Biological Shoulder Prosthesis
What Is Anatomic Shoulder Replacement?
Although this page retains the legacy label "Biological Shoulder Prosthesis," the operation described here is anatomic shoulder replacement, also called anatomic total shoulder arthroplasty. It replaces the damaged humeral head with a metal component and resurfaces the glenoid socket with a medical-grade plastic component while preserving the shoulder's normal ball-and-socket orientation. It is not a stem-cell or cartilage-regeneration procedure.
The goal is to reduce arthritic pain and restore useful movement when joint surfaces are irreversibly damaged. The implant reproduces anatomy, but movement and stability still depend on a functional rotator cuff, deltoid, shoulder-blade muscles and intact nerve supply. Results therefore reflect more than the prosthetic components alone.
When Is Anatomic Shoulder Replacement Considered?
The usual indication is advanced glenohumeral arthritis causing persistent pain, stiffness, sleep disturbance and loss of daily function despite an appropriate non-surgical programme. Primary osteoarthritis is common, but selected inflammatory, post-traumatic or other joint-destructive conditions may also be considered. The shoulder arthritis guide explains the underlying condition and earlier treatment options.
Surgery is not recommended from an X-ray alone. Pain location, movement, cuff strength, work and self-care limitations, general health and personal goals are considered together. The aim is meaningful symptom and function improvement, not a guarantee of a pain-free shoulder or unrestricted heavy use.
Who Is a Candidate and Who May Not Be Suitable?
A candidate generally has painful end-stage arthritis, adequate glenoid bone for fixation and a functioning rotator cuff that can centre the humeral head. The deltoid and nerve supply must also support active movement. Age is considered alongside health, bone quality, activity expectations and implant longevity rather than used as the only threshold.
Active infection is a contraindication until treated. A large irreparable rotator cuff tear, severe glenoid bone loss, major instability, non-functioning deltoid or uncontrolled medical disease can make an anatomic replacement unsuitable or require a different plan. Smoking, skin problems and inability to follow postoperative protection are modifiable risks discussed before elective surgery.
Anatomic vs Reverse Shoulder Replacement
An anatomic replacement keeps a ball on the humeral side and a socket on the glenoid side. It relies on the rotator cuff to balance the joint and guide motion. A reverse shoulder replacement places a ball on the glenoid and a socket on the humerus, changing the mechanics so the deltoid can contribute more to elevation when the cuff cannot function adequately.
Reverse replacement may be preferred for cuff-tear arthropathy, some irreparable cuff tears, selected complex fractures, severe bone loss or certain revision situations. It is not automatically better or worse. Cuff quality, glenoid anatomy, deformity and the reason for replacement determine which design is biomechanically appropriate.
Preparing for Shoulder Replacement
Preparation includes a history, examination and current shoulder X-rays. CT may define glenoid wear, version and bone stock for implant planning. Ultrasound or MRI is selected when rotator cuff integrity is uncertain. Blood tests and medical assessment review anaemia, infection risk, heart or lung conditions and medicines that affect surgery.
Tell the team about blood thinners, diabetes medicines, allergies, previous infection or clot and anaesthetic problems. Follow individual fasting and medication instructions. Arrange transport and home support, place essential items within easy reach and plan for dressing, washing and meal preparation with one arm protected.
- Discuss implant type, cuff condition and whether glenoid bone loss changes the plan.
- Address dental, skin or other active infections before elective implantation.
- Plan work leave and rehabilitation around the demands of the operated arm.
Implants and How Surgery Is Performed
The shoulder is commonly approached through the front, between the deltoid and pectoral muscles. The subscapularis tendon is managed to enter the joint and is repaired during closure. Damaged humeral cartilage and bone are prepared for a stemmed or stemless humeral component, selected according to anatomy and bone quality.
The glenoid is exposed, corrected within safe limits and prepared for a polyethylene socket. The humeral head size, height and rotation are trialled to balance movement and soft-tissue tension before final components are inserted. Implant fixation may use cement, bone integration or a combination according to component design and bone quality.
A general shoulder prosthesis overview may include anatomic, reverse, resurfacing and partial-replacement concepts. The operation actually selected should match the cuff, cartilage loss and bone anatomy rather than the legacy page name.
Anaesthesia and Procedure Time
Anatomic shoulder replacement is performed under general anaesthesia, often with a regional nerve block for early pain control. The anaesthetist tailors the plan to medical health and preferences. A block can leave the arm temporarily heavy or numb, so the sling, skin and hand must be protected until sensation returns.
Procedure time varies with deformity, implant system, bone grafting and additional tendon work. Hospital stay also differs with health, pain control, safe mobility and home support. A fixed operation or discharge time cannot account for these factors.
The First Days After Surgery
The arm is usually supported in a sling while the wound and subscapularis repair begin to heal. Early priorities are pain control, circulation, hand and elbow movement, safe walking and protection during transfers and sleep. Keep the dressing dry as instructed and take medicines only at the prescribed dose.
Permitted shoulder movement depends on the tendon-management technique and implant stability. Reaching behind the back, pushing up from a chair, supporting body weight through the arm and sudden external rotation can stress healing tissue. Another patient's exercise or sling schedule should not replace the protocol for the actual operation.
Shoulder Replacement Rehabilitation
Rehabilitation restores movement without overloading the repaired subscapularis and then rebuilds strength and function. Progress is based on wound healing, pain, movement quality and the shoulder's response after exercise. Stiffness and protection must be balanced rather than forcing motion or keeping the arm inactive for too long.
- Protection: use the sling as directed and maintain hand, wrist and elbow movement.
- Assisted motion: restore permitted elevation and rotation without forceful stretching.
- Active control: progress from assisted to independent movement when tendon healing allows.
- Strength and function: add cuff, deltoid, shoulder-blade and task-specific loading in stages.
Returning to Work, Driving and Activity
Desk work may resume before duties requiring lifting, pushing, pulling or overhead reach. The plan considers which arm was operated on, sling use, pain medicine, transport and opportunities to rest. Driving waits until the sling is no longer required for protection and the person can control the vehicle and respond safely in an emergency.
Walking and lower-body exercise usually progress before loaded upper-limb activity. Return to swimming, golf, gym work or manual tasks is gradual and depends on motion, strength and implant and tendon protection. Repetitive heavy overhead loading and impact may be discouraged to reduce stress on the prosthesis.
Risks, Outcome Factors and Alternatives
Risks include infection, bleeding, blood clots, anaesthetic problems, stiffness, fracture and injury to nearby nerves or vessels. Shoulder-specific concerns include instability, subscapularis or rotator cuff failure, component loosening or wear, glenoid problems, persistent pain and the possible need for revision shoulder arthroplasty.
Outcome is influenced by cuff and deltoid function, glenoid bone, implant position, subscapularis healing, smoking, health and rehabilitation. Alternatives before replacement include activity changes, medication, physiotherapy and selected injections. Shoulder arthroscopy or limited resurfacing may suit specific focal problems, but they do not reliably reverse advanced whole-joint arthritis.
When Should You Contact a Doctor?
After surgery, contact the clinical team for fever, increasing redness or wound drainage, uncontrolled pain, a sudden loss of movement or a new change after a fall. A cold or pale hand, new weakness or numbness, chest pain, shortness of breath or painful calf swelling requires urgent medical assessment.
For related conditions and procedures, visit the Shoulder page. To discuss whether an anatomic or reverse design fits your cuff function, bone anatomy and goals, use the Contact page to request an individual assessment.