TY - JOUR
T1 - Optimal anterior femoral offset for functional range of motion in total hip arthroplasty—a computer simulation study
AU - Hirata, Masanobu
AU - Nakashima, Yasuharu
AU - Hara, Daisuke
AU - Kanazawa, Masayuki
AU - Kohno, Yusuke
AU - Yoshimoto, Kensei
AU - Iwamoto, Yukihide
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (No. 24592268). We thank Junji Kishimoto, a statistician from the Digital Medicine Initiative, Kyushu University, for his valuable comments and suggestions in regards to the statistical analysis.
Publisher Copyright:
© 2014, SICOT aisbl.
PY - 2015/3/22
Y1 - 2015/3/22
N2 - Purpose: Compared to medial femoral offset (MFO), the role of anterior femoral offset (AFO) on range of motion (ROM) in total hip arthroplasty (THA) has not been fully examined. We therefore defined AFO as the anterior distance from the centre of the femoral head to the proximal femoral axis in the sagittal plane and determined the optimal AFO required for ROM needed for activities of daily living using a computer-simulated THA model.Methods: Various AFOs were obtained by changing stem anteversion (stem-AV) and stem tilt in the sagittal plane (stem-tilt) using a CT-based simulation software. The required ROM was defined as: flexion ≥ 110°, internal rotation at 90° flexion (IR) ≥ 30°, external rotation (ER) ≥ 30°, and extension ≥ 30°, and we determined AFO and MFO to satisfy required ROM.Results: AFO was positively correlated with stem-AV and anterior stem-tilt. MFO was negatively correlated with stem-AV and not influenced by stem-tilt. Flexion and IR increased with both increased AFO and MFO, whereas extension and ER decreased with increased AFO. A smoothing spline curve showed the optimal AFO and MFO for required ROM to be from 15 mm to 25 mm on average and more than 32.1 mm, respectively.Conclusions: This is the first study to show that AFO directly influenced ROM in THA. Optimal AFO as well as MFO should be reconstructed to achieve sufficient ROM.
AB - Purpose: Compared to medial femoral offset (MFO), the role of anterior femoral offset (AFO) on range of motion (ROM) in total hip arthroplasty (THA) has not been fully examined. We therefore defined AFO as the anterior distance from the centre of the femoral head to the proximal femoral axis in the sagittal plane and determined the optimal AFO required for ROM needed for activities of daily living using a computer-simulated THA model.Methods: Various AFOs were obtained by changing stem anteversion (stem-AV) and stem tilt in the sagittal plane (stem-tilt) using a CT-based simulation software. The required ROM was defined as: flexion ≥ 110°, internal rotation at 90° flexion (IR) ≥ 30°, external rotation (ER) ≥ 30°, and extension ≥ 30°, and we determined AFO and MFO to satisfy required ROM.Results: AFO was positively correlated with stem-AV and anterior stem-tilt. MFO was negatively correlated with stem-AV and not influenced by stem-tilt. Flexion and IR increased with both increased AFO and MFO, whereas extension and ER decreased with increased AFO. A smoothing spline curve showed the optimal AFO and MFO for required ROM to be from 15 mm to 25 mm on average and more than 32.1 mm, respectively.Conclusions: This is the first study to show that AFO directly influenced ROM in THA. Optimal AFO as well as MFO should be reconstructed to achieve sufficient ROM.
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U2 - 10.1007/s00264-014-2538-0
DO - 10.1007/s00264-014-2538-0
M3 - Article
C2 - 25252605
AN - SCOPUS:84925503163
SN - 0341-2695
VL - 39
SP - 645
EP - 651
JO - International Orthopaedics
JF - International Orthopaedics
IS - 4
ER -