An anatomic shoulder replacement replaces the joint surfaces worn away by osteoarthritis while reproducing the normal anatomy: a metal ball on the humerus, a polyethylene socket on the glenoid. It assumes that the rotator cuff tendons are intact, because they are what moves the shoulder afterwards.
It is the reference operation for primary shoulder osteoarthritis, that is, osteoarthritis of the shoulder that occurs without any associated tendon tear.
There is a single deciding factor and it fits in one sentence: the state of the rotator cuff.
If the rotator cuff is intact, the anatomic shoulder replacement is the right choice. It restores normal mechanics, a full range of movement and natural strength, because it lets the tendons do their work.
If the cuff is torn and cannot be repaired, an anatomic replacement would not work: the humeral head would ride up under the acromion and the shoulder would stay painful and weak. That is where the reverse shoulder replacement comes in, reversing the geometry of the joint so that the deltoid takes over the movement.
This choice is made on the CT scan and the MRI before surgery, not during the operation. It is explained and discussed with you in consultation.
This is the main indication. The cartilage of the shoulder wears down over the years, the joint becomes painful, gradually stiffens and grates. The pain becomes constant, including at night and at rest, and medical treatment is no longer enough.
The X-ray alone is never the deciding factor. A shoulder with severe osteoarthritis but little pain is not operated on. What triggers the decision is the impact on daily life and on sleep.
A fracture of the upper end of the humerus that has healed in a poor position can, years later, end in a destroyed joint. If the rotator cuff has stayed intact, an anatomic shoulder replacement remains possible.
The bone of the humeral head loses its blood supply and collapses, which destroys the joint surface even though the tendons are normal. This is a good indication for an anatomic shoulder replacement, often in younger patients.
I do not detach the muscles. The subscapularis, which the classic approach cuts and then repairs, stays intact throughout the operation. We preserve five tendons.
That changes three concrete things for you. There is no sling and no immobilisation after the operation. The dislocation rate in primary cases is zero, because the front stabiliser of the shoulder is never weakened. And rehabilitation starts on a shoulder that has never been locked up, so there is no stiffness to make up for.
The operation takes between forty-five minutes and one hour. The incision is about eight centimetres long.
The principle is to remove the worn humeral head and replace it with a prosthetic head mounted on a stem or on a short baseplate impacted into the humerus. On the shoulder blade side, the glenoid, which is the facing surface, receives a polyethylene socket when its wear justifies it.
The delicate step is not fitting the head, it is on the glenoid side. Its size and its orientation vary a great deal from one patient to another, and osteoarthritis deforms it. Planning from the CT scan before surgery makes it possible to define the exact position of the implant before going into theatre.
You are admitted as day surgery or with a single night on site. The details are set out on the shoulder operation page.
You use your arm for everyday tasks from day one, without a sling. You can drive again immediately.
Rehabilitation lasts three to four months, with three physiotherapy sessions per week. The week by week detail is on the after a shoulder replacement page.
The first result, the one that matters most to patients, is that the osteoarthritis pain goes. It is obtained from the operation itself, even before rehabilitation.
The second is the return of movement. This is where the anatomic shoulder replacement keeps a clear advantage over the reverse shoulder replacement: because it preserves the natural mechanics and the tendons, it usually allows you to regain a shoulder that lifts high and rotates, including internal rotation, the movement used to fasten a bra or reach a back pocket.
The third is strength. A rotator cuff left intact, not cut during the operation, allows a return to close to normal strength by the end of rehabilitation.
The infection rate is one per cent. The dislocation rate in primary cases is zero.
The limitation specific to the anatomic shoulder replacement comes from its very principle: it depends on the rotator cuff. If the tendons tear years after the implant is fitted, the anatomic replacement can become painful and lose range of movement. That is the main reason for conversion to a reverse shoulder replacement, and it is one of the things that weigh in the decision for a young patient with a fragile cuff.
Loosening, that is, the gradual detachment of the implant within the bone after many years, mainly concerns the glenoid socket. That is why radiographic follow-up remains useful even when the shoulder no longer hurts.
The anatomic replacement reproduces the normal anatomy, a ball on the humerus and a socket on the shoulder blade, and assumes that the rotator cuff tendons are intact. The reverse replacement inverts that geometry and hands the movement to the deltoid, which makes it possible to operate on a shoulder whose cuff is torn.
When the joint has been destroyed by osteoarthritis, by fracture sequelae or by necrosis, when the pain affects daily life and sleep, and when the rotator cuff tendons are intact.
Between forty-five minutes and one hour, with an incision of about eight centimetres, as day surgery or with one night in hospital.
No. Because I do not detach the muscles during the operation, there is no sling and no immobilisation, and the shoulder moves from day one.
This is the strong point of this replacement. By preserving the tendons and the natural mechanics, it usually allows you to regain full elevation and the rotations, including internal rotation, which is often limited after a reverse shoulder replacement.
Yes. It is in fact the most common revision scenario: if the rotator cuff tears years after the implant is fitted, the shoulder becomes painful and weak again, and conversion to a reverse shoulder replacement solves the problem.
There is no age threshold. Most patients are between sixty and eighty, but necrosis or fracture sequelae can lead to an anatomic replacement much earlier. In a young patient, we weigh the immediate benefit against the prospect of a revision several decades later.
The infection rate is one per cent and the dislocation rate in primary cases is zero. In the long term, the two things to watch are loosening of the glenoid socket and a secondary tear of the rotator cuff.
Around one hundred and fifty a year, anatomic and reverse combined.
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