Robotic assessment of patella tracking in total knee arthroplasty.

Objectives: Robotic tools have been developed to improve planning, accuracy and outcomes in total knee arthroplasty (TKA). The purpose of this study was to describe and illustrate a novel technique for assessing the patellofemoral (PFJ) in TKA using an imageless robotic platform.

Methods: A consecutive series of 30 R-TKA was undertaken by a single surgeon utilising the described technique.

Effects of the Medial Plateau Bearing Insert Conformity on Mid-Flexion Paradoxical Motion in a Posterior-Stabilized Total Knee Arthroplasty Design.

Background: One of the most common kinematic abnormalities reported for posterior-stabilized (PS) total knee arthroplasty (TKA) design is paradoxical anterior sliding during early and mid-flexion. PS TKAs have been designed such that the cam-post mechanism does not engage until later in flexion, making these implants vulnerable to anterior sliding during early and mid-flexion. The objective of this study is to investigate the biomechanical effect of increasing bearing conformity on a PS TKA.

Effects of Posterior Tibial Slope on a Posterior Cruciate Retaining Total Knee Arthroplasty Kinematics and Kinetics.

Background: It has been hypothesized that increasing posterior tibial slope can influence condylar rollback and play a role in increasing knee flexion. However, the effects of tibial slope on knee kinematics are not well studied. The objective of this study is to assess the effects of tibial slope on femorotibial kinematics and kinetics for a posterior cruciate retaining total knee arthroplasty design.

A Validated Forward Solution Dynamics Mathematical Model of the Knee Joint: Can It Be an Effective Alternative for Implant Evaluation?

Background: Mathematical modeling is among the most common computational tools for assessing total knee arthroplasty (TKA) mechanics of different implant designs and surgical alignments. The main objective of this study is to describe and validate a forward solution mathematical of the knee joint to investigate the effects of TKA design and surgical conditions on TKA outcomes.

Methods: A 12-degree of freedom mathematical model of the human knee was developed.

In Vivo Knee Kinematics for a Cruciate Sacrificing Total Knee Arthroplasty Having Both a Symmetrical Femoral and Tibial Component.

Background: Early total knee arthroplasty (TKA) designs were symmetrical, but lead to complications due to over-constraint leading to loosening and poor flexion. Next-generation TKAs have been designed to include asymmetry, pertaining to the trochlear groove, femoral condylar shapes, and/or the tibial component. More recently, an advanced posterior cruciate sacrificing (PCS) TKA was designed to include both a symmetrical femoral component with a patented V-shaped trochlear groove and a symmetrical tibial component with an ultracongruent insert, in an attempt to reduce inventory costs.

Kinematic Performance of Gradually Variable Radius Posterior-Stabilized Primary TKA During Various Activities: An In Vivo Study Using Fluoroscopy.

Background: Posterior-stabilized total knee arthroplasty (TKA) with gradually variable radii (G-curve) femoral condylar geometry is now available. It is believed that a G-curve design would lead to more mid-flexion stability leading to reduced incidence of paradoxical anterior slide. The objective of this study was to assess the in vivo kinematics for subjects implanted with this type of TKA under various conditions of daily living.

In Vivo Determination and Comparison of Total Hip Arthroplasty Kinematics for Normal, Preoperative Degenerative, and Postoperative Implanted Hips.

Background: The study objective is to analyze subjects having a normal hip and compare in vivo kinematics to subjects before and after receiving a total hip arthroplasty.

Methods: Twenty subjects, 10 with a normal hip and 10 with a preoperative, degenerative hip were analyzed performing normal walking on level ground while under fluoroscopic surveillance. Seven preoperative subjects returned after receiving a total hip arthroplasty using the anterior surgical approach by a single surgeon.