{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T09:24:11Z","timestamp":1787822651898,"version":"build-2784847793"},"reference-count":50,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"3Spine"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>The purpose of this study was to analyze the sensitivity of polyethylene stresses and strains, as proxies for wear and surface damage, to coronal and axial misalignment for a novel lumbar total joint replacement (LTJR) implanted at L5-S1. We hypothesized that these stresses and strains would remain below the levels associated with worst-case impingement in a spine wear simulator. A finite element model (FEM) of the L4-S1 spine was developed using CT-based anatomy from a representative Investigational Device Exemption study patient. An appropriately sized LTJR was virtually implanted at L5-S1 in a standardized baseline orientation, and component positioning was altered to achieve eight independent misalignment scenarios, spanning axial convergence angle, anterior\u2013posterior offset, and coronal tilt. Physiologic forward-bending loads were applied, and polyethylene contact pressure, von Mises stress, and effective strain were recorded. Peak values for the baseline scenario were 35.0 MPa, 19.9 MPa, and 4.8%, respectively. Convergence angle and anterior\u2013posterior offset had minimal effect, whereas coronal tilt produced the largest changes. Contact pressure and von Mises stress varied by &lt;20% due to misalignment, whereas effective strain was more sensitive, increasing from 4.8% at baseline to 9.9% with 20 degrees of coronal tilt. All values were comparable to prior L4-L5 findings and remained well below impingement levels. Within the bounds of reasonable misalignment, the device maintained bearing congruency and did not approach conditions associated with accelerated wear.<\/jats:p>","DOI":"10.3390\/bioengineering13090987","type":"journal-article","created":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T09:00:35Z","timestamp":1787821235000},"page":"987","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of Axial and Coronal Malalignment on Polyethylene Stresses in Lumbosacral Total Joint Replacement: A Finite Element Study"],"prefix":"10.3390","volume":"13","author":[{"given":"Steven A.","family":"Rundell","sequence":"first","affiliation":[{"name":"Explico Inc., Detroit, MI 48375, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3885-500X","authenticated-orcid":false,"given":"Steven M.","family":"Kurtz","sequence":"additional","affiliation":[{"name":"Implant Research Core, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA"},{"name":"Gyroid LLC, Haddonfield, NJ 08033, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2114-0358","authenticated-orcid":false,"given":"Hannah","family":"Spece","sequence":"additional","affiliation":[{"name":"Implant Research Core, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA"},{"name":"Gyroid LLC, Haddonfield, NJ 08033, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Scott D.","family":"Hodges","sequence":"additional","affiliation":[{"name":"Spine Motion Specialists, Chattanooga, TN 37402, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ron V.","family":"Yarbrough","sequence":"additional","affiliation":[{"name":"3Spine Inc., Chattanooga, TN 37402, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1007\/s00264-018-4241-z","article-title":"Adjacent segment degeneration after fusion spinal surgery\u2014A systematic review","volume":"43","author":"Hashimoto","year":"2019","journal-title":"Int. Orthop."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1097\/01.brs.0000256875.17765.e6","article-title":"Radiologic assessment of all unfused lumbar segments 7.5 years after instrumented posterior spinal fusion","volume":"32","author":"Vidal","year":"2007","journal-title":"Spine"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2152","DOI":"10.1007\/s00586-007-0515-7","article-title":"Disc Height Reduction in Adjacent Segments and Clinical Outcome 10 years after Lumbar 360\u00b0 Fusion","volume":"16","author":"Schulte","year":"2007","journal-title":"Eur. Spine J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"S110","DOI":"10.1097\/01.BRS.0000092209.27573.90","article-title":"Biomechanical evaluation of total disc replacement arthroplasty: An in vitro human cadaveric model","volume":"28","author":"Cunningham","year":"2003","journal-title":"Spine"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1097\/01.brs.0000256915.90236.17","article-title":"Evaluation of spinal kinematics following lumbar total disc replacement and circumferential fusion using in vivo fluoroscopy","volume":"32","author":"Auerbach","year":"2007","journal-title":"Spine"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1007\/s12178-017-9397-4","article-title":"Lumbar disc replacement surgery\u2014Successes and obstacles to widespread adoption","volume":"10","author":"Salzmann","year":"2017","journal-title":"Curr. Rev. Musculoskelet. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1311","DOI":"10.1097\/BRS.0b013e318059af6f","article-title":"Multidirectional testing of one-and two-level ProDisc-L versus simulated fusions","volume":"32","author":"Panjabi","year":"2007","journal-title":"Spine"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1016\/j.spinee.2004.11.011","article-title":"Analysis of a retrieved polyethylene total disc replacement component","volume":"5","author":"Kurtz","year":"2005","journal-title":"Spine J."},{"key":"ref_9","first-page":"290","article-title":"Retrieval analysis of a ProDisc-L total disc replacement","volume":"22","author":"Choma","year":"2008","journal-title":"Clin. Spine Surg."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2444","DOI":"10.1097\/BRS.0b013e318182c37b","article-title":"Posterior component impingement after lumbar total disc replacement: A radiographic analysis of 66 ProDisc-L prostheses in 56 patients","volume":"33","author":"Kafer","year":"2008","journal-title":"Spine"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1369","DOI":"10.1007\/s11999-016-4996-8","article-title":"Periprosthetic UHMWPE Wear Debris Induces Inflammation, Vascularization, and Innervation After Total Disc Replacement in the Lumbar Spine","volume":"475","author":"Veruva","year":"2017","journal-title":"Clin. Orthop. Relat. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1007\/s00586-007-0506-8","article-title":"Complications and reoperations of the SB Charite lumbar disc prosthesis: Experience in 75 patients","volume":"17","author":"Punt","year":"2008","journal-title":"Eur. Spine J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1097\/01.brs.0000251370.56327.c6","article-title":"Polyethylene wear debris and long-term clinical failure of the Charite disc prosthesis: A study of 4 patients","volume":"32","author":"Kurtz","year":"2007","journal-title":"Spine"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1097\/00007632-200300001-00009","article-title":"Complications of artificial disc replacement: A report of 27 patients with the SB Charite disc","volume":"28","author":"Oner","year":"2003","journal-title":"Spine"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e751","DOI":"10.2106\/JBJS.K.00522","article-title":"Severe impingement of lumbar disc replacements increases the functional biological activity of polyethylene wear debris","volume":"95","author":"Baxter","year":"2013","journal-title":"J. Bone Jt. Surg."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1001","DOI":"10.1007\/s00586-006-0257-y","article-title":"Total lumbar disc replacement in athletes: Clinical results, return to sport and athletic performance","volume":"16","author":"Siepe","year":"2007","journal-title":"Eur. Spine J."},{"key":"ref_17","unstructured":"National Library of Medicine (U.S.) (2026, April 22). MOTUS Total Joint Replacement Investigational Device Exemption Study. ClinicalTrials.gov, Available online: https:\/\/clinicaltrials.gov\/study\/NCT05438719."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"S45","DOI":"10.14444\/8746","article-title":"Total Joint Replacement of the Lumbar Spine: The Future of Motion Preservation","volume":"19","author":"Goldstein","year":"2025","journal-title":"Int. J. Spine Surg."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1080\/17434440.2025.2484252","article-title":"Optimizing the clinical adoption of total joint replacement of the lumbar spine through imaging, robotics and artificial intelligence","volume":"22","author":"Humphreys","year":"2025","journal-title":"Expert Rev. Med. Devices"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"829","DOI":"10.1016\/j.spinee.2020.12.001","article-title":"A novel lumbar total joint replacement may be an improvement over fusion for degenerative lumbar conditions: A comparative analysis of patient-reported outcomes at one year","volume":"21","author":"Sielatycki","year":"2021","journal-title":"Spine J."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Siskey, R.L., Yarbrough, R.V., Spece, H., Hodges, S.D., Humphreys, S.C., and Kurtz, S.M. (2023). In Vitro Wear of a Novel Vitamin E Crosslinked Polyethylene Lumbar Total Joint Replacement. Bioengineering, 10.","DOI":"10.3390\/bioengineering10101198"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Kurtz, S.M., Rundell, S.A., Spece, H., and Yarbrough, R. (2025). Sensitivity of Lumbar Total Joint Replacement Contact Stresses Under Misalignment Conditions\u2014Finite Element Analysis of a Spine Wear Simulator. Bioengineering, 12.","DOI":"10.3390\/bioengineering12030229"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"635","DOI":"10.14444\/8792","article-title":"Sensitivity of Lumbar Total Joint Replacement to Axial and Coronal Plane Misalignment Using Computational Modeling","volume":"19","author":"Rundell","year":"2025","journal-title":"Int. J. Spine Surg."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1007\/s00586-017-5400-4","article-title":"Is L5\u2013S1 motion segment different from the rest? A radiographic kinematic assessment of 72 patients with chronic low back pain","volume":"27","author":"Sabnis","year":"2018","journal-title":"Eur. Spine J."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Wang, K., Deng, Z., Chen, X., Shao, J., Qiu, L., Jiang, C., and Niu, W. (2023). The Role of Multifidus in the Biomechanics of Lumbar Spine: A Musculoskeletal Modeling Study. Bioengineering, 10.","DOI":"10.3390\/bioengineering10010067"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1177\/2192568217735802","article-title":"The role of sacral slope in the progression of a bilateral spondylolytic defect at L5 to spondylolisthesis: A biomechanical investigation using finite element analysis","volume":"8","author":"Ramakrishna","year":"2018","journal-title":"Glob. Spine J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"817","DOI":"10.1016\/j.jbiomech.2015.10.035","article-title":"Fundamental biomechanics of the spine\u2014What we have learned in the past 25 years and future directions","volume":"49","author":"Oxland","year":"2016","journal-title":"J. Biomech."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e70115","DOI":"10.1002\/jor.70115","article-title":"High demand loading conditions and their effect on polyethylene stresses in lumbar total joint replacement: Implications for spine wear protocols","volume":"44","author":"Kurtz","year":"2026","journal-title":"J. Orthop. Res.\u00ae"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Rundell, S.A., Spece, H., Yarbrough, R.V., and Kurtz, S.M. (2026). Polyethylene stresses in lumbar total joint replacement under elevated loading: Insights from an anatomic finite element model. Bioengineering, 13.","DOI":"10.3390\/bioengineering13010066"},{"key":"ref_30","unstructured":"(2018). Assessing Credibility of Computational Modeling Through Verification and Validation: Application to Medical Devices (Standard No. ASME V&V 40-2018)."},{"key":"ref_31","unstructured":"United States Food and Drug Administration (2025, November 04). Credibility of Computational Modeling and Simulation in Medical Device Submissions: Guidance for Industry and Food and Drug Administration Staff, Available online: https:\/\/www.fda.gov\/regulatory-information\/search-fda-guidance-documents\/assessing-credibility-computational-modeling-and-simulation-medical-device-submissions."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Rundell, S., Spece, H., Yarbrough, R., and Kurtz, S. (Ann. Biomed. Eng., 2026). The Effect of High Demand Loading Conditions on Polyethylene Stresses in Total Joint Replacement of the Lumbar Spine at L5-S1, Ann. Biomed. Eng., in press.","DOI":"10.1007\/s10439-026-04291-7"},{"key":"ref_33","unstructured":"Pieper, S., Haouchine, N., Hackney, D.B., Wells, W.M., Sanhinova, M., Balboni, T., Spektor, A., Huynh, M., Tanguturi, S., and Kim, E. (2024). Spine Metastatic Bone Cancer: Pre and Post Radiotherapy CT (Spine-Mets-CT-SEG) Dataset Version 1, The Cancer Imaging Archive."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1889","DOI":"10.1007\/s00586-019-06083-1","article-title":"Sagittal balance of the spine","volume":"28","author":"Thompson","year":"2019","journal-title":"Eur. Spine J."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Chaffin, D.B. (1998). Prediction of Population Strengths, SAE International. SAE Technical Paper.","DOI":"10.4271\/981307"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1080\/07408179108963856","article-title":"Three-dimensional biomechanical static strength prediction model sensitivity to postural and anthropometric inaccuracies","volume":"23","author":"Chaffin","year":"1991","journal-title":"IIE Trans."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1080\/10255842.2021.1922677","article-title":"Development of a finite element lumbar spine model to predict intervertebral disc herniation risk factors","volume":"25","author":"Rossman","year":"2022","journal-title":"Comput. Methods Biomech. Biomed. Eng."},{"key":"ref_38","unstructured":"White, A. (1990). Clinical Biomechanics of the Spine, Lippincott Williams & Wilkins."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"842","DOI":"10.1115\/1.1330735","article-title":"Total knee replacement polyethylene stresses during loading in a knee simulator","volume":"123","author":"Giddings","year":"2001","journal-title":"J. Tribol."},{"key":"ref_40","first-page":"76","article-title":"Stresses in polyethylene components of contemporary total knee replacements","volume":"317","author":"Bartel","year":"1995","journal-title":"Clin. Orthop. Relat. Res."},{"key":"ref_41","first-page":"768","article-title":"Effect of material selection on tibial post stresses in posterior-stabilized knee prosthesis: A comparison among conventional, cross-linked, and vitamin E-stabilized polyethylene","volume":"9","author":"Huang","year":"2020","journal-title":"Bone Jt. J."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3303","DOI":"10.1016\/j.jbiomech.2014.08.015","article-title":"Contact mechanics of modular metal-on-polyethylene total hip replacement under adverse edge loading conditions","volume":"47","author":"Hua","year":"2014","journal-title":"J. Biomech."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1016\/S0268-0033(01)00109-7","article-title":"The effect of malalignment on stresses in polyethylene component of total knee prostheses\u2013a finite element analysis","volume":"17","author":"Liau","year":"2002","journal-title":"Clin. Biomech."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1520\/JAI103556","article-title":"Derivation of clinically relevant boundary conditions suitable for evaluation of chronic impingement of lumbar total disk replacement: Application to standard development","volume":"8","author":"Rundell","year":"2011","journal-title":"J. ASTM Int."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"E590","DOI":"10.1097\/BRS.0b013e318241e415","article-title":"Lumbar total disc replacement impingement sensitivity to disc height distraction, spinal sagittal orientation, implant position, and implant lordosis","volume":"37","author":"Rundell","year":"2012","journal-title":"Spine"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"782","DOI":"10.1002\/ca.23073","article-title":"Lumbosacral plexus root thickening: Establishing normal root dimensions using magnetic resonance neurography","volume":"31","author":"Chaves","year":"2018","journal-title":"Clin. Anat."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Bassani, T., Casaroli, G., and Galbusera, F. (2019). Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0207997"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Chen, J., Hume, P.A., Wyatt, H., Yeung, T., and Choisne, J. (2025). Understanding the effect of lumbar lordosis angle on vertebral load distribution during walking. Comput. Methods Biomech. Biomed. Eng., 1\u201312.","DOI":"10.1080\/10255842.2025.2530658"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"953","DOI":"10.1016\/j.jbiomech.2015.11.003","article-title":"Sensitivity of lumbar spine loading to anatomical parameters","volume":"49","author":"Putzer","year":"2016","journal-title":"J. Biomech."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Knapik, G.G., Mendel, E., Bourekas, E., and Marras, W.S. (2026). Impact of vertebrae shape variation on lumbar spine loading: An image-based computational modeling study. Eur. Spine J., 1\u201315.","DOI":"10.1007\/s00586-026-09804-5"}],"container-title":["Bioengineering"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-5354\/13\/9\/987\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T09:16:43Z","timestamp":1787822203000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-5354\/13\/9\/987"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,27]]},"references-count":50,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["bioengineering13090987"],"URL":"https:\/\/doi.org\/10.3390\/bioengineering13090987","relation":{},"ISSN":["2306-5354"],"issn-type":[{"value":"2306-5354","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,27]]}}}