If you, any of your friends, or a family member suffers from shoulder pain, chances are the rotator cuff was brought up as a possible culprit, right? The rotator cuff is a group of muscles and tendons very important for the function of the shoulder. Four muscles form the rotator cuff: subscapularis, supraspinatus, infraspinatus, and teres minor. These muscles originate from the shoulder blade, and their tendons attach to the upper part of the arm bone or humerus. When tendon fibers become detached from bone, the term rotator cuff tear is used. Rotator cuff tears are one of the most common reasons of shoulder pain, and paradoxically, at the same time, there are many, many people that have a torn rotator cuff and never suffered pain or any other shoulder issues! Isn’t that something?
When I tell my patients that they have a torn rotator cuff, they always wonder: How and why did my tendons tear? Will they heal on their own? Will they get worse? Believe it or not, we do not have a perfect answer for many of these problems. But we do know a little bit…
Tear or wear?
Some shoulder specialists think we should change the name rotator cuff tendon tear to rotator cuff tendon wear… The reason is that most cuff tears are the consequence of the natural aging process. But humans do not age at the same rate: some of us get wrinkles or gray hair earlier in life, while some look forever young. The same is true for tendon fibers: they wear more rapidly in some people than others.
There is some speculation regarding why some people wear their cuff tendons earlier in life. There is no question that some individuals are more susceptible: certain studies have identified families with predisposition to tendon tearing, where many or most members of a family get them. Some occupations or activities may also make them more likely, especially those that require repetitive overhead activities.
The relationship between impingement and cuff wear continues to be debated. The bone at the very top of the shoulder, called acromion, may thicken over time by developing a bone spur on its undersurface. As a consequence, the passage for the cuff tendons narrows. As the tendon moves, it gets squeezed (pinched or encroached) time after time (hence the word “impingement”). In a way, the tendon suffers the same effect as a rope rubbing on a sharp rock: the rope fibers start to fray and tear, and eventually one day the whole rope may break!
A sudden injury may also contribute to cuff tear. This part gets tricky. In some individuals, a completely healthy, normal cuff will tear if the injury to the shoulder is bad enough. We call these tears acute traumatic tears, and they must be evaluated right away by a shoulder specialist (please read our post on acute rotator cuff tears Acute Tears of the Rotator Cuff: Why seek Help Immediately?). A different situation occurs when cuff tendons, that were chronically torn (worn) to some degree, get torn further by an injury: an acute extension of a chronic tear. These tear extensions may not do as well with surgery as a truly acute tear: since the tendon was already worn and deteriorated to some extent prior to the injury, the tendon quality does not hold sutures as well, and the muscle may be somewhat weakened as well.
What we know happens once the cuff is torn…
There are many things that we do not know about the natural history of rotator cuff disease. But a few things we know: (1) most torn rotator cuffs do not heal on their own; (2) in some people, the size of the tear gets bigger over time; (3) the muscles deteriorate to some extent once the tendons are torn, and (4) in some individuals arthritis ends up happening.
Cuff tears do not heal on their own. As mentioned, once one or more cuff tendons are no longer attached to bone, they do not reattach again on their own unless repaired surgically. Why? Muscle contraction pulls these torn tendons away from the bone. In addition, joint fluid may wash out the area of tearing and interfere with healing. Finally, these aged, worn tendons have somewhat compromised healing properties. The fact that cuff tears do not heal does not mean that they create major issues in every single individual: once inflammation subsides, the many other healthy muscles and tendons of the shoulder may compensate to some extent for the torn tendons. In fact, there are many individuals in the world that do not even know they have a worn/torn rotator cuff, since they never felt pain or weakness.
The 50% rule. For patients with a torn rotator cuff, approximately 50% of the tears increase in size within two years. Likewise, patients with a torn cuff that does not hurt have a 50% chance of developing pain in the ensuing 2-3 years. The chances are higher if the tendon tear is large to begin with, or if the tear size enlarges. Rotator cuff tendon tears can also result in muscle degeneration. Once the tendon is no longer connected to the bone, the muscle is no longer working much. As a result, cuff muscles may get smaller (atrophy) and strong muscle fibers are slowly replaced by fat tissue (fatty infiltration). Once the muscle is atrophied, fatty and long gone, repair of the corresponding tendon may be pointless, since atrophy and fatty infiltration may not reverse.
Arthritis may be the end result. In some individuals with long-standing large cuff tears, eventually the shoulder joint degenerates as well. A special tissue called articular cartilage covers the articulating bones at healthy joints; cartilage allows smooth painless motion. Cartilage disintegration is the main issue leading to arthritic symptoms. When shoulder arthritis is the final consequence of a cuff tear, the term cuff tear arthropathy is used. Cartilage damage is accompanied by an upward displacement of the humeral head and various degrees of bone wear. It is hard to know how many individuals with a torn cuff eventually develop cuff arthropathy. Once this happens, tendon repair is not very likely to help, and shoulder replacement becomes the best surgical solution (Shoulder Replacement: Anatomic and Reverse. What is the Difference?)
What does this all mean for me?
Chronic shoulder pain deserves a consultation with a shoulder specialist. At a minimum, you want to know where you stand in terms of your joint health. Cuff tears are a common reason for shoulder pain, but not the only one. If your shoulder specialist suspects that you may have a cuff tear, this will likely need to be confirmed with additional testing (most commonly, magnetic resonance or ultrasound). If you are found to have a painful cuff tear, just remember:
- Cuff tears may be the consequence of aging, certain activities or occupations, impingement, your own family predisposition or injuries. Not uncommonly, one or more of these factors are combined.
- Not every cuff tear hurts… or hurts forever. You may be able to get better with anti-inflammatories, one injection, and/or physical therapy. However, without surgery, your tear is unlikely to heal.
- If your tear was clearly a consequence of injury, you may have an acute tear (Acute Tears of the Rotator Cuff: Why seek Help Immediately?) and surgery is best for most of those. You could also have an acute extension of a chronic tear, in which case the benefits and risks of surgery need to be considered more carefully.
- For chronic wear and tear, without surgery, there is a 50/50 chance of getting worse. If you are lucky, your pain will go away and you will be able to function well. If not, your tear will get bigger, which could potentially lead to muscle degeneration and eventually arthritis. If you are recommended, or decide, not to have surgery, a repeat magnetic resonance or ultrasound may be justified 1-2 years later to determine whether your tear is getting larger, so that the opportunity for a good repair is not missed.
- If your cuff tear hurts, and hurts, and hurts… despite a good trial of nonoperative treatment, surgery will be likely your best bet.
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