Augmented Implants Can Improve Outcomes in Patients with B2 and B3 Glenoids
Dr. Eric Ricchetti discusses the findings of a study from Cleveland Clinic that evaluated clinical and radiographic outcomes in anatomic total shoulder arthroplasty patients with glenohumeral osteoarthritis and significant posterior bone loss who received a posteriorly augmented glenoid component.
A study from Cleveland Clinic has found that use of a posteriorly augmented glenoid component can improve pathologic glenoid retroversion and posterior subluxation of the humeral head in most patients with glenohumeral osteoarthritis and significant posterior bone loss (Walch B2 and B3 glenoids), with significant improvements in clinical outcome scores.
These findings were presented at the 2018 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in New Orleans.
The difficulty in treating Walch B2 and B3 glenoids with conventional polyethylene glenoid components led to the development of posteriorly augmented components to correct the pathology. The use of these components is indicated “in cases of glenohumeral osteoarthritis with moderate to severe posterior glenoid bone loss in which the standard technique of eccentric reaming of the glenoid would lead to incomplete correction of retroversion and/or excessive bone removal that creates significant joint line medialization” said Eric T. Ricchetti, MD, one of the study authors.
“This scenario commonly occurs in a B2 glenoid with moderate to severe glenoid bone loss and glenoid retroversion of 15 or more. Approximately 25% to 30% of our anatomic total shoulder arthroplasty patients meet criteria for use of this type of implant.”
For the study presented at the AAOS meeting, Dr. Ricchetti and his colleagues sought to evaluate clinical and radiographic outcomes in patients who had received a posteriorly augmented component, determine how well the deformity was corrected, and identify any factors associated with component loosening.
Between January 2010 and April 2015, a posteriorly augmented glenoid component was used in 122 consecutive anatomic total shoulder arthroplasties. The researchers looked at preoperative 3D CT scans to determine:
- Modified Walch classification
- Goutallier grade of fatty infiltration of the rotator cuff muscles
- Glenoid retroversion
- Humeral head subluxation
- Joint line medialization
- Posterior glenoid bone loss according to the glenoid vault model
Of the original group of 122 patients, 71 were determined to have a Walch B2 or B3 glenoid. Follow-up for this group was a minimum of 2 years (median 2.4 years, range 2-6 years). Postoperative radiographs were done during the follow-up period to assess center peg osteolysis, glenoid version, and humeral head subluxation. The researchers found that use of the posteriorly augmented glenoid component:
- Corrected mean glenoid retroversion from -24° to -11°
- Improved humeral head centering from 60 of 71 cases (85%) not centered preoperatively to 11 of 71 cases (15%) not centered postoperatively (P<0.0001)
- Improved Penn Shoulder Scores from 30 to 94 (P<0.0001)
- Improved range of motion and VR12 physical component scores significantly (P<0.0001)
With regard to risk factors for poor outcomes, greater amounts of superior inclination, preoperative humeral head subluxation, and postoperative humeral head subluxation were more likely to be found in patients who had 15 or more glenoid component retroversion (19/71, 27%; P<0.05). In addition, higher amounts of teres minor fatty infiltration and postoperative retroversion were more likely to be seen in patients with postoperative posterior subluxation (7/71, 10%; P<0.05).
Grade 1 center peg osteolysis was found in 11 of 71 patients (15%). Patients with greater preoperative joint line medialization and posterior glenoid bone loss were more likely to develop this central peg osteolysis than patients with less preoperative joint line medialization (5.5 mm vs 3.2 mm, respectively; P=0.0.24) and less preoperative posterior glenoid bone loss (7.0 mm vs 5.5 mm, respectively; P=0.032). This was an unexpected finding, suggesting that, “there may be a degree of posterior glenoid bone loss that even an augmented glenoid component may not be able to correct,” Dr. Ricchetti said. “Other surgical options, such as reverse total shoulder arthoplasty, may be considered in this situation.”
In fact, Dr. Ricchetti and his partners have adopted reverse total shoulder arthroplasty for most patients with advanced preoperative joint line medialization and posterior glenoid bone, typically seen with severe B3 glenoids, to reduce the risk of center peg osteolysis. The decision to use the reverse procedure is based on preoperative surgical planning with 3D CT imaging software. “If persistent joint line medialization is present when placing a posteriorly augmented glenoid component in the planning software, the decision is made to proceed with reverse total shoulder arthroplasty,” Dr. Ricchetti said.
He noted that the study has identified several potential risk factors for poor outcome with this implant – worse preoperative glenoid bone loss, posterior humeral head subluxation, and rotator cuff muscle fatty infiltration – and that he and his colleagues are continuing to follow the study cohort to determine if these risk factors ultimately lead to early clinical failure.
Ho J, Amini MH Entezari V, Jun BJ, Alolabi B, Ricchetti ET, Iannotti JP. Clinical and Radiographic Outcomes of a Posteriorly Augmented Glenoid Component in Anatomic Total Shoulder Arthroplasty for Primary Osteoarthritis with Posterior Glenoid Bone Loss (Paper 069). Presented at the 2018 Annual Meeting of the American Academy of Orthopaedic Surgeons, March 6-10, 2018, New Orleans, Louisiana.
Dr. Ho, Dr. Entezari, Dr. Jun, and Dr. Alolabi have no disclosures relevant to this study. Dr. Amini had disclosed that he is a paid consultant for Applied Biologics and that he receives research support from Arthrosurface. Dr. Ricchetti has disclosed that he receives research support from DePuy Synthes and that he is a paid consultant for DJO Surgical. Dr. Iannotti has disclosed that he has stock or stock options in Custom Orthopaedic Solutions; that he receives royalties from DePuy Synthes, Integra, Tornier, and Zimmer Biomet; and that he is a paid consultant and paid speaker for DJO Surgical.