Introduction

Definition of tennis elbow

Elbow tendinitis, commonly referred to as "tennis elbow," is a painful musculoskeletal condition that arises from repetitive use of the extensor muscles of the lateral side of the forearm. It is typically caused by minor trauma or repeated strain on the lateral epicondyle (Part of the elbow), leading to inflammation of the periosteum at the attachment site of the common extensor tendon muscle. (lateral epicondylitis). 

Tennis elbow causes pain on the outer side of the elbow, which can spread down the back of the forearm. Simple activities like pouring tea, turning a door handle, or shaking hands can make it worse. Many people with tennis elbow also feel pain when opening a door or lifting a glass.

On examination, tenderness over the lateral epicondyle and pain with resisted wrist extension (tilting the wrist upwards) are common clinical findings.¹

Importance of the extensor carpi radialis brevis (ECRB)

The extensor carpi radialis brevis (ECRB) is an important muscle in the back of the forearm that helps with wrist movement and stability. It starts at the lateral epicondyle of the humerus and the annular ligament of the radius and attaches to the base of the third metacarpal bone. 

The extensor carpi radialis brevis (ECRB) works together with the extensor carpi radialis longus (ECRL), which attaches to the second metacarpal bone. The ECRB helps straighten the wrist and move it to the side. It is controlled by the deep branch of the radial nerve (C7, C8) and plays an important role in activities like gripping, lifting, and typing. 

The ECRB is also part of the "mobile wad of Henry," a group of muscles that help with wrist stability. Because it is frequently used in repetitive movements, it is often involved in tennis elbow, highlighting its importance in wrist function.^1,2

Anatomy of the extensor carpi radialis brevis (ECRB)

• Location and Function:
  • Origin: Lateral epicondyle of the humerus
  • Insertion: Base of the third metacarpal
  • Primary role: Wrist extension and abduction
  • Innervation: Deep branch of the radial nerve (C7, C8)
  • Arterial supply: Radial artery³
• Anatomical relationship to other forearm muscles:
  • The extensor carpi radialis brevis is a small muscle on the outer back part of the forearm. It belongs to a group of surface-level forearm muscles that also includes the anconeus, brachioradialis, extensor carpi radialis longus muscle, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris. These muscles run along the back of the elbow and wrist, helping to straighten and move these joints. The main job of the extensor carpi radialis brevis is to lift the hand upward (extend the wrist) and slightly move it to the side (abduct the wrist)⁴

Pathophysiology of tennis elbow

Tennis elbow, or lateral epicondylitis, is a condition where the outer part of the elbow becomes sore and swollen due to repetitive use.. It occurs when you repeatedly move your wrist, grip objects tightly, or twist your forearm, causing small injuries to the tendon that connects to the elbow. 

This weakens the tendon over time, leading to pain and inflammation. Despite its name, most cases aren’t caused by playing tennis—only about 5% are. It’s common in people who perform a lot of repetitive hand and arm movements, such as typing, lifting, or using tools. Athletes in sports like squash, badminton, baseball, and swimming can also develop it from similar repetitive motions.^5,6

Clinical presentation of tennis elbow

Symptoms

Tennis elbow, or lateral epicondylitis, tends to develop gradually and can get worse over time. Initially, you might notice a dull pain, burning, or ache in the outer part of your elbow and forearm. If the repetitive actions causing this pain don’t stop, it can get worse and even spread down to your wrist, sometimes even when you're resting.

Some common signs include:

• Pain or a burning sensation on the outside of your elbow that gets worse when you move it
• Weak grip, which makes it harder to lift or hold small things like a coffee cup
• Discomfort when trying to lift your hand, especially when your palm is facing down on a surface
• Occasional pain at night

The pain tends to flare up with activities that require using your forearm, like gripping, lifting, turning a wrench, or even shaking hands. It usually affects the arm you use most, but both arms can sometimes be affected.^7,8

^Diagnosis

• Diagnostic Techniques:
  • Palpation & Inspection (To look and feel)
    • Tenderness is felt at the ECRB tendon originates just a few millimetres below the lateral epicondyle
  • Neuromuscular Assessment
    • Grip strength may be reduced
    • A neurological exam helps rule out nerve compression conditions that may mimic tennis elbow.
  • Provocative Tests (Tests that trigger pain at the lateral epicondyle)
    • Resisted wrist extension with the elbow fully extended and the forearm pronated
    • Resisted extension of the long fingers (especially the middle finger – Maudsley's test)
    • Maximal wrist flexion may provoke discomfort
    • Passive wrist flexion in pronation causes pain at the elbow
  • Tests to Rule Out Other Conditions
    • Elbow instability (LUCL insufficiency):
      • Chair test: Difficulty or pain when pushing up from a chair using the arms
      • Push-up test: Pain or instability when performing a push-up
    • Intraarticular issues (e.g., OCD or arthritis):
      • Reduced range of motion (ROM)
    • Posterolateral plica syndrome:
      • Pain or clicking with passive elbow flexion in pronation and supination

These tests help confirm tennis elbow and differentiate it from other elbow conditions.

Diagnosing tennis elbow is primarily based on clinical history and physical examination. However, imaging may be considered in specific cases to rule out other conditions or assess severity.

1. Radiographs (X-rays)
   • Recommended Views: Anteroposterior (AP) and lateral views of the elbow
   • Findings:
     • Usually normal and rarely altered treatment
     • May show calcifications near the lateral epicondyle in up to 50% of cases
     • Can reveal signs of previous surgery or degenerative joint changes
2. Magnetic Resonance Imaging (MRI)
   • Not required for diagnosis, but may be useful if the diagnosis is unclear or if symptoms persist despite treatment.
   • Findings:
     • Increased signal intensity at the ECRB tendon origin in up to 90% of cases
     • Thickening or thinning of the tendon, oedema, and tendon degeneration
   • Findings do not always correlate with symptom severity and should not determine management
3. Ultrasound (Ultrasonography)
   • Useful in experienced hands, but has variable sensitivity and specificity
   • Findings:
     • Thickened and hypoechoic (dark on ultrasound) ECRB tendon, indicating tendinopathy
   • Can be a helpful real-time imaging tool to assess tendon integrity and inflammation

These imaging techniques are typically used when symptoms persist despite treatment or when other conditions, such as fractures, tumours, or bursitis, are suspected.³

ECRB as a target in tennis elbow treatment

The extensor carpi radialis brevis (ECRB) tendon plays a key role in tennis elbow (lateral epicondylitis). Overuse and repetitive strain on the ECRB lead to degeneration, microtears, and inflammation, causing pain and weakness in the elbow.

Non-surgical treatments targeting ECRB

• Rest & Activity Modification: Avoiding repetitive wrist and elbow movements reduces strain on the ECRB
• Pain Management: Ice, NSAIDs, and topical treatments help reduce pain and inflammation
• Braces & Supports: Counterforce straps help offload stress from the ECRB
• Physical Therapy:
  • Eccentric exercises strengthen the ECRB and promote healing
  • Stretching and grip exercises improve flexibility and strength
• Injections & Other Therapies:
  • Steroid injections may provide short-term relief, but have risks
  • Platelet-rich plasma (PRP) helps with long-term healing
  • Extracorporeal shock wave therapy and acupuncture may aid recovery

Surgical treatments targeting ECRB

Surgery is considered if symptoms persist for 12+ months despite treatment. The goal is to remove damaged ECRB tissue and promote healing.

• Open Surgery: The surgeon removes the damaged ECRB tissue and reattaches the healthy portion to the bone
• Arthroscopic Surgery: A minimally invasive approach to clean up and repair the ECRB
• Percutaneous Tenotomy: A needle-like instrument removes damaged tendon fibres

Outcomes

• 80-90% of patients improve with non-surgical treatments within a year
• Only 2-4% require surgery
• Surgery has a 90-100% success rate in symptom relief, but up to 40% may still have some pain

The ECRB is the main target in tennis elbow treatment, with therapies aimed at reducing strain, promoting healing, and restoring function.^3,9

Preventing tennis elbow: strategies for injury reduction

Warm up and stretch properly

Before doing any activity that involves repetitive arm movements, like tennis or painting, it’s important to warm up first. Start with light exercises to get your blood flowing, then stretch your forearms, wrists, and hands. This helps get your muscles ready and lowers the risk of injury.

Use the right technique

Doing things the right way is key to avoiding tennis elbow. Whether it’s playing a sport, painting, or lifting weights, using poor form can put unnecessary stress on your tendons, making injuries more likely. If you're unsure about your technique, ask a coach or instructor to guide you and make sure you're doing it correctly.

Choose the right equipment

The gear you use plays a big part in preventing tennis elbow. For activities like tennis or golf, pick a racket or club with a grip that fits your hand comfortably. Too big or too small a grip can strain your forearm muscles. Also, using equipment that absorbs shock, like vibration-dampening rackets, can help lessen the impact on your arm.

Build strength gradually

It’s important not to push yourself too hard, too fast. Gradually increase the intensity of your workouts or activities so you don’t overload your tendons. Strengthening your forearm muscles, both flexors and extensors, can help keep everything balanced and reduce strain on your elbow.

Rest and recover

Your muscles and tendons need rest to stay healthy. Make sure to take breaks and rest between activities to avoid overuse injuries. Pay attention to your body and take a break if you feel any pain or discomfort—this can prevent small issues from turning into bigger problems later.

Do regular maintenance exercises

To keep your muscles in good shape and reduce the risk of injury, do regular exercises that keep them strong and flexible. This helps maintain overall elbow health and lowers the chances of getting tennis elbow.

Even after recovering from tennis elbow, it’s important to keep doing regular exercises to prevent it from coming back. Incorporating strengthening and stretching exercises for the forearm, wrist, and hand into your routine will help keep your muscles strong and flexible.

Identifying athletes at risk

To prevent tennis elbow, it’s important to recognise who might be more at risk based on different factors:

• Internal Factors: This includes things like the shape of your elbow, age, physical strength, and how well your muscles and joints work together
• External Factors: These include things like how often you play, how much rest you get, the equipment you use, the environment you're in, and your technique.

Athletes who play racquet sports or participate in overhead throwing activities are especially at risk because these movements involve repetitive use of the elbow. Things like longer or stiffer racquets, tight strings, and heavier or wet tennis balls can put more strain on your elbow and increase the chance of injury. Using the right grip size and making adjustments to your technique can help lower the risk.

Creating a prevention plan

A good prevention plan should mix scientific knowledge with real-life experience. While it’s impossible to prevent every injury, the goal is to minimise the risk and stop small problems from turning into bigger ones. A solid prevention plan should focus on the most common injuries and make sure symptoms are caught early, so you can address them before they get worse.^9,10

FAQ’s

Is the ERCB a muscle or a tendon?

ERCB is a muscle that attaches to the Lateral Epicondyle of the elbow by a tendon..

What is a positive test for tennis elbow?

Mill's Test: In this test, the patient sits with their arm relaxed at their side and the elbow straight. The examiner gently bends the wrist downward while turning the hand so the palm faces down. If this causes pain at the outer elbow or the upper part of the forearm muscles, it indicates a possible case of tennis elbow (lateral epicondylitis).

What causes tennis elbow besides tennis?

Tennis elbow isn't just caused by sports or certain jobs. Most people who get it are between the ages of 30 and 50, so age can play a part. Having other health issues that affect tendons or joints, like carpal tunnel syndrome, rheumatoid arthritis, or a rotator cuff injury, can increase the chances of developing tennis elbow. 

Summary

Tennis elbow, or lateral epicondylitis, is a painful condition caused by repetitive strain on the forearm muscles, particularly the extensor carpi radialis brevis (ECRB). This muscle, which helps with wrist movement and stability, attaches to the lateral epicondyle and plays a key role in gripping and lifting. Overuse of the ECRB leads to inflammation, causing pain on the outer elbow that can radiate down the forearm. Common activities such as  turning door handles or shaking someone's hand can worsen the pain. Treatment focuses on rest, physical therapy, and avoiding strain on the affected muscles.