Lateral Elbow Tendinopathy

Definition

There is no generally accepted definition of lateral epicondylitis, but in general terms it is a condition manifest as pain and tenderness over the lateral epicondyle of the humerus.

Epidemiology

Of the conditions that present as pain in the elbow, lateral epicondylitis is the only one whose incidence and prevalence have been formally assessed. It is overwhelmingly the most common cause of pain around the elbow.

The only population-based study to consider lateral epicondylitis revealed an overall prevalence of 1-3% in Sweden 1. The distribution revealed a peak prevalence in females in their fifth decade of 10% 1. Hamilton reported the presentations of lateral epicondylitis from a general practice covering 8500 patients2. He noted 77 new patients with lateral epicondylitis over a period of two years, an annual incidence of 4.23 per 1000. The sex distribution in this study was even. Again, the peak incidence was in the fourth and fifth decades.

In the industrial setting, studies have focused on particular groups of employees. Dimberg et al studied a random sample of engineering workers in Sweden 3. An overall prevalence of 7.4% was noted.

Other reports of the prevalence and incidence of lateral epicondylitis have only considered particular groups at risk, such as tennis players where the prevalence made be as high as 50% 4.

Risk Factors

The ideal study of risk factors for the development of lateral epicondylitis would be population-based, and would record likely risk factors before prospectively following the cohort and noting the development of the index condition. An alternative strategy would be to perform a case control study. No studies using either of these designs have been published. However, a number of studies have attempted to determine the effect of different work-related variables on the development of lateral epicondylitis.

Kurppa et al 5 performed a prospective study of 715 workers in strenuous and non-strenuous occupations. Of 57 new cases of lateral epicondylitis, 51 were found in the strenuous group. This equates to a relative risk of 7.2. This study may have been compromised by a healthy worker effect that made have led to those workers with a previous musculoskeletal problem being more likely to work in the office than on the factory floor. Notwithstanding this concern, these results are supported by other Scandinavian research that revealed an increased prevalence of epicondylitis in meat cutters when compared to a control group of construction foremen 6. It is sobering to note that none of the studies of occupational risk factors available meet the validity criteria proposed by Vender et al 7.

Risk Factors thought to be relevant:

• Tennis is associated with the condition in less than 10 in 100 patients, and is more common in recreational players. See Hatch et al for discussion about racket grip sizes.
• Repetitive movements especially wrist extension and supination
• New or sudden overuse of tendon (e.g. lifting a new baby, new exercise routine, new gardening, handling heavy tools or heavy load)
• Low job control
• Low social support
• Doesn't increase risk: keyboard use, working with arms above shoulder-height, exposure to hand-transmitted vibrations

Natural History

The principal criteria for a study of natural history of a condition are that an inception cohort is assembled from a recognisable population, and then they are followed up as completely as possible 8.

Binder et al 9 studied 60 patients prospectively that had been enrolled in a study of therapeutic ultrasound. They noted that after 12 months, 50% still had at least intermittent symptoms that had not required further treatment but that had restricted activity. Three patients had changed occupations. The entry criteria for this study were not detailed in this paper, but the setting was a tertiary rheumatology referral centre, so it would seem likely that the patients would have more severe or refractory disease.

Although not specifically addressing the question of natural history, a general practice-based study noted recurrence in 14 of 26 patients able to be followed up for more than twelve months 2. Other studies reportedly addressing the natural history of lateral epicondylitis lack adequate follow up 10.

There are no studies of the untreated natural history of lateral epicondylitis. Consequently, the natural history of lateral epicondylitis remains uncertain, but the best available evidence indicates that there is a significant recurrence rate, in the order of 50% over 12 months.

Pathogenesis

Formal histopathological studies of lateral epicondylitis are limited to those patients who have undergone surgery, and who, by definition, must have been suffering from chronic and refractory disease, and who are patently not representative of either the acute or typical clinical situation.

The extensor radialis brevis muscle is the most commonly involved muscle.

Pathology Studies

• In the study of Chard et al 11, 20 common extensor biopsy tendons were harvested from patients undergoing a lateral release procedure and compared to nine control biopsies taken from cadavers with no recorded history of elbow pain. The assessment does not appear to have been blinded. In the patient group, 13 biopsies had glycosaminoglycan infiltration, 6 had new bone formation at the site of tendon insertion, 4 had fibro-fatty change, 4 partial rupture, and 2 had fibrocartilage formation with or without calcification. Inflammatory changes, characterised by mild lymphocytic infiltration and giant cell formation were found in only one specimen. In contrast, the control (cadaveric) biopsies revealed patchy glycosaminoglycan infiltration of a mild degree in two specimens.
• In a smaller study of similar design but with blinded assessment, Regan et al 12 again noted a paucity of chronic inflammatory infiltrates, but found evidence of hyaline degradation in 11 of 11 biopsies, vascular proliferation in 10 biopsies, fibroblastic proliferation in 7 and calcific debris in 3. Only two of the controls had evidence of vascular proliferation.
• The third controlled study also found no evidence of ongoing inflammation, but evidence of ongoing repair reference required.
• One study looked at using high definition ultrasound studies in patients with the syndrome of lateral epicondylitis 13. Forty-one tennis players with symptoms for an average of 2.2 months were investigated with high definition, real time ultrasound, and the images independently reported. Six ultrasonographic diagnoses were made. Fifteen of 41 had tendonitis; five each of bursitis and enthesiopathy; four of peritendonitis; two had intra-muscular hematomas. Seven had multiple lesions and 3 were normal to ultrasound. No controls were used.
• Zeisig et al in 2006 investigated the common extensor origin with grey-scale ultrasonography and colour doppler in 17 patients in a total of 22 elbows, and compared them to 11 controls with 22 pain-free elbows. In 21/22 of the painful elbows, vascularity was shown. This was in contrast to only 2/22 of pain-free elbows. This was thought to correspond to vasculo-neural growth.

In summary, the pathology of acute lateral epicondylitis remains unknown. It seems likely that a variety of pathological lesions, principally affecting the common extensor tendon and its surrounding tissues are responsible. In chronic lateral epicondylitis, the extant pathological studies indicate a chronic repair and degenerative process with very little in the way of an active inflammatory component.

Factors thought to be relevant:

• Repeated microtearing and healing attempts
• Non inflammatory angiofibroblastic hyperplasia
• Formation of nonfunctional blood vessels
• Collagen scaffold disrupted by fibroblasts and vascular granulation

Diagnosis

• Onset of pain is insidious
• Can be diagnosed using the "Southampton examination schedule"
  • All three of epicondylar pain, epicondylar tenderness, pain on resisted extension of the wrist
  • Fairly accurate - sensitivity 73%, specificity 97%, kappa = 0.75
• Often also get pain with supination of the forearm, resisted third finger extension (with an extended elbow), pain on lifting a chair with a pronated hand.
• Can get wrist extension weakness
• Range of motion usually normal
• Imaging usually unnecessary, and extend of tendon damage is not correlated with the amount of pain. May be considered if no improvement.

Differential Diagnosis

• Osteomyelitis
• Arthritis
• Peripheral neuropathy
• Trauma
• Referred pain from neck,shoulder, wrist
• Posterior interosseous neuropathy
• Stress fracture
• Osteochondritis dissecans of capitellum and radius

Treatment

Doing Nothing

• Most patients recover at one year with or without treatment

Exercises

Effective exercise programmes incorporate progressive eccentric and isometric strengthening. Flexibility training may also be required. Eccentric exercise can be performed by holding a weight or a taut resistance band with the wrist extended. The wrist is then flexed against resistance.

There are inconsistencies in the methodological quality of research into eccentric strengthening for this condition. High quality research in other tendinopathies, in particular achilles tendinopathy, has shown benefit for including eccentric strengthening in a rehabilitation programme. One systematic review in 2003 showed mixed results. . A more recent review in 2014 found three high quality studies, seven medium quality studies, and two low quality studies. They concluded that the evidence supports the inclusion of eccentric strengthening as part of a multimodal approach to rehabilitation

Some of the better quality studies:

• Standard physical therapy versus standard therapy plus eccentric stregnthening. Patients in the eccentric strengthening group had marked reductions in pain, disability, and improvement in tendon appearance on ultrasound at one month. At completion the eccentric training group had no strength deficit.
• A similar smaller study found better outcomes in the eccentric strengthening group when using a rubber bar: File:rubber bar lateral elbow.jpg .

Rest

• Rest, avoid or alter activities responsible for symptoms

Activity Modification

• For tennis players: lighter racket with smaller grip and less string tension, use 2 - handed backhand

Orthotics

• braces, forearm straps, wrist cock-up splints may reduce pain and improve function (level 2)
• Counter-force brace recommended as inexpensive and easy to use. Apply 6-10cm distal to elbow joint.

Medication

• topical NSAIDs may help, inconsistent evidence for oral NSAIDs (level 2)
• topical GTN may help for patients having physical therapy (level 2)

PRP

• Injection platelet rich plasma (level 2)

Steroid injections

• Peritendinous steroid injections may provide short-term relief (up to 12 weeks), but result in increased pain and recurrence at one year (level 1)

Stretching

Bogduk wrote about stretching but this would not be a modern approach to treating this condition due to the compressive forces applied.

Complete recovery or much improvement at	Normal	Steroid	Physio	Steroid+Physio
4 weeks	10%	71%	39%	68%
26 weeks	83%	56%	89%	54%
52 weeks	93%	84%	100%	82%
recurrence at 52w	20%	55%	5%	54%

References

1. Allander E. Prevalence, incidence, and remission rates of some common rheumatic diseases or syndromes. Scand J Rheumatol 1974; 3:145-153. 2. Hamilton PG. The prevalence of humeral epicondylitis: a survey in general practice. J R Coll Gen Pract 1986; 36:464-465. 3. Dimberg L. The prevalence and causation of tennis elbow (lateral humeral epicondylitis) in a population of workers in an engineering industry. Ergonomics. 1987; 30:573-579. 4. Carroll R. Tennis elbow: incidence in local league players. Br J Sports Med 1981; 15:250-256. 5. Kurppa K, Viikari Juntura E, Kuosma E, Huuskonen M, Kivi P. Incidence of tenosynovitis or peritendinitis and epicondylitis in a meat-processing factory. Scand J Work Environ Health 1991; 17:32-37. 6. Roto P, Kivi P. Prevalence of epicondylitis and tenosynovitis among meatcutters. Scand J Work Environ Health 1984; 10:203-205. 7. Vender MI, Kasdan ML, Truppa KL. Upper extremity disorders: a literature review to determine work relatedness. J Hand Surg 1995; 20A:534-541. 8. Department of clinical epidemiology and biostatistics. How to read clinical journals: III to learn the clinical course and prognosis of disease. Can Med Assoc J 1981; 124:869-872. 9. Binder AI, Hazleman BL. Lateral humeral epicondylitis--a study of natural history and the effect of conservative therapy. Br J Rheumatol 1983; 22:73-76. 10. Coonrad RW, Hooper WR. Tennis elbow: its course, natural history and surgical management. J Bone Joint Surg 1973; 55A:1177-1182. 11. Chard MD, Cawston TE, Riley GP, Gresham GA, Hazleman BL. Rotator cuff degeneration and lateral epicondylitis: a comparative histological study. Ann Rheum Dis 1994; 53:30-34. 12. Regan W, Wold LE, Coonrad RW, Morrey BF. Microscopic histopathology of chronic refractory lateral epicondylitis. Am J Sports Med 1992; 20:746-749. 13. Maffulli N, Regine R, Carrillo F, Capasso G, Minelli S. Tennis elbow: an ultrasonographic study in tennis players. Br J Sports Med 1990; 24:151-155.