Numerical simulation of bone screw induced pretension: the cases of under-tapping and conical profile.

Even though screw induced pretension impacts the holding strength of bone screws, its implementation into the numerical simulation of the pullout phenomenon remains a problem with no apparent solution. The present study aims at developing a new methodology to simulate screw induced pretension for the cases of: (a) cylindrical screws inserted with under-tapping and (b) conical screws. For this purpose pullout was studied experimentally using synthetic bone and then simulated numerically.

A novel liver parenchyma transection technique using locking straight rigid ties. An experimental study in pigs.

Introduction: Technological advances have led to the development of many devices used in liver resections. However, no single transection tool is uniformly considered to be better than the others. This study aimed to develop an effective, fast, and cost-efficient technique for hepatic parenchymal transection.

Rotator cuff repair: a biomechanical ex vivo ovine study.

The purpose of this study was to assess load to failure of sutures, suturing techniques, and suture anchors used in rotator cuff surgery in order to explore their weaknesses. Ten types of sutures (absorbable and nonabsorbable), four types of suturing techniques, and eight types of suture anchors (bioabsorbable and metallic) were tested. Material Testing Machine and attached load cell were used to test the biomaterials in ex vivo ovine tissues.

Comparison of four reconstructive methods for diaphyseal defects of the humerus after tumor resection.

The objective of the current study was to compare quantitative data on the biomechanical analysis of different techniques for fixation of intercalary bone defects of the humerus, by means of consistently applied methodology on composite models. A total of 25 humeral specimens of composite models were used. An intercalary defect was created and reconstructed using plates, intramedullary nails, external fixators and segmental prosthetic implants.

The use of twin-ring Ilizarov external fixator constructs: application and biomechanical proof-of principle with possible clinical indications.

Background: In peri- or intra-articular fractures of the tibia or femur, the presence of short metaphyseal bone fragments may make the application of an Ilizarov external fixator (IEF) challenging. In such cases, it may be necessary to bridge the adjacent joint in order to ensure stable fixation. The twin-ring (TR) module of circular external fixation is proposed as an alternative method that avoids joint bridging, without compromising stability of fixation.

Intrinsic passive stiffness of 2 constructs of varus proximal femoral osteotomy: external fixator or blade plate.

Background: Despite the published clinical evidence of the implementation of external fixation of proximal femoral osteotomies, there is lack of specific laboratory justification.

Methods: Two groups of 5 adult composite femur constructs of varus proximal femoral osteotomy were tested under incremental and cyclical loading of up to 600N along the mechanical axis. Five were fixed with a blade plate and another 5 with a monolateral external fixator.

A parametric study of cylindrical pedicle screw design implications on the pullout performance using an experimentally validated finite-element model.

The present study aims to the design of a finite-element model simulating accurately the pullout behaviour of cylindrical pedicle screws and predicting their pullout force. Three commercial pedicle screws, subjected to pure pullout from synthetic bone, were studied experimentally. The results were used for the design, calibration and validation of a finite-element model.

Comparison of fixation methods of double-bundle double-tibial tunnel ACL reconstruction and double-bundle single-tunnel technique.

An experimental study was conducted in order to evaluate biomechanical methods of single-bundle reconstruction in ACL and compare it with a new double-bundle double-tibial tunnel technique. Twenty-four porcine cadaver knees, divided into 4 groups of 6 knees each and 48 proper extensors of the fourth toe tendons, were used for the fixation techniques. In groups A and B, a double-bundle technique with a single femoral and tibial tunnel was used, fixed to a femoral and tibial post with screws and with buttons, respectively.

Biomechanical evaluation of conventional internal contemporary spinal fixation techniques used for stabilization of complete sacroiliac joint separation: a 3-dimensional unilaterally isolated experimental stiffness study.

Study Design: Comparative 3-dimensional biomechanical testing.

Objective: To compare 5 fixation techniques, 3 using screws or screw and plates and 2 spinal, used for stabilization of complete unilateral sacroiliac dislocation in composite models.

Summary Of Background Data: Harrington compression rods have been used for posterior iliosacral stabilization.

ACL reconstruction and the implication of its tibial attachment for stability of the joint: anthropometric and biomechanical study.

The planar topography of the anterior cruciate ligament (ACL) insertion was investigated and correlated to the use of the double-bundle/double tibial tunnel ACL reconstruction technique within the ACL tibial insertion area. The anteroposterior and mediolateral length of the tibial ACL attachment and the distances of the tibial insertion area from the anterior and posterior tibial borders were measured and the stability of the joint was tested using the double-bundle/double tibial tunnel ACL reconstruction technique. The anteroposterior length, 19.