Mechanics Analysis of Patients Having a Sigma Mobile Bearing TKA

The University of Tennessee, Knoxville8 enrolled

Overview

Utilize previously developed mathematical model to determine in vivo knee mechanics (kinematics, forces, stresses, areas and sound) for subjects having a Sigma Posterior Stabilizing (PS) mobile bearing (MB) total knee arthroplasty (TKA). There are several hypotheses for this study, although the most prominent is: Subjects having a Sigma RP PS TKA will experience polyethylene bearing rotation at 10 years post-operative, similar to their previous evaluations at six months, two years and five years.

Additional hypotheses: * Subjects having a Sigma RP PS TKA will experience full ideal femorotibial contact mechanics. * Subjects having a Sigma RP PS TKA will experience optimal cam/post mechanics. * Subjects having a Sigma RP PS TKA will experience continuous axial rotation in deep flexion. * Subjects having a Sigma RP PS TKA will experience optimal distribution of tibio-femoral and cam/post contact forces over a broad area on the post. * Subjects having a Sigma RP PS TKA will experience a smooth transition of the cam on the post, not an abrupt slide as seen with fixed bearing PS TKA. * The use of the sound sensors will detect cam/post contact mechanics under in vivo conditions.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Knee Prosthesis Knee Replacement Arthroplasty

Interventions

Sigma Posterior Stabilizing Rotating Platform TKA Beaded PolyDEVICE

Sigma PS RP TKA including a polyethylene insert with 4 beads

Eligibility

Sex: ALLMin age: 40 YearsMax age: 85 Years

Medical Language ↔ Plain English

Inclusion Criteria: * At least six months post-operative * Between 40-85 years of age * Have a body weight of less than 250 lbs. * Judged clinically successful with a AKS greater than 90 * Have the DePuy Sigma mobile bearing TKA * Good-to-excellent post-operative passive flexion * Must be willing to sign the IC and HIPAA forms. Exclusion Criteria: * Pregnant females * Those not willing to sign the IC and HIPAA forms

Locations (3)

Porter Adventist Hospital, Colorado Joint Replacement

Denver, Colorado, United States

Perkins Hall, The University of Tennessee

Knoxville, Tennessee, United States

Science and Engineering Research Facility, The University of Tennessee

Knoxville, Tennessee, United States

Outcomes

Primary Outcomes

In Vivo Linear Knee Kinematics From Fluoroscopy Evaluation During Deep Knee Bend Activity

The values that were reported indicate the motion of the contact point from full extension to patient's maximum flexion. Throughout flexion, if the point translated forward (anteriorly) atop the tibial tray, the number was reported as positive. If the point traveled backwards (posteriorly) atop the tibial tray, the number was reported as negative.