In 1972, Dr Charles Neer introduced the idea that the main cause of rotator cuff pain and rotator cuff tears was due to the friction caused by the acromion on the supraspinatus tendon during humeral elevation. 

He in turn recommended a surgery referred to as “subacromial decompression” which involves the shaving of the acromion, removal of the subacromial bursa and cutting of the coracoacromial ligament to relieve this impingement of the supraspinatus tendon and improve symptoms.

Since then, shoulder decompression surgery has become a common practice among surgeons to treat patients with rotator cuff pain and the theory of shoulder impingement is still widely accepted among health care practitioners today. 

Despite its implementation over the last few decades, there has been no concrete evidence to support this theory in the treatment of rotator cuff pain. 

A study conducted by Beard et al, comparing decompression surgery to placebo surgeries (involving an arthroscopy only) found no difference in relief of symptoms.

A study conducted by Kolk et al, which compared the removal of the bursa along with the shaving of the acromion to the removal of the bursa only also did not find a statistically significant difference in the number of rotator cuff tears after twelve years.

Paavola et al, conducted a controlled trial which included an exercise group as well as the shoulder decompression and placebo surgery groups for comparison, and concluded that shoulder decompression surgery provided no benefit when compared to the placebo and exercise groups.

Furthermore, two systematic reviews investigating the effect of shoulder decompression surgery concluded that this surgery does not provide any benefits in terms of pain and function when compared to the placebo.

So, if shoulder impingement has not been proven to be the cause of rotator cuff related pain, then what could cause it? 

Due to the evidence questioning the theory of shoulder impingement, another theory proposing that damage of the rotator cuff tendons from excessive load has gained popularity over recent years. This is also known as rotator cuff tendinopathy.

Tendinopathy typically occurs from a sudden increase in the load of the tendons, and due to their poor vascularization and longer healing time, the tendon fails to heal properly resulting in abnormalities as well as symptoms of pain and discomfort. The abnormalities that occur are an increase in the non-collagenous matrix, disruption of collagen fibres, intracellular abnormalities, and proliferation of tenocytes with little to no inflammation.

Therefore, treatment should focus on the use of exercises to load the rotator cuff muscles correctly and gradually. Exercises to strengthen the muscles of the scapula  (lower and middle trapezius, and serratus anterior) should be included as well to support the rotator cuff in providing glenohumeral joint stability. The patient can then progress to more functional movements to strengthen the upper body in its entirety according to the patient’s goals and what activities they wish to return to.

Biokinetics Intern

Cameron Fletcher