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Applying Research to Simplify and Customize Shoulder Arthroplasty

“When you get an opinion from Johns Hopkins, you know it’s from the best in the world,” says Edward McFarland.

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“When you get an opinion from Johns Hopkins, you know it’s from the best in the world,” says Edward McFarland.

Shoulder surgeons at Johns Hopkins are exploring new and improved ways of diagnosing and treating patients requiring arthroplasty. Edward McFarland, professor of orthopaedic surgery, explains, “Our expertise stems from our extensive research on what implant types and ways of constructing implants work better than others. The breadth of clinical studies conducted in the shoulder division enables us to handle the toughest of the tough, in terms of complex cases.”

Recent studies by McFarland focus on the benefits of metal artifact reduction sequence–magnetic resonance imaging (MARS-MRI) when diagnosing and treating painful shoulder replacements. MARS-MRI reduces artifacts commonly caused by metal in joint replacements, which can distort magnetic waves, obscuring soft tissues around the arthroplasty. This innovation enables physicians to see fluid, infection or loosening of the replacement, which may not be visible on a typical MRI scan.

“Access to MARS-MRI has enabled us to conduct a long-term study assessing the cause of pain in patients coming to us with painful arthroplasties,” says McFarland. “Once we determine the cause, we can consider the right approach to treatment.”

McFarland and his team also seek to simplify methods of compensating for lost bone in patients undergoing shoulder arthroplasty. “Some surgeons may recommend putting in bone graft or using special, augmented components to make up for lost bone,” he says. “But we’ve found that if you selectively grind down bone so that the implant can be fixed securely, you can avoid these other, somewhat difficult treatments.” Their research shows that this glenoid-reaming technique is effective. McFarland confirms, “We have found in most instances you can safely ream the bone flat, without affecting range of motion, loosening or performance.”

To determine where to ream the bone, McFarland and his colleagues use 3D modeling, which creates a physical model of the scapula that includes the socket (also called the glenoid). Johns Hopkins is one of few tertiary care centers with the ability and resources to conduct 3D modeling of each patient’s shoulder before primary or revision surgery.

“We have had a lot of success with this method,” McFarland says. “It’s superior to conventional computed tomography. Not only can you look at the model, but you can also measure certain parameters digitally that allow you to come up with a more effective result.”

For the most complex arthroplasty cases, however, McFarland believes that the use of custom glenoid components has been revolutionary, particularly for patients with severe bone loss undergoing revision surgery. “Arthroplasties don’t last forever,” McFarland explains. “When shoulder replacements loosen, they tend to wear away the socket bone to a large extent. In these cases, conventional replacements don’t work as well, so we use custom components.” Few companies currently produce these components, but McFarland suggests that, as more manufacturers participate, the use of custom socket components will become more refined.

Robust research is a pillar of diagnostic and surgical innovation at Johns Hopkins. This drive toward continual improvement distinguishes Johns Hopkins physicians. “Here, you not only have specialists in every department, but ‘super specialists,’” McFarland says. “When you get an opinion from Johns Hopkins, you know it’s from the best in the world.”

Connect with Edward McFarland on Doximity.


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