Ian Byram, MD
Read complete study: Outcomes of Trabecular Metal-backed glenoid components in anatomic total shoulder arthroplasty.
The authors of this study present a series of 47 total shoulder arthroplasties performed with trabecular metal-backed glenoid components, reporting radiographic and clinical outcomes at an average follow-up of 41 months. The operative technique described involved placement of a trabecular metal peg-keel construct, with the vast majority placed in an uncemented, press-fit fashion. The authors noted that this method of implantation is not approved by the FDA, but this technique is “acceptable practice.” Patients were placed into a sling for four weeks and external rotation was limited for six weeks.
Five of the 47 patients (11%) underwent revision to reverse TSA for rotator cuff failure at an average of 12 months postoperative and were not included in the radiographic analysis. Despite excluding these patients, the authors still report an alarming rate of metal debris and osteolysis (25%) with one catastrophic failure at a minimum of two years follow-up. Notably, the majority of patients with radiographic changes were asymptomatic. For all revisions in this series, the authors note the “substantial central bone loss” in the glenoid vault, requiring bone grafting for reverse baseplate implantation. As a result of the high rate of metallic debris and osteolysis, the authors have discontinued the use of the trabecular metal glenoid.
“The authors still report an alarming rate of metal debris and osteolysis (25%) with one catastrophic failure at a minimum of two years follow-up.
For a short period of time in my practice, I utilized this same trabecular metal backed glenoid. Preparation for this implant requires perpendicular glenoid exposure and removal of bone from the central glenoid vault in a cross shape with a series of drill holes and punches. In my experience revising this implant, I also have noted severe central bone loss requiring bone grafting and occasional staged reconstruction.
Similar to the authors of this study, I had one catastrophic failure in a 50 year old male with normal bone density and no comorbidities.
His initial procedure was uncomplicated, and he regained appropriate motion and pain relief within three months of his index surgery.
Initial post-operative images
Unfortunately, at four years post-operative he developed aseptic loosening and complete dislocation of the implant. This failure occurred despite normal rotator cuff function and lack of infection. Due to his young age, his shoulder was revised to hemiarthroplasty with bone grafting of the glenoid.
Implant failure
As a result of this catastrophic failure and my experience with bone loss seen in revisions of this type of glenoid implant, I have discontinued its use in my practice.
In summary, this study highlights the high rate of metallic debris and osteolysis seen with the trabecular metal backed glenoid as well as issues of bone loss seen in revisions of this implant. My clinical experience with the trabecular metal glenoid mirrors that of the study, therefore I have discontinued its use.
Ian Byram, MD, is a shoulder and elbow specialist at the Bone and Joint Institute of Tennessee. Dr. Byram received his medical degree from the University of North Carolina School of Medicine and completed his residency at Vanderbilt University School of Medicine. He went on to complete a shoulder, elbow and sports medicine fellowship at Columbia University Medical Center. Dr. Bryam is an accomplished author of more than 20 peer-review articles and book chapters, and member of several professional societies.