SHOULDER IMPINGEMENT SYNDROME
What is impingement syndrome?
Impingement syndrome occurs when the tendons of the rotator cuff are compressed between the bones of the shoulder during movements of the arm.
How common is it?
It is the most common cause of shoulder pain. It is most commonly seen between the ages of 40 and 60.
Why does it occur?
The shoulder is the most mobile joint in the human body. Unfortunately this mobility also means that it is the least stable joint in the body. There is a group of muscles around the shoulder called the rotator cuff. The rotator cuff helps to keep the head of the humerus (the “ball”) centred in the socket when the arm is raised. For a variety of reasons, this function can become impaired, for example excessive overhead activities with the arm or an injury. Thus each time the patient tries to raise his arm above shoulder level, instead of the ball remaining in the centre of the socket it tends to rise up and squash the rotator cuff between it and the overlying shoulder blade. Some patients have bone spurs from their shoulder blade which contributes to the impingement.
What are the symptoms?
This syndrome generally causes an aching pain in the shoulder which can sometimes travel into the upper arm. The pain is made worse on trying to raise the arm above shoulder level or on reaching into the back pocket. Pain at night is typical and may disturb sleep particularly when laying on the affected side.
How is it diagnosed? Will any tests be required?
It can be diagnosed from the history and physical examination. Sometimes a local anaesthetic injection around the rotator cuff may be given to confirm the diagnosis. In more severe cases, a shoulder scan may be requested to rule out a tear of the rotator cuff tendons.
What happens if it is not treated?
Chronic impingement may lead to worsening inflammation ( bursitis and tendonitis) and even to thinning or rupture of the rotator cuff tendons.
How is it treated?
The initial goals of treatment are to decrease pain and reduce the degree of impingement by increasing the amount of room available for the rotator cuff tendons to move.
- Nonsurgical methods are used to start with. Simple painkillers and anti-inflammatory tablets are used in conjunction with physiotherapy and simple exercises.
- The next step is to administer a local anaesthetic and steroid injection into the space surrounding the rotator cuff. Some patients have only temporary benefit from an injection. If the effect of the injection wears off quickly than keyhole surgery is often the best option for long-term relief of pain.
- Keyhole surgery (Arthroscopic subacromial decompression) is performed as a day case operation. It is performed through two tiny 0.5 cm incisions. It involves the removal of soft tissue compressing the rotator cuff and removal of any bone spur from the shoulder blade which may be contributing to the compression. If a tear of the rotator cuff tendon is present this can be repaired at the same time. Some patients also have arthritis of the joint between the collar bone and shoulder blade ( called the AC Joint). These patients can benefit from removal of the worn joint surfaces by keyhole surgery ( AC Joint Excision) at the same time as the decompression.
How successful is surgery?
With proper patient selection, the success rate for relief of pain is about 90%.
What about recovery after keyhole surgery?
After surgery , a sling is used to rest the arm for the first day or two and then discarded. Physiotherapy and a home exercise program are started within days. Most people in non-physical professions can return to work within days. Driving is usually possible within a few days as well. Absorbable sutures are generally used and these do not require removal. The damaged rotator cuff may take several weeks to recover, therefore some symptoms may persist for 3 months or more.