A shoulder prosthesis replaces a damaged or destroyed shoulder joint and can both relieve pain and improve mobility. Such a prosthesis is used in particular in cases of advanced osteoarthritis or severe damage to the shoulder joint. Different types of prostheses are used depending on the individual situation and the condition of the surrounding muscles.

The shoulder prosthesis at a glance

The shoulder joint is essentially a ball-and-socket joint consisting of the head of the upper arm bone (humerus) and the shoulder socket (glenoid). However, these bony structures alone are not enough to stabilise the joint. The necessary stability is ensured by the rotator cuff – a muscle and tendon complex that surrounds and guides the shoulder joint.

A shoulder prosthesis is an artificial shoulder joint that is put in when the natural joint has been severely damaged – whether due to advanced osteoarthritis (wear and tear), a humerus head fracture or irreparable tears in the rotator cuff. In the case of shoulder joint osteoarthritis, however, a prosthesis is only used when other treatment methods are no longer sufficiently successful.

An artificial shoulder joint is made up of several components that vary depending on the type of prosthesis. They basically consist of a head, a shaft and a joint socket. These elements are made of high-quality materials such as titanium or polyethylene to ensure optimum durability and compatibility.

Treatment goal 

A shoulder prosthesis is most often inserted in cases of age-related wear of the shoulder joint (osteoarthritis). If pain and discomfort can no longer be sufficiently alleviated after all conservative treatment options have been exhausted, an artificial shoulder joint is often the only option. In addition, a prosthesis may be required in the event of severe comminuted fractures (where the bone has splintered or fragmented) of the humerus head or irreparable damage to the rotator cuff.

The main goal of a shoulder prosthesis is to restore pain-free mobility. The joint replacement is intended to improve shoulder function and to noticeably improve quality of life. Patients generally experience significant pain relief and are thus better able to carry out everyday activities without restrictions.

 Procedure

In most cases, the shoulder prosthesis operation is performed under regional anaesthesia (interscalene block). The patient is in a semi-seated position known as the ‘beach chair’ position. The course of treatment depends on the type of prosthesis used. A basic distinction is made between an anatomical shoulder prosthesis, a reverse shoulder prosthesis and a surface replacement prosthesis.

Anatomical shoulder prosthesis

The anatomical shoulder prosthesis is preferred when the rotator cuff is intact and muscle function is good. The aim of the anatomical shoulder prosthesis is to reproduce the natural joint structure as precisely as possible while preserving the tendon attachments of the rotator cuff.

When an anatomical shoulder prosthesis is inserted, the joint is first exposed. Depending on the severity of the osteoarthritis or the type of injury, the humerus head and joint socket are then precisely removed and replaced with a metal hemisphere that is anchored into the humerus via a stem. The joint socket is replaced by a plastic component and fastened to the shoulder blade with small pegs.

Reverse shoulder prosthesis

The reverse shoulder prosthesis is used in patients with a severely damaged or irreparably torn rotator cuff. In this type of surgery, the artificial joint head is inserted into the shoulder bone on the socket side, and the artificial joint socket is anchored in the humerus. This means that the positions of the head and socket are reversed in comparison to their natural positions in the joint. This reversal of the biomechanical conditions means that the deltoid muscle takes on the main function of arm lifting, allowing patients to achieve better shoulder function in spite of severe damage.

The implantation of a reverse shoulder prosthesis is not enough on its own to allow complete restoration of the active external rotation of the arm. In some cases, accompanying muscle replacement surgery may therefore be useful.

Surface replacement prosthesis

If the bone is largely intact, a surface replacement prosthesis may be a suitable alternative. The humeral head is covered with a cap prosthesis that replaces the damaged part of the joint. In some cases, the joint socket is also provided with a corresponding prosthesis. The cap prosthesis is particularly gentle on the bone, as it is anchored to the bone without a long stem.

After insertion of the shoulder prosthesis, the correct position is checked with an X-ray image. Finally, drainage tubes are inserted to allow discharge of wound secretions, and the surgical incision is closed. The procedure takes one to two hours.

Preparation and precautions

Before surgery, the exact extent of the osteoarthritis or the type of injury is carefully assessed using X-rays or MRI scans to determine the appropriate treatment method.

Blood-thinning medications are usually stopped a few days before the surgery, after consultation with the attending doctor, in order to reduce the risk of bleeding. In addition, routine examinations such as blood tests, allergy tests, an electrocardiogram and a blood pressure check are carried out.

Patients must arrive for the surgery on an empty stomach, i.e. they must not eat any solid food for six hours before the intervention. Clear fluids such as water or unsweetened infusions or teas are generally allowed up to two hours before the intervention. Other fluids such as fruit juice, milk or soup count as food and must not be consumed.

Aftercare and recovery 

Depending on the type of intervention, the hospital stay usually lasts between one and two weeks. Immediately after surgery, the shoulder prosthesis will already be so stable that initial light movement exercises are possible. For optimal healing, it is crucial to consistently continue with physiotherapy after discharge from hospital.

How long the patient needs to be off work depends on how strenuous their work is. While office workers are usually able to return to work after about six weeks, those in physically demanding occupations can require up to six months off. Sports that place a lot of strain on the shoulder are usually possible again after four to six months. The healing process is monitored by regular follow-up checks.

Following shoulder prosthesis surgery, patients can generally expect to be largely pain-free and to have improved mobility of the shoulder joint. Although the surgery cannot usually restore full movement of the shoulder, it does usually achieve a high degree of function for everyday life, and also means the patient can return to sports to a limited extent.

Potential complications

Like any surgery, shoulder joint replacement is associated with certain risks. As with all surgeries, infections, nerve injuries, bleeding or blood clots may occasionally occur. In rare cases, the shoulder prosthesis may loosen and require further surgery.

Careful follow-up care and regular medical check-ups enable potential complications to be detected and treated at an early stage in order to ensure a high level of functionality of the prosthesis in the long term.  

FAQ

When can I return to work after the surgery?

When you return to work depends heavily on the type of surgery and the kind of work you do. Office work is often possible after around six weeks; for physically demanding jobs, the recovery period can be up to six months.

What movements are allowed after the surgery?

After the surgery, gentle, controlled movements are generally allowed in order to promote blood circulation and prevent stiffness. It is essential to avoid jerky or heavy lifting movements in the first few weeks.

Is pain normal after the surgery?

Mild to moderate pain after surgery is normal in the first few days and is part of the healing process. However, it should be well controlled with the prescribed medication. If you have increasing or severe pain, you should be seen by a doctor.

When can I start exercising again?

Exercise should only be started after the incision has completely healed and after medical approval. Light activities are often possible after two to four weeks; intensive exercise, depending on the surgery, only after six to twelve weeks or even later.

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