Lateral Epicondylitis (Tennis Elbow)

Etiology

Tennis elbow is typically an overuse injury caused by repetitive strain from activities involving loaded gripping or repeated wrist extension. Although historically associated with tennis, the condition can result from any sport requiring repetitive wrist extension, radial deviation, or forearm supination. Lateral epicondylitis also occurs in athletes who participate in squash, badminton, and other activities involving similar movements. Poor mechanics, improper technique, or unsuitable equipment often precipitates the condition in athletes.[3]

Epidemiology

Tennis elbow is the most common cause of symptoms among patients presenting with elbow pain. The condition affects men and women equally, with an annual incidence of 1% to 3% in the US. Despite the term tennis elbow, tennis players account for only 10% of affected patients. Approximately half of all tennis players develop elbow pain, and 75% of these episodes represent true tennis elbow. The condition is more common in individuals older than 40 years. Risk factors in the general population include smoking, obesity, repetitive movement for at least 2 h/d, and vigorous activity involving physical loads greater than 20 kg. The natural course is favorable, with spontaneous recovery within 1 to 2 years in 80% to 90% of patients.[4][5][6]

Pathophysiology

This condition is primarily a degenerative overuse process affecting the extensor carpi radialis brevis and common extensor tendon. In addition to degenerative changes, histologic findings include granulation tissue, microruptures, abundant fibroblasts, vascular hyperplasia, disorganized collagen, and a notable absence of traditional inflammatory cells, including macrophages, lymphocytes, and neutrophils. Based on results from multiple histologic studies describing these microscopic features, the condition has also been termed angiofibroblastic dysplasia.[7][8] Ultrasonographic findings often include calcifications, intrasubstance tears, marked irregularity of the lateral epicondyle, and thickening and heterogeneity of the common extensor tendon.[9]

Histopathology

Results from multiple histologic studies of pathologic extensor carpi radialis brevis specimens identified various combinations of the following features:

• Hypertrophic or abundant fibroblasts
• Collagen disorganization
• Vascular hyperplasia
• Lack of inflammatory cells [8]

History and Physical

Patients typically report pain with an insidious onset, although further questioning often reveals a history of overuse without a specific traumatic event. The pain commonly begins 1 to 3 days after an unaccustomed activity involving repeated wrist extension. The history may also reveal use of new equipment or an atypical training circumstance, such as an unusually intense or prolonged workout. The condition can also be precipitated by an acute injury or strain, such as lifting a heavy object or performing a forceful backhand swing in tennis. Such an injury may progress to a chronic process, resulting in an acute-on-chronic overuse injury. Pain is usually localized to the lateral elbow, worsens with activity, and improves with rest. Severity ranges from mild discomfort during aggravating activities, such as tennis or repeated use of a hand tool, to pain triggered by simple tasks, such as lifting and holding a coffee cup, known as the coffee cup sign.

On examination, maximal tenderness is usually located over the lateral epicondyle, occasionally at a focal point 1 to 2 cm distal to it. Palpation of the entire tendon may produce discomfort, and the associated muscle may exhibit significant tightness. Pain typically increases or is reproduced with resisted wrist extension, especially when the elbow is extended and the forearm is pronated. Resisted extension of the third digit with the elbow extended is particularly painful because this maneuver increases stress on the tendon and supports the diagnosis. Radicular symptoms, numbness, and tingling should be absent. The presence of these symptoms suggests an alternative diagnosis, such as radial nerve entrapment, although both conditions may coexist.[10]

Evaluation

Lateral epicondylitis is a clinical diagnosis, and imaging is often unnecessary. A clinician may consider obtaining an elbow radiographic series, including anteroposterior and lateral views, when the history or physical examination suggests another injury or disorder. Potential indications for imaging include evaluation for concomitant degenerative joint changes, fractures, tumors, or bursitis. If the patient does not respond to nonoperative treatment, the clinician may consider MRI or ultrasonography to evaluate for tendon tears, stress fractures, or osteochondral defects.[11]

Treatment / Management

Nonoperative Management

First-line treatment of lateral epicondylitis includes rest from the aggravating activity according to pain severity. Ice applied after activity and oral or topical nonsteroidal anti-inflammatory drugs can help control pain. Forearm counterforce straps may be prescribed to reduce tension at the lateral epicondyle and should be worn during activity. However, the role of counterforce straps remains controversial because some patients may report pain over the area of maximal tenderness due to direct mechanical compression. A cock-up wrist splint may also be prescribed to reduce stress on the wrist extensors.[10]

Additionally, occupational or physical therapy may focus on forearm stretching and strengthening, followed by progressive eccentric strengthening of the common extensor tendon. Results from studies showed that these interventions may be beneficial. If pain does not respond to conservative measures, more advanced or invasive techniques may be considered, including topical nitrates, botulinum toxin, autologous platelet-rich plasma, and dextrose prolotherapy.

Surgical Management

A surgical procedure should be considered only as a last resort for lateral epicondylitis. Prolonged nonoperative treatment for 6 to 12 months should be attempted before a surgical procedure is considered. Specific surgical techniques vary across the literature. Most surgeons prefer varying degrees of extensor carpi radialis brevis debridement or release of the tendinous origin at the lateral epicondyle. If the surgeon elects not to detach the extensor carpi radialis brevis tendon, extensive debridement should be performed at its origin to remove pathologic tissue and expose a healthy, bleeding bone bed at the lateral epicondyle to promote healing.[12][13](A1)

Differential Diagnosis

The differential diagnosis for lateral epicondylitis includes, but is not limited to, any of the following conditions:

• Elbow bursitis
• Cervical radiculopathy
• Posterolateral elbow plica
• Posterolateral rotatory instability (PLRI)
• Radial nerve entrapment
• Radial tunnel syndrome, which may present with tenderness 3 to 4 cm distal and anterior to the lateral epicondyle, pain with resisted extension of the third digit, and pain with resisted forearm supination
• Occult fracture(s)
• Capitellar osteochondritis dissecans
• Triceps tendinitis
• Radiocapitellar osteoarthritis
• Herpes zoster [14]

Prognosis

The prognosis for lateral epicondylitis is generally favorable. Most patients experience pain relief within 12 months with conservative treatment, including ice, rest, and anti-inflammatory medications. For patients who do not improve with initial treatment, physical or occupational therapy may be beneficial. Patients who do not adhere to the prescribed treatment plan have a higher risk of symptom recurrence.

Complications

Complications of lateral epicondylitis can include recurrence of the injury when normal activity is resumed, rupture of the tendons with repeated steroid injections, and failure to improve with conservative treatment.

Postoperative complications include the following:

• Failure to address concomitant pathology
• Persistent pain, stiffness, or continued or worsening dysfunction when the primary cause of symptoms is not corrected
• Infection
• Blood loss
• Neurovascular injury
• Missed or untreated radial nerve entrapment, which may occur in up to 5% of patients treated for lateral epicondylitis
• Iatrogenic lateral ulnar collateral ligament injury, particularly when surgical dissection extends beyond the equator of the radial head
• Postoperative posterolateral rotatory instability resulting from substantial disruption of the extensor origin or lateral ulnar collateral ligament
• Iatrogenic radial nerve injury
• Heterotopic ossification, which may be reduced through copious saline irrigation after decortication and debridement

Patients should receive counseling about the potential risks and benefits of a surgical procedure before treatment.