A Novel Screw Drive for Allogenic Headless Position Screws for Use in Osteosynthesis—A Finite-Element Analysis

Abstract

Due to their osteoconductive properties, allogenic bone screws made of human cortical bone have advantages regarding rehabilitation compared to other materials such as stainless steel or titanium. Since conventional screw drives like hexagonal or hexalobular drives are difficult to manufacture in headless allogenic screws, an easy-to-manufacture screw drive is needed. In this paper, we present a simple drive for headless allogenic bone screws that allows the screw to be fully inserted. Since the screw drive is completely internal, no threads are removed. In order to prove the mechanical strength, we performed simulations of the new drive using the Finite-Element method (FEM), validated the simulations with a prototype screw, tested the novel screw drive experimentally and compared the simulations with conventional drives. The validation with the prototype showed that our simulations provided valid results. Furthermore, the simulations of the new screw drive showed good performance in terms of mechanical strength in allogenic screws compared to conventional screw drives. The presented screw drive is simple and easy to manufacture and is therefore suitable for headless allogenic bone screws where conventional drives are difficult to manufacture.

Advances in reparative materials for infectious bone defects and their applications in maxillofacial regions

“…As per current practice, typical bone graft materials used in clinical settings are categorized as autogenous, allogenic, xenogeneic, and alloplastic. [24][25][26] The existing literature and evidence indicate that each natural bone transplantation method has its respective advantages and disadvantages, accentuating the favorable aspects of autogenous bone transplantation and the ongoing need for reducing donor site morbidity. In the following sections, we will review various methods for natural bone transplantation and their respective applications.…”

The Development and Biomechanical Analysis of an Allograft Interference Screw for Anterior Cruciate Ligament Reconstruction

“…Following from the above considerations, three possible screw drives were shortlisted for further investigations. First, the so-called claw clutch, which is already used with the Shark Screw ® ; second, the so-called three-bore drive, which was recently described in a prior publication [30]; and third, a modified version of a conventional external hexagon head, at which the wrench size is smaller than the core diameter of the screw. All three drives allow the screw to be fully countersunk and permit easy manufacturing in cortical bone.…”

“…In order to make an estimation of whether the screw drives are able to withstand the torques occurring during graft fixation, a finite element analysis (FEA) using the software Fusion 360 (Autodesk, Inc.; San Rafael, CA, USA), similarly to a previous publication [30], was performed. All edges in the CAD design were given a small radius in order to avoid singularities due to sharp edges [31].…”

“…For this purpose, a first prototype of the allograft interference screw was designed and manufactured. On the one hand, the focus was particularly on the design of the screw drive, since not every screw drive that is used in metal or bioabsorbable screws can be manufactured in human cortical bone [30] and, on the other hand, on the design of the screw shape, the screw dimensions and the thread shape. Subsequently, an initial biomechanical analysis of the screw prototype regarding the overall performance of the implant in terms of ultimate failure torque of the screw and ultimate failure load of the graft fixation was performed using a bovine model.…”

Non-Union Treatment in the Foot, Ankle, and Lower Leg: A Multicenter Retrospective Study Comparing Conventional Treatment with the Human Allogeneic Cortical Bone Screw (Shark Screw®)

“…The Shark Screw ® represents an alternative solution for non-union treatment, utilizing human allogeneic cortical bone with a threaded design and a diameter of up to 5.0 mm [30]. Engineered for stable osteosynthesis, it can be used independently or in conjunction with metal plates or screws.…”