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Lateral Epicondylosis

Emerging Management Options

Thompson, Carolyn DO; Visco, Christopher MD

Current Sports Medicine Reports: May/June 2015 - Volume 14 - Issue 3 - p 215–220
doi: 10.1249/JSR.0000000000000162
Training, Prevention, and Rehabilitation: Section Articles
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Lateral epicondylosis is one of the most prevalent disorders of the arm and results in significantly decreased function among the workforce and athletes. Historically, the disorder has been diagnosed clinically and treated as an inflammatory entity. Management strategies have included anti-inflammatory medications and techniques, including oral nonsteroidal anti-inflammatories, injected corticosteroid, and physical therapy with modalities. More recent literature postulates a degenerative or compressive etiology, directing some clinicians to try new, more regenerative management strategies such as platelet-rich plasma and stem cell injections. To date, literature evaluating these new treatment methods has shown positive results, although no definitive conclusions can be drawn. More research is needed to evaluate these new treatment methods, and a new look at the diagnosis of the disorder with ultrasound imaging may be reasonable to consider.

Department of Rehabilitation, NewYork-Presbyterian Hospital Columbia and Cornell, Columbia University Medical Center, New York, NY.

Address for correspondence: Christopher J. Visco, MD, Department of Rehabilitation, NewYork-Presbyterian Hospital Columbia and Cornell, Columbia University Medical Center, New York, NY; E-mail: cv2245@cumc.columbia.edu.

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Introduction

Lateral epicondylosis is one of the most prevalent disorders of the arm and results in decreased function and productivity in the workplace (55). Shiri et al. (55) reviewed the Finnish National Health examination survey of 4,698 patients and found no gender predominance for lateral epicondylosis and the prevalence was highest in patients aged 45 to 54 years. Overall prevalence in that population was 1.3%, although numbers have been as high as 30% in some working populations (25). Development of lateral epicondylosis is associated with both current and former smoking as well as type 2 diabetes mellitus. Work tasks requiring handling of 1-kg tools or 20-kg loads, lifting for >3% of time, or repetitive movements >2 h·d−1 have been associated with lateral epicondylosis (25,31,55,61). Traditionally referred to as “tennis elbow,” the rate of lateral elbow pain has not been demonstrated to be increased specifically in tennis players, although the association with repetitive gripping could support some increased risk for those that play racket sports or any sport requiring repeated or prolonged gripping. Psychosocial factors such as low job control or social support also have been associated with the disorder (61). Additionally, lateral epicondylosis contributes to loss of work productivity, as up to 5% prolonged sickness absences have been attributed to the disorder (62). Symptoms may last from 6 months up to 2 years, with most patients “completely recovered” or “much improved” within 12 months with a “wait and see” conservative management approach (57). Given the prevalence and breadth of available interventions, practitioners caring for those with musculoskeletal disorders should be aware of the current management of lateral epicondylosis.

Lateral epicondylosis presents as pain on or around the lateral epicondyle, with or without radiation distally to the forearm or proximally to the lateral upper arm. Patients generally complain that pain is worse with activities involving wrist extension or activation of the common extensor mass (1). Chronic progression can result in constant pain that occurs at rest. Physical examination results typically reveal no changes upon inspection, except in cases where there is common extensor mass atrophy due to tendon tearing or muscle atrophy after corticosteroid injection (1). In most cases of lateral epicondylosis, there is tenderness over the extensor carpi radialis brevis (ECRB) attachment, lateral epicondyle, and/or the common extensor mass. There may be a palpable change in the enthesis on the affected side, particularly a fullness or firmness in chronic cases. Pain can be reproduced with resisted wrist extension with pronation and radial deviation (Cozen test), passive wrist flexion (Mill test), or directly activating the extensor digitorum communis (Maudsley test) by resisted third digit extension (24). This latter maneuver reveals an update in the understanding of the anatomy of the region, as the slip of the extensor digitorum communis inserting into the third digit may be the only slip to originate from the lateral epicondyle.

Differential diagnosis of lateral elbow pain is broad and includes impingement of radial plica, radiocapitellar articular pain, radial collateral ligament injury, distal biceps pathology, elbow instability, anconeus syndrome, mononeuropathy of deep radial nerve as it passes through the two heads of the supinator, posterior interosseus nerve syndrome, radial tunnel syndrome, lateral antebrachial neuralgia, brachial plexopathy, or cervical radiculopathy. The clinician considering the diagnosis of lateral epicondylosis should consider these alternatives, as the diagnostic evaluation and management will differ for each. Ultimately, the diagnosis of lateral epicondylosis is clinical, without specific objective diagnostic criteria based on imaging or laboratory testing. However, additional imaging of adjacent areas may be helpful in some cases, building evidence for the diagnosis or ruling out other causes in this differential. Specifically, radiographs of the elbow may help evaluate for osteoarthritis. Diagnostic ultrasound may help evaluate the proximal tendon attachment, as tendinopathic changes may be seen, including loss of normal fibrillar architecture, thickening, and hypoechoic appearance (40). Adjacent structures may be assessed, such as the radiocapitellar joint, capsule, radial collateral ligament, and distal biceps. The use of ultrasound-guided diagnostic injections to these structures can be useful in narrowing the differential in search for the primary pain generator. Electrodiagnostic testing also can help evaluate for the presence of cervical radiculopathy in the C5 or C6 distribution or other brachial plexus lesion that can cause lateral elbow pain localized to the upper trunk or lateral cord.

Until recent years, lateral epicondylosis was thought to be an inflammatory process, termed “lateral epicondylitis,” and treatment was aimed at combating this presumed inflammatory process. Conservative treatment has historically included rest, activity modification, nonsteroidal anti-inflammatory drugs (NSAID), and physical therapy. A review of the literature including an update on treatments for lateral elbow pain resulted in no firm conclusions regarding the benefit of using oral or topical NSAID (9). Outcomes included pain, function, quality of life, pain-free grip strength, overall treatment success, work loss, and adverse events. The review found that while topical NSAID may improve pain for up to 4 wk, evidence is of low quality (9). Similarly, definitive conclusions for use of oral NSAID could not be ascertained due to low-quality evidence, and adverse gastrointestinal effects were reported frequently (9,48). COX-2 inhibition has been linked to central pain inhibition and may be contributory to the benefit seen with NSAID (4).

Injected corticosteroids have been shown to result in improvement in outcome measures such as pain, grip strength, function, and work status in the short term but have mixed results for pain relief in long-term studies (21). Several reviews and meta-analyses have shown that beyond 8 to 12 wk, glucocorticoid injection is no more effective than placebo (7,21,38,39). Two studies actually showed that at 1 year, patients who received corticosteroid actually had worse outcomes than placebo or “wait and see” (20). One study has shown that any improvement past 12 wk is comparable with topical corticosteroid delivered by iontophoresis (58). Stefanou et al. (58) showed that both the injected and topical corticosteroid resulted in statistically significant decreases in pain and increase in grip strength at 6 months. Additionally, the topical group showed statistically significant improvement in work status at 6 months (58). However, neither the patients nor the investigators were blinded to the treatment in this study, and the topical medication was delivered over 24 h, rather than the traditional 20- to 60-min period.

In studies where patients have experienced short-term improvement in pain, there is little consensus for type or volume of corticosteroid or proper location for injection, as studies have not been consistent in their methods and no study to date has compared these variables. Multiple authors have proposed that the short-term pain relief experienced by patients receiving corticosteroid injections may relate to corticosteroid ability to inhibit pain-modulating neurotransmitters such as glutamate. Alfredson (2) has shown that glutamate is abundant at sites of enthesopathy, even though no inflammatory cells are present. If glutamate and its receptors are blocked temporarily by corticosteroid, only short-term pain relief can be expected with injection.

In addition to injected corticosteroids and NSAID, physical therapy has traditionally been a mainstay of treatment for lateral epicondylosis. Bisset’s (9) systematic review and others have shown that strengthening with stretching may be more effective than treatments such as ultrasound in the short term, although with low-level evidence (9,32). There has been a focus on eccentric exercise predicated on Alfredson’s (2) work that suggests that progressive loading is required to increase strength (50). Studies have shown mixed results regarding eccentric training in lateral epicondylosis. Eccentric exercise has been shown to increase grip strength and decrease pain, although with inconsistent statistically significant results. No definitive recommendations supporting eccentric exercise can be made based on the current literature.

Adjunctive modalities such as laser therapy, transcutaneous electrical nerve stimulation (TENS), acupuncture, and orthotics also have been attempted with limited evidence. A large review analyzing nine placebo-controlled studies with over 1,000 subjects concluded that shock wave therapy provides little to no benefit in either pain or function for lateral elbow pain (12). Similarly, in one randomized trial of more than 200 subjects, TENS did not provide additional benefit when used as an adjunct to conservative care (17). Acupuncture has shown short-term pain improvement but no long-term improvement over placebo, with a more recent Cochrane review citing insufficient evidence to support or refute the use of this treatment modality (28). There is limited literature on the use of orthoses such as counterforce braces, with low-quality methodology and small sample sizes, from which some short-term pain relief was shown, but no conclusive evidence supports long-term benefit (33,53). Botulinum toxin has been attempted to decrease pain associated with lateral epicondylosis. Literature on this treatment is limited with mixed results, and the associated adverse effect of weakness may be intolerable (34).

More recent literature postulates that the pathology is in fact more of a degenerative process where the deep portion of the ECRB tendon, after repeatedly sliding along the lateral edge of the capitellum during elbow flexion and extension, can form microtears (20,39). With the relative paucity of vasculature at the tendon’s undersurface, this repetitive microtrauma is thought to contribute to eventual tendinosis (20). An additional postulated theory suggests that a compressive load may enhance the development of tendinotic changes. Gripping with repeated supination and pronation leading to lateral epicondylosis may lead to excessive compressive load at the common extensor tendon (19). In light of these recent findings, attempts at regenerative treatments have been made primarily using platelet-rich plasma (PRP), although topical nitric oxide, prolotherapy, needle tenotomy, whole blood injection, and stem cell injections also have been used.

Some clinicians have attempted use of topical glyceryl trinitrate (GTN) in treatment with the goal of bringing increased blood flow to the degenerative area; however, evidence for this in the treatment of lateral epicondylosis is limited. Nitric oxide synthase (NOS) is thought to be important in tendon repair, as it affects the expression of genes known to have roles in healing (10). In rat models, NOS has been shown to have positive effects on extracellular matrix synthesis for tendon healing, and in human studies, GTN has had positive effects on pain in the short term (41,45,47). Early follow-up in a study by Paoloni (46) at 8 wk showed significantly decreased pain with activity compared with placebo among 154 patients in a randomized double-blind controlled trial. Similarly, although in a smaller number of patients, McCallum et al. (41) showed a decrease in patient-rated pain scores at 5 years when compared with week 0, but there were no statistical differences between the group treated with GTN and the group treated with placebo at 5 years in measures of pain with activity, at rest, or at night. There is currently no consensus in the literature regarding optimal length of time for use of GTN.

Prolotherapy has become a popular injectable treatment among some clinicians, with some positive but limited data. One prospective, double-blind, randomized pilot study using prolotherapy or saline injections in 24 subjects showed that prolotherapy provided significant improvement in pain and strength at 16 wk and at 1 year (54). Another randomized double-blind study comparing prolotherapy with corticosteroid injection in 24 subjects showed statistically significant decreases in pain among both groups at 3- and 6-month follow up, but there was no difference between the two groups at any time point (14).

PRP has been shown to promote tendon stem cells differentiation into tenocytes instead of nontenocytes, supporting the safety profile (65). The study by Zhang (65) also suggests that PRP injection can enhance tendon healing because tenocytes induced to differentiate by PRP are activated to proliferate quickly and produce abundant collagen to repair injured tendons that have lost cells and matrix. A small prospective study showed a trend toward improved tendon morphology evaluated by ultrasound after PRP injection at 6 months, with a change in vascularity at the myotendinous junction (16).

Many of the PRP studies have yielded favorable results, although study designs are variable and, arguably, the majority provided low-level evidence at best. Multiple noncontrolled studies have yielded positive results at 6- to 9-month follow-up (23,30,43,44). Two recent randomized controlled studies showed significant reduction in pain for greater than 6 months among both autologous whole blood and PRP groups, but the study designs did not include a placebo and there was no significant difference between groups (22,51). Favorable results have been demonstrated when comparing PRP with corticosteroid (27,49). A study of Peerbooms (49) demonstrated greater than 25% decrease in the disability of arm, shoulder, and hand (DASH) among the PRP group without reintervention at 2 years, while the corticosteroid group returned to baseline at the same time period.

In contrast, two prospective, randomized, controlled, double-blinded studies comparing autologous blood or PRP with corticosteroid and saline have shown less encouraging results. One study comparing corticosteroid, autologous blood, and saline showed that all had decreases in DASH scores at 2 to 6 months, but there were no significant differences in the DASH scores across the three groups (64). When PRP is compared with corticosteroid or saline, there was no significant difference at 3 months following treatment. All three groups had pain reduction at 3 months, but there was no difference between groups (36). Furthermore, each of the three groups had injection of lidocaine in the peritendon prior to their respective treatment, which has been postulated to inhibit tenocyte proliferation, blunting the effect of the PRP (15). While lidocaine used in this study may have changed outcomes, the short-term follow-up also could have affected outcomes, as more than 50% of subjects in each group abandoned treatment at 3 months. Other authors have suggested that this period is not long enough to see differences among groups because positive effects on pain and functional outcomes after PRP are not realized until after 3 months (63). Earlier studies have shown that lateral epicondylosis may be a self-limited process, suggesting that use of PRP may be altogether unnecessary (5,11).

Among PRP studies with both favorable and unfavorable results, no consistent concentration of platelets or type of growth factors has been used, confounding results. At this time, it is unclear whether these variables would affect outcomes. Specifically in a study comparing PRP with autologous whole blood, PRP had a significant improvement in pain scores when compared with autologous whole blood injection at 6 wk but no significant difference at 6 months, suggesting that a more platelet-rich injection could have potential for superiority over whole blood preparations, although only in the short term (60). Others have noted the contrary — that higher concentration of platelets can inhibit tendon healing (26,29). Effects of growth factors such as insulin-like growth factor, transforming growth factor-beta, vascular endothelial growth factor, and others have yet to be fully explored, and the possible negative effects of white blood cells are still being investigated (29).

Application techniques of PRP and postinjection rehabilitation protocols also vary. Some injection techniques have used multiple applications of the substance with varying times between injections, while others anecdotally combine needle tenotomy to the application. The literature on this combined technique is limited. In one prospective, randomized pilot study with 28 patients comparing dry needling with needling with PRP, there was a trend toward improvement in the short term with the addition of PRP, but there were no statistically significant data at any time point (59). In contrast, a favorable outcome was noted when ultrasound-guided needle tenotomy was performed alone in 30 of 52 patients, although the study was not blinded and nonrandomized (42). Postinjection rehabilitation protocols vary from study to study, with no consensus on optimal programs. Some studies mention exercise programs without specific protocols, while others specify eccentric strengthening in a supervised physical therapy session (49,60). Others do not mention a postinjection rehabilitation program.

Literature on stem cell use is just beginning to emerge with limited, and at times conflicting, conclusions in small studies, thus far. One prospective 12-patient pilot study using cultured dermal derived cells injected into areas of fibrillar discontinuity or intrasubstance tears with ultrasound guidance showed positive findings in multiple outcomes. Using the Patient-Rated Tennis Elbow Evaluation (PRTEE) scale, pain was significantly decreased at all time points up to 6 months and ultrasound findings showed a tendency toward improvement in the following tendon characteristics: size, fibrillar patten restoration, resolution of intrasubstance tears, and neovascularity (18). One other prospective study using noncultured bone marrow aspirate in 30 patients also showed significant decrease in PRTEE score at 12 wk (56). Although both trials showed positive results, more research is needed to draw conclusions, as both included limited numbers of participants and no control group.

Operative management similarly offers no gold standard approach. Among orthopedic surgeons surveyed at two international conferences in both the United States and Europe in 2011, conservative management of lateral epicondylosis is still the most prevalent form of treatment, with NSAID and corticosteroid injection at almost 40% each as the most used treatments (3). When surgical treatment is used, the most often used technique is arthroscopic debridement or release of the ECRB origin, and this technique has been shown by many investigators to be an effective treatment for recalcitrant lateral epicondylosis (6,13,37). Arthroscopic technique allows for exploration of the joint to evaluate for plica or other pathologic structural abnormalities that may contribute to lateral elbow pain and can be addressed during the same procedure (13). Other combined techniques including decortication of the lateral epicondyle after arthroscopic debridement have not shown favorable outcomes (35). For recalcitrant cases, there has been some low-level evidence to support denervation of the lateral humeral epicondyle, although more research is necessary (8,52).

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Conclusions

The last decade of literature has provided a host of novel methodologies for management of lateral epicondylosis. New evidence provides a more robust toolbox for treatment that includes topical treatments such as GTN and regenerative treatments such as PRP. However, the preliminary positive results should be tempered with a desire for more long-term follow-up and evaluation of clinical outcomes. Still, no definitive conclusion can be made concerning a standard of care for management of lateral epicondylosis. There are many areas for future investigation. Additional studies assessing topical treatments would be welcome, particularly those comparing the effect of topical analgesics with those of anti-inflammatories, given the hypothesized methodology of topical treatments. Effects of injectables seem to be beneficial regardless of injectate, suggesting that there may be a strong local tissue effect with the needle itself.

Regenerative treatments still need to have more structured outcome goals. For the consideration of a regenerative effect, a local tissue change and long-lasting benefit would be expected. Recent studies have used varying concentrations of injectate including platelet concentrate. This variability makes it more difficult to compare studies, and efforts at standardizing platelets, cell count, or concentration may help assess outcomes. Anesthetic agents may add another confounding effect to these studies, as lidocaine has been shown to have a toxic effect to tenocytes and chondrocytes.

Most studies to date have failed to comment on the use of imaging guidance with injection techniques. Ultrasound has become the bedside imaging modality of choice for preinjection assessment, and needle guidance, for accurate medication placement. Without imaging guidance, the investigator cannot be certain that the treatment reached the targeted structure. Ultrasound guidance should be considered in future investigations of injectates, particularly biologic or regenerative treatments.

Furthermore, because lateral epicondylosis is a clinical diagnosis at this time, it is difficult to determine whether the treatment used in each of the discussed studies was truly targeting the stated diagnosis. Future studies could show improved outcomes if the diagnosis was made more specific, dividing extensor carpi ulnaris (ECU) tendinopathy from other lateral elbow pain diagnoses, allowing for more targeted treatments for each. ECU tendinopathy could then be subdivided into midsubstance and enthesopathy using imaging, and both physical modalities and eccentric exercise could be revisited in new studies.

It is quite evident that there is a lack of discussion on the remainder of the human body when research pertains to the lateral elbow. Future research may do well to consider the kinetic chain in both the diagnosis and management of lateral elbow pain. Accompanying scapular dyskinesis and other biomechanical factors could be addressed, including discussion of postural shirts or other new orthoses.

The authors declare no conflicts of interest and do not have any financial disclosures.

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