Introduction
Do you get a sharp, debilitating pain in your shoulder when you are performing certain tasks? Brushing your hair, putting on clothes or showering? When you raise your arm out to the side and then upwards over your head, do you alternate between no pain and pain? For example, during the first part of the moment you don’t feel any pain, and then suddenly your shoulder “catches?” There is sharp pain, followed by no pain again as you continue to move your arm upwards. These are all signs of a condition called Shoulder Impingement Syndrome (SIS).
What is Shoulder Impingement Syndrome?
The tendons of the rotator cuff muscles that stabilize the shoulder get trapped as they pass through the shoulder joint in a narrow bony gap called the sub-acromial space. Impingement refers to the friction of tendons moving against bone. Repeated pinching and irritation of the tendons and bursa (the padding under the shoulder bone) can cause inflammation and pain.
Read on to discover common shoulder injuries, their symptoms, prevention methods, causes, treatment protocols, and rehabilitation exercises.
How common is Shoulder Impingement Syndrome?
Shoulder complaints are the third most common musculoskeletal problem after back and neck disorders. Women experience the highest incidents as do people aged 45–64 years. Of all shoulder disorders, shoulder impingement syndrome (SIS) accounts for 36%, making it the most common shoulder injury.
You shouldn’t experience impingement with normal shoulder function. When it does happen, the rotator cuff tendon becomes inflamed and swollen, a condition called rotator cuff tendonitis. Likewise, if the bursa becomes inflamed, you could develop shoulder bursitis. You can experience these conditions either on their own, or at the same time.
The injury can vary from mild tendon inflammation (tendonitis), bursitis (inflamed bursa), calcific tendonitis (bone forming within the tendon) through to partial and full thickness tendon tears. These may require surgery. Over time the tendons can thicken due to repeated irritation, perpetuating the problem as the thicker tendons battle to glide through the narrow bony sub-acromial space. The tendons can even degenerate and change in microscopic structure, with decreased circulation within the tendon resulting in a chronic tendinosis.
What Causes Shoulder Impingement?
Generally, SIS is caused by repeated, overhead movement of your arm into the “impingement zone.” This causes the rotator cuff to contact the outer tip of the shoulder blade (acromion). When this repeatedly occurs, the swollen tendon gets trapped and pinched under the acromion. The condition is frequently called Swimmer’s Shoulder or Thrower’s Shoulder, since the injury occurs from repetitive overhead activities. Injury could also arise from simple home chores, like hanging washing on the line, or a repetitive activity at work. In other cases, it can be caused by traumatic injury, like a fall.
Shoulder impingement has primary (structural) and secondary (posture & movement-related) causes:
Primary Rotator Cuff Impingement is due to a structural narrowing in the space where the tendons glide. Osteoarthritis, for example, can cause the growth of bony spurs, which narrow the space. With a smaller space, you are more likely to squash and irritate the underlying soft tissues (tendons and bursa).
Secondary Rotator Cuff Impingement is due to an instability in the shoulder girdle. This means that there is a combination of excessive joint movement, ligament laxity, and muscle weakness around the shoulder joint. Poor stabilisation of the shoulder blade by the surrounding muscles changes the physical position of the bones in the shoulder, which increases the risk of tendon impingement. Other causes include weakening of the rotator cuff tendons due to overuse, for example in throwing and swimming, or muscle imbalances between the shoulder muscles.
In summary, impingement usually occurs over time due to repetitive overhead activity, trauma, previous injury, poor posture, or inactivity.
Rotator Cuff Biomechanics
When your rotator cuff fails to work normally, it is unable to prevent the head of the humerus (upper arm) from riding up into the shoulder space. This causes the bursa or tendons to be squashed. Failure to properly treat this instability causes the injury to recur. Poor technique or bad training habits are a common cause of overuse injuries.
Over time pain causes further dysfunction by altering your shoulder movement patterns which may lead to a frozen shoulder. For this reason, it is vitally important that shoulder impingement syndrome is rested, and treated as soon as possible to avoid long-term damage and joint deterioration.
What are the Symptoms of Shoulder Impingement?
Rotator cuff impingement usually has the following symptoms:
- An arc of shoulder pain approximately when your arm is at shoulder height and/or when your arm is overhead
- Shoulder pain that extends from the top of the shoulder down the arm to the elbow
- Pain when lying on the affected shoulder, night pain, and disturbed sleep
- Shoulder pain at rest as your condition worsens
- Muscle weakness or pain when attempting to reach or lift
- Pain when putting your hand behind your back or head
- Pain reaching for the seat-belt, or out of the car window for a parking ticket
Who Suffers Shoulder Impingement?
Impingement syndrome is more likely to occur in people who engage in physical activities that require repeated overhead arm movements, such as tennis, golf, swimming, weight lifting, or throwing a ball. Occupations that require repeated overhead lifting or working above shoulder height also increase the risk of rotator cuff impingement.
How is Shoulder Impingement Diagnosed?
In the United Kingdom, only doctors can diagnose. However, physical therapists can form an accurate clinical impression using some specific manual tests. An ultrasound scan may be useful to detect associated injuries such as shoulder bursitis, rotator cuff tears, calcific tendonitis or shoulder tendinopathies. An x-ray can be used to see bony spurs that may have formed and narrow sub-acromial space. See your GP in the first instance to arrange a referral.
What does the Treatment Involve?
Many structures can be injured in shoulder impingement syndrome. How the impingement occurred is the most important question to answer. This is especially important if the onset was gradual. Your static and dynamic posture, muscle strength, and flexibility all have important roles to play. The rotator cuff is an important group of 4 muscles that control and stabilise the shoulder joint. It is essential to assess the muscles around the thoracic spine and shoulder blade and to treat these too, because they work together with the entire shoulder girdle. A good therapist will look beyond the obvious to get to the root of the problem. Only then can a bespoke treatment strategy be planned.
Stages of Rehabilitation
To effectively rehabilitate this injury and prevent recurrence, you need to work through specific stages with your therapist.
These stages may include:
- Early Injury: Protection, Pain Relief & Anti-inflammatory Treatment
- Regain Full Shoulder Range of Motion
- Restore Scapular Control and Scapulohumeral Rhythm
- Restore Normal Neck-Scapulo-Thoracic-Shoulder Function, including posture correction
- Restore Rotator Cuff Strength
- Restore High Speed, Power, Proprioception and Agility Exercises
- Return to Sport or Work
The early stages of treatment will involve manual therapy, including massage to relieve pain and relax shortened structures as well as mobilisation techniques to restore normal shoulder movement. Massage therapy is well-documented as an aid to deep relaxation, and hence improved sleep quality. Discover more about the role of massage therapy in stress relief here. Sleep is essential to any healing process. Find a Sports Massage Association (SMA)-registered therapist here: https://www.thesma.org/PublicMemberDirectory
Other Treatment Methods
Strapping and taping are known to provide additional support and reduce pain. Other modalities such as ultrasound and interferential therapy are particularly beneficial. As you move through each stage of treatment your therapist will prescribe rehabilitation exercises specific to your shoulder, posture, sport, and/or work demands. Find a Complementary and Natural Healthcare Council (CNHC)-registered practitioner here: https://www.cnhc.org.uk/#gsc.tab=0
Your doctor can administer a corticosteroid injection to relieve pain if conservative (non-surgical) methods fail to reduce the pain and inflammation. Once your pain settles, it is important to assess the strength and flexibility of the neck and thoracic spine to ensure that your shoulder impingement does not return once the injection has worn off.
Conclusion
Some shoulder impingements will respond positively and quickly to treatment. However, many others can be incredibly stubborn and frustrating, taking between 3-6 months to resolve. Each person will respond differently, depending on the severity of the injury. It is also important to note that each progression must be carefully monitored as attempting to progress too soon to the next level can lead to re-injury and frustration. For more specific advice about your shoulder impingement, drop me a line, or give me a call. Alternatively find a British Association of Sports Rehabilitators & Trainers (BASRaT)-registered therapist in your area: Register Check — BASRaT
Disclaimer
The information contained in this article is intended as general guidance and information only. It should not be relied upon as a basis for planning individual medical care or as a substitute for specialist medical advice. Please see your doctor if you are suffering from shoulder pain.