A ten-year radiologic comparison of two-all polyethylene glenoid component designs: a prospective trial

Background: Aseptic glenoid component loosening remains a common problem in total shoulder arthroplasty (TSA). This study presents long-term prospective follow-up of 2 cemented all-polyethylene glenoid components with different backside design geometry and the effect on the presence and progression of radiolucent lines (RLLs). Materials and methods: Fifty-six TSAs were performed for primary osteoarthritis. Two surgeons used an identical technique to implant 32 flat-back and 24 convex-back glenoids. In particular, the glenoid components were cemented after a minimal reaming and bone compaction. Standardized postoperative radiologic and clinical follow-up was at 2 and 10 years. Three independent observers evaluated the x-ray images for RLLs around the base plate and keel. The results were analyzed for progression and influencing factors. Results: At 10 years, progression of RLL was seen in both components, but there was no difference between the 2 glenoid designs (P = .16). Younger patient age (P = .03), hand dominance (P = .017), and presence of early RLLs (P = .018) were significant factors for progression of RLLs. Constant scores deteriorated with progression of RLLs (P = .006). The glenoid revision rate at 10 years was 5%. Conclusion: At 10 years there was no difference in the presence or progression of RRLs between a flat-back and a convex-back glenoid all-polyethylene design. Young age, hand dominance, and poor implantation technique influence glenoid RLLs and affect the clinical result of TSA. Level of evidence: Level II, Prospective Cohort, Treatment Study. (C) 2011 Journal of Shoulder and Elbow Surgery Board of Trustees.