Tennis elbow
Tennis elbow, also known as lateral epicondylitis, is an enthesopathy of the origin of the extensor carpi radialis brevis on the lateral epicondyle. It causes pain and tenderness over the bony part of the lateral epicondyle. Symptoms range from mild tenderness to severe, persistent pain. The pain may also extend into the back of the forearm. It usually has a gradual onset, but it can seem sudden and be misinterpreted as an injury.
Tennis elbow is often idiopathic. Its cause and pathogenesis are unknown. It likely involves tendinosis, a degeneration of the local tendon.
It is thought this condition is caused by excessive use of the muscles of the back of the forearm, but this is not supported by evidence. It may be associated with work or sports, classically racquet sports, but most people with the condition are not exposed to these activities. The diagnosis is based on the symptoms and examination. Medical imaging is not very useful.
Untreated enthesopathy usually resolves in 1–2 years. Treating the symptoms and pain involves medications such as NSAIDS or acetaminophen, a wrist brace, or a strap over the upper forearm. The role of corticosteroid injections as a form of treatment is still debated. Recent studies suggests that corticosteroid injections may delay symptom resolution.
Signs and symptoms
Patients typically feel pain or burning around the outer part of the elbow, which can move down the forearm and sometimes up to the upper arm. The pain is worsened by activities that involve wrist extension, such as gripping objects. Pain intensity varies from mild to severe and can be intermittent or constant, significantly impacting daily life. Patients also commonly report grip weakness and difficulty lifting.Terminology
The term "tennis elbow" is widely used, but the condition affects non-tennis players. More recently, with the explosive growth of pickleball, the term "pickleball elbow" is frequently used. Historically, the medical term "lateral epicondylitis" was most commonly used for the condition, but "itis" implies inflammation and the condition is not inflammatory. It is also referred to as enthesopathy of the extensor carpi radialis origin.Since histological findings reveal noninflammatory tissue, the terms "lateral elbow tendinopathy" and "tendinosis" are suggested. In 2019, a group of international experts suggested that "lateral elbow tendinopathy" was the most appropriate terminology. But a disease of an attachment point is most accurately referred to as an "enthesopathy."
Causes
The exact cause of lateral epicondylitis remains unclear. However, it is often linked to repetitive microtrauma resulting from excessive gripping, wrist extension, radial deviation, and/or forearm supination.Traditionally, people have speculated that tennis elbow is a type of repetitive strain injury resulting from tendon overuse and failed healing of the tendon, but there is no evidence of injury or repair, and misinterpretation of painful activities as a source of damage is common.
Pathophysiology
The extensor carpi radialis brevis is the most commonly affected muscle in lateral epicondylitis, along with other extensor carpal muscles. Due to its unique origin, the ECRB tendon is prone to abrasion during elbow movements, leading to repetitive microtrauma.Lateral epicondylitis was initially considered an inflammatory process, however there is no evidence of inflammation or repair. Therefore, the disorder is more appropriately referred to as tendinosis or tendinopopathy. Tendinosis, a degenerative condition with fibroblasts, abnormal collagen, and increased blood vessels. Repetitive stress causes microtears, scar tissue formation, and biomechanical changes, worsening symptoms over time.
Recently, successful results of a prospective therapeutic study of tennis elbow were published. It was observed that tennis elbow symptoms were most painful after awakening. It was hypothesized that a very common sleep position was interfering with healing and causing pain. The study evaluated if changing this position would avoid pressure on the lateral elbow while asleep. Patients who changed this sleep position reported successful resolution of symptoms, whereas those who were unable to change continued to have pain. The conclusion reached is that the pathophysiology of tennis elbow is due to an initial microscopic tear from a sprain/strain. This initial injury is aggravated at night by pressure on the sprain which delays healing. In other words, tennis elbow is neither a tendonitis nor a tendinosis, but more like a pressure sore. If the pressure is removed the initial injury goes on to heal. The importance of this finding is that other conditions characterized by nocturnal or early morning symptoms may also be worsened by a "pathological sleep position." We know this applies to carpal and cubital tunnel syndrome, plantar fasciitis, shoulder/neck pain and Gerd.
Clinical evaluation
Physical examination
Diagnosis is based on symptoms and clinical signs that are discrete and characteristic. For example, the extension of the elbow and flexion of the wrist causes outer elbow pain. The physical examination usually reveals marked tenderness at the origin of the extensor carpi radialis brevis muscle from the lateral epicondyle. Pain may worsen with resisted wrist extension, middle finger extension, and forearm supination with an extended elbow, although normal elbow movement is often maintained, even in severe cases.Cozen's test
Cozen's test is a physical examination performed to evaluate for tennis elbow involving pain with resisted wrist extension. 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. 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, repeat the test with the elbow in full extension.Medical imaging
Medical imaging is not necessary or helpful.Radiographs may demonstrate calcification where the extensor muscles attach to the lateral epicondyle. Medical ultrasonography and magnetic resonance imaging can demonstrate the pathology, but are not helpful for diagnosis and do not influence treatment.
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.
Table of Clinical classification of lateral epicondylitis phases.
| Phase | Description of pain changes at different phases |
| I | Mild pain after activity, usually recovers within 24 hours |
| II | Mild pain more than 48 hours after activity, no pain during activity, can be relieved with warm-up exercises, and recovers within 72 hours |
| III | Mild pain before and during activity, no significant negative impact on the activities, and can be partially relieved with warm-up exercises |
| IV | Mild pain accompanies the activities of daily living and has negative impact on the performance of activities |
| V | Harmful pain unrelated to activities, great negative impact on the performance of activities but does not prevent the activities of daily life. Need complete rest to control the pain |
| VI | Persistent pain despite complete rest and can prevent the activities of daily life |
| VII | Consistent pain at rest, aggravated after activities, and disturbed sleep |
Prevention
Activity modification is the best way to prevent the occurrence of lateral epicondylitis. Prevention can include avoiding extreme end range motions in extension and flexion, limit repetitive hand and wrist motions, and modification of heavy lifting with extended arms. Lifestyle factors such as smoking, alcohol drinking, and dietary habits are known to influence the prognosis of various medical conditions. Smokers showed a higher chance of developing lateral epicondylitis compared to non-smokers. Current research indicates that alcohol intake is not significantly associated with lateral epicondylitis.Treatment
Non-operative treatment
Non operative treatment resolves 90% of symptomatic lateral epicondylitis. Nonoperative care usually includes activity modification, physical therapy, non-steroidal anti-inflammatory medications, bracing, extracorporeal shock-wave therapy, and acupuncture. Modifying activity and avoiding overuse are key to treatment. Lifting with the palm up and avoiding palm-down movements can shift strain from the lateral to the medial epicondyle, easing pain. Patients should also improve lifestyle habits and avoid triggering activities. Following the RICE method can help relieve pain initially.Exercises
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.