Overview
Shoulder replacement resurfaces a joint whose cartilage has worn away, replacing the ball of the humerus with a metal head and the socket with a polyethylene component. There are two designs, and choosing between them is the central decision on this page. An anatomic total shoulder recreates the normal ball-and-socket and depends on a working rotator cuff to center and lift the arm. A reverse total shoulder puts the ball on the socket side and the cup on the humerus, so the deltoid can raise the arm on its own; it is used when the cuff is torn beyond repair or the socket is too worn for an anatomic component.
Either design reliably relieves the grinding pain of arthritis and restores the motion needed for dressing, reaching a shelf, swimming and golf. Dr. O'Donnell performs both, mostly as outpatient procedures at Bayside Surgery Center.
Who It's For
Replacement is recommended for shoulder arthritis causing daily pain, night pain and loss of rotation despite activity modification, an ultrasound-guided injection and therapy, once X-rays show bone-on-bone contact. The anatomic design is chosen when the rotator cuff is intact on MRI and the glenoid bone is adequate on CT; it gives the strongest shoulder and suits active patients in their 50s and 60s with osteoarthritis. The reverse design is chosen for cuff-tear arthropathy, a massive irreparable rotator cuff tear with arthritis; for an irreparable tear with pseudoparalysis; for a glenoid worn so far back that an anatomic socket cannot be seated; for displaced three- and four-part fractures in older patients when fixation is unlikely to hold; and for revision of a failed anatomic replacement.
Early arthritis with preserved motion is treated without surgery. A younger patient with a repairable cuff tear is generally better served by a rotator cuff repair than by a replacement. A stiff shoulder with normal joint space on X-ray is frozen shoulder, which resolves without an implant. A non-functioning deltoid rules out a reverse replacement.
Joint-space narrowing on an X-ray is not by itself a reason to replace a shoulder; many people with arthritic X-rays have tolerable symptoms. Dr. O'Donnell recommends replacement when the pain and loss of rotation on exam, the imaging and the patient's daily limitations agree, and therapy and an injection have been tried. See shoulder arthritis and, for cuff-tear arthropathy, rotator cuff tears.
What the Procedure Involves
Surgery is performed under general anesthesia with an interscalene block. Dr. O'Donnell plans implant sizes and socket position on a 3D CT reconstruction, so the glenoid component sits correctly on bone that is often asymmetrically worn. The approach is deltopectoral, between the deltoid and pectoralis muscles at the front of the shoulder. For an anatomic replacement the subscapularis tendon is taken down to enter the joint and repaired at the end; protecting that repair drives the first six weeks of rehabilitation.
The arthritic humeral head is removed at the anatomic neck and the socket is reamed to a fresh surface. In an anatomic replacement a polyethylene glenoid component is cemented into the socket and a metal head, sized to match the patient's own, is fixed on a short stem or stemless anchor in the humerus. In a reverse replacement a metal baseplate is screwed into the glenoid and a half-sphere (the glenosphere) fixed to it; a stem with a polyethylene cup goes into the humerus. Trial components are tested for stability before the final implants are placed.
The operation takes about 90 minutes to two hours. A special dressing is applied that stays on until the first follow-up visit, the arm goes into a sling, and most patients go home the same day.
Risks & How They Are Minimized
Infection is the most serious complication of any joint replacement. It is guarded against with antibiotics before the incision, a sealed dressing, and a skin preparation directed at the organism the shoulder carries. Dislocation is the main early risk of a reverse replacement and occurs with the arm extended behind the body, adducted and internally rotated, which is why reaching behind the back is prohibited for six weeks. After an anatomic replacement, failure of the subscapularis repair is the equivalent risk; external rotation is limited to 30° and resisted internal rotation avoided for six weeks.
Glenoid loosening is the long-term weakness of the anatomic design and the reason CT planning is used to seat the component on good bone. Scapular notching is reduced by lateralized reverse designs. The axillary nerve is protected by the approach; block numbness clears within a day. Blood clots are less common than after hip or knee replacement but are still prevented with early walking and two weeks of aspirin. Stiffness is the most common complaint and is addressed by passive motion from the first week.
Recovery & Rehabilitation
The anatomic and reverse protocols share a timeline but protect different things: the subscapularis repair after an anatomic replacement, the implant against dislocation after a reverse.
| Phase | Timing | What happens |
|---|---|---|
| Protected passive motion | Weeks 0–6 | Sling for 3–4 weeks. Pendulums, passive flexion to about 120°, passive external rotation to 30°, deltoid isometrics, ice. No weight bearing through the arm, no reaching behind the back. Anatomic: no resisted internal rotation. Reverse: no combined extension, adduction and internal rotation. |
| Active motion | Weeks 6–12 | Active-assisted then active motion in all planes, external rotation progressed beyond 30°, light cuff and scapular work. Reverse: deltoid activation with supine punches, target active elevation of 100–120°. |
| Strengthening | Weeks 12–16 | Progressive light resistive cuff, deltoid and scapular strengthening, functional reaching, endurance work. Advance when independent with daily activities. |
| Functional return | Months 4–6 | Continued strengthening. Golf, swimming and doubles tennis as cleared after an anatomic replacement; low-demand recreation after a reverse, with lifting kept light long term. |
Desk work is possible within one to two weeks, driving at four to six weeks, and golf, swimming and doubles tennis between four and six months.
Protocol summary
After an anatomic replacement the sling is worn for three to four weeks, passive external rotation is limited to 30° for six weeks to protect the subscapularis repair, and resisted internal rotation, extension behind the body, lifting, pushing and weight bearing through the arm are prohibited for six weeks. After a reverse replacement the same sling period and rotation limit apply, and the combined extension, adduction and internal-rotation position is avoided because it can dislocate the implant.
Phase I ends at six weeks with passive flexion of about 120° and external rotation to 30°. Strengthening begins at twelve weeks once active motion is functional with good scapulohumeral rhythm, and functional return follows independence with daily activities. Long-term lifting after a reverse replacement is limited to light loads.
Physical Therapy Protocols
Total Shoulder Replacement (Anatomic) PDF ↗Reverse Total Shoulder Replacement PDF ↗Frequently Asked Questions
What is the difference between a total and a reverse shoulder replacement?
An anatomic total shoulder replaces the ball and socket in their natural positions and needs an intact rotator cuff to work. A reverse replacement swaps them, putting the ball on the socket side, so the deltoid can lift the arm without a cuff. Anatomic is chosen for arthritis with a good cuff; reverse for cuff-tear arthropathy, a worn socket, some fractures and revisions.
Is shoulder replacement outpatient, and how long is surgery?
The operation takes about 90 minutes to two hours. Most patients go home the same day from Bayside Surgery Center under a nerve block plus general anesthesia; those with significant medical conditions stay one night. The special dressing applied in surgery stays on until your first follow-up.
How long do I wear a sling, and when can I drive, after shoulder replacement?
Three to four weeks in a sling. Passive motion starts in the first week, so the sling is mainly for comfort and protection at night. The restrictions that matter last six weeks: no reaching behind the back, no lifting or pushing, and external rotation limited to 30°. Driving usually resumes at four to six weeks.
When can I play golf or swim after shoulder replacement?
Golf, swimming and doubles tennis are cleared between four and six months after an anatomic replacement, once strengthening is complete. After a reverse replacement the same low-impact activities are usually possible, with lifting kept light long term. Phase criteria are in the anatomic and reverse protocols.
How long does a shoulder replacement last?
Most modern shoulder replacements are still functioning well at 15 to 20 years. Anatomic replacements fail most often through loosening of the socket component or a later cuff tear; reverse replacements through notching or instability. Both can be revised, one reason bone-preserving short-stem and stemless designs are used.
This page is for general education and is not a substitute for a medical evaluation. The right procedure depends on your individual diagnosis, anatomy, and goals. Kevin O'Donnell, MD sees patients from Coral Gables, Miami, Brickell, Pinecrest and Coconut Grove at 475 Biltmore Way, and out-of-town patients by telemedicine.