Positioning of the acetabular component: Intraoperative considerations
Total hip arthroplasty (THA) is a technically demanding procedure. Re-establishing a patient’s native biomechanics, such as center of rotation, is critical and can reduce the risk of complications and increase patient satisfaction. What should surgeons pay specific attention to when placing the acetabular cup? Accurate placement of this component is multi-factorial. In the final part of this article series we look at intraoperative considerations that will ensure patient-customized acetabular cup positioning. In addition, expert surgeons share insight on patients with protrusion and dysplasia and their views on the role of navigation in acetabular cup placement.
For many years conventional total hip arthroplasty (THA) was focused on medializing the prosthetic’s center of rotation (COR) compared to the native COR (see Part I). This was accomplished by medializing the acetabular component and using femoral offset to compensate for the increase. However, soft tissue around the hip will restrict the joint to its pre-existing range of mobility  and if the pre- and postoperative ranges are incongruent? Well, impingement and instability can be a problem .
In what has been referred to as a “kinematic revolution”, THA has evolved to include the consideration of a patient’s individual biomechanics when making decisions for implant component placement. Figure 1 illustrates the device components of a THA. Surgeons have moved away from a blanket approach to placement, towards one which seeks to restore a hip’s pre-existing range of mobility . Each patient presents unique acetabular orientation ; the thought is that native anteversion should be respected.
Let’s look at specific intra-operative actions surgeons can take to ensure an accurate, patient-specific acetabular cup placement. Part II of this article series addressed the planning phase, reiterating the need for thorough patient assessment, proper imaging, careful templating, and thoughtful preparation of a surgical strategy, including continency plans.
While supine positioning simplifies the assessment of the pelvis’s position and limb length during THA , more than 75% of surgeons perform THA with the patient in the lateral decubitus position  and the majority of these use a posterior approach . A direct anterior (minimally invasive) approach is also employed by some surgeons for THA; it has produced acceptable outcomes comparable to traditional THA in terms of cup placement [7, 8]. As we discuss further below, lateral decubitus positioning is associated with variation in pelvic tilt and despite assumptions that the pelvis is aligned with the coronal plane on the OR table, the alignment is in fact unknown.
With lateral decubitus positioning, the patient’s involved leg is in the "home position" (45° to 60° flexion, 20° to 30° internal rotation, and slight adduction), which is achieved by elevating the foot on a padded Mayo stand .
Adequate bolstering and support is of upmost importance and is intended to secure the patient in a known position throughout the procedure  – this, in theory, allows for straight-across comparison to preoperative x-rays and should facilitate execution of the acetabular cup’s planned anteversion and inclination.
However, research is showing this is not necessarily the case and undetected movement is common. Over a third of UK surgeons surveyed reported issues with the supports they use; a mere 31% considered their supports to be completely rigid. There is an identified need for further investigation and awareness around essential elements of patient support design . In particular, better tools to stabilize and specifically hold the pelvis in place are needed [11, 12].
Read the full article with your AO login
- Positioning may not be what you think it is
- Pelvic movement happens
- Pelvic movement and imaging
- What is an acceptable cup depth?
- Reaming: proceed carefully
- Anatomic or medialized placement?
- Cup height influences LLD and JRF
- Anatomical landmarks are independent of positioning
- Is there an ideal angular position?
- Harnessing technology for angular positioning
- Spinopelvic considerations utilizing dual mobility implants
This series of articles was created with the support of the following specialists (in alphabetical order):
Abu Dhabi, United Arab Emirates
University of British Columbia
Bas A Masri
University of British Columbia
This issue was created by Word+Vision Media Productions, Switzerland
- Hodson R. Precision Medicine. Nature Outlook. 2016 Sep;537(7619): Editorial. Available at: https://www.nature.com/articles/537S49a.pdf. Accessed January 22, 2019.
- Wikipedia. Precision Medicine. Wikipedia. Available at: https://en.wikipedia.org/wiki/Precision_medicine. Accessed January 22, 2019.
- The White House. The Precision Medicine Initiative. The White House - President Barak Obama. 2015 Jan. Available at: https://obamawhitehouse.archives.gov/precision-medicine. Accessed January 22, 2019.
- Pabinger C, Lothaller H, Portner N, et al. Projections of hip arthroplasty in OECD countries up to 2050. HIP International. 2018 May;28(5):498-506.
- Sloan N, Sheth, NP. Projected Volume of Primary and Revision Total Joint Arthroplasty in the United States, 2030-2060. Paper presented at: 2018 Annual Meeting Center - Research News. American Academy of Orthopedic Surgeons AAOS. Available at: http://aaos-annualmeeting-presskit.org/2018/research-news/sloan_tjr/. NA. Accessed January 22, 2019.
- Sorokina Y. Personalized Hip and Knee Replacements: U.S. Manufacturers Battle for Innovation Spotlight. 2018 Sep 13. Available at: https://www.odtmag.com/contents/view_online-exclusives/2018-09-13/personalized-hip-and-knee-replacements-us-manufacturers-battle-for-innovation-spotlight/48615. Accessed on January 22, 2019.
- Golish SR, Kurtz SM, and Boyan BD. Can 3D Printing Revolutionize Orthopaedic Devices? AAOS NOW. 2018 Jan. Available at: https://www.aaos.org/AAOSNow/2018/Jan/Cover/cover01/?ssopc=1. Accessed January 22, 2019.
- Badarudeen S, Shu A, Ong K, et al. Complications After Revision Total Hip Arthroplasty in the Medicare Population. J Arthroplasty. 2017 Jun;32(6):1954-1958.
- Journé A, Sadaka J, Bélicourt C, et al. New method for measuring acetabular component positioning with EOS imaging: feasibility study on dry bone. Int Orthop. 2012 Nov;36(11):2205–2209.
- Ng VY, Kean JR, Glassman AH. Limb-length discrepancy after hip arthroplasty. J Bone Joint Surg Am. 2013 Aug;95(15):1426-1436.
- Lecoanet P, Vargas M, Pallaro J, et al. Leg length discrepancy after total hip arthroplasty: Can leg length be satisfactorily controlled via anterior approach without a traction table? Evaluation in 56 patients with EOS 3D. Orthop Traumatol Surg Res. 2018 Dec;104(8):1143-1148.
- Pathak P, Gupta R, Meena H, et al. Limb length discrepancy after total hip arthroplasty: a systematic review. Int J Res Orthop. 2018 Sep;4(5):690-697.
- Colgan G, Walsh M, Bennett D, et al. Gait analysis and hip extensor function early post total hip replacement. J Orthop. 2016 Sep;13(3):171-176.
- Bennett D, Ryan P, O'Brien,S,et al. Gait kinetics of total hip replacement patients-A large scale, long-term follow-up study. Gait Posture. 2017 Mar;53:173-178.
- Foucher K. Gait abnormalities before and after total hip arthroplasty differ in men and women. J Biomed. 2016 Oct;49(14):3582-3586.
- Ardestani MM, Amenábar Edwards PP, Wimmer MA. Prediction of Polyethylene Wear Rates from Gait Biomechanics and Implant Positioning in Total Hip Replacement.Clin Orthop Relat Res. 2017 Aug;475(8):2027-2042.
- Madsen MS, Ritter MA, Morris HH, et al. The effect of total hip arthroplasty surgical approach on gait. J Orthop Res. 2004 Jan;22(1):44-50.
- Regenexx. The Age of Patients Getting Knee and Hip Replacements Continues to Decrease. 2018 Mar 27. Available at: https://www.regenexx.com/blog/knee-and-hip-replacements-in-younger-patients/. Accessed on January 27, 2019.
- Bayliss L, Culliford D, Pau A, et al. The effect of patient age at intervention on risk of implant revision after total replacement of the hip or knee: a population-based cohort study. Lancet. 2017 Apr;389(10077):1424–1430.
- Schreurs W, Hannink G. Total joint arthroplasty in younger patients: heading for trouble? Lancet. 2017 Feb;389(10077):1374-1375.
- Lee P, Lakstein D, Lozano B, et al. Mid-to long-term results of revision total hip replacement in patients aged 50 years or younger. Bone Joint J. 2014 Aug;96-B(8);1047-1051.
- Lin YT, Wu JS, Chen JH. The study of wear behaviors on abducted hip joint prostheses by an alternate finite element approach. Comput Methods Programs Biomed. 2016 Jul;131:143-155.
- Werner BC, Brown TE. Instability after total hip arthroplasty. World J Orthop. 2012 Aug;3(8):122-130.
- Dargel J, Oppermann J, Brüggemann G, et al. Dislocation Following Total Hip Replacement. Dtsch Arztebl Int. 2014 Dec;111(51-52):884–890.
- Ezquerra L, Quilez M, Pérez M, et al. Range of Movement for Impingement and Dislocation Avoidance in Total Hip Replacement Predicted by Finite Element Model. J Med Biol Eng. 2017 Jan;37(1):26-34.
- Jolles BM, Zangger P, Leyvraz PF. Factors predisposing to dislocation after primary total hip arthroplasty: a multivariate analysis. J Arthroplasty. 2002 Apr;17(3):282-288.
- Brooks P. Dislocation following total hip replacement: causes and cures. Bone Joint J. 2013 Nov;95-B(11 Suppl A);67-69.
- Scheerlinck T. Cup positioning in total hip arthroplasty. Acta Orthop Belg. 2014 Sep;80(3):336-47.
- Rivière C, Lazic S, Villet L, et al. Kinematic alignment technique for total hip and knee arthroplasty: The personalized implant positioning surgery. EFORT Open Rev. 2018;3(3):98-105.
- Echeverri S, Leyvraz P, Zambelli P, et al. Reliable acetabular cup orientation with a new gravity-assisted guidance system. J Arthroplasty. 2006 Apr;21(3):413-419.
- Harrison CL, Thomson AI, Cutts S, et al. Research Synthesis of Recommended Acetabular Cup Orientations for Total Hip Arthroplasty. J Arthroplasty. 2014 Feb;29(2):377-382.
- Bosker B, Verheyen C, Horstmann W, et al. Poor accuracy of freehand cup positioning during total hip arthroplasty. Arch Orthop Trauma Surg. 2007 Jul;127(5):375-379.
- Parcells B. Cup Placements: THA Technique. Available at: https://hipandkneebook.com/tha-chapters/2017/3/1/basic-hip-biomechanics. Accessed on January 29, 2019.
- Beverland DE, ONeill CKJ, Rutherford M, et al. Placement of the acetabular component. The Bone & Joint Journal. 2016 Jan:98-B(1 Suppl A):37-43.
- Snijders TE, Schlösser TPC, van Gaalen SM, et al. Trigonometric Algorithm Defining the True Three-Dimensional Acetabular Cup Orientation Correlation Between Measured and Calculated Cup Orientation Angles. JBJS Open Access. 2018 Sept:3(3);p e0063
- Karadsheh M. Hip Biomechanics. Orthobullets. Available at: https://www.orthobullets.com/recon/9064/hip-biomechanics. Accessed on February 27, 2019.
- Harris MD, MacWilliams BA, Bo Foreman K, et al. Higher medially-directed joint reaction forces are a characteristic of dysplastic hips: A comparative study using subject-specific musculoskeletal models. J Biomech. 2017 Mar;54:80-87.
- Bhaskar D, Rajpura A, Board T. Current Concepts in Acetabular Positioning in Total Hip Arthroplasty. Indian J Orthop. 2017 Jul;51(4):386-396.
- Bonnin MP, Archbold PH, Basiglini L, et al. Do we medialise the hip centre of rotation in total hip arthroplasty? Influence of acetabular offset and surgical technique. Hip Int. 2012 Jul-Aug;22(4):371-378.
- Fraysse F, Arnold J, Thewlis D. A method for concise reporting of joint reaction forces orientation during gait. J Biomech. 2016 Oct;49(14):3538-3542.
- Terrier A, Florencio FL, Rüdiger HA. Benefit of Cup Medialization in Total Hip Arthroplasty is Associated With Femoral Anatomy. Clin Orthop Relat Res. 2014 Oct;472(10):3159–3165.
- Cassidy KA, Noticewala MS, Macaulay W, et al. Effect of femoral offset on pain and function after total hip arthroplasty. J Arthroplasty. 2012 Dec;27(10):1863-1869.
- Houcke JV, Khanduja V, Pattyn C, et al. The History of Biomechanics in Total Hip Arthroplasty. Indian J Orthop. 2017 Jul-Aug;51(4):359-367.
- Naal FD, Kain MSH, Hersche O, et al. Clinical Orthopaedics and Related Research. 2009 Feb;467(4):923-928.
- Charnley J. Total hip replacement by low-friction arthroplasty. Clin Orthop Relat Res. 1970 Sep-Oct; 72():7-21.
- Charnley J. Low Friction Arthroplasty of the Hip – Theory and Practice. Berlin, Heidelberg: Springer-Verlag; 1979.
- Asayama I, Chamnongkich S, Simpson KJ, et al. Reconstructed hip joint position and abductor muscle strength after total hip arthroplasty. J Arthroplasty. 2005 Jun;20(4):414-420.
- Bonnin MP, Archbold PH, Basiglini L, et al. Should the acetabular cup be medialised in total hip arthroplasty. Hip Int. 2011 Jul-Aug;21(4):428-435.
- Malik A, Maheshwari A, Dorr LD. Impingement with total hip replacement. J Bone Joint Surg Am. 2007 Aug;89(8):1832-1842.
- Sexton SA, Yeung E, Jackson MP, et al. The role of patient factors and implant position in squeaking of ceramic-on-ceramic total hip replacements. J Bone Joint Surg Br. 2011 Apr;93(4):439-442.
- Hart AJ, Buddhdev P, Winship P, et al. Cup inclination angle of greater than 50 degrees increases whole blood concentrations of cobalt and chromium ions after metal-on-metal hip resurfacing. Hip Int. 2008;18:212–219.
- Shoji T, Yamasaki T, Izumi S, et al. The effect of cup medialization and lateralization on hip range of motion in total hip arthroplasty. Clin Biomech. 2018 Aug;57:121-128.
- Breusch SJ, Malchau H, Older J. Acetabulum. In: The Well-Cemented Total Hip Arthroplasty. Springer, Berlin, Heidelberg; 2005.
- Bicanic G, Barbaric K, Bohacek I, et al. Current concept in dysplastic hip arthroplasty: Techniques for acetabular and femoral reconstruction. World J Orthop. 2014 Sep;5(4):412-424.
- Flecher X, Ollivier M, Argenson JN. Lower limb length and offset in total hip arthroplasty. Orthop Traumatol Surg Res. 2016 Feb;102(1 Suppl):S9-20.
- Pathak PK, Gupta RP, Meena HS, et al. Limb length discrepancy after total hip arthroplasty: a systematic review. Int J Res Orthop. 2018 Sep;4(5)690-697.
- McWilliams AB, Grainger AJ, O'Connor PJ, et al. A review of symptomatic leg length inequality following total hip arthroplasty. Hip Int. 2013 Jan-Feb;23(1):6-14.
- Knutson GA. Anatomic and functional leg-length inequality: A review and recommendation for clinical decision-making. Part I, anatomic leg-length inequality: prevalence, magnitude, effects and clinical significance. Chiropr Osteopat. 2005; 13: 11. Published online 2005 Jul 20.
- Parvizi J, Sharkey PF, Bissett GA, et al. Surgical treatment of limb-length discrepancy following total hip arthroplasty. J Bone Joint Surg Am. 2003 Dec;85-A(12):2310–2317.
- Archbold P, Mohammed M, O’Brien S, et al. Limb length Restoration Following Total Hip Arthroplasty – Using the Transverse Acetabular Ligament and Caliper to Control the Height of the Acetabular and Femoral Components Respectively. Orthopaedic Proceedings. 2006; 88-B:SUPP_II: 281-281.
- Lee C, Jang J, Kim HW, et al. Three-dimensional analysis of acetabular orientation using a semi-automated algorithm. Computer Assisted Surgery. Published online 2019 Jan;DOI: 10.1080/24699322.2018.1545872.
- Maruyama M, Feinberg JR, Capello WN, et al. Morphologic Features of the Acetabulum and Femur: Anteversion Angle and Implant Positioning. Clin Orthop Relat Res. 2001 Dec;393:52-65. Presented at: 29th Open Meeting of the Hip Society and the American Association of Hip and Knee Surgeons: The Frank Stinchfield Award.
- Stem ES, O'Connor MI, Kransdorf MJ, et al. Computed tomography analysis of acetabular anteversion and abduction. Skeletal Radiol. 2006 Jun;35(6):385-389.
- Vanrusselt J, Vansevenant M, Vanderschueren G, et al. Postoperative radiograph of the hip arthroplasty: what the radiologist should know. Insights Imaging. 2015;6(6):591-600
- Lewinnek G, Lewis J, Tarr R, et al. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am. 1978 Mar;60(2):217-220.
- McCollum DE, Gray WJ. Dislocation after total hip arthroplasty. Causes and prevention. Clin Orthop Relat Res. 1990 Dec;261:159-170.
- Abdel M, von Roth P, Jennings M, et al. What Safe Zone? The Vast Majority of Dislocated THAs Are Within the Lewinnek Safe Zone for Acetabular Component Position. Clin Orthop Relat Res. 2016 Feb;474(2):386-391.
- Seagrave KG, Troelsen A, Malchau H, et al. Acetabular cup position and risk of dislocation in primary total hip arthroplasty: A systematic review of the literature. Acta Orthop. 2017 Feb; 88(1):217-220.
- Donnelly WJ, Crawford RW, Rimmington TD, et al. Acetabular Cup Placement, Are We Accurate? Orthopedic Proceedings. 2004 Apr:86-B(SUPP_IV);474.
- Murphy WS, Yun HH, Hayden B, et al. The Safe Zone Range for Cup Anteversion Is Narrower Than for Inclination in THA. Clin Orthop Relat Res. 2018 Feb;476(2):325-335.
- Yoon YS, Hodgson AJ, Tonetti J, et al. Resolving inconsistencies in defining the target orientation for the acetabular cup angles in total hip arthroplasty. Clin Biomech. 2008 Mar;23(3):253-259.
- Parcells B. Biomechanics. Available at: https://hipandkneebook.com/tha-chapters/2017/3/1/basic-hip-n?rq=pelvic%20tilt. Accessed on February 9, 2019.
- Schwarz TJ, Weber M, Dornia C, et al. Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study. Rofo. 2017 Sep;189(9):864-873.
- Babisch JW, Layher F, Amiot LP. The rationale for tilt-adjusted acetabular cup navigation. J Bone Joint Surg Am. 2008 Feb;90(2):357-365.
- Digioia AM, Jaramaz B, Blackwell M, et al. The Otto Aufranc Award. Image guided navigation system to measure intraoperatively acetabular implant alignment. Clin Orthop Relat Res. 1998 Oct:355;8-22.
- Marques CJ, Martin T, Kochman A, et al. Pelvic Tilt Angle Differences Between Symptom-Free Young Subjects and Elderly Patients Scheduled for THA: The Rationale for Tilt-Adjusted Acetabular Cup Implantation. Open Orthop J. 2018 Aug:12(1):364-372.
- Lembeck B, Mueller O, Reize P, et al. Pelvic tilt makes acetabular cup navigation inaccurate. Acta Orthop. 2005 Aug;76(4):517-523.
- Zhu J, Wan Z, Dorr LD. Quantification of pelvic tilt in total hip arthroplasty. Clin Orthop Relat Res. 2010 Feb;468(2):571–575.