{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,19]],"date-time":"2026-07-19T08:05:05Z","timestamp":1784448305585,"version":"3.55.0"},"reference-count":20,"publisher":"Surgical Technology Online","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Surg Technol Int."],"abstract":"<jats:p>Introduction: The acetabular \u201csafe zone\u201d has recently been questioned as a reliable reference for predicting total hip arthroplasty impingement and instability as many dislocations occur within the described parameters. Recently, an improved understanding of spino-pelvic mechanics has provided surgeons useful information to both identify those at a higher risk of dislocation and, in some cases, allows altering component positioning to accommodate the patient\u2019s individual \u201cfunctional\u201d range of motion. The purpose of this study was to create a new patient-specific impingement-free zone by considering range of motion (ROM) to prosthetic impingement for both high flexion and extension poses, thus demarcating a zone that avoids both anterior and posterior impingement, thereby creating an objective approach to identifying a patient\u2019s ideal functional safe zone.\nMaterials and Methods: A validated hip ROM three-dimensional simulator was utilized to create ROM-to-impingement curves for both high flexion as well as pivot and turn poses. The user imported a computerized tomography (CT) with a supine pelvic tilt (PT) value of zero and implant models (tapered wedge stem, 132\u00b0 neck angle, 15\u00b0 stem version, 36mm femoral head). Femur-to-pelvis relative motions were determined for three upright seated poses (femur flexed at 90\u00b0 and 40\u00b0 internal rotation, with 0\u00b0, 10\u00b0, and 20\u00b0 posterior PT), one chair rise pose (femur flexed at 90\u00b0 and 0\u00b0 internal rotation, with the pelvis flexed anteriorly until the pelvis made contact with the femur), and three standing pivot and turn poses (femur set at 5\u00b0 extension, and 35\u00b0 external rotation, with 5\u00b0 posterior PT, 0\u00b0, and 5\u00b0 anterior PT). ROM-to-impingement curves for cup inclination versus anteversion were graphed and compared against the Lewinnek safe zone. \nResults: The ROM-to-impingement curves provide an objective assessment of potential impingement sites as they relate to femoral rotation and pelvic tilt. The area between the stand and sit curves is the impingement-free area. A sitting erect pose with a simulated stiff spine (0\u00b0 PT) yielded less impingement-free combinations of cup inclination and version than poses with greater than 0\u00b0 posterior pelvic tilt. \nConclusion: The results demonstrate that the acetabular target zone has a relatively small margin for error between the sitting and standing ROM curves to impingement. Importantly, anterior and posterior pelvic tilt can markedly increase the risk of impingement, potentially leading to posterior or anterior dislocations, respectively. This study highlights the importance of correctly identifying the patient-specific functional range of motion to execute optimal component positioning.<\/jats:p>","DOI":"10.52198\/21.sti.38.os1399","type":"journal-article","created":{"date-parts":[[2021,4,8]],"date-time":"2021-04-08T08:58:48Z","timestamp":1617872328000},"source":"Crossref","is-referenced-by-count":3,"title":["Range of Motion to Impingement Curves Create a New Patient-Specific Impingement-Free Zone for Acetabular Cup Placement"],"prefix":"10.52198","author":[{"given":"Thomas","family":"McCarthy","sequence":"first","affiliation":[{"name":"Implant and Robotics Research Stryker Orthopaedics Mahwah, New Jersey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Thompson","sequence":"additional","affiliation":[{"name":"Stryker Orthopaedics Mahwah, New Jersey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jim","family":"Nevelos","sequence":"additional","affiliation":[{"name":"Implant and Robotics Research Stryker Orthopaedics Mahwah, New Jersey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hytham","family":"Salem","sequence":"additional","affiliation":[{"name":"Northwell Health Orthopaedics Lenox Hill Hospital New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brandon","family":"Naylor","sequence":"additional","affiliation":[{"name":"Northwell Health Orthopaedics Lenox Hill Hospital New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Mont","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery Northwell Health Lenox Hill Hospital New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"18996","published-online":{"date-parts":[[2021,2,10]]},"reference":[{"key":"ref0","doi-asserted-by":"publisher","unstructured":"1. Learmonth ID, Young C, Rorabeck C. The operation of the century: total hip replacement. Lancet 2007;370(9597)1508\u201319.","DOI":"10.1016\/s0140-6736(07)60457-7"},{"key":"ref1","doi-asserted-by":"publisher","unstructured":"2. Kim JT, Yoo JJ. Implant design in cementless hip arthroplasty. Hip Pelvis 2016; 28(2):65\u201375.","DOI":"10.5371\/hp.2016.28.2.65"},{"key":"ref2","doi-asserted-by":"publisher","unstructured":"3. Taunton MJ, Trousdale RT, Sierra RJ, et al. John Charnley Award: Randomized Clinical Trial of Direct Anterior and Miniposterior Approach THA: Which Provides Better Functional Recovery? Clin Orthop Relat Res 2018;476(2):216\u201329.","DOI":"10.1007\/s11999.0000000000000112"},{"key":"ref3","doi-asserted-by":"publisher","unstructured":"4. Meneghini RM, Smits SA, Swinford RR, et al. A randomized, prospective study of 3 minimally invasive surgical approaches in total hip arthroplasty. Comprehensive gait analysis. J Arthroplasty 2008;23(6 Suppl 1):68\u201373.","DOI":"10.1016\/j.arth.2008.05.014"},{"key":"ref4","doi-asserted-by":"publisher","unstructured":"5. Kremers HM, Larson DR, Crowson CS, et al. Prevalence of total hip and knee replacement in the United States. J Bone Jt Surg - Am Vol 2014;97(17): 1386\u201397.","DOI":"10.2106\/jbjs.n.01141"},{"key":"ref5","doi-asserted-by":"publisher","unstructured":"6. Sloan M, Premkumar A, Sheth NP. Projected volume of primary total joint arthroplasty in the u.s., 2014 to 2030. J Bone Jt Surg - Am Vol 2018;100(17):1455\u201360.","DOI":"10.2106\/jbjs.17.01617"},{"key":"ref6","doi-asserted-by":"publisher","unstructured":"7. Siddiqi A, White PB, Mistry JB, et al. Effect of bundled payments and health care reform as alternative payment models in total joint arthroplasty: a clinical review. J Arthroplasty 2017;32(8):2590\u20137.","DOI":"10.1016\/j.arth.2017.03.027"},{"key":"ref7","doi-asserted-by":"publisher","unstructured":"8. Mayfield CK, Haglin JM, Levine B, et al. Medicare reimbursement for hip and knee arthroplasty from 2000 to 2019: an unsustainable trend. J Arthroplasty 2020;35(5):1174\u20138.","DOI":"10.1016\/j.arth.2019.12.008"},{"key":"ref8","unstructured":"9. Ulrich SD, Seyler TM, Bennett D, et al. Total hip arthroplasties: What are the reasons for revision? Int Orthop 2008;32(5):597\u2013604."},{"key":"ref9","doi-asserted-by":"publisher","unstructured":"10. Lewinnek G, Lewis J, Tarr R, Compere C, Zimmerman J. Dislocations after total hip replacement arthroplasties. JBJS 1978;60:217\u201320.","DOI":"10.2106\/00004623-197860020-00014"},{"key":"ref10","doi-asserted-by":"publisher","unstructured":"11. Tezuka T, Heckmann ND, Bodner RJ, et al. Functional safe zone is superior to the Lewinnek safe zone for total hip arthroplasty: Why the Lewinnek safe zone is not always predictive of stability. J Arthroplasty 2019; 34(1):3\u20138.","DOI":"10.1016\/j.arth.2018.10.034"},{"key":"ref11","doi-asserted-by":"publisher","unstructured":"12. Sadhu A, Nam D, Coobs BR, et al. Acetabular component position and the risk of dislocation following primary and revision total hip arthroplasty: A matched cohort analysis. J Arthroplasty 2017;32(3): 987\u201391.","DOI":"10.1016\/j.arth.2016.08.008"},{"key":"ref12","doi-asserted-by":"publisher","unstructured":"13. Abdel MP, von Roth P, Jennings MT, 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;474(2):386\u201391.","DOI":"10.1007\/s11999-015-4432-5"},{"key":"ref13","doi-asserted-by":"publisher","unstructured":"14. Buckland AJ, Ayres EW, Shimmin AJ, et al. Prevalence of sagittal spinal deformity among patients undergoing total hip arthroplasty. J Arthroplasty 2020; 35(1):160\u20135.","DOI":"10.1016\/j.arth.2019.08.020"},{"key":"ref14","doi-asserted-by":"publisher","unstructured":"15. Luthringer TA, Vigdorchik JM. A preoperative workup of a \u201chip-spine\u201d total hip arthroplasty patient: A simplified approach to a complex problem. J Arthroplasty 2019;34(7S):S57\u201370.","DOI":"10.1016\/j.arth.2019.01.012"},{"key":"ref15","doi-asserted-by":"publisher","unstructured":"16. Kanawade V, Dorr LD, Banks SA, et al. Precision of robotic guided instrumentation for acetabular component positioning. J Arthroplasty 2015;30(3):392\u20137.","DOI":"10.1016\/j.arth.2014.10.021"},{"key":"ref16","doi-asserted-by":"publisher","unstructured":"17. DelSole EM, Vigdorchik JM, Schwarzkopf R, et al. Total hip arthroplasty in the spinal deformity population: Does degree of sagittal deformity affect rates of safe zone placement, instability, or revision? J Arthroplasty 2017;32(6):1910\u20137.","DOI":"10.1016\/j.arth.2016.12.039"},{"key":"ref17","doi-asserted-by":"publisher","unstructured":"18. McCarthy TF, Nevelos J, Elmallah, RK, et al. The effect of pelvic tilt and femoral head size on hip range-of-motion to impingement. J Arthroplasty 2017; 32(11):3544\u20139.","DOI":"10.1016\/j.arth.2017.06.016"},{"key":"ref18","doi-asserted-by":"publisher","unstructured":"19. McCarthy TF, Alipit V, Nevelos J, et al. Acetabular cup anteversion and inclination in hip range of motion to impingement. J Arthroplasty 2016;31(9):264\u20138.","DOI":"10.1016\/j.arth.2016.01.067"},{"key":"ref19","doi-asserted-by":"publisher","unstructured":"20. De Martino I, D\u2019Apolito R, Soranoglou VG, et al. Dislocation following total hip arthroplasty using dual mobility acetabular components. 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