Tennis elbow

Signs and symptoms

Symptoms associated with tennis elbow include, but are not limited to: radiating pain from the outside of the elbow to the forearm and wrist, pain during extension of wrist, weakness of the forearm, a painful grip while shaking hands or torquing a doorknob, and not being able to hold relatively heavy items in the hand. The pain is similar to the condition known as golfer's elbow, but the latter occurs at the medial side of the elbow.

Causes

Tennis elbow is a type of repetitive strain injury resulting from tendon overuse and failed healing of the tendon. In addition, the extensor carpi radialis brevis muscle plays a key role.

Early experiments suggested that tennis elbow was primarily caused by overexertion. However, studies show that trauma such as direct blows to the epicondyle, a sudden forceful pull, or forceful extension cause more than half of these injuries. Repeatedly mis-hitting a tennis ball in the early stages of learning the sport causes shock to the elbow joint and may contribute to contracting the condition.

Cyriax proposes one explanation of how tennis elbow may come about. The hypothesis states that there are microscopic and macroscopic tears between the common extensor tendon and the periosteum of the lateral humeral epicondyle. An operation conducted in this study showed that 28 out of 39 patients showed tearing at the tendon cuff. Kaplan stated that the radial nerve was significantly involved in tennis elbow. He noted the constriction of the radial nerve by adhesions to the capsule of the radiohumeral joint and the short extensor muscle of the wrist. He found evidence that many differed in how they contracted tennis elbow. Disorders such as calcification of the rotator cuff, bicipital tendinitis, or carpal tunnel syndrome may increase chances of tennis elbow.

Pathophysiology

Histological findings include granulation tissue, microrupture, degenerative changes, and there is no traditional inflammation. As a consequence, “lateral elbow tendinopathy or tendinosis” is used instead of “lateral epicondylitis”.

Examination of tennis elbow tissue reveals noninflammatory tissue, and therefore, the term “angio-fibroblastic tendinosis” is used.

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. Therefore, the disorder is more appropriately referred to as tendinosis or tendinopathy rather than tendinitis.

Colour Doppler ultrasound reveals structural tendon changes, with vascularity and hypo-echoic areas that correspond to the areas of pain in the extensor origin.

The pathophysiology of lateral epicondylitis is degenerative. Non-inflammatory, chronic degenerative changes of the origin of the extensor carpi radialis brevis (ECRB) muscle are identified in surgical pathology specimens. It is unclear if the pathology is affected by prior injection of corticosteroid.

Tennis players generally believe tennis elbow is caused by the repetitive nature of hitting thousands of tennis balls, which leads to tiny tears in the forearm tendon attachment at the elbow.

The extensor digiti minimi also has a small origin site medial to the elbow that this condition can affect. The muscle involves the extension of the little finger and some extension of the wrist allowing for adaption to "snap" or flick the wrist—usually associated with a racquet swing. Most often, the extensor muscles become painful due to tendon breakdown from over-extension. Improper form or movement allows for power in a swing to rotate through and around the wrist—creating a moment on that joint instead of the elbow joint or rotator cuff. This moment causes pressure to build impact forces to act on the tendon causing irritation and inflammation.

Some suggest an overuse theory advancing that the extensor carpi radialis brevis has a small origin and does transmit large forces through its tendon during repetitive grasping. It has also been implicated as being vulnerable during shear stress during all movements of the forearm.

At least one author questions that lateral epicondylitis is caused by repetitive microtrauma/overuse, maintaining the theory is likely overstated and lacks scientific support.

Other speculative risk factors for lateral epicondylitis include taking up tennis later in life, unaccustomed strenuous activity, decreased mental chronometry and speed and repetitive eccentric contraction of muscle (controlled lengthening of a muscle group).

Prevention

Another factor of tennis elbow injury is experience and ability. The proportion of players who reported a history of tennis elbow had an increased number of playing years. As for ability, poor technique increases the chance for injury much like any sport. Therefore, an individual must learn proper technique for all aspects of their sport. The competitive level of the athlete also affects the incidence of tennis elbow. Class A and B players had a significantly higher rate of tennis elbow occurrence compared to class C and novice players. However, an opposite, but not statistically significant, trend is observed for the recurrence of previous cases, with an increasingly higher rate as ability level decreases.

Other ways to prevent tennis elbow:

Vibration dampeners (otherwise known as "gummies") are not believed to be a reliable preventative measure. Rather, proper weight distribution in the racket is thought to be a more viable option in negating shock.

Diagnosis

To diagnose tennis elbow, the physician performs a battery of tests in which he places pressure on the affected area while asking the patient to move the elbow, wrist, and fingers. X-rays can confirm and distinguish possibilities of existing causes of pain that are unrelated to tennis elbow, such as fracture or arthritis. Medical ultrasonography and magnetic resonance imaging (MRI) are other valuable tools for diagnosis but are frequently avoided due to the high cost. MRI screening can confirm excess fluid and swelling in the affected region in the elbow, such as the connecting point between the forearm bone and the extensor carpi radialis brevis.

Diagnosis is made by clinical signs and symptoms that are discrete and characteristic. With the elbow fully extended, the patient feels points of tenderness over the affected point on the elbow—which is the origin of the extensor carpi radialis brevis muscle from the lateral epicondyle (extensor carpi radialis brevis origin). There is also pain with passive wrist flexion and resistive wrist extension (Cozen's test). Resisted middle finger extension might indicate the involvement of Extensor Digitorum also. These tests shall be used to measure the prognosis of the condition.

Depending upon severity and quantity of multiple tendon injuries that have built up, the extensor carpi radialis brevis may not be fully healed by conservative treatment. Nirschl defines four stages of lateral epicondylitis, showing the introduction of permanent damage beginning at Stage 2.

1. Inflammatory changes that are reversible
2. Nonreversible pathologic changes to origin of the extensor carpi radialis brevis muscle
3. Rupture of ECRB muscle origin
4. Secondary changes such as fibrosis or calcification.

Treatment

Evidence for the treatment of lateral epicondylitis before 2010 was poor. There were clinical trials addressing many proposed treatments, but the trials were of poor quality.

A 2009 study looked at using eccentric exercise with a rubber bar in addition to standard treatment: the trial was stopped after 8 weeks because the improvement using the bar for therapy was so significant. Based on small sample size and a follow-up only 7 weeks from commencement of treatment, the study shows short-term improvements. This along with other studies allowed doctors to conclude that approximately 80-95% of all tennis elbow cases can be treated without surgery. However, long-term results have not yet been determined.

In some cases, severity of tennis elbow symptoms mend without any treatment, within six to 24 months. Tennis elbow left untreated can lead to chronic pain that degrades quality of daily living.

Physical

There are several recommendations regarding prevention, treatment, and avoidance of recurrence that are largely speculative including stretches and progressive strengthening exercises to prevent re-irritation of the tendon and other exercise measures.

One way to help treat minor cases of tennis elbow is to simply relax the affected arm. The rest lets stress and tightness within the forearm slowly relax and eventually have the arm in working condition—in a day or two, depending on the case.

Evidence from the Tyler study suggests that eccentric exercise using a rubber bar is highly effective at eliminating pain and increasing strength. The exercise involves grasping a rubber bar, twisting it, then slowly untwisting it.

Moderate evidence exists demonstrating that joint manipulation directed at the elbow and wrist and spinal manipulation directed at the cervical and thoracic spinal regions results in clinical changes to pain and function. There is also moderate evidence for short-term and mid-term effectiveness of cervical and thoracic spine manipulation as an add-on therapy to concentric and eccentric stretching plus mobilisation of wrist and forearm. Although not yet conclusive, the short-term analgesic effect of manipulation techniques may allow more vigorous stretching and strengthening exercises, resulting in a better and faster recovery process of the affected tendon in lateral epicondylitis.

Low level laser therapy, administered at specific doses and wavelengths directly to the lateral elbow tendon insertions, offers short-term pain relief and less disability in tennis elbow, both alone and in conjunction with an exercise regimen. Recently, dry needling has gained popularity to treat various types of tendinopathies and pain of muscular origin. Even in lateral epicondylitis, dry needling is widely used by physical therapists across the world. Proponents believe that dry needling causes a tiny local injury that brings about various desirable growth factors in the vicinity. Dry needling also aims at eliciting local twitch response (LTR) in the extensor muscles—as in some cases of tennis elbow the extensor muscles of the forearm would harbor trigger points, which itself could be a major source of pain.

Orthotic devices

Orthosis is a device externally used on the limb to improve the function or reduce the pain. Orthotics are useful therapeutic interventions for initial therapy of tennis elbow. 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 musculotendinious fibers. Wrist extensor orthosis maintains the wrist in the slight extension. This position reduces the overloading strain at the lesion area.

Studies indicated both type of orthoses improve the hand function and reduce the pain in people with tennis elbow.

Medication

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. 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. Evidence for oral NSAIDs is mixed.

Evidence is poor for long term improvement from injections of any type, whether corticosteroids, botulinum toxin, prolotherapy or other substances. Corticosteroid injection may be effective in the short term however are of little benefit after a year, compared to a wait-and-see approach. A recent 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). Complications from repeated steroid injections include skin problems such as hypopigmentation and fat atrophy leading to indentation of the skin around the injection site. 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.

Surgery

In recalcitrant cases surgery may be an option. Surgical methods include:

Surgical techniques for lateral epicondylitis can be done by open surgery, percutaneous surgery or arthroscopic surgery, with no evidence that any particular type is better or worse than another.

Prognosis

Response to initial therapy is common, but so is relapse (25% to 50%) and/or prolonged, moderate discomfort (40%).

Epidemiology

In tennis players, about 39.7% have reported current or previous problems with their elbow. Less than one quarter (24%) of these athletes under the age of 50 reported that the tennis elbow symptoms were "severe" and "disabling," while 42% were over the age of 50. More women (36%) than men (24%) considered their symptoms severe and disabling. Tennis elbow is more prevalent in individuals over 40, where there is about a four-fold increase among men and two-fold increase among women. Tennis elbow equally affects both sexes and, although men have a marginally higher overall prevalence rate as compared to women, this is not consistent within each age group, nor is it a statistically significant difference.

Playing time is a significant factor in tennis elbow occurrence, with increased incidence with increased playing time being greatery for respondents under 40. Individuals over 40 who played over two hours doubled their chance of injury. Those under 40 increased it 3.5 fold compared to those who played less than two hours per day.