Previous in vivo fluoroscopic studies have documented that subjects having a PS TKA experience a more posterior condylar contact position at full extension, a high incidence of reverse axial rotation and mid flexion instability. More recently, a PS TKA was designed with a Gradually Reducing Radius (Gradius) curved condylar geometry to offer patients greater mid flexion stability while reducing the incidence of reverse axial rotation and maintaining posterior condylar rollback. Therefore, the objective of this study was to assess the in vivo kinematics for subjects implanted with a Gradius curved condylar geometry to determine if these subjects experience an advantage over previously designed TKA. In vivo kinematics for 30 clinically successful patients all having a Gradius designed PS fixed bearing TKA with a symmetric tibia were assessed using mobile fluoroscopy. All of the subjects were scored to be clinically successful. In vivo kinematics were determined using a 3D-2D registration during three weight-bearing activities: deep-knee-bend (DKB), gait, and ramp down (RD). Flexion measurements were recorded using a digital goniometer while ground reaction forces were collected using a force plate as well. The subjects then assessed for range of motion, condyle translation and axial rotation and ground reaction forces.Background
Methods
The direct anterior approach (DAA) for total hip arthroplasty (THA) is marketed with claims of superiority over other approaches. Femoral exposure can be technically challenging and potentially lead to early failure. We examined whether surgical approach is associated with early THA failure. A retrospective review of 478 consecutive early revision THAs within five years of primary THA at three academic centers from 2011 through 2014 was performed. Exclusion criteria resulted in a final analysis sample of 341 early failure THAs. Primary surgical approach was documented for each revision, along with time to revision, and failure etiology.Background
Methods
