Summer and silly season is almost upon us. More people get involved in outdoor and water sports and the occasional game of backyard cricket with the family at Christmas. We tend to see a lot more people with shoulder injuries. 80% of shoulder pain in primary care relate to problems with the Rotator Cuff. (1)
The next questions we get asked in clinic are…
1) What is the Rotator Cuff?
2) What does it do?
3) Why does it hurt so much?
4) What do I have to do to return my shoulder to normal function?
5) How long will this take to get better?
What is the Rotator Cuff?
It is a group of 4 muscles (supraspinatus, infraspinatus, subscapularis, teres minor) that originate from the scapula and cuffs the top of the humerus.
What does it do?
1) Simply, it enables the shoulder to rotate for both rapid movement and repetitive tasks
(Fun fact – Throwing is the fastest movement produced by body. The shoulder can rotate at ~9,000 degrees/second)
2) Stabilises the head of humerus onto the glenoid fossa through motion ‘dynamic stability’
3) Enables full range of movement of the shoulder
Why does it hurt so much?
The glenohumeral joint is the most mobile in the body. The more mobile the joint, the less stability it has. If you damage your rotator cuff, you lose the ability to perform the 3 tasks above as effectively.
The rotator cuff tendons are torn or highly irritated and this contributes to mechanical pain from poor movement patterns.
Common injuries include partial thickness and full thickness rotator cuff tears, rotator cuff tendinopathy/tendinosis or rotator cuff sprains. These conditions all fall under the umbrella term ‘Rotator Cuff Related Shoulder Pain’. RCRSP is synonymous with subacromial shoulder pain, which are both tending to replace the term ‘subacromial impingement’ in clinical practice. RCRSP accounts for 80% of all shoulder pain in primary care (1).
Other soft tissue structures that can contribute to shoulder pain include the long head of biceps, subacromial bursa and damage to the glenoid labrum.
What do I have to do to return my shoulder to normal function?
Exercise Therapy
There is strong evidence for supervised and home-based strengthening exercises for the rotator cuff and scapula muscles in the effective management of RCRSP, in both the short (<1 month) and long term (>3 months)(2). Strength and conditioning programs for the shoulder should be around 8-12 weeks (3,4).
Manual Therapy
Studies show that manual therapy can be more effective when combined with exercise therapy vs exercise alone at relieving pain in short term (5). The effect on shoulder function with manual therapy is mixed. Some studies show it can improve function in short term, and some suggest it does not change shoulder function when compared to exercise alone (6).
Corticosteroid injection
Steroid injection has been shown to be superior in improving short term pain and function when compared to physiotherapy at 6 weeks, but they can contribute to worse outcomes at 12 weeks (7). This may be due to steroids causing fibroblast and tenocyte necrosis and reducing the natural healing ability of the tendon. Injections can also increase the risk of rotator cuff tears.
(7)
How long will it take to get better?
This depends on the level of damage to the rotator cuff. Some cuff tears will require surgery if there is a severe loss of function, but many rotator cuff injuries can be managed conservatively. Interestingly 40% of people who play overhead sports have partial thickness rotator cuff tears and experience pain free movement.
Simple shoulder sprains may take 4-6 weeks to naturally settle. However, most cases of RCRSP take a minimum of 3months to return to full function.
Chronic tendinopathies or chronic partial thickness tears can be difficult to treat and can take closer to 12-18 months to improve.
Other factors to consider in prolonged shoulder pain include comorbidities (diabetes, thyroid dysfunction, hyperlipidaemia, HTN) and psychosocial factors including work stress, depression, smoking history and fear of movement.
2) https://pubmed.ncbi.nlm.nih.gov/25920340/
3) https://www.jospt.org/doi/full/10.2519/jospt.2020.8498
4) https://onlinelibrary.wiley.com/doi/abs/10.1111/sae.12009
5) https://bjsm.bmj.com/content/51/18/1340
6) https://pubmed.ncbi.nlm.nih.gov/27488037/
7) https://www.shoulderphysio.com/blog/how-do-we-treat-rotator-cuff-pain-without-the-knife