Many common shoulder ailments can be caused by underlying shoulder impingement syndrome. In fact, it is the most common problem in the shoulder and it is thought that up to 20% of people will suffer symptoms at some time!Shoulder impingement, or better described as subacromial impingement syndrome (SAIS), can contribute to a spectrum of shoulder pathologies, such as:
- Partial thickness rotator cuff tears
- Tendinopathies – Irritation to the tendons of the rotator cuff and/or biceps leading to inflammation (tendonitis) and/or degeneration (tendinosis)
- Calcific tendinitis
- Subacromial bursitis
Signs and symptoms of impingement
Shoulder pain, weakness and loss of shoulder range of motion are of the most commonly reported signs and symptoms. Pain is often exacerbated by over head activities. Many patients report pain in the upper arm, which occasionally can radiate into the forearm and hand. Shoulder pain at night is common, particularly when a patient lies on their affected shoulder.
The onset of symptoms may be acute, following an injury, or gradually worsening over time, particularly in older patients with no specific history of injury.
Who is at risk?
SAIS most commonly occurs in people who engage in repeated overhead movements. Sports that require repetitive overhead motions include tennis, swimming, baseball and volleyball and are thus common culprits for impingement syndromes if shoulder biomechanics is suboptimal. In the workplace, painting, carpentry and construction work may contribute. But even after years of seemingly normal use, older individuals may gradually develop impingement syndromes too.
How does it occur?
The ball and socket style shoulder joint (glenohumeral joint) requires a great deal of dynamic stabilisation from the muscles of the rotator cuff. The rotator cuff consists of four short muscles originating on the shoulder blade, with the tendons of each attaching to the head of the humerus (upper arm bone) close to the glenohumeral joint. When the shoulder is in motion, it is primarily this muscular cuff that stabilises the ball of the humerus within the socket of the shoulder blade.
As you raise your arm the space between the humeral head and the acromion (outer most tip of the shoulder blade) naturally reduces. If this space reduces beyond its normal range it can eventually cause pain and pathology by compressing the structures that pass through the subacromial space.
Possible causes of SAIS
The possible causes of SAIS may be many and varied, ranging from boney spurs which reduce the subacromial space, poor dynamic stabilisation of the shoulder joint by the rotator cuff muscles, or an unstable shoulder joint with ligamentous laxity. It is very important to determine the cause of the impingement in order to effectively reduce it!
Although the rotator cuff muscles are capable of generating torque (creating shoulder joint rotations), they also depress the humeral head. Without an intact or effectively working rotator cuff, particularly during the first 60 degrees of arm elevation, the upward directed muscular pull of large shoulder muscles may cause the humeral head to jam upwards underneath the bony acromion. An effective rotator cuff will act to depress the humeral head to limit its superior migration as the arm is elevated above the head.
Diagnosis
The diagnosis of SAIS is usually made from a detailed history and a physical examination. During the physical examination, an Osteopath will use a variety of orthopaedic tests in which your shoulder is manoeuvred into a range of motion whereby the subacromial space is reduced to assess for replication of your signs and symptoms. Furthermore, neck, upper back, and rib mobility, as well as stability and muscular control of the shoulder blade and shoulder joint are often assessed to ensure optimal stability during movement.
Diagnostic imaging such as x-ray and ultrasound may be utilised to assess the integrity of the subacromial space and its contents if deemed necessary.
Treatment
Conservative treatment with manual therapy is often sufficient to treat SAIS. Importantly, this involves resting from aggravating activities! To help restore your shoulder’s natural mechanics, an osteopath will use a variety of manual techniques, including a specifically tailored exercise rehabilitation program to improve muscular control and stability of both the shoulder blade and the shoulder joint.
Medications such as anti inflammatories may be used for a short period of time to reduce inflammation of impinged structures. In more severe cases, or if conservative management fails, cortisone injections may be considered.
In Summary
Shoulder pain can be caused by a number of different pathologies, and an osteopath can help determine the precise reason for your shoulder pain! Subacromial impingement syndrome is one very common reason for shoulder pain in many populations and whilst it can be debilitating for some, it is also very effectively treated using osteopathy.