TY - JOUR
T1 - The Effect of Screw Design and Cortical Augmentation on Insertional Torque and Compression in Coracoid-Glenoid Fixation in a Sawbones Model
AU - Rabinowitz, Justin
AU - Lin, Jackie J.
AU - Greenhouse, Alyssa
AU - Rao, Meghana V.
AU - Provencher, Matthew
AU - Parada, Stephen
AU - Friedman, Richard J.
AU - Eichinger, Josef K.
N1 - Funding Information:
The authors report the following potential conflicts of interest or sources of funding: Arthrex, Smith & Nephew, and DePuy Synthes Mitek Sports Medicine loaned the authors the necessary surgical equipment and donated the disposable implants for this study. The Medical University of South Carolina provided an internal department grant to J.R. to sponsor additional equipment purchases for this project. M.P. receives royalties from Arthrex and is a consultant for Arthrex, Joint Research Foundation, and SLACK. S.P. is a consultant for Arthrex and Exactech and receives research support from Exactech. R.J.F. performs consulting and research for total shoulder arthroplasty for Exactech. J.K.E. receives nonfinancial support from Arthrex, Smith & Nephew, and DePuy Mitek. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
Publisher Copyright:
© 2019
PY - 2020/3
Y1 - 2020/3
N2 - Purpose: To compare screw insertional torque and coracoid-glenoid compression from 4 fixation techniques with different screw design parameters and cortical augmentation for the Latarjet procedure. Methods: Simulated Latarjet procedures were performed with 4 fixation techniques using laminated polyurethane blocks with dimensions similar to the coracoid-glenoid construct. The groups included DePuy Synthes Mitek 3.5-mm partially threaded screws with top hats, Arthrex 3.75-mm fully threaded screws with a 2-hole plate, Arthrex 3.75-mm fully threaded screws, and Smith & Nephew 4.0-mm partially threaded screws. Screws were inserted using a digital torque-measuring screwdriver to determine maximum insertional torque. Pressure-sensitive film was used to measure the maximum contact pressure and the effective pressure distribution (EPD) between the coracoid and glenoid; the EPD represents the percentage of the film's surface area that experienced pressure greater than 10 MPa. One-way analysis of variance and post hoc tests were used for statistical analysis. Results: Significant differences were found between the 4 fixation groups for each variable measured. The 2 cortically augmented systems produced significantly higher maximum insertional torque than the non–cortically augmented systems (P < .001 for both). The 3.75-mm screws with a 2-hole plate yielded significantly higher contact pressures than the 4.0-mm screws (P = .028). This group also had a high EPD, with a mean value more than double the values of the non–cortically augmented systems (P = .037 and P < .001). Conclusions: Cortically augmented fixation methods showed higher maximum insertional torque, maximum contact pressure, and EPD between the surfaces of the coracoid and glenoid in this Sawbones model. Clinical Relevance: Various implants are available for the Latarjet procedure, but their biomechanical characteristics have not yet been fully elucidated. Graft fracture and nonunion represent 2 modes of failure that may be related to insertional torque and coracoid-glenoid compression. This study compared screw insertional torque and compression achieved using 4 fixation techniques with different screw design parameters and cortical augmentation in a Sawbones model.
AB - Purpose: To compare screw insertional torque and coracoid-glenoid compression from 4 fixation techniques with different screw design parameters and cortical augmentation for the Latarjet procedure. Methods: Simulated Latarjet procedures were performed with 4 fixation techniques using laminated polyurethane blocks with dimensions similar to the coracoid-glenoid construct. The groups included DePuy Synthes Mitek 3.5-mm partially threaded screws with top hats, Arthrex 3.75-mm fully threaded screws with a 2-hole plate, Arthrex 3.75-mm fully threaded screws, and Smith & Nephew 4.0-mm partially threaded screws. Screws were inserted using a digital torque-measuring screwdriver to determine maximum insertional torque. Pressure-sensitive film was used to measure the maximum contact pressure and the effective pressure distribution (EPD) between the coracoid and glenoid; the EPD represents the percentage of the film's surface area that experienced pressure greater than 10 MPa. One-way analysis of variance and post hoc tests were used for statistical analysis. Results: Significant differences were found between the 4 fixation groups for each variable measured. The 2 cortically augmented systems produced significantly higher maximum insertional torque than the non–cortically augmented systems (P < .001 for both). The 3.75-mm screws with a 2-hole plate yielded significantly higher contact pressures than the 4.0-mm screws (P = .028). This group also had a high EPD, with a mean value more than double the values of the non–cortically augmented systems (P = .037 and P < .001). Conclusions: Cortically augmented fixation methods showed higher maximum insertional torque, maximum contact pressure, and EPD between the surfaces of the coracoid and glenoid in this Sawbones model. Clinical Relevance: Various implants are available for the Latarjet procedure, but their biomechanical characteristics have not yet been fully elucidated. Graft fracture and nonunion represent 2 modes of failure that may be related to insertional torque and coracoid-glenoid compression. This study compared screw insertional torque and compression achieved using 4 fixation techniques with different screw design parameters and cortical augmentation in a Sawbones model.
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U2 - 10.1016/j.arthro.2019.10.011
DO - 10.1016/j.arthro.2019.10.011
M3 - Article
C2 - 31901392
AN - SCOPUS:85077149745
SN - 0749-8063
VL - 36
SP - 689
EP - 695
JO - Arthroscopy - Journal of Arthroscopic and Related Surgery
JF - Arthroscopy - Journal of Arthroscopic and Related Surgery
IS - 3
ER -