Shoulder Prosthesis: Types, Surgery and Recovery

What is a Shoulder Prosthesis?

A shoulder prosthesis (also called shoulder arthroplasty or shoulder endoprosthesis) is an artificial joint implant that replaces a damaged or destroyed shoulder joint, either fully or partially. The shoulder joint consists of the head of the upper arm bone (humerus) and the socket of the shoulder blade (scapula, also called the glenoid). When this joint is severely damaged by disease or injury and conservative treatments are no longer effective, a shoulder prosthesis can significantly improve a patient's quality of life.

Causes and Indications

Several conditions may make a shoulder prosthesis necessary:

• Shoulder osteoarthritis (omarthrosis): Degeneration of the articular cartilage, leading to pain and restricted movement.
• Rheumatoid arthritis: A chronic inflammatory joint disease that destroys cartilage and bone.
• Proximal humeral fracture: Complex fractures of the humeral head, particularly in elderly patients.
• Cuff tear arthropathy: Joint destruction resulting from long-standing rotator cuff tears.
• Avascular necrosis: Death of bone tissue due to insufficient blood supply.
• Bone tumors: Tumors requiring removal of the joint.

Types of Shoulder Prostheses

Hemiarthroplasty (Partial Replacement)

In a hemiarthroplasty, only the humeral head is replaced with an implant while the natural glenoid socket is preserved. It is commonly used for humeral head fractures or early-stage arthritis.

Total Shoulder Arthroplasty (TSA)

A total shoulder arthroplasty replaces both the humeral head and the glenoid socket. It is the most frequently used option for advanced shoulder osteoarthritis with an intact rotator cuff.

Reverse Shoulder Arthroplasty

The reverse shoulder prosthesis inverts the anatomical arrangement of the joint: the ball component is placed on the shoulder blade side and the socket component on the upper arm. It is primarily used in patients with a severely damaged or torn rotator cuff and in cuff tear arthropathy. This type of prosthesis has proven particularly successful in recent decades.

Resurfacing Arthroplasty

A resurfacing arthroplasty is a bone-preserving procedure in which only the surface of the humeral head is capped with a thin metal component. It is suitable for younger patients with good bone stock.

Diagnosis and Preoperative Planning

Before a shoulder prosthesis is implanted, comprehensive diagnostic measures are carried out:

• X-rays to assess bone quality and joint structure.
• Magnetic resonance imaging (MRI) to evaluate soft tissues, especially the rotator cuff.
• Computed tomography (CT) for detailed bone analysis and prosthesis planning.
• Laboratory tests to rule out infections or systemic diseases.

The patient's general health is also assessed, and a thorough informed consent discussion takes place before the procedure.

The Surgical Procedure

The operation is usually performed under general or regional anesthesia and takes approximately 1.5 to 3 hours. The surgeon accesses the shoulder joint through an incision, removes the damaged joint components, and implants the prosthetic parts. Depending on the prosthesis type, the components are fixed with or without bone cement. The typical hospital stay is 5 to 10 days.

Postoperative Care and Rehabilitation

Intensive physiotherapy begins immediately after the operation and is crucial to a successful outcome. Rehabilitation proceeds in several phases:

• Early phase (0–6 weeks): Immobilization in a shoulder sling, passive range-of-motion exercises to prevent stiffness.
• Intermediate phase (6–12 weeks): Progressively active-assisted exercises and muscle strengthening.
• Late phase (from 3 months onward): Active strengthening and coordination exercises, gradual return to daily activities.

Full rehabilitation can take 6 to 12 months. Most patients experience significant pain relief and improved range of motion.

Risks and Complications

As with any surgical procedure, shoulder arthroplasty carries potential risks:

• Infection: Superficial or deep wound infections that may require revision surgery.
• Prosthesis loosening: Over time, the implant may loosen and require replacement surgery.
• Nerve and vascular injury: Rare damage to surrounding structures.
• Instability: Dislocation of the prosthesis, particularly with reverse implants.
• Periprosthetic fracture: Fracture of the upper arm around the implant.
• Restricted mobility: Despite surgery, shoulder movement may remain limited in some cases.

Outcomes and Prognosis

Shoulder arthroplasty achieves very good results in modern orthopedic surgery. Studies show that more than 90% of patients report significant pain relief after the procedure. Modern shoulder prostheses frequently last 15 to 20 years. In younger patients, a revision operation may become necessary during their lifetime.

References

1. German Society for Orthopaedics and Trauma Surgery (DGOU): Guidelines on Shoulder Arthroplasty, 2022.
2. Gerber C, Pennington SD, Nyffeler RW. Reverse total shoulder arthroplasty. Journal of the American Academy of Orthopaedic Surgeons. 2009;17(5):284–295.
3. Zumstein MA, Pinedo M, Old J, Boileau P. Problems, complications, reoperations, and revisions in reverse total shoulder arthroplasty: A systematic review. Journal of Shoulder and Elbow Surgery. 2011;20(1):146–157.