What it is
Anatomic total shoulder replacement (aTSA) replaces both worn surfaces of the shoulder while keeping the joint’s normal architecture: a metal ball on a stem in the humerus, articulating with a new socket fixed to the glenoid. The anatomy is reproduced rather than altered, and the rotator cuff continues to power and stabilise the shoulder — which is why the state of that cuff determines whether this is the right operation.
Who it suits
The classic indication is osteoarthritis with an intact, functioning rotator cuff: a patient with deep shoulder pain, night pain, and progressive loss of rotation and reach, whose imaging shows joint space loss and whose cuff is sound.
It is also used for inflammatory arthritis and some cases of avascular necrosis, provided the cuff and glenoid bone stock allow.
It is not appropriate when the rotator cuff is irreparable. Without a working cuff the ball rides upward against the new socket, which loosens — the reason reverse total shoulder replacement exists. In a highly active patient, pyrocarbon hemiarthroplasty may be preferable, precisely because it avoids the glenoid component.
The advantage over reverse replacement
Where the cuff is intact, anatomic replacement generally delivers better movement — particularly rotation — and more natural shoulder mechanics than a reverse. Registry work consistently shows anatomic replacement producing superior motion and functional scores, with equivalent implant survivorship. Reaching behind the back and across the body tends to be better preserved.
That is why cuff status, not age alone, drives the decision.
What the evidence shows
- Survivorship is high. Registry data across multiple national joint registries reports implant survival between 93.1% and 98.9% at five and eight years, across a series of more than 2,000 anatomic replacements.
- Revision is uncommon — approximately 2.3%, with a surgical complication rate of around 10.2%.
- The characteristic long-term issue is the rotator cuff, not the implant. Secondary rotator cuff tear is the commonest complication after anatomic replacement, occurring in about 3.7% of patients — but only 1.1% required revision surgery for it.
- New Zealand registry data (2026) in inflammatory arthritis found anatomic replacement gave superior functional outcomes with equivalent survivorship compared to reverse — a useful corrective, since reverse has been increasingly used in this group out of concern about later cuff failure.
The surgery and recovery
- General anaesthesia, usually with a nerve block for post-operative comfort
- Hospital stay is typically one to two nights
- A sling is worn in the early weeks
- Physiotherapy restores movement first, then strength — the repaired subscapularis must be protected
- Light everyday tasks resume within weeks; most patients are substantially comfortable by 6–12 weeks, with improvement continuing to around 12 months
- Driving is usually possible at about six weeks
Is it right for me?
The decision rests on the state of your rotator cuff, the shape and bone stock of your glenoid, your age and your demands. If the cuff is sound, anatomic replacement is the operation that most closely restores a normal shoulder — and that is what makes it the benchmark against which the alternatives are judged.