title: Number of pegs influence focal stress distributions and micromotion in glenoid implants: a finite element study.
abstract: The present study was conducted to compare the stability of four commercially available implants by investigating the focal stress distributions and relative micromotion using finite element analysis. Variations in the numbers of pegs between the implant designs were tested. A load of 750 N was applied at three different glenoid positions (SA: superior-anterior; SP: superior-posterior; C: central) to mimic off-center and central loadings during activities of daily living. Focal stress distributions and relative micromotion were measured using Marc Mentat software. The results demonstrated that by increasing the number of pegs from two to five, the total focal stress volumes exceeding 5 MPa, reflecting the stress critical volume (SCV) as the threshold for occurrence of cement microfractures, decreased from 8.41 to 5.21 % in the SA position and from 9.59 to 6.69 % in the SP position. However, in the C position, this change in peg number increased the SCV from 1.37 to 5.86 %. Meanwhile, micromotion appeared to remain within 19-25 µm irrespective of the number of pegs used. In conclusion, four-peg glenoid implants provide the best configuration because they had lower SCV values compared with lesser-peg implants, preserved more bone stock, and reduced PMMA cement usage compared with five-peg implants.
authors.affiliation: Medical Devices Technology Group (MediTeg), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
authors.forename: Abdul Hadi Abdul
authors.initials: AH
authors.lastname: Wahab
authors.affiliation: Medical Devices Technology Group (MediTeg), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia. rafiq@biomedical.utm.my.
authors.forename: Mohammed Rafiq Abdul
authors.initials: MR
authors.lastname: Kadir
authors.affiliation: Sport Innovation and Technology Centre (SITC), Institute of Human Centered Engineering (IHCE), Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
authors.forename: Muhammad Noor
authors.initials: MN
authors.lastname: Harun
authors.affiliation: Tissue Engineering Group, Department of Orthopaedic Surgery (NOCERAL), Faculty of Medicine, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia.
authors.forename: Tunku
authors.initials: T
authors.lastname: Kamarul
authors.affiliation: Sport Innovation and Technology Centre (SITC), Institute of Human Centered Engineering (IHCE), Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
authors.forename: Ardiyansyah
authors.initials: A
authors.lastname: Syahrom
mesh_terms: D001843:Bone Cements / Q000494:pharmacology; D020342:Finite Element Analysis; D061165:Glenoid Cavity / Q000187:drug effects / Q000502:physiology*; D007595:Joint Prosthesis; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000187:drug effects / Q000502:physiology*; D013314:Stress, Mechanical; D016474:Weight-Bearing
chemical_list: D001843:Bone Cements
keywords: Biomechanics; Finite element analysis; Orthopedics; Stress critical volume; Total shoulder arthroplasty