Subacromial impingement of the shoulder is a clinical sign of the rotator cuff tendons becoming impinged as they pass through the subacromial space to insert onto the humerus. This mechanism causes repeated irritation to the tendons and bursae leading to inflammation, pain and injury to the tendon. Several conditions are linked to impingement including bone spurs, bursal hypertrophy, rotator cuff disease, SLAP lesions, biceps tendinopathy and instability.
Subacromial impingement can be grouped into two groups, with both contributing to rotator cuff tendinopathy. As physiotherapists we can identify impingement signs by a couple of clinical tests, with no imaging required.
Caused by abnormalities of the superior structures e.g. a beaked or curved acromion. Tends to be the cause of impingement for those >35 years of age.
Caused by poor scapula stabilisation resulting in excessive protraction and rotation which reduces the subacromial space. Can also be caused by poor muscle balance between the shoulder elevators and rotator cuff so the humerus is moved superiorly. Usually occurs in people <35 years of age.
Signs and Symptoms
- Pain with overhead and weight-bearing activities
- Painful arc with abduction between 70°-120°
- Pain and restriction with internal rotation
- Positive impingement testing
- Pain with resisted contraction of the rotator cuff muscles
- Sometimes instability will be reported and evident on clinical examination
- Rest from aggravating activities initially
- Ice and anti-inflammatory medication
- Massage and electrotherapy
- Correction of biomechanical abnormalities through a targeted exercise program
- Technique/postural correction if applicable