Tennis elbow, also known as lateral epicondylitis, is a common overuse injury that causes pain and inflammation on the outside of the elbow. It is typically caused by repetitive strain on the muscles and tendons of the forearm that attach to the elbow, and is often seen in people who engage in activities that involve repetitive arm and wrist movement, such as tennis, golf, and typing.

Clinical features: Tennis elbow typically presents with pain and tenderness on the outside of the elbow, especially when the wrist is extended or the elbow is straightened. 

There may also be weakness in the hand and wrist, and difficulty gripping objects. 

The pain may radiate down the arm or up into the upper arm.

Causes: Tennis elbow is caused by repetitive strain on the muscles and tendons of the forearm that attach to the elbow. 

This strain can be caused by a variety of activities, including sports such as tennis and golf, and occupations such as painting and carpentry. 

It can also be caused by improper technique or equipment during these activities.

Risk factors: There are several factors that can increase the risk of developing tennis elbow, including:

Age: Tennis elbow is more common in people over the age of 40.

Gender: Tennis elbow is more common in men than in women.

Previous elbow injury: People who have had a previous elbow injury are more likely to develop tennis elbow.

Occupation: Jobs that involve repetitive arm and wrist movement, such as typing or painting, can increase the risk of developing tennis elbow.

Examination: A physical examination by a healthcare provider is usually sufficient to diagnose tennis elbow. The provider will look for tenderness and swelling on the outside of the elbow, and will test for weakness in the hand and wrist.

Pathophysiology: Tennis elbow is caused by inflammation and degeneration of the tendons that attach to the lateral epicondyle, a bony prominence on the outside of the elbow. This inflammation and degeneration is usually the result of repetitive strain on the tendons.

Assessment: The assessment of a patient with tennis elbow typically includes a thorough history and physical examination, as well as imaging tests such as X-rays or MRI to rule out other conditions that may be causing the symptoms.

Investigation: In addition to imaging tests, other investigation may be needed to diagnose and manage tennis elbow, such as:Blood tests: These may be ordered to check for inflammation or other underlying conditions that may be contributing to the symptoms.

Nerve conduction studies: These tests measure the speed and strength of the nerve impulses in the arm and hand. They may be used to help diagnose tennis elbow and other conditions that affect the nerves in the arm.

Differential diagnosis: Tennis elbow must be distinguished from other conditions that can cause similar symptoms, such as:

Osteoarthritis: This is a degenerative joint condition that can cause pain and tenderness in the elbow.

Bursitis: This is inflammation of the fluid-filled sacs (bursae) that cushion the bones, muscles, and tendons around the elbow.

Fractures: A break in the bone can cause pain and swelling in the elbow.

Treatment: Treatment for tennis elbow typically involves a combination of rest, ice, and physiotherapy. 

Other treatments that may be recommended include:Nonsteroidal anti-inflammatory drugs (NSAIDs): These medications can help reduce inflammation and pain.

Corticosteroid injections: These injections can help reduce inflammation and pain.Physical therapy: This can help improve strength, flexibility

Tennis elbow, or lateral epicondylitis, is a condition that causes pain and inflammation in the tendons that attach the forearm muscles to the elbow. 

Physiotherapy can be an effective treatment for tennis elbow, and there are several tests that a physiotherapist may use to diagnose and evaluate the condition. Some of these tests may include:

Palpation: The physiotherapist will gently press on the affected area to identify any tenderness or swelling.

Range of motion: The physiotherapist will assess the range of motion in your elbow, wrist, and fingers to determine if there are any limitations due to pain or stiffness.

Strength testing: The physiotherapist will assess the strength in your wrist and hand muscles to determine if there is any weakness or imbalance.

Provocative tests: The physiotherapist may perform specific tests to reproduce or exacerbate your pain, such as the Cozen's test or the Mill's test. These tests can help confirm the diagnosis of tennis elbow.

Functional testing: The physiotherapist may also assess your ability to perform tasks that require grip or wrist strength, such as lifting weights or holding objects.These tests can help the physiotherapist determine the severity of your tennis elbow and develop a treatment plan that is tailored to your specific needs. 

Treatment may include exercises to strengthen and stretch the affected muscles, manual therapy to improve mobility and reduce pain, and modalities such as ice or heat to manage inflammation.