Impingement Syndrome

Why does it occur?

Several factors can contribute to impingement syndrome. These include individual anatomical shape, bony spurs, posture, muscle balance and control and shoulder stability.

The tendon of suprapinatus muscle which helps lift the arm away from the body to the overhead position gets caught between the bone of the tip of the shoulder and the underlying ball of the shoulder joint. This causes the tendon to rub and become inflamed and roughened. Occasionally the tendon can be so damaged it can tear.

What are the symptoms?

Pain moving the arm away from the body is the characteristic symptom of impingement. This is often described as a painful arc, starting as the arm reaches 80 degrees away from the body and often improving if the arm can be taken beyond 120 degrees. Pain is often felt bringing the arm back down again. This movement can also feel weak as well as painful. Often patients find the shoulder is painful in bed

Investigations

X-rays can show the shape of the shoulder bones and subtle changes of impingement

Ultrasound and MRI scans can demonstrate impingement changes, An  MRI scan is very good at demonstrating impingement changes in the tendons.

Treatment options

  • Non-operative treatment

Pain killers can improve symptoms in mild cases

A steroid injection into the sub-acromial space (between the tendon and the shoulder tip) can often help discomfort and allow physiotherapy to progress. The injection can last several months.

Physiotherapy can improve shoulder posture, control and strength.

  • Operative treatment

One of the most common shoulder procedures is an arthroscopic subacromial decompression. This is performed when impingement symptoms persist despite non operative measures. The procedure is done under general anaesthetic as a day case or with an overnight stay.  Using keyhole techniques instruments are inserted into the shoulder and the subacromial space. Usually three 1cm incisions are needed. Soft tissue and bone are removed to prevent the tendon rubbing.

Complications

Infection is very rare after arthroscopic surgery

Some patients develop stiffness that does not respond to physiotherapy and may require a further procedure to treat the stiffness. This can occur in up to 5% of cases.

Rehabilitation after surgery

After the operation a sling is used for a day or two if needed. Most patients discard the sling quickly and start using the arm at waist/table level. It may take 6 weeks to be able to confidently raise the arm overhead. Some patients benefit from physiotherapy to help regain shoulder function.

Frequently asked questions

When can I drive a car?  Most people are able to return to driving between 1 and 2 weeks after the operation. Some times it takes a bit longer. You should only drive once you feel your shoulder is mobile and strong enough to do so.