title: A multicenter analysis of axial femorotibial rotation after total knee arthroplasty.
abstract: A multicenter analysis was done to determine in vivo femorotibial axial rotation magnitudes and patterns in 1,027 knees (normal knees, nonimplanted ACL-deficient knees, and multiple designs of total knee arthroplasty). All knees were analyzed using fluoroscopy and a three-dimensional computer model-fitting technique during a deep knee bend and/or gait. Normal knees showed 16.5 degrees and 5.7 degrees of internal tibial rotation during a deep knee bend and gait, respectively. Rotation magnitudes and the percent having normal axial rotation patterns decreased in all total knee arthroplasty groups during a deep knee bend. During gait, all knee arthroplasty groups had similar rotational patterns (limited magnitudes). Average axial rotational magnitudes in gait and a deep knee bend were similar among major implant categories (ie, fixed-bearing versus mobile-bearing, etc). Average values in normal knees and ACL-retaining total knee arthroplasty patients (16.5 degrees and 8.1 degrees , respectively) were higher than in groups in which the ACL was absent (< 4.0 degrees ). All total knee arthroplasty groups had at least 19% of patients have a reverse axial rotational pattern during a deep knee bend and at least 31% during gait. Normal axial rotation patterns are essential for good patellar tracking, reduction of patellofemoral shear forces, and maximization of knee flexion.
authors.affiliation: Department of Mechanical, Aerospace & Biomedical Engineering, University of Tennessee, Knoxville, TN 80222, USA. dadtkamd@aol.com
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Dennis
authors.forename: Richard D
authors.initials: RD
authors.lastname: Komistek
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: Mahfouz
authors.forename: Scott A
authors.initials: SA
authors.lastname: Walker
authors.forename: Abby
authors.initials: A
authors.lastname: Tucker
mesh_terms: D000704:Analysis of Variance; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D005269:Femur / Q000502:physiology*; D005471:Fluoroscopy; D005684:Gait / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000502:physiology*; D007720:Knee Prosthesis; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation; D013977:Tibia / Q000502:physiology*; D016474:Weight-Bearing