Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model
Background: Nonunion following hindfoot arthrodesis may be caused by failure to maintain compression at the arthrodesis site. The ability of lag screws, commonly used in arthrodesis, to maintain compression in hindfoot bones has not been well characterized. The aim of this work was to quantify the s...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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SAGE Publishing
2021-06-01
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| Series: | Foot & Ankle Orthopaedics |
| Online Access: | https://doi.org/10.1177/24730114211015203 |
| _version_ | 1818602901528903680 |
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| author | Amanda L. Rugg BS Melissa R. Requist BS, BM Brooks W. Johnson BS, MD Michelle M. Son MD Alicia Alvarez L. Daniel Latt MD, PhD |
| author_facet | Amanda L. Rugg BS Melissa R. Requist BS, BM Brooks W. Johnson BS, MD Michelle M. Son MD Alicia Alvarez L. Daniel Latt MD, PhD |
| author_sort | Amanda L. Rugg BS |
| collection | DOAJ |
| description | Background: Nonunion following hindfoot arthrodesis may be caused by failure to maintain compression at the arthrodesis site. The ability of lag screws, commonly used in arthrodesis, to maintain compression in hindfoot bones has not been well characterized. The aim of this work was to quantify the stress relaxation response of hindfoot bone with initial and repeated compression with a lag screw. Methods: Ten sets of 25-mm-diameter bone cylinders were cut from the talus and calcaneus in fresh-thawed cadaveric feet. A load cell was compressed between cylinders with an 8.0-mm partially threaded cannulated lag screw simulating arthrodesis. For 7 sets, screws were tightened by 3 quarter-turns, rested for 3 minutes, retightened 1 quarter-turn, and rested for 30 minutes. Three sets served as controls in which screws were not retightened. Results: Maximum compression after initial screw tightening and retightening averaged 275 and 337 N ( P = .07), respectively. Compression 3 minutes after initial screw tightening and retightening averaged 199 and 278 N ( P = .027), respectively. The compression recorded 3 minutes after screw retightening was an average of 40% higher than that recorded 3 minutes after initial tightening. The average compression 30 minutes after screw retightening was 255 N, a compression loss of 25% from the average maximum compression after retightening. Eighty percent of this compression loss happened in an average of 5.5 minutes. Conclusion: Hindfoot bones exhibit compression loss over time during simulated arthrodesis. Compression maintenance in bone is improved with screw retightening. Further work is needed to understand the mechanism of action and determine optimum time for recompression. Clinical Relevance: Retightening lag screws before wound closure may improve compression at the arthrodesis site and thereby decrease the chance of nonunion. Level of Evidence: N/A, laboratory experiment. |
| first_indexed | 2024-12-16T13:14:38Z |
| format | Article |
| id | doaj.art-0ffd52f18f7c405c8dbd01c89ddd5a12 |
| institution | Directory Open Access Journal |
| issn | 2473-0114 |
| language | English |
| last_indexed | 2024-12-16T13:14:38Z |
| publishDate | 2021-06-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | Foot & Ankle Orthopaedics |
| spelling | doaj.art-0ffd52f18f7c405c8dbd01c89ddd5a122022-12-21T22:30:30ZengSAGE PublishingFoot & Ankle Orthopaedics2473-01142021-06-01610.1177/24730114211015203Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis ModelAmanda L. Rugg BS0Melissa R. Requist BS, BM1Brooks W. Johnson BS, MD2Michelle M. Son MD3Alicia Alvarez4L. Daniel Latt MD, PhD5 Department of Orthopaedic Surgery, College of Medicine, Tucson, AZ, USA Department of Biomedical Engineering, , Tucson, AZ, USA Department of Orthopaedic Surgery, College of Medicine, Tucson, AZ, USA Department of Orthopaedic Surgery, College of Medicine, Tucson, AZ, USA Department of Physiology, College of Medicine, Tucson, AZ, USA College of Engineering, , Tucson, AZ, USABackground: Nonunion following hindfoot arthrodesis may be caused by failure to maintain compression at the arthrodesis site. The ability of lag screws, commonly used in arthrodesis, to maintain compression in hindfoot bones has not been well characterized. The aim of this work was to quantify the stress relaxation response of hindfoot bone with initial and repeated compression with a lag screw. Methods: Ten sets of 25-mm-diameter bone cylinders were cut from the talus and calcaneus in fresh-thawed cadaveric feet. A load cell was compressed between cylinders with an 8.0-mm partially threaded cannulated lag screw simulating arthrodesis. For 7 sets, screws were tightened by 3 quarter-turns, rested for 3 minutes, retightened 1 quarter-turn, and rested for 30 minutes. Three sets served as controls in which screws were not retightened. Results: Maximum compression after initial screw tightening and retightening averaged 275 and 337 N ( P = .07), respectively. Compression 3 minutes after initial screw tightening and retightening averaged 199 and 278 N ( P = .027), respectively. The compression recorded 3 minutes after screw retightening was an average of 40% higher than that recorded 3 minutes after initial tightening. The average compression 30 minutes after screw retightening was 255 N, a compression loss of 25% from the average maximum compression after retightening. Eighty percent of this compression loss happened in an average of 5.5 minutes. Conclusion: Hindfoot bones exhibit compression loss over time during simulated arthrodesis. Compression maintenance in bone is improved with screw retightening. Further work is needed to understand the mechanism of action and determine optimum time for recompression. Clinical Relevance: Retightening lag screws before wound closure may improve compression at the arthrodesis site and thereby decrease the chance of nonunion. Level of Evidence: N/A, laboratory experiment.https://doi.org/10.1177/24730114211015203 |
| spellingShingle | Amanda L. Rugg BS Melissa R. Requist BS, BM Brooks W. Johnson BS, MD Michelle M. Son MD Alicia Alvarez L. Daniel Latt MD, PhD Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model Foot & Ankle Orthopaedics |
| title | Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model |
| title_full | Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model |
| title_fullStr | Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model |
| title_full_unstemmed | Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model |
| title_short | Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model |
| title_sort | mechanical effects of lag screw retightening in a simulated hindfoot arthrodesis model |
| url | https://doi.org/10.1177/24730114211015203 |
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