Tennis Elbow (Lateral Epicondylitis)

Overview

Tennis Elbow, also known as lateral epicondylitis, is one of the most common causes of lateral elbow pain.

It is an overuse injury involving degeneration and tendinosis of the origin of the extensor carpi radialis brevis (ECRB) tendon at the lateral epicondyle of the humerus.

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Anatomy and Pathophysiology

Primary Muscle Involved

The main muscle involved is the:

• Extensor Carpi Radialis Brevis (ECRB)

Origin

• Lateral epicondyle of the humerus
• Common extensor tendon

Insertion

• Base of the third metacarpal

Function

• Wrist extension
• Radial deviation (abduction) of the wrist

Innervation

• Radial nerve

The ECRB tendon is particularly vulnerable to repetitive eccentric overload.

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Pathology

Histological Findings

Despite the term “epicondylitis,” the condition is primarily degenerative rather than inflammatory.

Common findings include:

• Disorganized collagen
• Angiofibroblastic hyperplasia
• Fibroblast hypertrophy
• Microtears at the tendon origin
• Vascular granulation tissue

This process is better described as tendinosis.

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Causes and Risk Factors

Sports-Related Causes

Approximately 40–50% of tennis players may develop symptoms due to:

• Poor swing mechanics
• Incorrect grip size
• Repetitive backhand strokes
• Excessive wrist extension

Occupational Causes

Common in individuals performing:

• Repetitive gripping
• Heavy lifting
• Tool use
• Manual labor

Repetitive wrist extension and forearm pronation increase stress on the ECRB tendon.

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Clinical Presentation

Symptoms

Patients commonly complain of:

• Lateral elbow pain
• Pain during gripping
• Weak grip strength
• Pain with lifting objects
• Pain during repetitive wrist extension
• Difficulty with daily activities such as carrying groceries

Pain may also interfere with sleep.

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Physical Examination

Tenderness

Point tenderness is typically located over:

• The lateral epicondyle
• ECRB origin

Provocative Test

Pain increases with:

• Resisted wrist extension
• Elbow fully extended

This is a classic examination finding.

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Differential Diagnosis

Radial Tunnel Syndrome

Radial Tunnel Syndrome should always be considered, especially if symptoms fail to improve as expected.

Key Differences

Radial tunnel syndrome involves compression of the posterior interosseous nerve.

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Other Differential Diagnoses

Additional conditions to exclude include:

• Cervical radiculopathy
• Posterior interosseous nerve syndrome
• Triceps tendinopathy
• Osteoarthritis of the elbow

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Imaging

X-rays

Usually normal.

Occasionally may show:

• Calcification near the extensor origin

Imaging is mainly used to exclude other pathology.

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Nonoperative Treatment

First-Line Management

Most patients improve without surgery.

Treatment Options

• Activity modification
• NSAIDs
• Ice therapy
• Physiotherapy
• Bracing or counterforce straps

Physiotherapy

Particularly effective interventions include:

• Eccentric strengthening exercises
• Tendon gliding exercises
• Stretching programs

Evidence suggests physiotherapy provides better long-term relief than corticosteroid injections.

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Injection Therapy

Corticosteroid Injection

May provide short-term symptom relief.

Important Considerations

• Useful for acute pain control
• Repeated injections should be limited
• Excessive steroid use may weaken tendon tissue

PRP Injection

Platelet-rich plasma (PRP) may be used in chronic cases, although evidence remains variable.

Ultrasound guidance can improve injection accuracy.

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Prognosis

Success Rate

Approximately:

• 90–95% improve with conservative treatment

Recovery may take:

• 6–12 months

Most cases eventually resolve regardless of the specific conservative method used.

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Surgical Treatment

Indications

Reserved for patients with:

• Persistent symptoms
• Failed prolonged nonoperative treatment

Procedure

Typical surgery involves:

• Debridement of diseased ECRB tendon
• Release of the ECRB origin

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Surgical Complication

Posterolateral Rotatory Instability (PLRI)

Excessive release near the lateral collateral ligament complex can injure the:

• Lateral ulnar collateral ligament (LUCL)

This may result in:

Posterolateral Rotatory Instability

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Important Associated Conditions

Intersection Syndrome

Definition

An overuse inflammatory condition occurring where:

• First dorsal compartment tendons cross
• Second dorsal compartment tendons

The second compartment contains:

• ECRB
• Extensor carpi radialis longus (ECRL)

Clinical Findings

Pain is usually:

• Dorsoradial forearm
• Approximately 4–6 cm proximal to the wrist

Common in repetitive wrist extension activities.

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ECRB in Surgical Approaches

Thompson Dorsal Approach

The interval between:

• ECRB
• Extensor digitorum

is used to expose the proximal radius.

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Tendon Transfer in High Radial Nerve Palsy

Important Transfer

In Radial Nerve Palsy:

• Pronator teres may be transferred to ECRB

Purpose

To restore:

• Wrist extension
• Functional hand positioning