Biomechanical Evaluation of All-Polyethylene Pegged Bony Ingrowth Glenoid Fixation Techniques on Implant Micromotion.
Newer glenoid components that allow for hybrid cement fixation via traditional cementation of peripheral pegs and bony ingrowth into an interference-fit central peg introduce the possibility of long-term biological fixation. However, little biomechanical work has been done on the initial stability of these components and the various fixation options. We conducted a study in which all-polyethylene glenoid components with a centrally fluted peg were implanted in polyurethane blocks with interference-fit, hybrid cement, and fully cemented fixation (5 per fixation group). Biomechanical evaluation of glenoid loosening, according to ASTM Standard F-2028-12, subjected the glenoids to 50,000 cycles of rim loading, and glenoid component motion was recorded with 2 differential variable reluctance transducers fixed to each glenoid prosthesis. Fully cemented fixation exhibited significantly less mean distraction in comparison with interference-fit fixation (P < .001) and hybrid cement fixation (P < .001). Hybrid cement fixation exhibited significantly less distraction (P < .001), more compression (P < .001), and no significant difference in glenoid translation (P = .793) in comparison with interference-fit fixation. Fully cemented fixation exhibited the most resistance to glenoid motion in comparison with hybrid cement fixation and interference-fit fixation. However, hybrid cement fixation and interference-fit fixation exhibited equivocal motion. Given these results, cementation of peripheral pegs may confer no additional initial stability over that provided by uncemented interference-fit fixation.
Brett P
BP
Wiater
James E
JE
Moravek
Michael D
MD
Kurdziel
Kevin C
KC
Baker
Division of Shoulder and Elbow Surgery, Department of Orthopaedic Surgery, Beaumont Health System, Royal Oak, MI. mwiater@beaumont.edu.
J Michael
JM
Wiater
D000072228:Arthroplasty, Replacement, Shoulder; D001696:Biomechanical Phenomena; D001843:Bone Cements; D006801:Humans; D008422:Materials Testing; D020959:Polyethylene; D011474:Prosthesis Design; D012785:Shoulder Joint; D000072227:Shoulder Prosthesis
D001843:Bone Cements; D020959:Polyethylene