Repetitive strain injury is an umbrella term that refers to soft tissue irritation, microtrauma and strain resulting from repetitive activities. It can affect the muscles, tendons and nerves. Lateral epicondylitis (tennis elbow) is a specific example of a repetitive strain injury.
Causes
Almost any repetitive movement can result in repetitive strain injury if done long enough. It often results from occupational activities, where the same movement is performed for many hours at a time, day after day. Some common examples of activities are:
- Working on an assembly line in a factory, doing the same movements over and over
- Using a computer mouse or keyboard (affecting the wrist and forearm)
- Having a poor posture for an extended period whilst reading or using a computer (affecting the neck and shoulders)
- Texting or scrolling on a smartphone (affecting the base of the thumb)
Certain characteristics of an activity increase the risk of repetitive strain injury, such as:
- Small repetitive activities (e.g., scrolling on a smartphone)
- Vibration (e.g., using power tools)
- Awkward positions (e.g., painting a ceiling)
Presentation
Usually, there will be a history of repetitive activities, often related to work.
Symptoms will be located in an area related to the activity. They can include:
- Pain, exacerbated by using the associated joints, muscles and tendons
- Aching
- Weakness
- Cramping
- Numbness
On examination, the area may be tender to palpation. There may be mild swelling in the area. It may be possible to recreate the pain by having the patient perform specific movements that add resistance to the affected soft tissues.
Diagnosis
The diagnosis is usually made clinically, based on the history and examination findings, without investigations.
Investigations may be necessary to rule out other differential diagnoses (e.g., arthritis, inflammatory conditions or nerve compression), such as:
- X-rays (e.g., to look for osteoarthritis)
- Ultrasound (e.g., to look for synovitis in rheumatoid arthritis or rotator cuff tears)
- Blood tests (e.g., inflammatory markers and rheumatoid factor for rheumatoid arthritis)
Management
The RICE mnemonic can be applied to most soft tissue injuries. This stands for:
- R – Rest
- I – Ice
- C – Compression
- E – Elevation
Rest and adapting activities are essential. If the repetitive movement continues, the condition will get worse. This often involves the patient discussing their duties with the occupational health department at their place of work to amend their work tasks.
Other potentially helpful options include:
- Analgesia (e.g., NSAIDs)
- Physiotherapy
- Steroid injections (in specific scenarios)
Last updated August 2021