Injury to the rotator cuff

The subscapularis muscle is the anterior muscle of the rotator cuff and also its largest muscle. It occupies the entire front surface of the shoulder blade, i.e. it fits between the shoulder blade and the back. It tapers towards the humeral head and becomes tendinous in its upper parts, while the lower third remains muscular. At the humeral head, the tendon is attached to the small tuberosity, the tuberculum minus. Although it is a large and strong muscle, it only has a small range of motion. It serves to rotate the arm inwards. It is assisted by other large and powerful muscles. However, if you want to put your hand behind your back, e.g. to take your wallet out of your trousers or pull your trousers up, you need the subscapularis. The muscle is innervated (controlled) by the upper and lower subscapular nerve.

The supraspinatus muscle is the upper muscle of the rotator cuff and originates above the spina, the bony wall of the shoulder blade in its pit, the supraspinatus fossa. Its tendon must pass through the very narrow space below the acromion. The tendon then runs over the humeral head and finally attaches to the large tuberosity, the greater tuberosity. The muscle is very important for shoulder mobility because it supports the lateral elevation of the arm. It ensures that the deltoid muscle cannot pull the humeral head up into the joint and trap it under the acromion (impingement). This keeps the humeral head in the joint so that it can perform a rotational movement and thus lift the arm. However, it is the tendon of the supraspinatus itself that is often trapped under the acromion and can then cause pain. The muscle is innervated by the suprascapular nerve, which runs through a narrow passage before reaching the muscle.

The infraspinatus muscle is the posterior, upper muscle of the rotator cuff and occupies the entire posterior space of the shoulder blade below the spina. It tapers towards the humeral head and its tendon attaches to the posterior upper part of the greater tuberosity slightly behind the supraspinatus. At the insertion point, its tendon fibres partially intersect with those of the supraspinatus. It is an external rotator, which means that it is responsible for the outward rotation of the arm. It is innervated by the same nerve as the supraspinatus, but this nerve has to pass through another constriction on the way.

The teres minor muscle, the so-called small round muscle, is the smallest muscle of the rotator cuff. It runs from the outer lower edge of the shoulder blade to the lower part of the greater tuberosity. Together with the infraspinatus muscle, it is the only external rotator of the shoulder joint. This function is extremely important as it allows us to raise the hand in front of the face. The muscle is innervated by branches of the axillary nerve, which also innervates the large and important deltoid muscle.

The deltoid muscle is not part of the rotator cuff, but is the most important muscle for arm movements in the shoulder joint. It is a large, strong muscle that rounds the shoulder nicely. Its course is a bit like that of an epaulette: it originates from the outer collarbone and the acromion and runs towards the upper arm, where it is attached to the outer side slightly above the centre. If you lift your arm sideways, you can feel and see the deltoid muscle working very clearly. It is controlled by the axillary nerve, which is therefore a very important nerve in the shoulder.

Due to its anatomy, the pull of the muscle goes straight upwards at the beginning of the movement when the arm hangs down at the side of the body. However, this prevents a rotational movement in the joint because the lever arm is missing. This is where the rotator cuff comes in.

There are many other muscles that are involved in the movement of the arm. However, they do not play a role in understanding the rotator cuff.

The task of the rotator cuff is to dynamically stabilise the humeral head in the joint. This means that an external force or the pull of the various muscles on the upper arm must not cause the humeral head to dislocate from the joint. This risk exists because the glenoid cavity on the shoulder is flat and small and cannot surround the humeral head as it can on the hip.

The anterior muscle (subscapularis) and the two posterior muscles (infraspinatus and teres minor) wrap around the humeral head like reins around a horse's head. In this way, the various forces acting forwards or backwards can be absorbed dynamically. As a major exception, the two posterior muscles also serve the actual arm movement when the arm is turned outwards (rotated).

To understand how the upper muscle, the supraspinatus, works, you need to visualise the traction vectors of the supraspinatus and the deltoid. These are at right angles to each other, namely the deltoid vector vertically and the supraspinatus vector horizontally. This means that the deltoid pulls the upper arm straight upwards. Because this upward pull has no lever arm and therefore no torque, the humeral head would slide upwards out of the joint until it painfully hits the acromion. This is prevented by the horizontal pull of the supraspinatus. Because the muscle runs over the humeral head and presses it inwards onto the joint, it not only holds it in the joint and thus prevents it from sliding upwards, but also initiates the lateral lifting of the arm from the body. This helps the deltoid muscle to create a lever arm so that it can powerfully lift the arm sideways upwards.

Tendons are used to transfer the force of a muscle to the bones. They have to withstand almost superhuman forces, as the forces are large and the lever arms are generally small. During the crawl movement of the arm, the force on the subscapularis can be up to 1725 N. If a weight of 25 kg is held in the laterally outstretched arm, the force that the deltoid muscle has to exert is approximately 12,400 N. Because the tendons cannot be stretched, they are the ones that tear, rarely the muscles. And because they have to withstand large loads in a small space, they do not have their own blood supply. This means that they regenerate slowly and are therefore more susceptible to wear and tear.

Tendons tear either due to an accident, e.g. a fall on the shoulder, or as a result of wear and tear. There are two reasons for wear and tear. It can be caused by overloading, e.g. in throwing sports, tennis, etc. or by ageing of the tendon (degenerative). A tendon can either tear completely or only partially. If it is only partially torn, it is possible that not the entire thickness of the tendon is torn. The tendons of the rotator cuff are built up in layers (like the duvet). It is therefore possible that only the innermost layer (which faces the joint cavity) has a tear, but the layers above it are intact (a so-called PASTA lesion). More rarely, the superficial layer tears and the deep layer remains intact. However, it is also possible that the tendon is torn in all layers, but not across the entire width of its anchorage. This is similar to tearing a piece of paper from a block, but only halfway through.

Degenerative tears usually occur in older people, often those who used to put a lot of strain on their joint. However, because the rotator cuff is there to guide the humeral head in the joint, if it tears after a certain time, this leads to incorrect loading in the joint and to the humeral head rising up. Over time, this inevitably leads to wear and tear of the entire joint, to osteoarthritis. In these cases, it is important to clarify very precisely which symptoms have which cause. Is the pain coming from the joint or from a torn tendon? Is the mobility impaired because of the rotator cuff or because of wear and tear on the joint cartilage? Do other factors such as rheumatism or neck problems play a role? Is the patient bothered by the pain, the loss of function or both? All these questions (and more) must be clarified precisely in order to be able to establish a customised therapy for the patient.

The two most important symptoms of a torn tendon are pain and loss of function, i.e. the inability to move the arm. The severity of these symptoms depends greatly on the type and cause of the tear and on the person suffering from the tear.

In the case of so-called traumatic ruptures, pain naturally occurs immediately. Depending on the extent of the tear, the pain may be very severe immediately and then subside, or it may be less severe but persist for a long time. Because the pain often reduces significantly after a few days, patients often do not go to the doctor. It is very typical for the accident that the arm can hardly be moved immediately afterwards (pseudoparesis). This can also improve over time. In any case, however, the strength in the arm is reduced.

If the rotator cuff has been injured in an accident, there is usually a significant loss of strength or function. There are patients who are not bothered by this and can live like this because they don't need their arm much anyway. But this is not the case for most people. They need to be able to use their arm fully again for work and sport. Depending on the type and size of the tear, an attempt can be made to achieve an improvement with physiotherapy. However, success should not be too long in coming. This is because a torn tendon retracts and its muscle breaks down (atrophies) and becomes fatty - eventually to such an extent that the tendon can no longer be sutured. In most cases, however, your specialist will suggest an operation, not only to straighten the shoulder, but also to preserve it for the future. This is because a torn tendon can no longer be sutured at some point.

Tears caused by overloading often affect athletes and people who do physical labour. It not only affects people who work overhead, but also professions such as hairdressers, chefs, dentists and teachers. They are often no longer very young, but have high demands on their shoulder joint due to their job. The supraspinatus tendon is most frequently affected. This is because it has to pass under the very narrow acromion and can become chafed in the process. It also makes almost a right angle at its insertion every time the arm is raised. This leads to friction within the tendon and thus to small fibre tears, similar to when you wear out your sock. This is more likely to happen in older people because the tissue becomes more brittle. And in terms of the joints, people are already ageing by the age of 40. It is not uncommon for the tendon to be only partially torn. In this case, the function is usually quite well preserved, but the pain is very severe. As a rule of thumb, it is assumed that a tear that is smaller than 50 per cent of the tendon thickness can heal. Above this, the tear is expected to progress.

It is important that a specialist is consulted. Your family doctor (or the emergency doctor) is your first point of contact, but further diagnosis should not be delayed, especially in the event of an accident. The specialist will ask you in detail about your symptoms, e.g. how the accident happened, pain when strapping in, dressing, working overhead or even at night. He will then examine you and check how good the mobility and strength in the joint are. The doctor will often already have a suspected diagnosis. This is confirmed by an X-ray and often an MRI. Sometimes ultrasound is also used.

In addition to painkillers and physiotherapy, an injection of cortisone can also be used for pain therapy. However, it should be used with caution, as cortisone does not help the tendon to heal. However, the side effects of cortisone are very minor with a single injection. Around half of all people with a tear due to wear and tear have got used to it and learnt to live well with it with the help of physiotherapy. However, the other half remain symptomatic. These are often people with high demands on their joint. If the non-surgical options have been exhausted and the symptoms still persist, then the time has come to discuss surgery. Depending on the condition of the patient as a whole and the joint in particular, various operations will be suggested.

The anterior muscle, the subscapularis, plays a special role in rotator cuff tears. This is because it serves as the anterior boundary of the shoulder joint and is therefore particularly important for holding the humeral head in the joint. If it tears off, this boundary is lost and the humeral head will slide forwards out of the joint when the arm is raised (subluxation). This blocks movement and is extremely painful. Not in the case of a small lesion at the very top of the tendon (grade I according to Lafosse), but if the tear progresses, the humeral head risks subluxation. This is why the classification of the extremely methodical Dr Lafosse also includes a grade V for this tear, in which subluxation is described. None of this would be so bad if the torn tendon could be replaced by another one. Unfortunately, these replacement operations (tendon transfer) are really only a replacement and not sufficient for satisfactory function. However, another surgical technique is currently being developed that involves moving the tendon of the latissimus dorsi muscle and may one day be able to deliver better results. If there is an injury to the subscapularis muscle, your specialist may therefore urge you to undergo surgery even for a minor injury in order to avert serious consequences in the future.

Most shoulder operations today are performed using keyhole surgery, or arthroscopy. This modern technique has a number of advantages, above all the fact that a joint does not have to be opened and therefore the injuries around the operation are much less. Instead of a large incision, depending on the operation, a few very small incisions are made that are barely visible later. The operation is then performed using a camera and special instruments. This type of operation is not stressful for the body and recovery is very quick. However, the shoulder can sometimes hurt a little and swell up. A catheter can be inserted to relieve the pain and the swelling will disappear on its own after a day. In most cases, the immobilisation that used to be administered in the past is only needed immediately after the operation to protect the shoulder. You can usually leave hospital after three to five days, even without the immobilisation.

However, an operation has to heal, otherwise it won't hold. This is why you are generally not allowed to use your arm for six weeks. During this time, however, you already have physiotherapy, where you learn to move your arm passively. This is extremely important, as otherwise the joint becomes stiff. After six weeks, you can then start to move the joint yourself again and then build up your strength and mobility together with the physiotherapy. This always takes a long time. The recovery period after shoulder surgery often takes six months or more.

The most important thing is good health. This includes getting enough exercise, eating healthily and trying to live as stress-free a life as possible despite having a shoulder problem. Physiotherapy is often prescribed even before the operation to keep the joints mobile and the muscles active. The exercises should be done daily at home. In the case of major surgery, it may be useful to take nutritional supplements (vitamins and proteins) before and after the operation to help strengthen the immune system. This can help to reduce the risk of infection. However, the risk of infection is very low during arthroscopy. Smoking should be avoided whenever possible. It impedes blood circulation and therefore healing. Before every operation, the family doctor will carry out a check-up to rule out any nasty surprises. After the operation, it is very important to follow the doctor's instructions. Rest is necessary, especially during the healing phase, but not inactivity. Daily exercises will be instructed. They are the key to recovery. Five minutes a day is better than a quarter of an hour every three days.

The cost of such an operation depends on various factors, such as the duration and complexity of the procedure and the length of hospitalisation. As a rule, your health insurance will cover the costs in full if you have the appropriate insurance.

Private or semi-private insurance is required for treatment at our specialist centre.

If the treatment is self-financed, we will be happy to provide you with a cost estimate after a thorough examination. This also applies in particular to foreign patients.