title: Computed Tomography Analysis of Postsurgery Femoral Component Rotation Based on a Force Sensing Device Method versus Hypothetical Rotational Alignment Based on Anatomical Landmark Methods: A Pilot Study.
abstract: Rotation of the femoral component is an important aspect of knee arthroplasty, due to its effects on postsurgery knee kinematics and associated functional outcomes. It is still debated which method for establishing rotational alignment is preferable in orthopedic surgery. We compared force sensing based femoral component rotation with traditional anatomic landmark methods to investigate which method is more accurate in terms of alignment to the true transepicondylar axis. Thirty-one patients underwent computer-navigated total knee arthroplasty for osteoarthritis with femoral rotation established via a force sensor. During surgery, three alternative hypothetical femoral rotational alignments were assessed, based on transepicondylar axis, anterior-posterior axis, or the utilization of a posterior condyles referencing jig. Postoperative computed tomography scans were obtained to investigate rotation characteristics. Significant differences in rotation characteristics were found between rotation according to DKB and other methods (P < 0.05). Soft tissue balancing resulted in smaller deviation from anatomical epicondylar axis than any other method. 77% of operated knees were within a range of ±3° of rotation. Only between 48% and 52% of knees would have been rotated appropriately using the other methods. The current results indicate that force sensors may be valuable for establishing correct femoral rotation.
authors.affiliation: Memorial Bone & Joint Research Foundation, 1140 Business Center Drive, Suite 101, Houston, TX 77043, USA.
authors.forename: Stefan W
authors.initials: SW
authors.lastname: Kreuzer
authors.affiliation: Memorial Bone & Joint Research Foundation, 1140 Business Center Drive, Suite 101, Houston, TX 77043, USA.
authors.forename: Amir
authors.initials: A
authors.lastname: Pourmoghaddam
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Leffers
authors.affiliation: UT Physicians Orthopedics, 9305 Pinecroft Drive, Suite 400, The Woodlands, TX 77380, USA.
authors.forename: Clint W
authors.initials: CW
authors.lastname: Johnson
authors.affiliation: Memorial Bone & Joint Research Foundation, 1140 Business Center Drive, Suite 101, Houston, TX 77043, USA; Research Focus Cognition Sciences, Division of Training and Movement Sciences, Faculty of Human Sciences, University of Potsdam, Am Neuen Palais 10, Building 12, 14469 Potsdam, Germany.
authors.forename: Marius
authors.initials: M
authors.lastname: Dettmer