Anatomic or reverse shoulder replacement: which one do I need?
The deciding factor is your rotator cuff. If the cuff still works, an anatomic replacement keeps the shoulder's natural ball-and-socket geometry. If the cuff is torn or no longer functioning, a reverse replacement lets the deltoid lift the arm instead.
The short answer.
Anatomic and reverse shoulder replacements are built on opposite mechanics, and the rotator cuff decides between them. An anatomic replacement keeps the ball on the humerus and the socket on the glenoid, so the centre of rotation stays where the natural joint puts it. That only works if the rotator cuff is intact. A reverse replacement swaps them, putting a metal ball on the scapula and a polyethylene socket on the humerus. Moving the centre of rotation downward and medially gives the deltoid the leverage to lift the arm, which is what makes it the operation for a shoulder whose cuff no longer works.3
Side by side.
| Anatomic | Reverse | |
|---|---|---|
| Rotator cuff | Must be intact and working | Torn or no longer functioning |
| Geometry | Ball on humerus, socket on glenoid, as in the natural shoulder | Reversed: ball on scapula, socket on humerus |
| What lifts the arm | The rotator cuff | The deltoid |
| Usual reason | End-stage glenohumeral arthritis with an intact cuff | Cuff tear arthropathy, irreparable cuff tear, some fractures and revisions |
| Expected motion | Functional overhead and behind-the-back reach | Active elevation to or near horizontal; external rotation less predictable |
| Mako robotic planning | Not currently approved; CT planning and navigation used | Approved and used |
| Hospital stay | Typically one night | Typically one night |
How the decision is actually made.
The choice is made from your imaging and your examination, not from a preference for one implant. Dr Coory assesses cuff status, bone stock, the pattern of glenoid wear and what you need the shoulder to do. Where the cuff is intact and the arthritis is the problem, the anatomic replacement restores the joint you already had. Where the cuff has failed, no amount of good technique will make an anatomic replacement lift the arm, and the reverse is the operation that will.2
This is also why a second opinion is reasonable if you have been offered one operation and are unsure. The two are not interchangeable, and the reasoning should be explained to you in terms of your own cuff and your own bone.
Seeing it.
Both procedure pages carry a short animation showing the two implants side by side, which makes the change in geometry easier to follow than any description. See it on the anatomic total shoulder replacement page or the reverse total shoulder replacement page. The recovery roadmap sets out the five-phase journey that follows either operation.
Frequently asked questions.
What decides whether I need an anatomic or a reverse shoulder replacement?
Rotator cuff status is the deciding factor. An anatomic replacement relies on a functioning rotator cuff to lift and rotate the arm. If the cuff is torn or deficient, an anatomic replacement will not lift the arm and the operation will fail. The reverse design moves the centre of rotation downward and medially so the deltoid can do the lifting instead. Bone stock, the pattern of glenoid wear and your own functional goals are also weighed.
Is one better than the other?
Neither is better in general terms. They are different operations for different shoulders. In the right shoulder each is highly reliable, and in the wrong shoulder each fails. The question is not which operation is superior but which one matches your cuff status and anatomy.
Can I have an anatomic replacement if my rotator cuff is torn?
Generally no. The anatomic design depends on the cuff to elevate and rotate the arm. Where the cuff is torn or no longer functioning, a reverse replacement is the operation that restores active elevation.
Which one lasts longer?
Australian National Joint Replacement Registry data show implant survivorship above 95 per cent at ten years for anatomic total shoulder replacement, and modern designs are expected to last considerably longer. Survivorship is only meaningful when the implant is matched to the shoulder, which is why selection matters more than the comparison.
What movement should I expect afterwards?
After an anatomic replacement most patients regain functional motion, meaning comfortable overhead and behind-the-back reach. After a reverse replacement, active forward elevation to or near horizontal is the typical result, while active external rotation is less reliably restored and depends on residual teres minor function. In both operations the pain relief is more predictable than the final range of motion.
Is Mako robotic planning available for both?
No. The Mako shoulder platform is currently approved for reverse total shoulder replacement only. Anatomic total shoulder replacement is performed with conventional, well-validated instrumentation, supplemented by CT-based planning and navigation.
How long is the recovery for each?
Dr Coory uses an accelerated protocol for reverse shoulder replacement: one night in hospital, a sling for one week, active-assisted range from week one, driving at around two weeks once off opioid analgesia, most daily activities by six weeks and the final outcome at nine to twelve months. One night in hospital is also typical for anatomic replacement. Progression in both is based on clinical milestones rather than the calendar alone.
Do I need a referral, and is it covered?
A GP or specialist referral is needed to claim the Medicare rebate on your consultation. Total shoulder replacement is covered under MBS item numbers and by most private health funds at appropriate hospital cover tiers. Dr Coory's reception team provides a written estimate before surgery.
References.
- Australian Orthopaedic Association National Joint Replacement Registry, Annual Report (shoulder arthroplasty survivorship). AOANJRR →
- Anatomic total shoulder replacement: indications, technique and recovery, Dr Joe Coory. Procedure page →
- Reverse total shoulder replacement: indications, technique and recovery, Dr Joe Coory. Procedure page →