective treatment programme for patients with lateral epicondylitis would have significant benefits for patient recovery and for the delivery of an improved service by healthcare providers.7
Exercise programmes incorporating eccentric muscle activity are becoming increasingly popular as they are considered to provide a more effective treatment than other forms of exercise therapy.8,9 At present, the role of eccentric exercise in the treatment of lateral epicondylitis is not entirely clear. A systematic review by Malliaras et al.10showed promising results in support of eccentric exercise as a treatment for lateral epicondylitis, however the review sourced only one electronic database, was restricted to four articles and failed to consider the methodological quality of each study.
The aim of this systematic review was to investigate the effectiveness of eccentric exercise as a physical therapy intervention for patients with lateral epicondylitis.
Methods
Six electronic databases were searched (ProQuest, Medline via EBSCO, AMED, Scopus, Web of Science, and CINAHL). Existing systematic reviews and major publications on lateral epicondylitis were sourced to identify appropriate search terms. The search strategy combined terms appropriate to: the condition (lateral epicondylitis, lateral epicondyle, lateral epicondylalgia, tennis elbow, elbow tendinopathy), the therapy goal (intervention, management, treatment, rehabilitation), and the intervention (physiotherapy, physical therapy, exercise, strengthening, eccentric and resistance). The search protocol used on the Scopus database is provided at Appendix A (available online). The search was completed on 26 February 2013 (Figure 1).
Figure 1.
A flow-chart of the methodology used in this review.
An initial review was undertaken of all titles and abstracts. All articles considered appropriate were read in full to establish if they met the eligibility criteria. Where it was unclear from the abstract about the suitability of the study, the full article was retrieved and read. Only randomized control studies or controlled clinical trials were included in the review, and studies had to include:
- at least one treatment programme involving an eccentric exercise therapy, either exclusively or in conjunction with other treatments;
- patients who had undergone a diagnostic test for lateral epicondylitis, or had been diagnosed by a General Practitioner; and
- at least one functional or disability outcome measure.
Studies were excluded if patients had received corticosteroid injections prior to the intervention or as part of the treatment or comparative therapy. Only articles published in English were included in the review.
The methodological quality of those studies meeting the inclusion/exclusion criteria was assessed using the Modified Cochrane Musculoskeletal Injuries Group score sheet (Appendix B, available online).11 The Modified Cochrane Musculoskeletal Injuries Group score sheet comprises 13 questions, scored between zero and two (maximum score of 26), which assesses aspects of study design and outcome measures. At least two independent reviewers assessed and scored each article. Where there was disagreement over the quality rating of a study, discussions took place between the two reviewers to reach a consensus. Each study was rated as either ‘low quality’ (with a Cochrane Musculoskeletal Injuries Group score of less than or equal to 12), ‘medium quality’ (a score greater than 12, but less than 18), or ‘high quality’ (a score equal to or greater than 18). The cut-off points for each level of grading were based on the overall distribution of scores.
Results
A flowchart of the selection process used to identify studies is shown in Figure 1. Of the 392 articles, 32 underwent a full-text review, of which 12 met the inclusion criteria. One article12 identified two studies (a pilot study and a clinical study) within the one article, but only the pilot study met the criteria for this review. The important characteristics of each study (e.g. the number of participants, and the treatment and comparison groups) were extracted from each article and tabulated (Tables 1 and 2). Details of the eccentric exercise programmes (e.g. exercise, frequency, duration) are shown in Tables 3 and 4.
Table 1.
The main characteristics of the randomized trials included in the review.
Table 2.
The main characteristics of the controlled clinical trials included in the review.
Table 3.
The exercise parameters of the eccentric programmes used in the randomised trials.
Table 4.
The exercise parameters of the eccentric programmes used in the controlled clinical trials.
The 12 studies involved 616 participants consisting of 336 females and 280 males. A total of 326 participants underwent eccentric exercise as part of their rehabilitation. None of the 12 studies provided rationale for the exercise parameters used in their treatment programmes. All 12 studies used a visual analogue scale as an outcome measure for pain, and eight studies12,14⇓⇓–17,20,21,23 measured grip strength (Tables 1 and 2). Seven studies14⇓⇓⇓⇓⇓–20 used a variety of questionnaires to measure function and/or disability (Tables 1 and 2).
Of the 12 studies, two13,22 were considered to be ‘low’ quality, seven12,14⇓⇓⇓–18,20were ‘medium’ quality, and three19,21,23 were ‘high’ quality (Table 5, available online). Eight studies12⇓⇓⇓⇓⇓⇓–18,23 were randomized trials and four studies19⇓⇓–22 were controlled clinical trials. According to the intervention and comparison treatment, studies were grouped into four categories: (1) isolated eccentric exercise programme versus different therapies, (2) eccentric exercise and adjunct therapies versus the same adjunct therapies, (3) eccentric exercise and adjunct therapies versus different therapies, and (4) identical eccentric exercise programmes with different study parameters.
Only one low-quality study13 (Cochrane Musculoskeletal Injuries Group Score of 11 out of 26) investigated the effects of an isolated eccentric exercise programme on pain levels. The eccentric exercise group and control group both reported a significant reduction in pain from baseline at the four-week follow-up (p < 0.01). However, no significant difference existed between the groups at week four (p > 0.05). This suggests that an isolated eccentric exercise programme offered no greater benefits for improving pain in patients with lateral epicondylitis when compared with a programme of iontophoresis, ultrasound, and stretches.
Four studies exposed participants to the same therapies, while adding an eccentric exercise programme to one group (Tables 1 and 2). All four studies reported improvements in outcome measure from baseline in both groups. Of these, two high-quality studies (Cochrane Musculoskeletal Injuries Group Score of 18 out of 1619 and 20 out of 2623) and one medium-quality study (Cochrane Musculoskeletal Injuries Group Score of 15 out of 2615) found that the addition of eccentric exercise led to greater reduction in pain, disability, and/or improvement in grip strength compared with the same adjunct therapies exclusive of eccentric exercise. However, one medium-quality study (Cochrane Musculoskeletal Injuries Group Score of 16 out of 2614) found no difference in three functional-related measures, grip strength, and pain when eccentric exercise was added to the adjunct treatment (i.e. stretches).
Five medium-quality studies (Cochrane Muscu-loskeletal Injuries Group Score of 16 out of 26,16 14 out of 26,12 14 out of 26,17 16 out of 26,20 and 18 out of 2618) found that eccentric exercise when combined with adjunctive therapies resulted in significant improvements in pain, function, and grip strength from baseline (Table 1). Four12,17,18,20 of the five studies showed improved benefits of the multimodal treatment programme inclusive of eccentric exercise when compared with different therapy treatments. However, one study16 found that the eccentric exercise and adjunct therapies were less effective than a Cyriax therapy programme exclusive of eccentric exercise.
One high-quality study (Cochrane Musculoskeletal Injuries Group Score of 20 out of 2621) and one low-quality study (Cochrane Musculoskeletal Injuries Group Score of 12 out of 2622) exposed participants to the same eccentric exercise programmes, but altered another aspect of the treatment programme (Table 1). The low-quality study22showed the addition of ice to the eccentric exercise programme offered no additional improvements in pain, and the one high-quality study21 comparing a regularly supervised physiotherapy group with an unsupervised home programme group found significantly decreased pain and improved function at 24 weeks in the supervised group compared with the unsupervised group. Both studies found improvements in pain and function from baseline in all eccentric exercise programmes.
Discussion
This systematic review found that patients with lateral epicondylitis who underwent an eccentric exercise programme, either in isolation or as an adjunct to other therapies, decreased pain and improved function and grip strength in comparison to their baseline measures. Seven out of the nine studies that involved eccentric exercise as part of a multimodal therapy programme showed improved outcomes for pain, function, and/or grip strength in comparison to other combined treatment programmes. The one study that investigated isolated eccentric exercise found no significant improvements in pain when compared with a multimodal treatment programme. However, this study was considered to be of low quality. Overall, the majority of consistent findings support the inclusion of eccentric exercise as part of multimodal therapy programme for improving outcomes in patients with lateral epicondylitis. Findings from this review are in contrast with the systematic review by Woodley et al.9 that found limited evidence that eccentric exercise has a positive effect on pain, function, and patient satisfaction/return-to-work when compared with other treatment interventions. However, their findings were based on three randomized controlled trials, one of which was deemed to be of low quality.
A systematic review by Raman et al.8 found ‘moderate research evidence’ to support isotonic eccentric exercise for improving pain, strength, and function over time. However, findings appeared inconclusive as to the additional benefits of eccentric exercise when added to an existing multimodal treatment programme and compared with other forms of treatment.
As in Raman et al.’s8 review, we chose to exclude those studies that incorporated steroid injections immediately prior to, or as part of, the treatment programme. Steroid injections have been found to have significant short-term effects on pain, function, and grip strength when compared with other physiotherapy treatments.17,24
This review is not without its limitations. Of the 12 studies included in the review, only three19,21,23 were of high quality and only eight12⇓⇓⇓⇓⇓–18,23 involved randomized controlled trials. The most common methodological weakness was the lack of blinding of participants and treatment providers, with all studies scoring zero for question F and 11 studies scoring 0 for question E on the quality scoring sheet (Table 5, available online). The blinding of participants and therapists to the exercise therapy intervention is problematic and remains a challenge in studies of this nature.
Given that 11 of the studies incorporated eccentric exercise programmes alongside other therapy treatments, it is difficult to infer whether the effects observed are solely owing to the eccentric exercise, or stem from the combined effects of the treatment protocols. However, multimodal treatment protocols are reflective of real world practice.25
As none of the 12 studies had control groups who did not participate in any form of treatment, it is not known what affect the natural healing process had on recovery. There is evidence to suggest that some patients with lateral epicondylitis do recover within 12 months without treatment.25 However, given the pain and loss of function that this condition causes, it would be difficult to find individuals with lateral epicondylitis who had not sought some form of treatment.
The wide variation of diagnostic criteria used across the 12 studies reflects the lack of consensus regarding lateral epicondylitis classification.6 This is of concern, as conditions such as radial nerve entrapment, radius fractures, or neck dysfunctions have a similar clinical presentation to lateral epicondylitis, such as tenderness in close proximity to the lateral epicondyle, and pain in the upper forearm muscles.26 This highlights the need for a consensus on the diagnostic criteria for lateral epicondylitis and a set of agreed clinical assessment criteria based on well-defined methodological approaches (e.g. consensus based on an expert opinion or statistical modelling), similar to those proposed by Boocock et al.27
The failure to accurately report exercise protocols and the substantial variation in exercise parameters made it difficult to assess the effectiveness of each study’s ability to isolate an eccentric exercise component and provide a progressive muscle stimulus (Tables 3 and 4). For example, Martinez-Silvestrini et al.14 describes in detail the use of the contralateral hand to lengthen the resistance band at the end of each eccentric exercise repetition in order to exclude a concentric component of the exercise, whereas Pienimaki et al.17 only offered one pictorial explanation of the eccentric component and failed to mention aspects of the concentric element of the exercise. In the study by Wen et al.,13 the contralateral hand was the only procedure used to provide resistance during the exercise. This method is likely to be highly variable and unlikely to provoke a progressive increase in resistance over the duration of the therapy treatment. Progressively increasing the intensity of exercise is considered an important component of an exercise programme to promote the necessary stimulus required for tendon healing.28
A major concern across the studies was the lack of reporting of compliance and adherence to the exercise programmes, with only four studies20,21,22,23 documenting exercise adherence. Evidence from the literature29 suggests that compliance and adherence are important mediators impacting the effectiveness of an exercise programme, along with psychosocial factors, such as low-efficacy and poor social support. Also, it cannot be assumed that improvements were sustained as only three studies followed participants beyond 24 weeks.12,20,21 This is disappointing, given the high recurrence rate of lateral epicondylitis.25
Pain, grip strength, and functional and disability measures were the primary outcome measures reported by studies. However, measurement methods varied widely and there was often insufficient data from which to estimate effect sizes arising from the treatment protocols. Few studies reported on sample size or the statistical power of their study.
The findings of this review are important to clinicians and other healthcare providers given the direct and indirect costs associated with the rehabilitation of patients with lateral epicondylitis.1,2 Exercise programmes prescribed by therapists and which can be performed at home30 are inexpensive and have limited ongoing costs attached to the treatment. As the study by Stasinopoulos et al.21 reported, supervision is important to ensure ongoing adherence and the effective implementation (i.e. progressions, frequency, and performance) of a physical therapy treatment programme.
This review found no adverse effects arising from the prescription of eccentric exercise as a treatment for lateral epicondylitis. The absence of adverse effects, coupled with evidence of improved pain and function recovery in comparison to other treatment therapies, lends support to the inclusion of eccentric exercise within a multimodal treatment programme for the rehabilitation of patients with lateral epicondylitis. The standardisation of lateral epicondylitis diagnostic testing and clearly defined eccentric exercise parameters should be a priority for future research. Studies should also consider the long-term effectiveness of these exercise programmes.
Clinical messages
- Eccentric exercise, used in isolation or as an adjunctive therapy, decreases pain and improves function in lateral epicondylitis patients when compared with baseline.
- When compared with other treatment therapies, evidence supports the use of multimodal treatment programmes inclusive of eccentric exercise for improving pain and function in lateral epicondylitis patients.
Article Notes
- Conflict of interest The authors are responsible for the content and writing of this article. The authors declare that there is no conflict of interest.
- Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
- Received April 29, 2013.
- Accepted April 30, 2013.
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