Casey A Myers1, Peter J Laz2, Kevin B Shelburne2, Dana L Judd3, Daniel N Huff4, Joshua D Winters3, Jennifer E Stevens-Lapsley5, Paul J Rullkoetter2. 1. Center for Orthopaedic Biomechanics, University of Denver, Denver, CO, USA. Electronic address: Casey.Myers@du.edu. 2. Center for Orthopaedic Biomechanics, University of Denver, Denver, CO, USA. 3. Physical Therapy Program, University of Colorado, Aurora, CO, USA. 4. DePuy Synthes Products, Inc., Warsaw, IN, USA. 5. Physical Therapy Program, University of Colorado, Aurora, CO, USA; Geriatric Research Education and Clinical Center, VA Eastern Colorado Healthcare System, Denver, CO, USA.
Abstract
BACKGROUND: Component alignment is an important consideration in total hip arthroplasty. The impact of changes in alignment on muscle forces and joint contact forces during dynamic tasks are not well understood, and have the potential to influence surgical decision making. The objectives of this study were to assess the impact of femoral head/stem and cup component placement on hip muscle and joint contact forces during tasks of daily living and to identify which alignment parameters have the greatest impact on joint loading. METHODS: Using a series of strength-calibrated, subject-specific musculoskeletal models of patients performing gait, sit-to-stand and step down tasks, component alignments were perturbed and joint contact and muscle forces evaluated. FINDINGS: Based on the range of alignments reported clinically, variation in head/stem anteversion-retroversion had the largest impact of any degree of freedom throughout all three tasks; average contact forces 413.5 (319.1) N during gait, 262.7 (256.4) N during sit to stand, and 572.7 (228.1) N during the step down task. The sensitivity of contact force to anteversion-retroversion of the head/stem was 31.5 N/° for gait, which was similar in magnitude to anterior-posterior position of the cup (34.6 N/m for gait). Additionally, superior-inferior cup alignment resulted in 16.4 (4.9)° of variation in the direction of the hip joint contact force across the three tasks, with the most inferior cup placements moving the force vector towards the cup equator at the point of peak joint contact force. INTERPRETATION: A quantitative understanding of the impact and potential tradeoffs when altering component alignment is valuable in supporting surgical decision making.
BACKGROUND: Component alignment is an important consideration in total hip arthroplasty. The impact of changes in alignment on muscle forces and joint contact forces during dynamic tasks are not well understood, and have the potential to influence surgical decision making. The objectives of this study were to assess the impact of femoral head/stem and cup component placement on hip muscle and joint contact forces during tasks of daily living and to identify which alignment parameters have the greatest impact on joint loading. METHODS: Using a series of strength-calibrated, subject-specific musculoskeletal models of patients performing gait, sit-to-stand and step down tasks, component alignments were perturbed and joint contact and muscle forces evaluated. FINDINGS: Based on the range of alignments reported clinically, variation in head/stem anteversion-retroversion had the largest impact of any degree of freedom throughout all three tasks; average contact forces 413.5 (319.1) N during gait, 262.7 (256.4) N during sit to stand, and 572.7 (228.1) N during the step down task. The sensitivity of contact force to anteversion-retroversion of the head/stem was 31.5 N/° for gait, which was similar in magnitude to anterior-posterior position of the cup (34.6 N/m for gait). Additionally, superior-inferior cup alignment resulted in 16.4 (4.9)° of variation in the direction of the hip joint contact force across the three tasks, with the most inferior cup placements moving the force vector towards the cup equator at the point of peak joint contact force. INTERPRETATION: A quantitative understanding of the impact and potential tradeoffs when altering component alignment is valuable in supporting surgical decision making.
Authors: Tobias Renkawitz; Markus Tingart; Joachim Grifka; Ernst Sendtner; Thomas Kalteis Journal: Expert Rev Med Devices Date: 2009-09 Impact factor: 3.166
Authors: Anisha B Patel; Rohan R Wagle; Molly M Usrey; Matt T Thompson; Stephen J Incavo; Philip C Noble Journal: J Arthroplasty Date: 2009-12-21 Impact factor: 4.757
Authors: Dana L Judd; Joshua D Winters; Jennifer E Stevens-Lapsley; Cory L Christiansen Journal: Clin Biomech (Bristol, Avon) Date: 2015-12-31 Impact factor: 2.063
Authors: Tim A Weber; Sebastian Dendorfer; Joachim Grifka; Gijsbertus J Verkerke; Tobias Renkawitz Journal: Biomed Res Int Date: 2015-10-25 Impact factor: 3.411
Authors: Casey A Myers; Peter J Laz; Kevin B Shelburne; Dana L Judd; Joshua D Winters; Jennifer E Stevens-Lapsley; Bradley S Davidson Journal: J Biomech Date: 2019-06-06 Impact factor: 2.712