Biomechanical Analysis of Plate Fixation Compared With Various Screw Configurations for Use in the Latarjet Procedure

Rachel M Frank; Martina Roth; Coen Abel Wijdicks; Nicole Fischer; Alberto Costantini; Giovanni Di Giacomo; Anthony A Romeo

doi:10.1177/2325967120931399

Biomechanical Analysis of Plate Fixation Compared With Various Screw Configurations for Use in the Latarjet Procedure

Orthop J Sports Med. 2020 Jul 14;8(7):2325967120931399. doi: 10.1177/2325967120931399. eCollection 2020 Jul.

Authors

Rachel M Frank¹, Martina Roth², Coen Abel Wijdicks³, Nicole Fischer², Alberto Costantini⁴, Giovanni Di Giacomo⁴, Anthony A Romeo⁵

Affiliations

¹ Department of Orthopedics, University of Colorado School of Medicine, Aurora, Colorado, USA.
² Arthrex, Munich, Germany.
³ Arthrex, Naples, Florida, USA.
⁴ Concordia Hospital for Special Surgery, Rome, Italy.
⁵ Rothman Orthopaedics, New York, New York, USA.

Abstract

Background: The biomechanical properties of coracoid fixation with a miniplate during the Latarjet procedure have not been described.

Purpose: To determine the biomechanical properties of miniplate fixation for the Latarjet procedure compared with various screw fixation configurations.

Study design: Controlled laboratory study.

Methods: A total of 8 groups (n = 5 specimens per group) were tested at a screw insertion angle of 0°: (1) 3.75-mm single screw, (2) 3.75-mm double screw, (3) 3.75-mm double screw with washers, (4) 3.75-mm double screw with a miniplate, (5) 4.00-mm single screw, (6) 4.00-mm double screw, (7) 4.00-mm double screw with washers, and (8) 4.00-mm double screw with a miniplate. In addition, similar to groups 1 to 3 and 5 to 7, there were 30 additional specimens (n = 5 per group) tested at a screw insertion angle of 15° (groups 9-14). To maintain specimen uniformity, rigid polyurethane foam blocks were used. Testing parameters included a preload of 214 N for 10 seconds, cyclical loading from 184 to 736 N at 1 Hz for 100 cycles, and failure loading at a rate of 15 mm/min until 10 mm of displacement or specimen failure occurred.

Results: All single-screw constructs and 77% of 15° screw constructs failed before the completion of cyclical loading. Across all groups, group 8 (4.00-mm double screw with miniplate) demonstrated the highest maximum failure load (P < .001). There were no differences in failure loads among specimens with single-screw fixation (groups 1, 5, 9, and 12; P > .05). All specimens in groups 9, 10, 11, 12, 13, and 14 (insertion angle of 15°) had significantly lower maximum failure loads compared with specimens in groups 2, 3, 4, 6, 7, and 8 (insertion angle of 0°) (P < .001 for all).

Conclusion: These results indicate significantly superior failure loads with the miniplate compared with all other constructs. Across all fixation techniques and screw sizes, constructs with screws inserted at 0° performed better than constructs with screws inserted at 15°.

Clinical relevance: The use of a miniplate for coracoid fixation during the Latarjet procedure may provide a more durable construct for the high-demand contact athlete.

Keywords: Latarjet; biomechanics; glenoid reconstruction; instability; shoulder.