Biomechanical comparison between various screw fixation angles for Latarjet procedure: a cadaveric biomechanical study

Kai-Lan Hsu; Ming-Long Yeh; Fa-Chuan Kuan; Chih-Kai Hong; Hao-Chun Chuang; Wei-Ming Wang; Wei-Ren Su

doi:10.1016/j.jse.2022.02.031

Biomechanical comparison between various screw fixation angles for Latarjet procedure: a cadaveric biomechanical study

J Shoulder Elbow Surg. 2022 Sep;31(9):1947-1956. doi: 10.1016/j.jse.2022.02.031. Epub 2022 Apr 6.

Authors

Kai-Lan Hsu¹, Ming-Long Yeh², Fa-Chuan Kuan³, Chih-Kai Hong⁴, Hao-Chun Chuang⁴, Wei-Ming Wang⁵, Wei-Ren Su⁶

Affiliations

¹ Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan; Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Division of Traumatology, National Cheng Kung University Medical Center, Tainan, Taiwan; Skeleton Materials and Bio-compatibility Core Lab, Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
² Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
³ Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan; Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Division of Traumatology, National Cheng Kung University Medical Center, Tainan, Taiwan; Skeleton Materials and Bio-compatibility Core Lab, Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Division of Orthopaedics, Department of Surgery, National Cheng Kung University Hospital Dou Liou Branch, National Cheng Kung University, Yunlin, Taiwan.
⁴ Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Skeleton Materials and Bio-compatibility Core Lab, Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
⁵ Department of Statistics and Institute of Data Science, College of Management, National Cheng Kung University, Tainan, Taiwan.
⁶ Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Skeleton Materials and Bio-compatibility Core Lab, Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Electronic address: suwr@ms28.hinet.net.

PMID: 35398164
DOI: 10.1016/j.jse.2022.02.031

Abstract

Background: The Latarjet procedure is a reliable treatment for the management of anterior glenohumeral instability with glenoid bone loss. However, the biomechanical properties of different fixation angles between screw and glenoid surface (α angle) have rarely been studied. The aim of the study was to investigate and compare the fixation stability, failure load, and failure mechanism between different α angles for Latarjet procedures, which were performed on cadaver specimens.

Methods: Twenty-four shoulder specimens (8 in each of 3 groups) were dissected free of all soft tissue, and a 25% glenoid defect was created. The coracoid process was osteomized and fixed with 2 screws at 3 different α angles: 0° (group A), 15° (group B), and 30° (group C). Specimens were mounted to a testing apparatus, and cyclic loading (100 cycles at 1 Hz) was applied with a staircase protocol (50, 100, 150, and 200 N). Gross graft displacement and interface displacement were measured. The ultimate failure loads and failure mechanisms were recorded.

Results: There was no significant difference in gross displacement under any cyclic load between 3 groups. However, a significant larger interface displacement was noted in group C than in group A in 150-N cyclic loading (P = .017). Under failure strength testing, all 24 specimens failed because of screw cutout from the glenoid, and the ultimate failure load was similar among the three groups.

Conclusion: Compared with the 0° α angle, the displacement after cyclic loading did not significantly increase when the α angle was increased to 15° but significantly increased at 30° for Latarjet procedures, which were performed on cadaver specimens. The results suggest that surgeons should apply the screws as parallel as possible to the glenoid surface when performing the Latarjet procedure. Although mild deviation may not reduce fixation stability, α angles greater than 30° should be avoided.

Keywords: Latarjet procedure; cadaveric biomechanical; glenoid bone loss; α angle.

MeSH terms

Biomechanical Phenomena
Bone Screws / adverse effects
Cadaver
Humans
Joint Instability* / etiology
Joint Instability* / surgery
Shoulder Joint* / surgery