Lateral elbow tendinopathy

Effectiveness of eccentric strengthening in the treatment of lateral elbow tendinopathy: A systematic review with meta-analysis
By Todd Hargrove

Key Points
1. Eccentric strengthening of the wrist extensors was found to be more effective than other strengthening protocols in the treatment of lateral elbow tendinopathy (LET).
2. Further research is needed to clarify the optimal dosage and progression of eccentric strengthening to manage LET.

BACKGROUND AND OBJECTIVE
Lateral elbow tendinopathy (LET) is a common condition in the upper limb, affecting up to 3% of the population annually. Eccentric strengthening has shown promise as a method to treat LET. Accordingly, the authors of this paper performed a meta-analysis to help determine whether eccentric strengthening is superior to other forms of strengthening and pain-relieving modalities for managing LET.

METHODS
Five electronic databases were searched.
The authors found 8 studies involving 564 participants that met the inclusion criteria.
A meta-analysis was performed using a random effects model with standardized mean differences, test of heterogeneity, and sensitivity analysis.

RESULTS
Most of the studies compared eccentric strengthening with other forms of strengthening. The eccentric strengthening programs generally

Too much rest can make tendon degeneration worse, therefore healing requires proper loading.

used 3 sets of 10-15 repetitions, and lasted between 3 and 12 weeks. All studies used a visual analogue scale (VAS) as an outcome measure for pain, and most used grip strength as a measure of function.

In the short term, eccentric strengthening was more effective than other methods in reducing pain and improving function. The long-term results were inconclusive. The authors also noted that studies with supervised exercise had larger effect sizes than those with home exercise.

The included studies did not provide adequate detail on intensity and progression of load over time. Many studies ceased exercise before 6-12 weeks, which is probably the minimum time frame necessary to allow tissue healing and positive tendon adaptation.

The authors concluded that an eccentric strengthening program with adequate intensity and duration may be the most effective treatment method for LET, and that more research is needed to determine proper dosage.

Lateral elbow tendinopathy affects up to 3% of the population annually.

Example of eccentric strengthening exercise

LIMITATIONS
In several studies, other therapies were used in addition to eccentric strengthening, such as icing, joint mobilization, and ultrasound. This does not allow us to isolate the effect from eccentric strengthening alone. Furthermore, there was substantial heterogeneity among the included studies, making comparison difficult.

CLINICAL IMPLICATIONS
LET affects 3% of the population annually (1). The primary symptom is pain at the lateral epicondyle during activities that require contraction of the extensor muscles of the forearm. Pain may radiate downward from the elbow, affecting grip strength and functional hand use (2).

Tendinopathy occurs when the tendon is loaded excessively without adequate recovery. As a result, the tendon degenerates, causing collagen fibre misalignment, increased cellularity, and revascularization (3, 4). These changes weaken the tendon structure, leading to increased risk of rupture.

Too much rest can make tendon degeneration worse, therefore healing requires proper loading. Tendons can be loaded through isometric, concentric or eccentric muscle contractions. Eccentric loading may be especially good at stimulating adaptive tissue remodelling at the musculotendinous junction. It may also be able to elongate the muscle-tendon unit, which could reduce tension on the tendon.

Based on the results from this study and other trends in the literature, the authors recommend eccentric strengthening for LET with 3 sets of 10 to 15 repetitions, and with pain no greater than 5/10 on VAS, for a period of at least 6 weeks.
1. Walker-Bone K, Palmer KT, Reading I, Coggon D, Cooper C. Prevalence and impact of musculoskeletal disorders of the upper limb in the general population. Arthritis Rheum. 2004;51(4):642e651.
2. Ahmad Z, Siddiqui N, Malik SS, Abdus-Samee M, Tytherleigh-Strong G, Rushton N. Lateral epicondylitis: a review of pathology and management. Bone Joint J. 2013;95 B(9):1158e1164.
3. Riggin CN, Morris TR, Soslowsky LJ. Tendinopathy II: Etiology, Pathology, and Healing of Tendon Injury and Disease. Academic Press. Boston: Academic Press; 2015:149e183.
4. Ashe MC, McCauley T, Khan KM. Tendinopathies in the upper extremity: a paradigm shift. J Hand Ther. 2004;17(3):329e334.