Biomechanics of subtrochanteric fracture fixation using short cephalomedullary nails: A finite element analysis.

A finite element analysis was performed to evaluate the stresses around nails and cortical bones in subtrochanteric (ST) fracture models fixed using short cephalomedullary nails (CMNs). A total 96 finite element models (FEMs) were simulated on a transverse ST fracture at eight levels with three different fracture gaps and two different distal locking screw configurations in both normal and osteoporotic bone. All FEMs were fixed using CMNs 200 mm in length.

Effect of stem position and length on bone-stem constructs after cementless hip arthroplasty.

Aims: There are concerns regarding initial stability and early periprosthetic fractures in cementless hip arthroplasty using short stems. This study aimed to investigate stress on the cortical bone around the stem and micromotions between the stem and cortical bone according to femoral stem length and positioning.

Methods: In total, 12 femoral finite element models (FEMs) were constructed and tested in walking and stair-climbing.

Biomechanical comparison of the angle of inserted screws and the length of anterior cervical plate systems with allograft spacers.

Background: Comparative studies of the biomechanical effects of plates of varying lengths and different screw insertion angles on allograft spacers are lacking.

Methods: Finite element model analysis of a previously validated, three-dimensional, intact cervical spinal segment model of C3-6 was conducted in the present study. On the C5-6 segment, anterior discectomy and fusion were performed using allograft spacers and different combinations of anterior plates and screws.

Biomechanical comparison of cervical discectomy/fusion model using allograft spacers between anterior and posterior fixation methods (lateral mass and pedicle screw).

Background: The purpose of this study is to investigate effects of different fixation methods on the physical stress on allospacers, endplate-vertebral body, and implants using finite element model analyses.

Methods: Stress distribution and subsidence risk according to the fixation methods under the condition of hybrid motion control were analyzed. The detailed finite element model of a previously validated, three-dimensional, intact cervical spinal segment model, with C5-C6 segmental fusion using allospacer, was used to evaluate the biomechanical characteristics of different fixation combinations, such as anterior plate/screws, lateral mass screw, and posterior pedicle screw.

Effect of fracture levels on the strength of bone-implant constructs in subtrochanteric fracture models fixed using short cephalomedullary nails: A finite element analysis.

Objectives: This study was conducted to investigate the stress around nails and cortical bones in subtrochanteric (ST) fractures fixed using short cephalomedullary nails (CMNs) in finite element models (FEMs) and to determine the appropriate short CMN type for different fracture levels.

Methods: The following three types of short CMNs were used: type A, which is 170 mm in length and has 1 distal locking screw; type B, 200 mm in length and 1 distal screw; and type C, 200 mm in length and 2 distal screws. A total of 24 FEMs were tested on a transverse ST fracture at 8 levels [0, 10, 20, 25, 30, 35, 40 and 50 mm below the lower margin of lesser trochanter (LT)], and were fixed using 3 different CMN types.