Reverse Shoulder Replacement
The reverse shoulder replacement is a remarkable device that has truly revolutionized shoulder replacement surgery. Prior to its development, patients suffering from shoulder arthritis with a large rotator cuff tear or those with simply a large irreparable tear without arthritis had very few treatment options. Patients were often treated with surgeries that were unreliable and unpredictable with regard to pain relief and functional improvement. Since the introduction of the RSP which received FDA approval in 2005, surgeons now have an excellent tool to manage these difficult cases which is both reliable and predictable in regards to pain relief and restoration of function. Ten year data on the third generation design has demonstrated greater than 90% survivability at 10 years.
The Difference of a “Reverse” Shoulder Replacement
The reverse shoulder replacement is different than a standard shoulder replacement in that, during the surgery, the anatomy of the shoulder is reversed placing the ball (glenosphere) on the socket side and the socket (shell) on the ball side. By doing so, the large deltoid muscle becomes the substitute for the torn or absent rotator cuff and is put under a little more tension to make it work just a little harder and more efficiently. It is similar to pulling a rubber band just a bit further and getting a lot more spring in return. The deltoid essentially becomes the “workhorse” for the shoulder restoring strength and stability. The smooth surface created between the new ball (glenosphere) and plastic socket (polyethylene shell) also restores the smooth gliding motion of the joint further improving motion, function, and ultimately pain.
Indications for Reverse Shoulder Replacement
The reverse shoulder replacement is utilized and intended for patients older than 65 with deficiency of the rotator cuff. Due to its stabilizing effect on the shoulder, many patients with longstanding tears of the rotator cuff will also develop arthritis. The combination of a rotator cuff tear with arthritis is called rotator cuff arthropathy and is the primary indication for reverse shoulder replacement. Fairly frequently, patients may merely have a torn tendon that is not repairable or possibly has failed multiple surgeries without arthritis. This too, can also be an indication for surgery but typically depends on the overall starting motion and the severity of pain. Finally, reverse shoulder replacement has also been utilized in the setting of proximal humeral fractures in the elderly, revision surgery, and failed total shoulder replacement.
What are the Benefits of a Reverse Shoulder Replacement?
Dramatic improvements have been demonstrated in pain relief, range of motion, and ability to perform daily activities (i.e., eating, drinking, grooming). The return of independence is probably the key benefit that patients experience, as they are able to regain function and use of the arm. The average motion following reverse shoulder replacement is 120 degrees of forward elevation.
How long does the surgery take and how long am I in the hospital?
The surgery typically takes 1-2 hours and is performed under a general anesthetic usually in combination with a regional block to help “deaden” the arm and provide pain relief for up to 12-18 hours following surgery. Patients typically remain in the hospital for 36-48 hours and are released to home after discharge.
How long is the recovery process?
Patients typically remain in a sling or immobilizer for 4-6 weeks. Therapy is generally started the 2nd to 3rd week following surgery and usually continues on an outpatient basis for 4-6 weeks. The therapy is intended to provide you the tools to succeed on your own at home and is not intended to forcefully stretch your arm in positions that may cause the parts to dislocate. It is very important to find a therapist that you both trust and is familiar with this type of surgery and Dr. Badman can provide assistance in this regard. Most patients know a difference in their pain by the 4th-6th week and are resuming normal activities by 4 months. Functional improvements and betterment of pain can be seen for up to 12-18 months following surgery.
Are all reverse shoulder replacements the same?
There are two main philosophies pertaining to reverse total shoulder implant design. The original version that first worked consistently was designed upon the principles of Paul Grammont, a European surgeon, and introduced in the early 90’s. His theory was to “medialize” the center of rotation of the shoulder in hopes that this would lead to less stress on the “glenosphere” and fewer implant related complications seen with early attempts beginning in the 1970’s. Several companies (Depuy, Tournier) have marketed remarkably similar styles of shoulder components based on these early principles and these are termed “Grammont” style implants. Although great advances were made, other issues began to occur with this design, especially that of scapular notching. Scapular notching is a phenomenon where the implant actually starts to impinge against the bone of the socket and gradually grinds it away thru continual abutment of the two surfaces. This has been reported in nearly every series published on Grammont style reverse total shoulders with several studies reporting incidences as high as 100%. This was initially felt to be an insignificant finding but several subsequent reports have demonstrated a statistically poorer outcome in patients with notching and there remains grave concern of catastrophic failure of the device caused by breakdown of the bone and ultimate loss of fixation.
Dr. Mark Frankle appreciated the work of Dr. Grammont but had concerns over the “medialization” principle and some of the non-anatomic design features of the Grammont style implants. He believed “lateralization” was necessary to maintain a more anatomic center of rotation which he felt would avoid notching and maintain tension on any residual rotator cuff tendon. This in turn would improve strength, stability and potentially motion. In the mid 90’s, therefore, he began working on the concept and finally released the American version (RSP-Reverse Shoulder Prosthesis) currently produced by DJO Ortho and FDA approved in 2005. Although initially openly ridiculed for the design by many well regarded shoulder experts, Dr. Frankle has continued to research the implant and remains one of the leading experts on reverse shoulder arthroplasty. His design through peer-reviewed research has essentially eliminated the incidence of major scapular notching and a recent publication also reported a 91% survivability at 5 years. In fact, many of the Grammont style manufacturers have gradually swayed to a lateral offset style by modifying their technique in hopes their notching complication can be reduced.