Short-term clinical and radiographic outcomes of a hybrid all-polyethylene glenoid based on preoperative glenoid morphology.

BACKGROUND: The primary purpose of this study was to compare 2-year anatomic total shoulder arthroplasty (TSA) functional and radiographic outcomes between Walch type A and B glenoids treated with an all-polyethylene glenoid designed for hybrid fixation with peripheral cement and central osseous integration. The secondary purpose was to evaluate outcomes based on central peg technique. The hypotheses were that there would be no difference in short-term radiographic or functional outcome scores based on preoperative glenoid morphology or central peg technique. METHODS: We performed a multicenter retrospective review of patients who underwent TSA with the same hybrid all-polyethylene glenoid and had minimum 2-year follow-up. Patient-reported outcomes and radiographic outcomes were analyzed based on preoperative Walch morphology and central peg technique. Radiographic analysis included preoperative glenoid morphology; preoperative and postoperative glenoid version, glenoid inclination, and posterior humeral head subluxation; and postoperative glenoid radiolucencies according to the Wirth and Lazarus classifications. RESULTS: A total of 266 patients with a mean age of 64.9 ± 8.2 years were evaluated at a mean of 28 months postoperatively. Postoperatively, there were significant improvements in all functional outcome measures (P < .001), range-of-motion measures (forward elevation, external rotation at 0°, external rotation at 90°, internal rotation by spinal level, and internal rotation at 90°; P < .001), and strength measures (Constant, external rotation, and modified belly press; P < .001). There were no clinically meaningful differences in functional outcomes or statistically significant differences in radiographic appearance between Walch type A and B glenoids. Subgroup analysis revealed that glenoids with a cemented central peg had the worst radiographic outcomes based on Lazarus scoring. CONCLUSION: Patients undergoing TSA with a hybrid in-line pegged glenoid have excellent clinical outcomes at short-term follow-up regardless of preoperative glenoid morphology. Different central peg techniques do not appear to play a significant role in the risk of glenoid component lucencies at 2 years postoperatively.

Clinical and radiographic outcomes of hybrid glenoid fixation with a central porous titanium post: analysis of 713 consecutive shoulders.

BACKGROUND: Hybrid glenoid component fixation represents an emerging technology in total shoulder arthroplasty (TSA) design. However, there is a paucity of larger-scale studies reporting the outcomes following implantation of these components. This study aimed to determine the outcomes following primary TSA using hybrid glenoid component fixation with a central porous titanium post. METHODS: A retrospective review of 2 institutional databases identified patients aged ≥ 18 years who underwent primary elective hybrid TSA between 2009 and 2018 with a minimum of 2 years of follow-up. Outcomes evaluated included the visual analog scale pain score, range of motion, American Shoulder and Elbow Surgeons (ASES) score, complications, and implant survivorship free from reoperation or revision. Postoperative imaging was assessed for glenoid radiolucent lines and evidence of aseptic glenoid component loosening (AGL). RESULTS: A total of 713 shoulders in 666 patients with a mean age of 61 ± 6 years were included in the study at a mean follow-up period of 4.3 years (range, 2.0-9.1 years); male shoulders comprised 50.9% of shoulders. Notable clinical improvements were observed with respect to the visual analog scale pain score (7.0 to 1.4, P < .001), active forward elevation (91° to 155°, P < .001), active external rotation (21° to 50°, P < .001), and the ASES score (38.6 to 82.7, P < .001), with all exceeding the substantial clinical benefit threshold for TSA. The active internal rotation score also showed significant improvement (3.1 to 5.7, P < .001). Glenoid radiolucent lines were identified in 57 TSAs (8.2%), with 1 radiographically loose glenoid component (0.1%). There were 54 complications (7.6%), with postoperative rotator cuff tear as the most common complication (n = 15, 2.1%); only 4 cases (0.6%) of glenoid-related complications (AGL) were observed. The Kaplan-Meier rate of survival free from revision surgery was 98.7% at 1 year, 98.5% at 2 years, and 96.7% at 5 years. CONCLUSIONS: Hybrid glenoid component fixation of anatomic TSA with a central porous titanium post demonstrated statistically significant and clinically meaningful improvements in pain, range of motion, and ASES scores. Although AGL remains a concern, only 0.6% of TSAs sustained glenoid-related complications at a mean follow-up period of 4.3 years and the rate of survivorship free from revision was 96.7% at 5 years. These favorable clinical findings support the theoretical advantages of hybrid glenoid fixation; however, large comparative investigations with long-term follow-up are needed to validate these results.

Five-year minimum clinical and radiographic outcomes of total shoulder arthroplasty using a hybrid glenoid component with a central porous titanium post.

BACKGROUND: To determine the effectiveness of hybrid glenoid components in reducing the frequency of glenoid component loosening, we evaluated clinical and radiographic outcomes at a minimum 5-year follow-up in 45 shoulders that underwent total shoulder arthroplasty (TSA) using a system with a central porous titanium post to augment the cemented peripheral pegs. METHODS: Function and pain were evaluated with the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment score, visual analog scale, active shoulder range of motion, and strength. Postoperative radiographs were analyzed for radiolucent lines, progressive loosening, and at-risk signs. RESULTS: The mean American Shoulder and Elbow Surgeons score improved from 40.4 to 83.7 (P < .0001) and the mean visual analog scale from 5.9 to 0.8 (P < .0001). Forward elevation improved from 113° to 151° (P < .001), internal rotation from 49° to 60° (P = .035), and mean external rotation from 36° to 50° (P = .0006). Radiographs showed glenoid component radiolucency in 29 shoulders. Radiolucencies were confined to the area under the glenoid faceplate in 6 and were only around the central post in 13. Nine TSAs (20%) demonstrated 2 or more columns of involvement but were not judged to be at-risk. One implant (2.2%) had glenoid component failure and was revised to a hemiarthroplasty. CONCLUSION: Anatomic TSA using a hybrid glenoid component with a central porous titanium post demonstrated a low rate of mechanical failure and a rate of radiolucent lines comparable to reports of all polyethylene implants. Further evaluations are needed to demonstrate the long-term durability of these implants and to determine the significance and fate of the radiolucent lines, particularly relative to the central post.

Hybrid Glenoid Designs in Anatomic Total Shoulder Arthroplasty: A Systematic Review.

Background: Hybrid glenoid components in total shoulder arthroplasty (TSA) utilize both polyethylene and metal components to provide short-term stability and long-term biologic fixation through bone ingrowth. Questions/Purpose: We sought to systematically review the literature for studies that assessed outcomes of TSA performed using hybrid glenoid components. Methods: PubMed, Medline, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Embase were searched systematically for articles measuring clinical and patient-reported outcomes and rates of complication and revision following TSA using a hybrid glenoid component. Results: Seven studies with 593 shoulders were included in this review. The mean age of patients was 65 ± 1 years, and 46% of the population was male. Mean follow-up was 50 months (4.2 years). The overall complication rate was 7% and rate of revision was 2.5%; glenoid radiolucency was present in 33% of shoulders at mean follow-up of 50 months. Mean improvements in forward elevation, external rotation, internal rotation score, and abduction were 49°, 28°, 2 points, and 42°, respectively. Mean improvements in Constant, American Shoulder and Elbow Surgeons (ASES), and University of California, Los Angeles (UCLA) scores were 36 points, 52 points, and 17 points, respectively. Conclusion: Our review found that TSA using hybrid glenoid components results in low rates of complication and revision at early follow-up. Long-term studies are warranted to understand more fully the role of hybrid glenoid components in TSA.

Mechanical behavior of hybrid glenoid components compared to all-PE components: a finite element analysis.

PURPOSE: The purpose of this finite element study was to compare bone and cement stresses and implant micromotions among all-polyethylene (PE) and hybrid glenoid components. The hypothesis was that, compared to all-PE components, hybrid components yield lower bone and cement stresses with smaller micromotions. METHODS: Implant micromotions and cement and bone stresses were compared among 4 all PE (U-PG, U-KG, A-KG, I-KG) and 2 hybrid (E-hCG, I-hPG) virtually implanted glenoid components. Glenohumeral joint reaction forces were applied at five loading regions (central, anterior, posterior, superior and inferior). Implant failure was assumed if glenoid micromotion exceeded 75 µm or cement stresses exceeded 4 MPa. The critical cement volume (CCV) was based on the percentage of cement volume that exceeded 4 MPa. Results were pooled and summarized in boxplots, and differences evaluated using pairwise Wilcoxon Rank Sum tests. RESULTS: Differences in cement stress were found only between the I-hPG hybrid component (2.9 ± 1.0 MPa) and all-PE keeled-components (U-KG: 3.8 ± 0.9 MPa, p = 0.017; A-KG: 3.6 ± 0.5 MPa, p = 0.014; I-KG: 3.6 ± 0.6 MPa, p = 0.040). There were no differences in cortical and trabecular bone stresses among glenoid components. The E-hCG hybrid component exceeded micromotions of 75 µm in 2 patients. There were no differences in %CCV among glenoid components. CONCLUSIONS: Finite element analyses reveal that compared to all-PE glenoid components, hybrid components yield similar average stresses within bone and cement. Finally, risk of fatigue failure of the cement mantle is equal for hybrid and all-PE components, as no difference in %CCV was observed. LEVEL OF EVIDENCE: IV, in-silico.