Tennis Elbow Explained: Causes, Symptoms & Treatment of Lateral Epicondylitis

• October 18, 2025
• Kiera Masterson
• 8 Comments

Lateral Epicondylitis is a common overuse injury that affects the outer part of the elbow. It’s the medical name for what most people call tennis elbow. The condition occurs when the common extensor tendon, which attaches to the lateral epicondyle of the humerus, becomes inflamed or micro‑torn due to repetitive strain.

What Triggers Lateral Epicondylitis?

Even though the name suggests a tennis‑related problem, the injury shows up in anyone who repeats wrist‑extension or forearm‑pronation motions. Typical triggers include:

• Racket sports - especially backhand strokes that force the forearm muscles to contract forcefully.
• Manual labour - painters, carpenters, and plumbers often lift tools that strain the elbow.
• Computer use - prolonged mouse clicking or typing with a tight grip can accumulate micro‑damage.
• Bad equipment - grip size that’s too small or too large forces the forearm muscles to work harder.

When the load exceeds the tendon’s capacity to repair, tiny tears appear. The body’s inflammatory response then causes pain, swelling, and reduced grip strength.

Spotting the Symptoms

Even a mild case can hamper daily activities. Look out for these signs:

1. Sharp or aching pain on the outer elbow, especially when gripping or lifting.
2. Stiffness that worsens after periods of inactivity (like waking up in the morning).
3. Weakness when trying to turn a screwdriver or shake hands.
4. Pain that radiates down the forearm toward the wrist.

If you notice any of these, an early visit to a physiotherapist or primary‑care doctor can prevent chronic problems.

Key Anatomy: The Extensor Carpi Radialis Brevis (ECRB)

Extensor carpi radialis brevis (ECRB) is the muscle most often blamed for lateral epicondylitis. It originates near the elbow and extends the wrist. Because the ECRB shares its tendon with the common extensor group, it bears a disproportionate share of the repetitive load.

When the ECRB’s tendon is overworked, microscopic degeneration - called tendinosis - sets in. This is why “tennis elbow” is technically a tendonitis/tendinosis condition rather than a simple inflammation.

Diagnosing the Condition

Doctors usually start with a physical exam. They’ll ask you to perform a series of maneuvers, such as:

• Resisted wrist extension - the doctor presses against your hand while you try to lift your wrist.
• Cozen’s test - you make a fist, extend the wrist, and the doctor palpates the lateral epicondyle.

If the exam is inconclusive, imaging may be ordered:

• Ultrasound - shows tendon thickening or tears in real‑time.
• MRI - provides a detailed view of soft‑tissue damage.

Most cases are identified clinically; advanced imaging is reserved for persistent or atypical symptoms.

Non‑Surgical Treatment Options

For 80‑90 % of patients, conservative care resolves the problem in 3‑6 months. Below is a quick rundown of the most common approaches.

Most clinicians start with physiotherapy and activity modification, reserving injections or shockwave for stubborn pain.

Step‑by‑Step Home Management Plan

1. Identify the aggravating activity. Keep a simple log of when pain spikes - e.g., after 30 minutes of racquet play.
2. Apply ice for 10‑15 minutes, three times a day, during the first 48 hours of flare‑up.
3. Start gentle wrist extensor stretches: straighten the arm, palm down, pull the hand toward you with the other hand for 20‑30 seconds, repeat 3×.
4. Progress to eccentric loading: hold a light dumbbell (1‑2 kg), lower the wrist slowly over 3 seconds, then use the opposite hand to return to start. Perform 2 sets of 15 reps twice daily.
5. Consider a counterforce strap during activities. Place it 2‑3 cm distal to the lateral epicondyle and tighten until you feel comfortable pressure.
6. Schedule a physiotherapy session within a week to fine‑tune the program and add manual mobilizations.

Consistency is key. Most patients notice a drop in pain after 2‑3 weeks if they stick to the plan.

When to Seek Professional Help

While many cases resolve with self‑care, watch for red flags that merit a clinician’s eyes:

• Pain that persists beyond 12 weeks despite home measures.
• Significant loss of grip strength (more than 30 % compared to the other side).
• Numbness or tingling down the forearm - may indicate nerve involvement.
• Visible swelling, bruising, or a palpable lump near the elbow.

Early intervention can prevent chronic tendinosis that sometimes requires surgical release.

Surgical Options - A Last Resort

If conservative care fails after 6‑9 months, orthopedic surgeons may discuss two main procedures:

• Open or arthroscopic release of the common extensor tendon - cuts the damaged tissue to allow healthy regrowth.
• Debridement plus repair of the ECRB origin - removes scar tissue and re‑anchors the tendon.

Success rates hover around 85 % with a typical rehab timeline of 3‑4 months before returning to full activity.

Prevention: Protect Your Elbows for Life

Even if you never pick up a racket again, the same mechanics can crop up in everyday tasks. Here are easy habits to keep the tendons happy:

• Warm up with arm circles and light wrist stretches before any repetitive work.
• Use tools with ergonomic handles; switch hands when possible.
• Strengthen forearm extensors with dumbbell curls and reverse curls twice weekly.
• Take micro‑breaks - a 30‑second pause every 15 minutes reduces cumulative loading.

Prevention is cheaper, faster, and less painful than treating a flare‑up.