Samatchai Chamnongkich

Biomechanical influence of TKA designs with varying radii on bilateral TKA patients during sit-to-stand

BackgroundCompared to the design of a traditional multi-radius (MR) total knee arthroplasty (TKA), the single-radius (SR) implant investigated has a fixed flexion/extension center of rotation. The biomechanical effectiveness of an SR for functional daily activities, i.e., sit-to-stand, is not well understood. The purpose of the study was to compare the biomechanics underlying functional performance of the sit-to-stand (STS) movement between the limbs containing an MR and an SR TKA of bilateral TKA participants.MethodsSagittal plane kinematics and kinetics, and EMG data for selected knee flexor and extensor muscles were analyzed for eight bilateral TKA patients, each with an SR and an MR TKA implant.ResultsCompared to the MR limb, the SR limb demonstrated greater peak antero-posterior (AP) ground reaction force, higher AP ground reaction impulse, less vastus lateralis and semitendinosus EMG during the forward-thrust phase of the STS movement. No significant difference of knee extensor moment was found between the two knees.ConclusionSome GRF and EMG differences were evident between the MR and SR limbs during STS movement. Compensatory adaptations may be used to perform the STS.

Difference in Hip Prosthesis Femoral Offset Affects Hip Abductor Strength and Gait Characteristics During Obstacle Crossing

The purpose of this article is to determine if individuals with high rather than low femoral offset of a total hip arthroplasty achieve improved hip abductor muscle strength and thus improved their ability to step over an obstacle safely. These outcomes will help surgeons decide whether increasing the femoral offset helps a patients physical function.