Computational prediction of the long-term behavior of the femoral density after THR using the Silent Hip stem.

Aseptic loosening due to the progressive periprosthetic bone resorption following total hip replacement is a crucial concern, that causes complications and failure of the arthroplasty surgery. The mismatch in stiffness between the hip implant and the surrounding femoral bone is one of the key factors leading to bone density resorption. This paper aimed to investigate the long-term response of the femoral bone after THR using the Silent Hip stem.

Biomechanical Analysis Using FEA and Experiments of Metal Plate and Bone Strut Repair of a Femur Midshaft Segmental Defect.

This investigation assessed the biomechanical performance of the metal plate and bone strut technique for fixing recalcitrant nonunions of femur midshaft segmental defects, which has not been systematically done before. A finite element (FE) model was developed and then validated by experiments with the femur in 15 deg of adduction at a subclinical hip force of 1 kN. Then, FE analysis was done with the femur in 15 deg of adduction at a hip force of 3 kN representing about 4 x body weight for a 75 kg person to examine clinically relevant cases, such as an intact femur plus 8 different combinations of a lateral metal plate of fixed length, a medial bone strut of varying length, and varying numbers and locations of screws to secure the plate and strut around a midshaft defect.

Long-term response of femoral density to hip implant and bone fracture plate: Computational study using a mechano-biochemical model.

Although bone fracture plates can provide appropriate stability at the fracture site and lead to early patient mobilization, they significantly change the loading pattern in the bone after union (Stress shielding). This phenomenon results in a bone density decrease, which may cause premature failure of the implant. This paper presents the first study that quantifies the long-term response of femoral density to hip implantation and plating (lateral and anterior plating) using a mechano-biochemical model which considers the coupling effect between mechanical loading and biochemical affinities as stimuli for bone remodeling.

An Effective Approach for Optimization of a Composite Intramedullary Nail for Treating Femoral Shaft Fractures.

The high stiffness of conventional intramedullary (IM) nails may result in stress shielding and subsequent bone loss following healing in long bone fractures. It can also delay union by reducing compressive loads at the fracture site, thereby inhibiting secondary bone healing. This paper introduces a new approach for the optimization of a fiber-reinforced composite nail made of carbon fiber (CF)/epoxy based on a combination of the classical laminate theory, beam theory, finite-element (FE) method, and bone remodeling model using irreversible thermodynamics.

On optimization of a composite bone plate using the selective stress shielding approach.

Bone fracture plates are used to stabilize fractures while allowing for adequate compressive force on the fracture ends. Yet the high stiffness of conventional bone plates significantly reduces compression at the fracture site, and can lead to subsequent bone loss upon healing. Fibre-reinforced composite bone plates have been introduced to address this drawback.

Investigating stress shielding spanned by biomimetic polymer-composite vs. metallic hip stem: A computational study using mechano-biochemical model.

Periprosthetic bone loss in response to total hip arthroplasty is a serious complication compromising patient's life quality as it may cause the premature failure of the implant. Stress shielding as a result of an uneven load sharing between the hip implant and the bone is a key factor leading to bone density decrease. A number of composite hip implants have been designed so far to improve load sharing characteristics.

Biomechanical assessment of composite versus metallic intramedullary nailing system in femoral shaft fractures: A finite element study.

Background: Intramedullary nails are the primary choice for treating long bone fractures. However, complications following nail surgery including non-union, delayed union, and fracture of the bone or the implant still exist. Reducing nail stiffness while still maintaining sufficient stability seems to be the ideal solution to overcome the abovementioned complications.

Biomechanical analysis of a new carbon fiber/flax/epoxy bone fracture plate shows less stress shielding compared to a standard clinical metal plate.

Femur fracture at the tip of a total hip replacement (THR), commonly known as Vancouver B1 fracture, is mainly treated using rigid metallic bone plates which may result in "stress shielding" leading to bone resorption and implant loosening. To minimize stress shielding, a new carbon fiber (CF)/Flax/Epoxy composite plate has been developed and biomechanically compared to a standard clinical metal plate. For fatigue tests, experiments were done using six artificial femurs cyclically loaded through the femoral head in axial compression for four stages: Stage 1 (intact), stage 2 (after THR insertion), stage 3 (after plate fixation of a simulated Vancouver B1 femoral midshaft fracture gap), and stage 4 (after fracture gap healing).

Predicting bone remodeling in response to total hip arthroplasty: computational study using mechanobiochemical model.

Periprosthetic bone loss following total hip arthroplasty (THA) is a serious concern leading to the premature failure of prosthetic implant. Therefore, investigating bone remodeling in response to hip arthroplasty is of paramount for the purpose of designing long lasting prostheses. In this study, a thermodynamic-based theory, which considers the coupling between the mechanical loading and biochemical affinity as stimulus for bone formation and resorption, was used to simulate the femoral density change in response to THA.