Redesigning metal interference screws can improve ease of insertion while maintaining fixation of soft-tissue anterior cruciate ligament reconstruction grafts
Author(s)
Type
Journal Article
Abstract
Purpose: To compare the fixation strength and loads on insertion of a titanium alloy interference screw with a modified tip against a conventional titanium interference screw. Methods: Slippage of bovine digital extensor tendons (as substitutes for human tendon grafts) under cyclic loading and interference fixation strength under a pullout test were recorded in 10 cadaveric knees, with 2 tunnels drilled in each femur and tibia to provide pair-wise comparisons between the modified-tip screw (MS) and conventional screw (CS). To analyze screw insertion, 10 surgeons blindly inserted pairs of the MS and CS into bone-substitute blocks (with polyester shoelaces as graft substitutes), with insertion loads measured using a force/torque sensor. Results: No differences were found between the MS and CS either in graft slippage from the femur (P = .661) or tibia (P = .950) or in ultimate load to failure from the femur (P = .952) or tibia (P = .126). On insertion, the MS required less axial force application (78 ± 38 N, P = .001) and fewer attempted turns (2 ± 1, P < .001) to engage with the bone tunnel than the CS (99 ± 43 N and 4 ± 4, respectively). In 90% of the paired insertion tests, the screw identified by the surgeon as being easier to initially insert was the MS. Conclusions: The MS was found to be easier to engage with the bone tunnel and initially insert than the CS while still achieving similar immediate postsurgical fixation strength. Clinical Relevance: The study shows that screw designs can be improved to ease insertion into a bone tunnel, which should reduce any likelihood of ligament reconstruction graft damage.
Date Issued
2020-04-01
Date Acceptance
2020-01-12
Citation
Arthroscopy and Sports Medicine Rehabilitation, 2020, 2 (2), pp.e137-e144
ISSN
2666-061X
Start Page
e137
End Page
e144
Journal / Book Title
Arthroscopy and Sports Medicine Rehabilitation
Volume
2
Issue
2
Copyright Statement
© 2020 by the Arthroscopy Association of North America. Published byElsevier Inc. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/32368750
PII: S2666-061X(20)30005-5
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2020-04-06