The impact of standard combined anteversion definitions on gait and clinical outcome within one year after total hip arthroplasty.
OBJECTIVE
Different target areas within the concept of combined cup and stem anteversion have been published for total hip arthroplasty (THA). We asked whether component positioning according to eight standard combined anteversion rules is associated with (1) more physiological gait patterns, (2) higher improvement of gait variables and (3) better clinical outcome after THA.


METHODS
In a prospective clinical study, 60 patients received cementless THA through an anterolateral MIS approach in a lateral decubitus position. Six weeks postoperatively, implant position was analysed using 3D-CT by an independent external institute. Preoperatively, six and 12 months postoperatively range of motion, normalized walking speed and hip flexion symmetry index were measured using 3D motion-capture gait analysis. Patient-related outcome measures (HHS, HOOS, EQ-5D) were obtained by an observer blinded to 3D-CT results. Eight combined anteversion definitions and Lewinnek's "safe zone" were evaluated regarding their impact on gait patterns and clinical outcome.


RESULTS
Combined cup and stem anteversion according to standard combined anteversion definitions as well as cup placement within Lewinnek's "safe zone" did not influence range of motion, normalized walking speed and/or hip flexion symmetry index six and 12 months after THA. Similarly, increase of gait parameters within the first year after THA was comparable between all eight combined anteversion rules. Clinical outcome measures like HHS, HOOS and EQ-5D did not show any benefit for either of the combined anteversion definitions.


CONCLUSIONS
Standard combined cup and stem anteversion rules do not improve postoperative outcome as measured by gait analysis and clinical scores within one year after THA.
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany. markus.weber@klinik.uni-regensburg.de.
Markus
M
Weber
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.|Regensburg Centre of Biomedical Engineering, Ostbayerische Technische Hochschule Regensburg, 93053, Regensburg, Germany.
Tim
T
Weber
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
Michael
M
Woerner
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
Benjamin
B
Craiovan
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
Michael
M
Worlicek
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
Sebastian
S
Winkler
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
Joachim
J
Grifka
Department of Orthopaedic Surgery, Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
Tobias
T
Renkawitz
D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D060750:Bone Anteversion / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006622:Hip Prosthesis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D011446:Prospective Studies; D016059:Range of Motion, Articular; D014057:Tomography, X-Ray Computed
Combined anteversion; Gait analysis; Outcome; Total hip arthroplasty