The shoulder is perhaps the most complicated joint in the body. Many of the other joints, such as the elbow and fingertip joints, are like simple hinges. They can only bend in one direction and straighten out. The shoulder, however, is what we call a ‘ball and socket’ joint and this design allows the shoulder the freedom to move in all directions. Unfortunately, this extra movement in the shoulder joint makes it unstable, and therefore prone to injury.

Image from South Californian Orthopedic Institute

Muscles

The shoulder joint relies a great deal on muscles for its stability. There are big muscles around the shoulder such as pectoralis major, latissimus dorsi and deltoid. It is their role to provide the strength and movement to the shoulder joint in activities such as reaching overhead and lifting. There are also four smaller muscles known as the rotator cuff that surround and protect the shoulder joint.

Image from South Californian Orthopoedic Institute

What is shoulder impingement?

Shoulder impingement occurs when one of the rotator cuff tendons get caught between the two bones (humerus and acromion) of the shoulder joint when raising the arm over the head. It is commonly associated with sports or activities that involve repetitive overhead actions (eg tennis, swimming, cricket and weight training), but can happen to anyone. This can cause a ‘catching’ pain as the arm is raised over the head. As time goes on, it can lead to a degeneration of the rotator cuff tendons (tendinopathy) or inflammation of a fluid filled sac between the tendons and the acromion known as the bursa (bursitis), which progressively worsens as activity continues.

What are the symptoms of shoulder impingement?

The most common complaint is aching located in the top and front of the shoulder, or on the outer side of the upper arm (deltoid area). The pain is usually increased when the arm is lifted to the overhead position and is often described as a ‘catching’ sensation. Frequently, the pain seems to be worse at night, and often interrupts sleep. As the condition progresses, there may also be weakness in the arm and an inability to raise the arm above the head.

What are the causes of shoulder impingement?

There are many factors which can predispose a person to rotator cuff injury, which include;

• Overusing the shoulder, especially if you’re not used to the activity.
• Poor sporting technique
• Weakness of the stabilising and rotator cuff muscles in the shoulder
• Poor posture
• An abnormal bone growth in the shoulder

How can physiotherapy help?

This condition often needs a period of rest or modified activity to prevent the rotator cuff from being further damaged.

Reduction of inflammation
In the initial phase of the injury, the aim is to reduce the inflammation and pain around the shoulder. Physiotherapy techniques such as ultrasound, laser and gentle massage can be helpful in achieving this. As the pain settles, it is important to get full movement back in the shoulder using mobilisation techniques, and exercises.

Strengthening the weakened muscles
Once the initial phase is over, we begin to strengthen the muscles that have been weakened, especially the rotator cuff. It’s important to strengthen the shoulder gradually and not overwork the rotator cuff too early. Your physiotherapist will advise on this.

photograph of shoulder massage

Return to activity

As with all injuries, it is important to make a gradual return to activity or sport as the healing tendons allow. Your physiotherapist will advise you as to how quickly you should begin activity. The goal in this phase is to also correct any faults with your technique, which will hopefully prevent the condition from recurring in the future.

What else can be done?

In severe cases of shoulder impingement, or where the bursa is inflamed, a corticosteroid injection into the shoulder can help to reduce the inflammation. This can be done by a shoulder specialist, or by some GPs.

When a rotator cuff tendon has been completely torn, surgery is required to repair the damaged tendon. Following the surgery, it is most important to gradually regain full movement and strength in the shoulder, and correct any biomechanical faults, to ensure that the problem doesn’t recur.