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Feng X, Luo Z, Li Y, Yao Y, Qi W, Chen B, Liang H. Fixation stability comparison of bone screws based on thread design: buttress thread, triangle thread, and square thread. BMC Musculoskelet Disord 2022; 23:820. [PMID: 36042443 PMCID: PMC9426233 DOI: 10.1186/s12891-022-05751-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 08/08/2022] [Indexed: 11/10/2022] Open
Abstract
Background The influence of thread profile on the fixation stability of bone screws remains unclear. This study aimed to compare the fixation stability of screws with different thread profiles under several loading conditions. Methods Bone screws that differed in thread profile (buttress, triangle, and square thread) only were made of stainless steel. Their fixation stabilities were evaluated individually by the axial pullout test and lateral migration test, besides, they were also evaluated in pairs together with a dynamic compression plate and a locking plate in polyurethane foam blocks under cyclic craniocaudal and torsional loadings. Results The triangle-threaded and square-threaded screws had the highest pullout forces and lateral migration resistance. When being applied to a dynamic compression plate, higher forces and more cycles were required for both triangle- and square-threaded screws to reach the same displacement under cyclic craniocaudal loading. On the other hand, the triangle-threaded screws required a higher torque and more cycles to reach the same angular displacement under cyclic torsional loading. When being applied to a locking plate, the square-threaded screws needed higher load, torque, and more cycles to reach the same displacement under both cyclic craniocaudal and torsion loadings. Conclusions The triangle-threaded screws had superior pullout strength, while square-threaded screws demonstrated the highest lateral migration resistance. Moreover, dynamic compression plate fixation with triangle- and square-threaded screws achieved more favorable fixation stability under craniocaudal loading, while triangle-threaded screws demonstrated superior fixation stability under torsional loading. Locking plate fixation with a square-threaded screw achieved better fixation stability under both loading types.
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Affiliation(s)
- Xiaoreng Feng
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, No. 42 Dongshan Road, Jiangcheng District, 529500, Yangjiang, China.,Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No. 1838 North Guangzhou Avenue, Guangzhou, 510515, China
| | - Zhaopei Luo
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, No. 42 Dongshan Road, Jiangcheng District, 529500, Yangjiang, China
| | - Yupeng Li
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, No. 42 Dongshan Road, Jiangcheng District, 529500, Yangjiang, China
| | - Yiyi Yao
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, No. 42 Dongshan Road, Jiangcheng District, 529500, Yangjiang, China
| | - Weichen Qi
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Bin Chen
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No. 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
| | - Hongfeng Liang
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, No. 42 Dongshan Road, Jiangcheng District, 529500, Yangjiang, China.
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Feng X, Zhang S, Liang H, Chen B, Leung F. Development and initial validation of a novel undercut thread design for locking screws. Injury 2022; 53:2533-2540. [PMID: 35249737 DOI: 10.1016/j.injury.2022.02.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Locking screws with a typical buttress thread have high levels of failure in patients with osteoporotic bones. This study aims to develop a novel thread design for the locking screw and compare its fixation stability with the typical buttress thread. METHODS Locking screws with a novel thread design that possess an undercut feature and locking screws with a typical buttress thread were manufactured from stainless steel. Their fixation stabilities were then evaluated individually under a lateral migration test and evaluated in pairs together with a locking plate (LP) in an osteoporotic bone substitute under cyclic craniocaudal and torsional loadings. A finite element analysis (FEA) model was constructed to analyze the stress distributions present in the bone tissue adjacent to the novel thread versus the buttress thread. RESULTS The biomechanical test revealed that the novel thread had a significantly higher lateral migration strength than the buttress thread. When applied to a LP, the locking screw with the novel thread requires more cycles and higher forces or torque to resist migration up to 5 mm or 10° than the buttress thread. The FEA simulation showed that the novel thread can make the stress distribute more evenly at the adjacent bone tissue when compared with the buttress thread. CONCLUSIONS The locking screw with the novel undercut thread had superior lateral migration resistance during both initial and continued migration and superior fixation stability when applied to a LP under both cyclic craniocaudal loading and torsional loading than the locking screw with a typical buttress thread.
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Affiliation(s)
- Xiaoreng Feng
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, Yangjiang, 529500, China; Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Sheng Zhang
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Hongfeng Liang
- Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, Yangjiang, 529500, China
| | - Bin Chen
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
| | - Frankie Leung
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, the University of Hong Kong, Pok Fu Lam, Hong Kong.
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Abstract
AIMS To draw a comparison of the pullout strengths of buttress thread, barb thread, and reverse buttress thread bone screws. METHODS Buttress thread, barb thread, and reverse buttress thread bone screws were inserted into synthetic cancellous bone blocks. Five screw-block constructs per group were tested to failure in an axial pullout test. The pullout strengths were calculated and compared. A finite element analysis (FEA) was performed to explore the underlying failure mechanisms. FEA models of the three different screw-bone constructs were developed. A pullout force of 250 N was applied to the screw head with a fixed bone model. The compressive and tensile strain contours of the midsagittal plane of the three bone models were plotted and compared. RESULTS The barb thread demonstrated the lowest pullout strength (mean 176.16 N (SD 3.10)) among the three thread types. It formed a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains within the surrounding bone structure. The reverse buttress thread demonstrated the highest pullout strength (mean 254.69 N (SD 4.15)) among the three types of thread. It formed a considerably larger region with high compressive strains and a slightly smaller region with high tensile strains within the surrounding bone structure. CONCLUSION Bone screws with a reverse buttress thread design will significantly increase the pullout strength. Cite this article: Bone Joint Res 2021;10(2):105-112.
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Affiliation(s)
- Xiaoreng Feng
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Orthopaedics & Traumatology, Yangjiang People's Hospital, Yangjiang, China
| | - Weichen Qi
- Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Christian X Fang
- Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - William W Lu
- Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Frankie K L Leung
- Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Bin Chen
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
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