Augmented, non-augmented glenoid in TSA yielded similar outcomes

Further research should be done into augmented components for patients with more severe deformity.

CHICAGO — Patients who underwent anatomic total shoulder arthroplasty with a posterior augmented pegged glenoid experienced similar outcomes when compared with patients who received a non-augmented pegged glenoid, according to results presented at the American Shoulder and Elbow Surgeons Annual Meeting.

“A posterior augmented glenoid for a patient with anatomic shoulder arthroplasty with increased retroversion is a viable treatment option, but clearly th[ese are] early results and we need to follow these patients longer to see what the long-term outcome is,” Richard J. Friedman, MD, chief of shoulder and elbow surgery in the department of orthopedics and physical medicine at The Medical University of South Carolina, told Orthopedics Today.

Augmented vs non-augmented glenoid

Friedman and colleagues collected Simple Shoulder Test, University of California Los Angeles, ASES, Constant and Shoulder Pain and Disability Index metrics among 91 patients undergoing primary anatomic total shoulder arthroplasty with a posterior-augmented pegged glenoid.

“Then we had a similar matched group for age, gender and follow-up with another 91 patients that had a similar designed component that was non-augmented,” Friedman said.

Patients in the non-augmented group had significantly worse preoperative outcomes in four of the five metrics vs. patients in the augmented group, but these differences were not clinically meaningful, he said.

Augmented group outcomes

“At latest follow-up the augmented group had significantly better outcomes defined by all five of the outcome metrics compared to the age, gender and follow-up matched non-augmented group,” Friedman said.

Furthermore, he said there was significantly more strength and active abduction, forward flexion and external rotation in the augmented group at the latest follow-up, and some of those differences were clinically meaningful. The augmented group had significantly more improvements in active abduction, forward flexion and external rotation, according to Friedman. He noted 78% and 63% of patients in the augmented and non-augmented groups, respectively, had radiographic data available, with no differences found in the incidence of radiolucent lines, the average line grade or the distribution of a line between grade 1 and grade 5.

“Complication rates were similar for both groups,” Friedman said. “In the augmented group, we had one aseptic glenoid loosening and we had three aseptic glenoid loosenings in the non-augmented group.”

Surprising findings

According to Friedman, the results of this study may be surprising to some orthopedic surgeons, since many surgeons did not believe augmented components would lead to good outcomes.

“I think a lot of people would be surprised that, in fact, there was no difference in the outcome, that the augmented [components] worked well because a lot of people thought the augments were not a good idea,” Friedman told Orthopedics Today. “They thought that they would fail early because the stresses would be such that they would not last, but it turns out that they do as well as the non-augmented [components].”

Since the component used in this study had an 8° augment, he said future research should focus on a more augmented component for patients with more severe deformity at longer-term follow-up.

“If you have someone with a 25° deformity, 8° still does not get you corrected close to where you want to be,” Friedman said. “If we had a 12° or 16° component, that may get you closer. I think we will be looking at larger augmented components to see how they do for the more severe deformities.” – by Casey Tingle

Reference:

Friedman RJ, et al. Paper 21. Presented at: American Shoulder and Elbow Surgeons Annual Meeting; Oct. 12-14, 2018; Chicago.

For more information:

Richard J. Friedman, MD, can be reached at 96 Jonathan Lucas St., CSB 708, MSC 622, Charleston, SC 29425; email: friedman@musc.edu.

Disclosure: Friedman reports he is a consultant for Exactech.