This operation is indicated when your rotator cuff has become irreparably deficient and this has caused painful arthritis or significant functional problems. Sometimes, a reverse total shoulder is also performed to treat complex proximal humerus fractures. The operation is ideally reserved for patients over 70 years of age, although sometimes it is the only option to help younger patients with complex problems.
In a heathy shoulder the upward pull of your deltoid muscle (the outer muscle that forms your shoulder contour) is balanced by the pull of your rotator cuff (which snugs the ball into the socket and keeps the humeral head depressed). In patients with a failed rotator cuff this balance is lost and there is a tendency for the humeral head to migrate upwards underneath the acromion of the shoulder blade. This is often painful, it also makes it very hard for patients to raise their arm and it causes arthritis as the ball is not working correctly in its socket.
By reversing the ball and socket this improves the physics in your shoulder if your rotator cuff has failed. It moves the centre of rotation of the shoulder more medially and lower down. In doing so the lever arm of the deltoid muscle is doubled and the muscle is tensioned - this makes it much more powerful - enough to allow you once again to raise your arm. Also, the ball which now lies on the shoulder blade blocks upward migration of the humerus, so the fulcrum is maintained in the optimum position to allow the arm to be raised up. The x-ray below shows a reverse geometry total shoulder replacement in a patient who was absolutely delighted with his outcome six months after his surgery.
This operation normally involves a 2-3 day stay after surgery. It is performed under a general anaesthetic and regional nerve block. An incision is made over the front of your shoulder and your damaged joint surfaces are removed. These are replaced by precision engineered metal and plastic implants. As mentioned above, in a reverse total shoulder, the ball and socket are switched around, so the ball now sits on your shoulder blade and the socket is now on your arm bone.
You will wake up with a sling on and your arm will still be numb because of the nerve block. We will help you achieve pain control as your nerve block wears off over the next 12-24hrs.
You will need a shoulder X-ray the day after your operation to confirm your implants are OK and a routine blood test . You will be given injections to thin your blood on the night of your surgery and until you are up and about after your operation (normally a day or two only).
Your physiotherapist will go through your rehabilitation plan with you and most patients can go home by day two after surgery.
Please keep your wound dry and covered with a dressing for two weeks.
You will come out of your sling between four and six weeks and increase your range of movement exercises from then. Strengthening will begin at about three months.
Patients have normally achieved significant pain relief by three months, but It can take well over a year for you to achieve the full functional benefit from your replacement surgery.
Patients vary in their symptoms after surgery, but in general you can expect to return to:
Office work after three to four weeks (in a sling)
Household daily activities after eight to twelve weeks
Heavier activities may take 16-24 weeks
Driving is allowed once you are confident and competent to control a car both for routine and emergency manoeuvres. It will probably take eight weeks for you to be ready.
For the large majority this is an operation that rids patients with debilitating arthritis and/or loss of function of their constant pain and it restores function to their previosuly disabled shoulder.
Overall, about 85% of patients are very happy with their reverse shoulder replacement.
About 10% will feel better than they were before their operation, but still experience significant pain or restricted function.
About 1 patient in 20 (5%) will feel their shoulder is no better or worse off after the surgery. These unfortunate few are normally those who have had a significant complication.
The ideal joint replacement functions well for the rest of your life. The younger you are when you have surgery, the greater your chance of your replacement wearing out. Implant designs and surgical techniques are continuously evolving to optimise both implant longevity and clinical function. Studies show that 90% of reverse replacements will last 10 years and many will last much longer than this. Of course, our techniques and implants have moved on from a decade ago, but this remains a good estimate of durability.
The reverse shoulder replacement relies on your deltoid muscle to move your arm. Recent studies have shown that some patients find that their function begins to deteriorate after 7-10 years. This is thought to be because this deltoid muscle has been 'over-worked' and starts to wear out. Again modern implantation techniques and designs are seeking to minimize this issue, but it remains something to consider, particularly if you are young (e.g. below 70yrs).
Shoulder replacement surgery is major surgery a bit like a total hip replacement and some patients will unfortunately suffer complications. Specific risks of reverse shoulder replacement include:
Anaesthetic problem (less than 1%) - significant or life threatening problems with your heart, lungs, brain or kidneys are very rare with modern planned surgery.
Blood Clot (1 in 500). You will be given stockings to wear and blood-thinning injections during your admission to minimise this risk.
Infection (approx. 2% risk) - Whilst we undertake every precaution to minimise the risk of infection happening to you, this risk cannot be completely negated. If you develop a deep infection, you may need further surgery, or even removal of your joint replacement, a period on antibiotics and revision surgery. This is a lengthy and arduous process for the patient and the final outcome is generally less good after an infection.
Stiffness (10%) - Range of motion is never completely normal after a shoulder joint replacement. The aim is for you to be able to raise your arm to, or above shoulder height, but sometimes even this is not achieved. Inwards and/or outwards rotation of your shoulder may remain restricted, but you can normally do your hair and manage personal hygiene. For ladies, you may never be able to reach behind your back to your bra clasp . Most patients enjoy an improvement in function compared to their pre-operative range but a minority will still feel significantly restricted.
Instability (1-2%) -Your joint replacement relies on implant positioning, soft tissue balance and muscle forces for stability. Very occasionally a replaced joint is unstable. If this is a recurrent, this may require revision surgery.
Ongoing pain (5-10%) - Some patients continue to experience pain on certain movements and, occasionally, more constant pain in their shoulder that doesn’t settle down. A cause for this is not always found, although your surgeon will want to exclude causes such as infection or loosening of your implants.
Fracture (1-2%) - This is rare, but fractures to the socket or your arm bone can happen as your bones are prepared for replacement. Fractures can often be treated at the same time as your replacement, but they may occasionally prevent completion of your replacement while the fracture is addressed. If you fall on your arm with a shoulder replacement, your bones may break around the implant and sometimes this causes a well-functioning replacement to loosen and require revision.
Implant Loosening or failure to integrate (<5%) - this is uncommon. The implants are designed to integrate with your bone to provide durable fixation. If this doesn't happen or the initial fixation isn't secure enough, then the implants may displace and necessitate revision surgery.
Nerve injury (1%) - Important nerves pass close to your shoulder joint. While it is very rare for nerves to be cut, they may get stretched during your operation. The risk of nerve injury is higher if your surgery is happening in a previously-operated region (in revision surgery it can be very hard to identify nerves in scar tissue). Most stretching-type nerve injuries recover with time, but permanent muscle weakness in the shoulder or arm could result.
Notching - Notching happens when the socket (now on the humerus side) rubs against the outer wall of the shoulder blade. Over time this causes erosion of the shoulder blade in the form of a visible notch on x-ray. For the majority of patients this notch has no impact on function or pain. Modern techniques and implant designs seek to minimize notching and the rate is now lower. It is rare for notching to cause failure of the replacement or warrant revision surgery.
Bleeding - Less than 10% of patients will require a transfusion after this operation, and major bleeding is very rare.