Biomechanics and imaging evaluation on stable structure of pelvis / 中国骨伤

The treatment of difficulty and prognosis of pelvic fracture are directly related to the pelvic girdle stability. Diagnosis of pelvic fracture is mainly imaging manifestations based on biomechanics of pelvic anatomy. With the progress of biomechanics experiment technology, previousopinion has changed, such as separation of symphysis pubis 2.5 cm could not be seen as distinguishing feature of type I and II for anterior-posterior compression;displacement of sacroilliac joints less than 1 cm could cause loss of vertical stability;lateral extrusion could also cause vertical instability;part description of Young-Burgess classification is not suitable for experiment results;ligament plays an important role in restricting displacement and having proprioceptors;SPECT-CT could improve sensitivity of diagnosis, but could not evaluate stability of pelvic fractures precisely.

Dislocation risk after total hip arthroplasty / 医用生物力学

Objective To investigate and analyze the risk of dislocation failure after total hip arthroplasty (THA). Methods The optical motion capture system was used to obtain the kinematic data of the lower limbs during actions of daily living (ADLs) from normal people. The visual hip prosthesis motion analysis software was designed and developed to measure the maximum safe motion space of the hip prosthesis with different design parameters and judge the safety of the hip prosthesis by analyzing the relative motion relation between the cup and prosthetic stem. Results Based on the measured kinematics data, the motion analysis software could compare the range of motion of the natural joints and that after THA. Thus, the relationship between the dislocation of hip prosthesis and ADLs was obtained and the dislocation risk after THA was investigated. Conclusions There is a high risk when activities that require a high flexion motion are performed, especially for the kneeling and squatting activity.