title: Does Computer-Assisted Femur First THR Improve Musculoskeletal Loading Conditions?
abstract: We have developed a novel, computer-assisted operation method for minimal-invasive total hip replacement (THR) following the concept of "femur first/combined anteversion," which incorporates various aspects of performing a functional optimization of the prosthetic stem and cup position (CAS FF). The purpose of this study is to assess whether the hip joint reaction forces and patient's gait parameters are being improved by CAS FF in relation to conventional THR (CON). We enrolled 60 patients (28 CAS FF/32 CON) and invited them for gait analysis at three time points (preoperatively, postop six months, and postop 12 months). Data retrieved from gait analysis was processed using patient-specific musculoskeletal models. The target parameters were hip reaction force magnitude (hrf), symmetries, and orientation with respect to the cup. Hrf in the CAS FF group were closer to a young healthy normal. Phase-shift symmetry showed an increase in the CAS FF group. Hrf orientation in the CAS FF group was closer to optimum, though no edge or rim-loading occurred in the CON group as well. The CAS FF group showed an improved hrf orientation in an early stage and a trend to an improved long-term outcome.
authors.affiliation: Faculty of Mechanical Engineering, Laboratory for Biomechanics, Ostbayerische Technische Hochschule Regensburg, 93053 Regensburg, Germany ; Department of Orthopaedic Surgery, Regensburg University Medical Center (UKR), 93077 Bad Abbach, Germany.
authors.forename: Tim A
authors.initials: TA
authors.lastname: Weber
authors.affiliation: Faculty of Mechanical Engineering, Laboratory for Biomechanics, Ostbayerische Technische Hochschule Regensburg, 93053 Regensburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dendorfer
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center (UKR), 93077 Bad Abbach, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.affiliation: Department of Rehabilitation Medicine, University Medical Center Groningen (UMCG), University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, Netherlands ; Department of Biomechanical Engineering, University of Twente, Drienerlolaan 5, 7522 NB Enschede, Netherlands.
authors.forename: Gijsbertus J
authors.initials: GJ
authors.lastname: Verkerke
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center (UKR), 93077 Bad Abbach, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Renkawitz
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D005269:Femur / Q000503:physiopathology / Q000601:surgery*; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D018482:Muscle, Skeletal / Q000503:physiopathology; D013314:Stress, Mechanical; D025321:Surgery, Computer-Assisted