The Effect of Pitch Variation and Diameter Variation on Screw Pullout

Gustafson, Peter A.; Veenstra, Joshua; Bearden, Cody R; Jastifer, James R.

doi:10.1177/1938640018789999

Cited by 14 publications

(11 citation statements)

References 17 publications

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“…Likewise, there exist many reports of the effects of screw design, insertion technique, and variation in natural and synthetic bone substrates on pullout strength, but none are specific to the proximal humerus nor included consideration of cross elements. 8,12,13,20,36,38,41 As such, our study is unique in both implant design and application.…”

Section: Discussionmentioning

confidence: 99%

Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study

González-Hernández¹,

Pietrzak

Jain³

et al. 2020

Journal of Shoulder and Elbow Surgery

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Section: Discussionmentioning

confidence: 99%

Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study

González-Hernández¹,

Pietrzak

Jain³

et al. 2020

Journal of Shoulder and Elbow Surgery

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show abstract

“…Primary stability can be evaluated under in-vivo and ex-vivo conditions by using common mechanical testing methods, such as resonance frequency analysis (RFA), percussion testing (Periotest M, Medizintechnik Gulden, Germany), IT, and cutting torque resistance analysis (CRA) (165)(166)(167)(168)(169)(170)(171)(172)(173)(174)(175)(176). Measures of primary stability of an implant, including pullout, pushout, and bending, can be evaluated under ex-vivo conditions and in select in vivo applications (177)(178)(179)(180)(181)(182)(183)(184)(185).…”

Section: Stability Of the Implant In Bonementioning

confidence: 99%

“…The following methods of mechanical testing methods discussed in this literature review are used to test entire constructs, such as an orthopedic plate and screws used to repair a long-bone fracture (205). Tests such as these must be conducted ex vivo because they aim to test the stability of a construct by stressing the construct until the construct fails (143,(177)(178)(179). Pullout tests have been commonly used to test the stability of orthopedic implants (143,(177)(178)(179).…”

Section: Testing Stability Ex Vivomentioning

confidence: 99%

“…Tests such as these must be conducted ex vivo because they aim to test the stability of a construct by stressing the construct until the construct fails (143,(177)(178)(179). Pullout tests have been commonly used to test the stability of orthopedic implants (143,(177)(178)(179). Tensile stress is applied to an implant or entire construct in a testing frame until the implant breaks or the implant is pulled from the tissue into which it has been implanted becomes displaced (177,178,180,181).…”

Section: Testing Stability Ex Vivomentioning

confidence: 99%

“…Pullout tests have been commonly used to test the stability of orthopedic implants (143,(177)(178)(179). Tensile stress is applied to an implant or entire construct in a testing frame until the implant breaks or the implant is pulled from the tissue into which it has been implanted becomes displaced (177,178,180,181). The rate of displacement must be adjusted according to the method of testing a specific construct.…”

Section: Testing Stability Ex Vivomentioning

confidence: 99%

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Bone and Cartilage Interfaces With Orthopedic Implants: A Literature Review

et al. 2020

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The interface between a surgical implant and tissue consists of a complex and dynamic environment characterized by mechanical and biological interactions between the implant and surrounding tissue. The implantation process leads to injury which needs to heal over time and the rapidity of this process as well as the property of restored tissue impact directly the strength of the interface. Bleeding is the first and most relevant step of the healing process because blood provides growth factors and cellular material necessary for tissue repair. Integration of the implants placed in poorly vascularized tissue such as articular cartilage is, therefore, more challenging than compared with the implants placed in well-vascularized tissues such as bone. Bleeding is followed by the establishment of a provisional matrix that is gradually transformed into the native tissue. The ultimate goal of implantation is to obtain a complete integration between the implant and tissue resulting in long-term stability. The stability of the implant has been defined as primary (mechanical) and secondary (biological integration) stability. Successful integration of an implant within the tissue depends on both stabilities and is vital for short- and long-term surgical outcomes. Advances in research aim to improve implant integration resulting in enhanced implant and tissue interface. Numerous methods have been employed to improve the process of modifying both stability types. This review provides a comprehensive discussion of current knowledge regarding implant-tissue interfaces within bone and cartilage as well as novel approaches to strengthen the implant-tissue interface. Furthermore, it gives an insight into the current state-of-art biomechanical testing of the stability of the implants. Current knowledge reveals that the design of the implants closely mimicking the native structure is more likely to become well integrated. The literature provides however several other techniques such as coating with a bioactive compound that will stimulate the integration and successful outcome for the patient.

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Relation between diameter of a lateral screw and pull‐out strength in distal clavicle fracture in plates with different geometry: A cadaveric biomechanical study

Yoon

Choi

et al. 2021

Journal Orthopaedic Research

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Plate fixation has recently gained popularity among the various surgical methods used to treat Neer type II distal clavicle fractures. The use of a low‐profile distal clavicle locking plate is logically considered a better option when there is no significant difference in the fixation strength between insertions of 3.5‐ and 2.7‐mm diameter screws. Therefore, the purpose of this biomechanical study was to investigate any differences in fixation strength among varying sizes of screws that are used to treat distal clavicle fractures. The study was performed with 20 paired shoulder girdles from 10 fresh frozen cadavers. To create a type IIA fracture of Neer classification, osteotomy was performed perpendicularly to the longitudinal axis of the clavicle at the medial end point of the conoid ligament. Two custom‐made fixtures designed to be attached to both upper and lower sides of the Instron were fabricated for the evaluation. The mean maximum pull‐out strength for fixation using 3.5‐mm diameter screws was 241.9 ± 67.8 N, whereas the mean pull‐out strength in fixation with 2.7‐mm diameter screws was 228.1 ± 63.0 N. There was no statistically significant difference between the two groups. Distal fragment fixation with distal clavicle locking plates using two 2.7‐mm diameter screws showed comparable biomechanical pull‐out strength at the time‐zero setting to fixations with a hook plate using two 3.5‐mm diameter screws. Therefore, the fixation of the distal fragment with a low‐profile plate and 2.7‐mm screws may be preferred as an alternative option if the distal fragment of the fractured clavicle is not extremely small.

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The Effect of Pitch Variation and Diameter Variation on Screw Pullout

Abstract: Level V: Mechanical study.

Cited by 14 publications

References 17 publications

Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study

Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study

Bone and Cartilage Interfaces With Orthopedic Implants: A Literature Review

Relation between diameter of a lateral screw and pull‐out strength in distal clavicle fracture in plates with different geometry: A cadaveric biomechanical study

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