Tennis elbow

The term "tennis elbow" is widely used (although informal), but the condition should be understood as not limited to tennis players.[18][19] Historically, the medical term "lateral epicondylitis" was most commonly used for the condition, but "itis" implies inflammation and the condition is not inflammatory.[3][18][19][20][21]

Since histological findings reveal noninflammatory tissue, the terms "lateral elbow tendinopathy" and "tendinosis" are suggested.[22][23] In 2019, a group of international experts suggested that "lateral elbow tendinopathy" was the most appropriate terminology.[24] But a disease of an attachment point (or enthesia) is most accurately referred to as an "enthesopathy."[25]

Diagnosis is based on symptoms and clinical signs that are discrete and characteristic. For example, extension of the elbow and flexion of the wrist causes outer elbow pain. There is point tenderness at the origin of the extensor carpi radialis brevis muscle from the lateral epicondyle (extensor carpi radialis brevis origin).[16]

Cozen's test is a physical examination performed to evaluate for tennis elbow involving pain with resisted wrist extension.[28] The test is said to be positive if a resisted wrist extension triggers pain to the lateral aspect of the elbow owing to stress placed upon the tendon of the extensor carpi radialis brevis muscle.[29] The test is performed with extended elbow. NOTE: With elbow flexed the extensor carpi radialis longus is in a shortened position as its origin is the lateral supracondylar ridge of the humerus. To rule out the ECRB (extensor carpi radialis brevis), repeat the test with the elbow in full extension.

Medical imaging is not necessary or helpful.[30]

Radiographs (X-rays) may demonstrate calcification where the extensor muscles attach to the lateral epicondyle.[16] Medical ultrasonography and magnetic resonance imaging (MRI) can demonstrate the pathology, but are not helpful for diagnosis and do not influence treatment.[31][32]

Longitudinal sonogram of the lateral elbow displays thickening and heterogeneity of the common extensor tendon that is consistent with tendinosis, as the ultrasound reveals calcifications, intrasubstance tears, and marked irregularity of the lateral epicondyle. Although the term “epicondylitis” is frequently used to describe this disorder, most histopathologic findings of studies have displayed no evidence of an acute, or a chronic inflammatory process. Histologic studies have demonstrated that this condition is the result of tendon degeneration, which replaces normal tissue with a disorganized arrangement of collagen. Colour Doppler ultrasound reveals structural tendon changes, with vascularity and hypo-echoic areas that correspond to the areas of pain in the extensor origin.[33]

Stretching and isometric strengthening are the most common recommended exercises. The muscle is stretched with the elbow straight and the wrist passively flexed. Isometric strengthening can be done by pushing the top of the hand up against the undersurface of a table and holding the wrist straight.[36]

Counterforce orthosis reduces the elongation within the musculotendinous fibers

Wrist extensor orthosis reduces the overloading strain at the lesion area

Orthosis is a device externally used on the limb to improve the function or reduce the pain. Orthotics may be useful in tennis elbow; however, long-term effects are unknown.[37] There are two main types of orthoses prescribed for this problem: counterforce elbow orthoses and wrist extension orthoses. Counterforce orthosis has a circumferential structure surrounding the arm. This orthosis usually has a strap which applies a binding force over the origin of the wrist extensors. The applied force by orthosis reduces the elongation within the musculotendinous fibers. Wrist extensor orthosis maintains the wrist in the slight extension.

Other approaches that are not experimentally tested include eccentric exercise using a rubber bar, joint manipulation directed at the elbow and wrist, spinal manipulation directed at the cervical and thoracic spinal regions, low level laser therapy, and extracorporeal shockwave therapy.[38][39][40][41][42]

Although anti-inflammatories are a commonly prescribed treatment for tennis elbow, the evidence for their effect is usually anecdotal with only limited studies showing a benefit.[43] A systematic review found that topical non-steroidal anti-inflammatory drugs (NSAIDs) may improve pain in the short term (up to 4 weeks) but was unable to draw firm conclusions due to methodological issues.[44] Evidence for oral NSAIDs is mixed.[44]

Evidence is poor for long term improvement from injections of any type, whether corticosteroids, botulinum toxin, prolotherapy, or other substances.[45] Corticosteroid injection may be effective in the short term;[46] however, they are of little benefit after a year, compared to a wait-and-see approach.[47] A randomized control trial comparing the effect of corticosteroid injection, physiotherapy, or a combination of corticosteroid injection and physiotherapy found that patients treated with corticosteroid injection versus placebo had lower complete recovery or improvement at 1 year (Relative risk 0.86). Patients that received corticosteroid injection also had a higher recurrence rate at 1 year versus placebo (54% versus 12%, relative risk 0.23).[48] Complications from repeated steroid injections include skin problems such as hypopigmentation and fat atrophy leading to indentation of the skin around the injection site.[46] Steroid injections appear to be more effective than shock wave therapy.[49] Botulinum toxin type A to paralyze the forearm extensor muscles in those with chronic tennis elbow that has not improved with conservative measures may be viable.[50]

Surgery is an option.[51][52][53] Surgical methods include:[54]

• Lengthening, release, debridement, or repair of the origin of the extrinsic extensor muscles of the hand at the lateral epicondyle

Surgical techniques for lateral epicondylitis can be done by open surgery, percutaneous surgery, or arthroscopic surgery, with no high-quality evidence that any particular type is better or worse than another.[55][52] Side effects include infection, damage to nerves, and inability to straighten the arm.[56] A review of the evidence related to surgery found that published studies were of low quality and did not show that surgery was any more effective than other treatments.[55] A subsequent research trial showed that surgery was no more effective than sham surgery, where patients only received a skin incision, although the trial was limited by a small number of patients.[57]

Evidence from imaging studies suggests that about 1 in 5 humans have detectable enthesopathy of the extensor carpi radialis brevis origin in their lifetime.[58] Symptoms likely vary and are self-limited. The signal changes on MRI seem permanent. There is no evidence that specific occupations or activities are associated with enthesopathy.[59]

Symptoms suggestive of lateral epicondylitis are present in about 1% of the adult population and are most common between ages 40 and 60.[59] The prevalence varies somewhat between studies, likely as a result of varied diagnostic criteria and limited reliability between different observers.[59] The data regarding symptoms of lateral epicondylitis in relation to occupations and sports are inconsistent and inconclusive.[59] The shortcomings of the evidence that addresses the relationship between symptoms and occupation/sport include: variation in diagnostic criteria, limited reliability of diagnosis, confounding association of psychosocial factors, selection bias due to a high non-response rate, and the fact that exposures are usually by subjective patient reports and symptomatic patients might receive greater exposure.