William N. Levine, MD, Chair of the Department of Orthopedic Surgery at NewYork-Presbyterian/
Shoulder specialists will value this prosthesis’ adaptability and flexibility to support their surgical approaches and complement diverse patient pathology.
— Dr. William N. Levine
Surgeons can use this new device for anatomic, reverse, and revision shoulder arthroplasty to alleviate pain and maximize range of motion. It is a fully convertible system that employs proprietary technologies to align each surgeon's approach to an individual patient's anatomy and execute the replacement with extraordinary precision. “This system was designed to help surgeons restore the center of rotation and achieve optimal range of motion after anatomic or reverse shoulder arthroplasty,” says Dr. Levine. "Shoulder specialists will value its adaptability and flexibility to support their surgical approaches and complement diverse patient pathology.”
The Problem with Current Prostheses
There are hundreds of shoulder replacement prostheses available on the market and surgeons have two distinct options to choose from:
- Anatomic replacement, in which a metal ball replaces the head of the humerus and a plastic socket is implanted into the glenoid of the shoulder joint. The late Charles Neer II, MD — considered the patriarch of shoulder surgery — invented this device in the 1940s while he was at Columbia, making the hospital a globally renowned premier destination to learn and undergo shoulder arthroplasty. The anatomic option is suited for patients with functioning rotator cuff muscles.
- Reverse total shoulder replacement, which inverts the two components. The ball inserts into the socket side and the socket onto the humerus. This approach makes shoulder surgery an option for patients who do not have a functioning rotator cuff.
Pre-operative image of shoulder before total shoulder arthroplasty
The humeral prosthesis for an anatomic replacement is positioned at the humeral resection line. However, for patients who require revision to a reverse shoulder replacement (typically due to failure of the rotator cuff over time), the humeral prosthesis in traditional systems is not in the optimal position. This leads to either overstuffing of the shoulder or to have to perform a much bigger revision surgery by removing the anatomic humeral stem and revising the humerus altogether.
Other “convertible” prostheses exist but have legitimate practical concerns. “They're convertible in theory because you can take off the metal anatomic head and put on a reverse tray,” Dr. Levine explains. “But because the humeral component is not in the right place to begin with, the reverse replacement ends up being too stiff and too tight.”
This new prosthesis is the only total shoulder replacement system of its kind on the market. “Our task as a design team was to create a humeral component that could be used for either type of procedure, anatomic or reverse, so we could convert an anatomic replacement into a reverse replacement without having to change the humeral component,” he continues. “And that was not an easy task. We designed the humeral prosthesis so that it sits 5mm inside the resection margin, allowing us to convert it from an anatomic to a reverse shoulder replacement without changing anything else.”
Benefits for Surgeons
This new device offers a more reproducible way to implant the humeral prosthesis into the correct position. Eight humeral tray combinations provide more sizing and placement options for aligning the humerus with the glenoid without lengthening the arm. The system allows for 5mm of additional joint space below the resection, giving surgeons more to work with if a revision is needed in the future.
Post-operative image showing the new shoulder prosthesis
“The specially designed instruments enable surgeons to accurately insert the components into the humeral canal every time. An impactor system includes a visual cue that indicates exactly where the prosthesis is within the canal,” Dr. Levine explains. “From the surgeon's perspective, this immediate feedback is extremely comforting. It takes the guesswork out of it.”
We have created something that improves surgeons’ ability to provide the highest level of care to their patients.
— Dr. William N. Levine
Benefits for Patients
Total shoulder arthroplasty is best suited for patients with severe arthritis that is significantly impacting their life. “I don’t treat X-rays and I don’t treat MRIs. I ask my patients how their pain is affecting their quality of life,” Dr. Levine contends. “This is a treatment for people who have exhausted all non-operative therapies and have lost all of the cartilage on the ball and the socket. They have bone rubbing on bone, terrible pain, loss of motion, and significant dysfunction. These patients tell me, ‘I can't live like this.’”
This new prosthesis was developed first and foremost with the patient in mind. It allows orthopedic surgeons to perform either an anatomic or reverse shoulder replacement with the comfort of knowing that conversion of a failed anatomic replacement is easier and more reproducible than with prior arthroplasty systems. Many report a reduction in arthritis pain within two weeks. The first three postoperative months are spent healing and increasing range of motion, followed by three months recovering function and building strength. Most people who play golf or tennis can return to their sport by five months after surgery. Complete recovery can take up to one year.
A Commitment to Innovation
Advancing medical and surgical innovations is a vital part of NewYork-Presbyterian’s mission and Dr. Levine’s work. “We spent hundreds and hundreds of hours in laboratories with sawbones and early designs that were nowhere near what the final design was. But we asked the questions and then we figured out a scientific approach,” He says.
Dr. Levine expects the new system to become the dominant prosthesis used in shoulder arthroplasty. “At NewYork-Presbyterian, we strive to be the leaders in shoulder surgery, clinical care, education, and research,” Dr. Levine concludes. “We have created something that improves surgeons’ ability to provide the highest level of care to their patients.”
Many physicians and scientists maintain relationships and collaborate with external organizations to foster scientific innovation and provide expert guidance. William Levine, MD is a paid consultant. The institution makes these disclosures public to ensure transparency.
