title: Leg length and offset differences above 5mm after total hip arthroplasty are associated with altered gait kinematics.
abstract: We aimed to investigate the relationship between postoperative leg length/offset (LL/OS) reconstruction and gait performance after total hip arthroplasty (THA). In the course of a prospective randomized controlled trial, 60 patients with unilateral hip arthrosis received cementless THA through a minimally-invasive anterolateral surgical approach. One year post-operatively, LL and global OS restoration were analyzed and compared to the contralateral hip on AP pelvic radiographs. The combined postoperative limb length/OS reconstruction of the operated hip was categorized as restored (within 5mm) or non-restored (more than 5mm reduction or more than 5mm increment). The acetabular component inclination, anteversion and femoral component anteversion were evaluated using CT scans of the pelvis and the femur. 3D gait analysis of the lower extremity and patient related outcome measures (HHS, HOOS, EQ-5D) were obtained pre-operatively, six months and twelve months post-operatively by an observer blinded to radiographic results. Component position of cup and stem was comparable between the restored and non-restored group. Combined LL and OS restoration within 5mm resulted in higher Froude number (p<0.001), normalized walking speed (p<0.001) and hip range-of-motion (ROM) (p=0.004) during gait twelve months postoperatively, whereas gait symmetry was comparable regardless of LL and OS reconstruction at both examinations. Clinical scores did not show any relevant association between the accuracy of LL or OS reconstruction and gait six/twelve months after THA. In summary, postoperative LL/OS discrepancies larger than 5mm relate to unphysiological gait kinematics within the first year after THA. DRKS00000739, German Clinical Trials Register.
authors.affiliation: Department of Orthopedic Surgery, Regensburg University, Medical Center, Bad Abbach, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Renkawitz
authors.affiliation: Department of Orthopedic Surgery, Regensburg University, Medical Center, Bad Abbach, Germany; Faculty of Mechanical Engineering, Laboratory for Biomechanics, Ostbayerische Technische Hochschule Regensburg, 93053 Regensburg, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Weber
authors.affiliation: Department of Orthopedic Surgery, Regensburg University, Medical Center, Bad Abbach, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Dullien
authors.affiliation: Department of Orthopedic Surgery, Regensburg University, Medical Center, Bad Abbach, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Woerner
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 Orthopedic Surgery, Regensburg University, Medical Center, Bad Abbach, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.affiliation: Department of Orthopedic Surgery, Regensburg University, Medical Center, Bad Abbach, Germany. Electronic address: markus.weber@ukr.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Weber
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007870:Leg Length Inequality / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000503:physiopathology* / Q000601:surgery; D011183:Postoperative Complications / Q000503:physiopathology* / Q000601:surgery; D011184:Postoperative Period; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Biomechanics; Gait analysis; Leg length; Offset; THA