Reverse total shoulder arthroplasty (RTSA) is performed more and more for a variety of shoulder conditions, and it has been shown to provide excellent pain relief and increased range of motion in these cases. One of the indications for this procedure is severe glenoid bone loss, especially in patients who are unable to be fitted with standard or augmented glenoid components. Ed McFarland, the Wayne H. Lewis Professor of Shoulder and Elbow Surgery and Professor of Orthopaedic Surgery at Johns Hopkins, says that, for this group of patients, “your only other option is to bone graft, and some of these patients have so much bone loss that grafting is not really very successful. Grafting around the glenoid is very tricky and technically difficult, and the results are modest at best.”
McFarland’s solution for patients with extensive bone loss — either primary or after failed cemented arthroplasty, for example — is to use custom-fitted glenoid components. Through the use of CT imaging and 3D reconstruction, a custom baseplate is produced that is tailored to the patient’s anatomy and reconstructs the glenoid vault. Preoperative planning with the manufacturer’s engineers involves 3D bone model and screw trajectory scans, which guide the creation of “a custom glenoid baseplate that directs the screws into the bone where it is present, creating a very stable implant,” says McFarland. This obviates the need for bone grafting and allows even patients with severely deficient glenoid to be treated.
McFarland and colleague Umasuthan Srikumaran see patients with a high level of complexity. “This implant is reserved for people with very severe bone loss that really can’t be dealt with safely or reliably with other means.” The team has particular expertise with revision cases, which often include this special subset of patients whose conditions are especially challenging. “We do a lot of revision cases; they’re fairly routine for us, and we take on some of the most difficult challenges as they relate to shoulder arthroplasty.”
McFarland’s team has investigated short-term clinical and radiographic results after RTSA using the custom implant, focusing not only on the benefits associated with the use of these implants, but also on complications for which surgeons need to be prepared. Delays related to scheduling or the patient’s overall health can result in ongoing bone loss and consequently a prosthesis that may no longer fit well at the time of surgery. Surgeons must anticipate intraoperative changes, such as reduced amount or quality of bone, and be able to change directions mid-operation by modifying the fixation or switching to a different type of prosthesis.
McFarland hopes that wider use of this system will mean faster production of each implant, facilitating quicker relief for patients and optimal fit at the time of surgery. “One of the things that makes Hopkins great, I think, is the fact that every division here, every department has people who are tops in their fields. Everyone in our department,” McFarland says, “has a mission to take care of patients … the patient comes first, and that’s how we run our office and our surgeries and our clinics, and pretty much everything we do here.”
