Loosening performance of cemented glenoid prosthesis design pairs.
OBJECTIVE
The purpose of this pilot study (n=3) was to compare the loosening performance of glenoid prosthesis design pairs where only one design variable differed.


METHODS
Glenoids were subjected to dynamic edge loading in a biaxial test setup.


BACKGROUND
Glenoid component loosening is the primary concern in total shoulder arthroplasty.


METHODS
After the humeral head was cycled 100,000 times to the superior and inferior edges of the glenoid, the tensile edge displacements were measured under superior and inferior off-center loading.


CONCLUSIONS
Based on this study, a rough-backed design had dramatically better loosening performance than a smooth-backed; curved-backed was superior to flat-backed; a less-constrained articular surface was better than a more-constrained articular surface; pegs outperformed a keel; threaded pegs were marginally preferable to cylindrical pegs; and an all-polyethylene design rocked slightly less than a metal-mesh-backed design.


CONCLUSIONS
A comparison of the laboratory loosening behavior of glenoid prostheses may lead to improved designs, subsequently leading to a reduction in the incidence of clinical loosening.
Sulzer Orthopedics Ltd., P.O. Box 65, 8404, Winterthur, Switzerland. carolynanderic@telus.net
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D001696:Biomechanical Phenomena; D006801:Humans; D007595:Joint Prosthesis / Q000009:adverse effects; D010865:Pilot Projects; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012785:Shoulder Joint / Q000503:physiopathology