Biomechanics of the unilateral posterosuperior, unipedicular, and bipedicular approaches for treatment by percutaneous vertebroplasty: a comparative study.

Percutaneous vertebroplasty (PVP) via the unilateral posterosuperior approach has achieved good clinical results for the treatment of osteoporotic vertebral compression fractures. This study compared the biomechanical performance of a single vertebral body after PVP by the unilateral posterosuperior, unipedicular, and bipedicular approaches. Twenty-one vertebral bodies from the osteoporotic spine segments (T11-L1) of seven older female cadavers were randomly assigned to the unipedicular (group A), bipedicular (group B), or unilateral posterosuperior approach group (group C).

Pullout strength of reinserted pedicle screws using the previous entry point and trajectory.

Purpose: This study compared the biomechanics of reinserted pedicle screws using the previous entry point and trajectory with those of correctly inserted pedicle screws.

Methods: The study used 18 lumbar vertebrae (L1-6) from three fresh calf spines to insert 6.5 × 40-mm pedicle screws.

Risk of vertical transmission of hepatitis B after amniocentesis in HBs antigen-positive mothers.

Background & Aims: Despite appropriate immunoprophylaxis, HBV vertical transmission (VT) occurs in 5-10% of infants born to HBs-antigen (HBsAg)+ mothers. We investigated whether amniocentesis increases the risk of transmission.

Methods: We performed a case-control study on infants who were born to HBsAg+ mothers without antiviral exposure and completed appropriate immunization.

Biomechanical analysis of the impact of fibular osteotomies at tibiotalar joint: A cadaveric study.

Background: Osteotomy of the fibula is a common orthopedic procedure performed for various indications, including harvesting fibula for grafting purposes. The effect of fibular osteotomy and need for tibiofibular syndesmotic fixation fusion at different levels on tibiotalar joint is matter of debate. We performed a biomechanical analysis of the impact of fibular osteotomies at different levels and whether the fixation of distal tibiofibular joint mitigates instability caused by the osteotomy.

A distal femoral supra-condylar plate: biomechanical comparison with condylar plate and first clinical application for treatment of supracondylar fracture.

Purpose: An anatomical supra-condylar plate is designed and analysed by biomechanical testing.

Methods: The biomechanical properties of the supra-condylar and condylar plate were compared in six matched pairs of cadaveric femurs. A transverse osteotomy gap was created to simulate an OTA/AO type A3 supracondylar fracture.

Biomechanical evaluation of stability and three-dimensional movements of the atlantoaxial joint after artificial atlanto-odontoid joint arthroplasty.

Objective: To investigate the stability and three-dimensional movements of the atlantoaxial joint after artificial atlanto-odontoid joint (AAOJ) arthroplasty.

Method: Ten sets of AAOJ implanted in bony specimens from 10 adults were used to test the pull-out strength of the atlas-axis components with a MTS858 Mini Bionix machine. Another twelve human cadaveric specimens including C(0)-C(4) were used to evaluate the three-dimensional movements of C(1)-C(2) under five different conditions in sequence, that is, the complete specimen, anterior decompression, posterior transarticular screws fixation, AAOJ arthroplasty and fatigue test.

[Biomechanical evaluation of TiNi shape-memory sawtooth-arm embracing plate and its effect on fracture healing].

Objective: To investigate the detailed biomechanics of TiNi shape-memory sawtooth-arm embracing plate (TiNi SMA) by comparing with limited-contact dynamic compression plate (LC-DCP) and static interlocking intramedullary nail (SIiN), so as to provide theoretical evidence for clinical application.

Methods: Eight paired cadaveric femurs immersed in formaldehyde were harvested from eight specimens of adults. After making X-ray films and modeling midpiece transverse fracture, one side randomly was fixed by TiNi SMA (group A) and SIiN (group C) orderly, the other side was fixed by LC-DCP (group B).