Robotic Assisted TKA May Allow for Smaller Poly Sizes compared to Manual TKA with Simultaneous Removal of Hardware

Robotic Assisted TKA May Allow for Smaller Poly Sizes compared to Manual TKA with Simultaneous Removal of Hardware | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Robotic Assisted TKA May Allow for Smaller Poly Sizes compared to Manual TKA with Simultaneous Removal of Hardware Andrew D. Lachance, Alexander Edelstein, Shaya Shahsavarani, Roman Steika, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4896732/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 3 You are reading this latest preprint version Abstract Introduction: TKA after previous hardware around the knee is a challenge to preserve bone while boney landmarks are distorted. Robotic assisted (RA) TKA may assist in simultaneous hardware removal and TKA due to preoperative planning and retention of bone. The aim of this study is to identify if there are differences in component and functional outcomes dependent during simultaneous removal of hardware around the knee and TKA. Methods: A retrospective chart review was performed on patients undergoing simultaneous ROH and TKA over a 10-year period at a single institution. Patients were required to have at least 6 months of follow up. Data extracted included surgical technique, demographics, range of motion (ROM) at 1 year, complications, need for augments and utilization of revision components. Results: There were a total of 31 simultaneous ROH and TKA found in the EMR that met inclusion criteria including 23 manual and 8 RA-TKA with ROH. RA-TKA patients had significantly smaller poly sizes (p=0.017). There was a trend for decreased need for augments (p=0.544) and stems (p=0.315) in the RA-TKA group although this was not statistically significant. Postoperative flexion (p=0.973) or extension (p=0.351) at 1 year did not vary. Notably, one patient in the manual revision group required a hinged knee, and one manual patient required an MUA. Conclusion: Patients undergoing ROH and RA-TKA had a statistically significant decrease in poly size with a trend of less revision component utilization. RA may allow for more boney preservation via CT guided preoperative planning and precise boney cuts. Introduction Intra articular fractures of the distal femur and tibial plateau place patients at an increased risk of developing post traumatic arthritis, Total knee arthroplasty (TKA) serves as the standard of treatment for symptomatic or debilitating post-traumatic arthritis ( 1 , 2 ). However, complications following TKA after previous open reduction and internal fixation (ORIF) around the knee joint, or other surgery requiring implants, have higher complication rates compared to native primary TKA( 3 – 7 ). Arthroplasty cases involving hardware are more complicated as they require the decision to retain or remove hardware as well as consideration of larger exposure requirements. Some studies have suggested that retaining hardware may lead to higher rates of complications, specifically mechanical complications( 8 ) while others have found no difference( 9 ). However, all previous studies have looked at removal of hardware utilizing manual total knee arthroplasty with a lack of focus on cases performed with robotic assisted TKA (RA-TKA). There may be some benefits to RA-TKA in primary and revision arthroplasty as it has demonstrated improved alignment when compared to conventional TKA, ( 10 – 12 ). RA-TKA may have decreased postoperative pain, enhanced early functional status and decreased time to hospital discharge compared to manually preformed TKA( 13 ). Previous concerns of RA-TKA in patients with retained hardware includes obscurity of the preoperative CT scan (required when using systems such as MAKO, and TSOLUTION ONE), making the bony boundaries and details difficult to identify during preoperative planning. However, there has been significant utilization of RA-TKA with preoperative CT planning with successful outcomes in revision and conversion TKA( 14 – 20 ). We hypothesize that robotic assisted TKA has equivalent outcomes to manual TKA with simultaneous hardware removal and is a safe and effective technique for these patients. Methods Institutional review board approval was obtained prior to initiation of this study. Patients eligible for this study were identified through a retrospective review of electronic health records for individuals with prior implants undergoing TKA from January 1, 2014, to December 31, 2023, at a single institution by 6 different surgeons. Inclusion criteria were adult patients (18 years old) who underwent a TKA with hardware in the distal femur or proximal tibial with at least 6 months of follow-up. Patients were excluded from the study if they did not meet the above criteria, if there were insufficient notes in the electronic medical record, or had any other procedure done at the time of TKA other than removal of hardware. Manual TKA utilized the Zimmer Biomet Persona® system ( Warsaw, IN ). RA-TKA were performed with CT-based robotic-assisted technology and utilized Stryker implants (Stryker, Mako, Kalamazoo, MI). Data collection All data was compiled and reviewed by the investigators via accessing the patient’s Electronic Medical Record with their Medical Record Number. Data extracted from the patient’s chart included demographics, date of surgery, laterality, and range of motion (ROM.) Surgical data was collected from the operative report including whether surgery was performed manually vs with robotic assist, implant type, poly size, need for augmentation, and utilization of revision components (cones, stems, or sleeves). Complications included any patients requiring manipulation under anesthesia (MUA), having an infection, having a range of motion (ROM) less than 90 degrees at long-term follow-up, or requiring secondary revision surgery. All statistical analysis was conducted in SPSS using the Fisher exact test for nominal variables and two-tailed t-test for continuous variables. Results There were a total of 31 simultaneous ROH and TKA found in the EMR that met inclusion criteria. Of those 31, eight were robotic and 23 were manual TKAs. Of the 25 manual TKAs, two were excluded from final analysis because one had an ORIF done at the time of TKA and one had no operative note in the electronic health record. Average age of all patients was 61.6 +/- 11.6 (P = 0.748) with an average BMI 31 +/- 6.49 (P = 0.210). Eighteen patients (58%) were male (P = 0.412). Average ASA classification was 2.5 +/- 0.5 (P = 0.922). Average length of stay was 67.8 +/- 36.5 hours (P = 0.156). Six patients (12.9%) were diabetic, four patients (12.9%) were smokers, 26 cases (83.9%) had tibial hardware removal, and seven cases (22.6%) had femoral hardware removal. These demographic data are summarized in Table 1 . Table 1 Demographic data for all included patients All (n = 31) Manual (n = 23) Robotic (n = 8) P Value Sex (male) 18 (58%) 15 (65.2%) 3 (37.5%) 0.412 Age (years +/-SD) 61.6 +/- 11.6 62.0 +/- 12.6 60.6 +/- 8.85 0.748 BMI (kg/m2 +/- SD) 31.0 +/- 6.49 29.9 +/- 5.43 34.2 +/- 8.39 0.210 ASA 2.5 +/- 0.51 2.5 +/- 0.51 2.5 +/- 0.53 0.922 LOS (hours +/- SD) 67.8 +/- 36.5 74.8 +/- 30.7 47.75 +/- 46.0 0.156 Diabetes 6 (19.4%) 6 (26.1%) 0 (0%) 0.137 Smoker 4 (12.9%) 4 (17.4%) 0 (0%) 0.281 Follow up (months) 68+/-33 78+/-30 37+/-18 < .001 Tibial Hardware Removal 26 (83.9%) 20 (87.0%) 6 (75%) 0.957 Femoral Hardware Removal 7 (22.6%) 5 (21.7%) 2 (24%) 0.792 Of all 31 TKAs, 20 (64.5%) had cemented components (P = 0.095), two (6.45%) had augments (P = 0.544) both of which were tibial augments, 12 (38.7%) had stemmed components (P = 0.017) all of which had tibial stems, two (6.45%) had femoral stems (P = 0.544), and one (3.22%) had hinged component (P = 0.742) (Table 2 ). Polyethylene size had a mean of 11.9 +/- 2.60 mm (P = 0.017) with robotic TKAs having a significantly smaller polyethylene size. Of the 31 TKAs, 13 (41.9%) had CR implants (P = 0.0002) with robotic TKAs having a significantly higher proportion of CR components. These data are summarized in Table 2 . Table 2 Implant data for all patients. Significant data between the manual and robotic groups are in bold. All (n = 31) Manual (n = 23) Robotic (n = 8) P Value Cement 20 (64.5%) 18 (78.3%) 2 (25%) 0.095 Augments 2 (6.45%) 2 (8.70%) 0 (0%) 0.544 Tibial augments 2 (6.45%) 2 (8.70%) 0 (0%) 0.544 Femur augments 0 (0%) 0 (0%) 0 (0%) 1 Size of poly (mm +/- SD) 11.9 +/- 2.60 12.2 +/- 2.48 10.2 +/- 1.64 0.017 Need for Stems 12 (38.7%) 10 (43.5%) 2 (25%) 0.315 Femoral stem 2 (6.45%) 2 (8.70%) 0 (0%) 0.544 Tibial stem 12 (38.7%) 10 (43.5%) 2 (25%) 0.315 Hinged implant 1 (3.22%) 1 (4.35%) 0 (0%) 0.742 CR implant 13 (41.9%) 5 (21.7%) 8 (100%) 0.000163 In the postoperative followup, of all 31 TKAs, there was one (3.22%) complication which was in the manual group, comprised arthrofibrosis, and was managed by MUA. There were no revisions among all patients. Mean range of motion was 117.8 +/- 11.4 degrees (P = 0.927), mean extension was 0.17 +/- 0.91 degrees (P = 0.351), and mean flexion was 118 +/- 11.4 degrees (P = 0.973). These data are summarized in Table 3 . Table 3 Postoperative data for all patients. All (n = 31) Manual (n = 25) Robotic (n = 8) P Value Complications 1 (3.22%) 1 (4.35%) 0 (0%) 0.742 MUA 1 (3.22%) 1 (4.35%) 0 (0%) 0.742 Need for Revision 0 (0%) 0 (0%) 0 (0%) 1 Range of motion at 1 year (degrees +/- SD) 117.8 +/- 11.4 117.5 +/- 11.5 118 +/- 12.0 0.927 Extension at 1 year (degrees +/- SD) 0.17 +/- 0.91 0 +/- 0 0.63 +/- 1.77 0.351 Flexion at 1 year (degrees +/- SD) 118 +/- 11.4 117.95 +/- 11.5 118.125 +/- 11.9 0.973 Discussion Patients with retained hardware around the knee joint are more likely to develop arthritis and, in that case, may require a removal of some or all of the hardware to allow for proper positioning of the implants, making TKA more difficult. The decision to remove vs. retain hardware in a staged or simultaneous procedure may be a challenging clinical decision to make. Robotic assisted TKA has not been utilized previously for patients with retained hardware requiring a simultaneous ROH and TKA. Benefits include not only being able to accurately position the implants around the retained hardware, but to pre-operatively plan whether some or all of the hardware even needs to be removed. While there are concerns that CT preoperative planning may be obscured due to hardware, there have been several studies showing successful surgery with prior UKA, PFA or TKA ( 14 – 20 ). The successful outcomes of RA-TKA with prior hardware further supports CT guided RA-TKA with hardware around the knee is feasible. In this study, RA-TKA allowed for significantly smaller poly sizes and a trend towards fewer cases requiring revision components for adequate fixation. These results suggest that RA may allow for less bony resection in these areas with previous hardware while balancing the knee. CT guided preoperative and intraoperative planning may in fact allow for more bone retention as the location of the ORIF hardware is precisely known. These results are similar to Yun et al. ( 15 ) who found robotic assisted conversion of UKA to TKA required significantly fewer augments, fewer revision components and a non-significant decrease in polyethylene thickness compared to manual conversion. Notably this was not replicated in a similar study by Lachance et al.( 19 ) comparing robotic vs. manual conversion UKA to TKA. As thicker polyethylene sizes are associated with increased poly wear and need for revision( 21 , 22 ), the use of robotic assistance to predictably place smaller polyethylene components may benefit patients in long term follow up. One concern for concurrent ROH and TKA is bone loss from the ROH, which may require increased fixation methods including stems and augments. In this series, there were no patients with early loosening, suggesting good fixation with primary and revision components. While not statistically, significant, there were more patients in the manual TKA group requiring stemmed implants, augments and cementation. Stemmed components may provide some benefit for patients after ROH through increased stability and reduced micromotion at the bone-implant interface, especially in patients with bone loss from prior hardware ( 23 , 24 ). Stems are commonly used as a means to try to reduce tibial loosening in patients at high risk of this complication( 25 ). However, if a patient already has a stem and revision is required for loosening or infection, there may be decreased bone stock in the subsequent surgery, making revision more difficult and requiring longer stemmed implants( 26 ). Patients may also suffer from stem tip pain and have a higher risk for fracture around the stem( 27 , 28 ). When compared to shorter stems, long stems have increased stress shielding on the the surrounding bone. ( 29 ), ( 30 , 31 ). Utilization of stems in a primary TKA also increases cost of surgical intervention( 25 ). These findings suggest there may be some clinical benefit in utilizing RA-TKA for patients with previous hardware around the knee. Our study is likely underpowered to detect a true statistical significance due to the rarity of the case. Between manual and RA-TKA, similar range of motion was seen postoperatively at one year. One patient in the manual TKA group with limited ROM required an MUA which did not result in significantly improved function. ROM has been a problem with hardware around the knee( 32 ) likely secondary to scarring and thickening of the joint capsule and previous injury around the knee. The goal of postoperative ROM is generally around 110 degrees of flexion for symmetrical stair gait ( 33 ), which was reached by all but one patient in the RA-TKA group and two manual patients. Several studies have shown improved ROM in RA-TKA when compared to manual TKA( 34 , 35 ). RA-TKA has been found to have a reduction in the early postoperative local inflammatory response and pains scores ( 36 ). In theory, decreased pain and inflammation is thought to lead to faster recovery and shorter length of stay( 37 , 38 ). Notably, robotic patients were able to be discharged at 48 vs. 75 hours, suggesting potentially better early recovery directly after surgery, although there are a plethora of patient factors affecting this. Further study is required to determine differences in ROM for manual vs. robotic TKA in patients with ROH. At one-year post-op, no patients in either group had a significant complication requiring revision surgery. However, our study was underpowered to pick up differences in infection risk. A recent retrospective review by Baker et al. evaluated a total of 16,099 cases and found a statistically significant increase in prosthetic joint infection in patients undergoing concomitant removal of hardware and TKA compared to staged removal of hardware, at 3 months and 1-year post-op, with an infection rate of 3.95% in the concomitant group at 1-year[39]. It was also found that patients who had their ROH performed greater than three months prior to their TKA had a decreased risk of infection. Interestingly, another study demonstrated that concomitant ROH and TKA is more likely to be done through one incision whereas staged ROH and TKA is likely to be done through multiple incisions( 39 ). Despite the theoretical risk of infection or wound complications with multiple incisions, there was no difference in the rate of reoperation, complication, or revision between the concomitant or staged groups. While there may be a decreased infection rate in staged ROH and TKA, for select patients wishing or who may be better served by one surgery, our data suggests a similar rate of infection between RA-TKA and manual. These findings are limited by our small sample size. Notable limitations include the significant heterogeneity in the type of retained hardware that was in place about the knee prior to TKA. Most notably, there was no standardization for patients that had all their retained hardware removed or had some hardware retained. In addition, different preoperative hardware may change how much bone is able to be retained vs. resected. The sample size is limited to the unique nature of patients with previous hardware prior to TKA. Surgeries were performed by six different surgeons which may slightly change instrumentation utilized. Range of motion was performed by several practitioners which is also an additional variable. Additionally, long term follow up is required to make definitive claims. Taken together, our results suggest that simultaneous removal of hardware with TKA is a safe and effective procedure. RA-TKA may allow for the use of smaller polyethylene sizes with a decreased need for revision components, suggesting improved bone preservation. Similar range of motion and revision rates were documented at 1 year. Longer term outcomes are required to determine the efficacy and safety of RA vs. manual TKA with simultaneous hardware removal. Declarations Author Contribution A.L, A.E and S.S. wrote the mansucriptS.S. prepared the statistics and collected dataR.S. editted the manuscriptM.S. and J.L. were responsible for the creation of the projectAll authors reviewed the manuscript References Davis JT, Rudloff MI. Posttraumatic Arthritis After Intra-Articular Distal Femur and Proximal Tibia Fractures. Orthop Clin North Am. 2019;50(4):445-59. Jagdev SS, Pathak S, Kanani H, Salunke A. Functional outcome and incidence of osteoarthritis in operated tibial plateau fractures. Archives of Bone and Joint Surgery. 2018;6(6):508. Boureau F, Benad K, Putman S, Dereudre G, Kern G, Chantelot C. Does primary total knee arthroplasty for acute knee joint fracture maintain autonomy in the elderly? A retrospective study of 21 cases. Orthopaedics & Traumatology: Surgery & Research. 2015;101(8):947-51. Weiss NG, Parvizi J, Trousdale RT, Bryce RD, Lewallen DG. Total knee arthroplasty in patients with a prior fracture of the tibial plateau. JBJS. 2003;85(2):218-21. Saleh KJ, Sherman P, Katkin P, Windsor R, Haas S, Laskin R, et al. Total knee arthroplasty after open reduction and internal fixation of fractures of the tibial plateau: a minimum five-year follow-up study. JBJS. 2001;83(8):1144-8. Scott C, Davidson E, MacDonald D, White T, Keating J. Total knee arthroplasty following tibial plateau fracture: a matched cohort study. The Bone & Joint Journal. 2015;97(4):532-8. Lizaur-Utrilla A, Collados-Maestre I, Miralles-Muñoz FA, Lopez-Prats FA. Total Knee Arthroplasty for Osteoarthritis Secondary to Fracture of the Tibial Plateau. A Prospective Matched Cohort Study. J Arthroplasty. 2015;30(8):1328-32. Manrique J, Rasouli MR, Restrepo C, Maltenfort MG, Beri J, Oliver J, et al. Total Knee Arthroplasty in Patients with Retention of Prior Hardware Material: What is the Outcome? Arch Bone Jt Surg. 2018;6(1):23-6. Apinyankul R, Hui AY, Hwang K, Segovia NA, Amanatullah DF, Huddleston JI, et al. Complications, Implant Survivorships, and Functional Outcomes of Conversion Total Knee Arthroplasty With Prior Hardware. J Arthroplasty. 2023;38(6s):S66-S70.e2. Zhang J, Ndou WS, Ng N, Gaston P, Simpson PM, Macpherson GJ, et al. Robotic-arm assisted total knee arthroplasty is associated with improved accuracy and patient reported outcomes: a systematic review and meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2021:1-19. Lei K, Liu L, Chen X, Feng Q, Yang L, Guo L. Navigation and robotics improved alignment compared with PSI and conventional instrument, while clinical outcomes were similar in TKA: a network meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2021:1-13. Song E-K, Seon J-K, Yim J-H, Netravali NA, Bargar WL. Robotic-assisted TKA reduces postoperative alignment outliers and improves gap balance compared to conventional TKA. Clinical Orthopaedics and Related Research®. 2013;471:118-26. Kayani B, Konan S, Ayuob A, Onochie E, Al-Jabri T, Haddad FS. Robotic technology in total knee arthroplasty: a systematic review. EFORT open reviews. 2019;4(10):611. Kalavrytinos D, Koutserimpas C, Kalavrytinos I, Dretakis K. Expanding Robotic Arm-Assisted Knee Surgery: The First Attempt to Use the System for Knee Revision Arthroplasty. Case Reports in Orthopedics. 2020;2020:4806987. Yun AG, Qutami M, Chen C-HM, Pasko KBD. Management of failed UKA to TKA: conventional versus robotic-assisted conversion technique. Knee Surgery & Related Research. 2020;32(1):1-8. MacAskill M, Blickenstaff B, Caughran A, Bullock M. Revision total knee arthroplasty using robotic arm technology. Arthroplasty Today. 2022;13:35-42. Steelman K, Carlson K, Ketner A. Utilization of robotic arm assistance for revision of primary total knee arthroplasty: a case report. Journal of Orthopaedic Case Reports. 2021;11(8):50. Ngim H, Tang AW. Robotic assisted Revision Total Knee Arthroplasty: The future of Arthroplasty. Lachance AD, Edelstein A, Stilwell M, Lutton J. No Difference in Range of Motion, Components, or Complications Following Conversion of Robotic-Assisted Total Knee Arthroplasty Compared to Manual TKA After Undergoing Manual or Robotic-Assisted Unicompartmental Knee Arthroplasty. Arthroplasty Today. 2023;24:101269. Lachance AD, Steika R, Lutton J, Austin D. Conversion of Patellofemoral Arthroplasty to Robotic-Assisted Total Knee Arthroplasty. Arthroplasty Today. 2023;23:101215. Pijls BG, Van der Linden-Van der Zwaag HM, Nelissen RG. Polyethylene thickness is a risk factor for wear necessitating insert exchange. Int Orthop. 2012;36:1175-80. Rajamäki A, Niemeläinen M, Junnila M, Lehtovirta L, Karsikas M, Ponkilainen V, et al. Thicker polyethylene inserts (≥ 13 mm) increase the risk for early failure after primary cruciate‐retaining total knee arthroplasty (TKA): a single‐centre study of 7643 TKAs. Knee Surgery, Sports Traumatology, Arthroscopy. 2023;31(3):1018-25. Walsh CP, Han S, Canham CD, Gonzalez JL, Noble P, Incavo SJ. Total knee arthroplasty in the osteoporotic tibia: a biomechanical evaluation of the role of stem extensions and cementing techniques. JAAOS-Journal of the American Academy of Orthopaedic Surgeons. 2019;27(10):370-4. Au AG, Raso VJ, Liggins A, Amirfazli A. Contribution of loading conditions and material properties to stress shielding near the tibial component of total knee replacements. Journal of biomechanics. 2007;40(6):1410-6. Hinman AD, Prentice HA, Paxton EW, Kelly MP. Modular tibial stem use and risk of revision for aseptic loosening in cemented primary total knee arthroplasty. The Journal of Arthroplasty. 2021;36(5):1577-83. Pasquier GJM, Huten D, Common H, Migaud H, Putman S. Extraction of total knee arthroplasty intramedullary stem extensions. Orthopaedics & Traumatology: Surgery & Research. 2020;106(1):S135-S47. Mihalko WM, Whiteside LA. Stem pain after cementless revision total knee arthroplasty. Journal of Surgical Orthopaedic Advances. 2015;24(2):137-9. Cipriano CA, Brown NM, Della Valle CJ, Moric M, Sporer SM. Intra-operative periprosthetic fractures associated with press fit stems in revision total knee arthroplasty: incidence, management, and outcomes. The Journal of Arthroplasty. 2013;28(8):1310-3. Barlow BT, Oi KK, Lee YY, Joseph AD, Alexiades MM. Incidence, indications, outcomes, and survivorship of stems in primary total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2017;25(11):3611-9. Xie S, Conlisk N, Hamilton D, Scott C, Burnett R, Pankaj P. Metaphyseal cones in revision total knee arthroplasty: the role of stems. Bone & joint research. 2020;9(4):162-72. Lonner JH, Klotz M, Levitz C, Lotke PA. Changes in bone density after cemented total knee arthroplasty: influence of stem design. The Journal of arthroplasty. 2001;16(1):107-11. Sun X, Su Z. A meta-analysis of unicompartmental knee arthroplasty revised to total knee arthroplasty versus primary total knee arthroplasty. Journal of orthopaedic surgery and research. 2018;13(1):1-9. Rowe P, Myles C, Walker C, Nutton R. Knee joint kinematics in gait and other functional activities measured using flexible electrogoniometry: how much knee motion is sufficient for normal daily life? Gait & posture. 2000;12(2):143-55. Fary C, Cholewa J, Ren AN, Abshagen S, Anderson MB, Tripuraneni K. Multicenter, prospective cohort study: immediate postoperative gains in active range of motion following robotic-assisted total knee replacement compared to a propensity-matched control using manual instrumentation. Arthroplasty. 2023;5(1):62. Alrajeb R, Zarti M, Shuia Z, Alzobi O, Ahmed G, Elmhiregh A. Robotic-assisted versus conventional total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials. European Journal of Orthopaedic Surgery & Traumatology. 2023:1-11. Fontalis A, Kayani B, Asokan A, Haddad IC, Tahmassebi J, Konan S, et al. Inflammatory Response in Robotic-Arm-Assisted Versus Conventional Jig-Based TKA and the Correlation with Early Functional Outcomes: Results of a Prospective Randomized Controlled Trial. J Bone Joint Surg Am. 2022;104(21):1905-14. Archer A, Salem HS, Coppolecchia A, Mont MA. Lengths of Stay and Discharge Dispositions after Total Knee Arthroplasty: A Comparison of Robotic-Assisted and Manual Techniques. J Knee Surg. 2023;36(4):404-10. Mitchell J, Wang J, Bukowski B, Greiner J, Wolford B, Oyer M, et al. Relative Clinical Outcomes Comparing Manual and Robotic-Assisted Total Knee Arthroplasty at Minimum 1-Year Follow-up. Hss j. 2021;17(3):267-73. Smith EJ, Katakam A, Box HN, Healy WL, Bedair HS, Melnic CM. Staged vs concurrent hardware removal during conversion total knee arthroplasty. The Journal of Arthroplasty. 2020;35(12):3569-74. Tables Tables 1 to 3 are available in the Supplementary Files section Additional Declarations No competing interests reported. Supplementary Files rohtkafibures.docx Cite Share Download PDF Status: Under Review Version 1 posted Editor assigned by journal 14 Aug, 2024 Submission checks completed at journal 14 Aug, 2024 First submitted to journal 11 Aug, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4896732","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":340369287,"identity":"3b37be53-cae6-4176-98be-2d760efe2336","order_by":0,"name":"Andrew D. Lachance","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBklEQVRIiWNgGAWjYHACAyBmlmFg4AHz5EDEgQdEaOGBaTEGa0kgRUtiA4jEp4V/dvO2Dx/brHn4288e/FxQY5M+P+zwQ6AtdnK6Ddi1SNw5VjxzZls6j8SZvGTpGcfScjfeTjMAakk2NjuAw5obOcbMvNsO8zDc4DGQ5m04nLtxdgJIy4HEbTi0yIO0/AVqkb/BY/ybt+F/uuHs9A94tRiAtDACtRjc4DED2nIgQV46B78thjfSihl7/6XzGJ7JMbPmOZZsuEE6p+BAggFuv8jdSN7M8OOMtZzc8TPGt3lq7OTlZ6dv/vChwk4Op/cxnQpWaUCschCQbyBF9SgYBaNgFIwEAADfil+FZ7DF3QAAAABJRU5ErkJggg==","orcid":"","institution":"Guthrie Robert Packer Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Andrew","middleName":"D.","lastName":"Lachance","suffix":""},{"id":340369288,"identity":"77cee5bb-58af-4ff3-bab9-54b9def1d156","order_by":1,"name":"Alexander Edelstein","email":"","orcid":"","institution":"Guthrie Robert Packer Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"","lastName":"Edelstein","suffix":""},{"id":340369289,"identity":"52edb0b4-ecfd-467e-83e2-795c6f140819","order_by":2,"name":"Shaya Shahsavarani","email":"","orcid":"","institution":"Guthrie Robert Packer Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shaya","middleName":"","lastName":"Shahsavarani","suffix":""},{"id":340369290,"identity":"a54185cb-fee0-40b7-9498-a7ae3623bf75","order_by":3,"name":"Roman Steika","email":"","orcid":"","institution":"Guthrie Robert Packer Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Roman","middleName":"","lastName":"Steika","suffix":""},{"id":340369291,"identity":"3ed112b2-2eb3-41fd-9985-417fbdf3599a","order_by":4,"name":"Mason Stilwell","email":"","orcid":"","institution":"Guthrie Robert Packer Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mason","middleName":"","lastName":"Stilwell","suffix":""},{"id":340369292,"identity":"95dab1e2-316b-4caa-9315-b3b09cd78000","order_by":5,"name":"Jeffrey Lutton","email":"","orcid":"","institution":"Guthrie Robert Packer Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jeffrey","middleName":"","lastName":"Lutton","suffix":""}],"badges":[],"createdAt":"2024-08-11 22:48:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4896732/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4896732/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":64312721,"identity":"50a688a6-1945-4426-b24d-c8bdfa0a0faf","added_by":"auto","created_at":"2024-09-11 13:52:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":392891,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4896732/v1/1ded8235-63dd-48a8-8e4f-b0676430fce9.pdf"},{"id":64312234,"identity":"6014aefe-1e08-4d8f-b88d-af40cd36aa79","added_by":"auto","created_at":"2024-09-11 13:44:51","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":17006,"visible":true,"origin":"","legend":"","description":"","filename":"rohtkafibures.docx","url":"https://assets-eu.researchsquare.com/files/rs-4896732/v1/08f40f394ea5028af0da0996.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Robotic Assisted TKA May Allow for Smaller Poly Sizes compared to Manual TKA with Simultaneous Removal of Hardware","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIntra articular fractures of the distal femur and tibial plateau place patients at an increased risk of developing post traumatic arthritis, Total knee arthroplasty (TKA) serves as the standard of treatment for symptomatic or debilitating post-traumatic arthritis (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). However, complications following TKA after previous open reduction and internal fixation (ORIF) around the knee joint, or other surgery requiring implants, have higher complication rates compared to native primary TKA(\u003cspan additionalcitationids=\"CR4 CR5 CR6\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Arthroplasty cases involving hardware are more complicated as they require the decision to retain or remove hardware as well as consideration of larger exposure requirements. Some studies have suggested that retaining hardware may lead to higher rates of complications, specifically mechanical complications(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) while others have found no difference(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). However, all previous studies have looked at removal of hardware utilizing manual total knee arthroplasty with a lack of focus on cases performed with robotic assisted TKA (RA-TKA).\u003c/p\u003e \u003cp\u003eThere may be some benefits to RA-TKA in primary and revision arthroplasty as it has demonstrated improved alignment when compared to conventional TKA, (\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). RA-TKA may have decreased postoperative pain, enhanced early functional status and decreased time to hospital discharge compared to manually preformed TKA(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Previous concerns of RA-TKA in patients with retained hardware includes obscurity of the preoperative CT scan (required when using systems such as MAKO, and TSOLUTION ONE), making the bony boundaries and details difficult to identify during preoperative planning. However, there has been significant utilization of RA-TKA with preoperative CT planning with successful outcomes in revision and conversion TKA(\u003cspan additionalcitationids=\"CR15 CR16 CR17 CR18 CR19\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). We hypothesize that robotic assisted TKA has equivalent outcomes to manual TKA with simultaneous hardware removal and is a safe and effective technique for these patients.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e Institutional review board approval was obtained prior to initiation of this study. Patients eligible for this study were identified through a retrospective review of electronic health records for individuals with prior implants undergoing TKA from January 1, 2014, to December 31, 2023, at a single institution by 6 different surgeons. Inclusion criteria were adult patients (18 years old) who underwent a TKA with hardware in the distal femur or proximal tibial with at least 6 months of follow-up. Patients were excluded from the study if they did not meet the above criteria, if there were insufficient notes in the electronic medical record, or had any other procedure done at the time of TKA other than removal of hardware. Manual TKA utilized the Zimmer Biomet Persona\u0026reg; system (\u003cem\u003eWarsaw, IN\u003c/em\u003e). RA-TKA were performed with CT-based robotic-assisted technology and utilized Stryker implants (Stryker, Mako, Kalamazoo, MI).\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eData collection\u003c/h2\u003e \u003cp\u003eAll data was compiled and reviewed by the investigators via accessing the patient\u0026rsquo;s Electronic Medical Record with their Medical Record Number. Data extracted from the patient\u0026rsquo;s chart included demographics, date of surgery, laterality, and range of motion (ROM.) Surgical data was collected from the operative report including whether surgery was performed manually vs with robotic assist, implant type, poly size, need for augmentation, and utilization of revision components (cones, stems, or sleeves). Complications included any patients requiring manipulation under anesthesia (MUA), having an infection, having a range of motion (ROM) less than 90 degrees at long-term follow-up, or requiring secondary revision surgery. All statistical analysis was conducted in SPSS using the Fisher exact test for nominal variables and two-tailed t-test for continuous variables.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThere were a total of 31 simultaneous ROH and TKA found in the EMR that met inclusion criteria. Of those 31, eight were robotic and 23 were manual TKAs. Of the 25 manual TKAs, two were excluded from final analysis because one had an ORIF done at the time of TKA and one had no operative note in the electronic health record.\u003c/p\u003e \u003cp\u003eAverage age of all patients was 61.6 +/- 11.6 (P\u0026thinsp;=\u0026thinsp;0.748) with an average BMI 31 +/- 6.49 (P\u0026thinsp;=\u0026thinsp;0.210). Eighteen patients (58%) were male (P\u0026thinsp;=\u0026thinsp;0.412). Average ASA classification was 2.5 +/- 0.5 (P\u0026thinsp;=\u0026thinsp;0.922). Average length of stay was 67.8 +/- 36.5 hours (P\u0026thinsp;=\u0026thinsp;0.156). Six patients (12.9%) were diabetic, four patients (12.9%) were smokers, 26 cases (83.9%) had tibial hardware removal, and seven cases (22.6%) had femoral hardware removal. These demographic data are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic data for all included patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll (n\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eManual (n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRobotic (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP Value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex (male)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (58%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 (65.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (37.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.412\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years +/-SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e61.6 +/- 11.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e62.0 +/- 12.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60.6 +/- 8.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.748\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m2 +/- SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31.0 +/- 6.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.9 +/- 5.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34.2 +/- 8.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.210\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eASA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.5 +/- 0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.5 +/- 0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5 +/- 0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.922\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLOS (hours +/- SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e67.8 +/- 36.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e74.8 +/- 30.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47.75 +/- 46.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.156\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (19.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (26.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.137\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmoker\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (12.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (17.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.281\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow up (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68+/-33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78+/-30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37+/-18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTibial Hardware Removal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26 (83.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20 (87.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.957\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemoral Hardware Removal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (22.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (21.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (24%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.792\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eOf all 31 TKAs, 20 (64.5%) had cemented components (P\u0026thinsp;=\u0026thinsp;0.095), two (6.45%) had augments (P\u0026thinsp;=\u0026thinsp;0.544) both of which were tibial augments, 12 (38.7%) had stemmed components (P\u0026thinsp;=\u0026thinsp;0.017) all of which had tibial stems, two (6.45%) had femoral stems (P\u0026thinsp;=\u0026thinsp;0.544), and one (3.22%) had hinged component (P\u0026thinsp;=\u0026thinsp;0.742) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Polyethylene size had a mean of 11.9 +/- 2.60 mm (P\u0026thinsp;=\u0026thinsp;0.017) with robotic TKAs having a significantly smaller polyethylene size. Of the 31 TKAs, 13 (41.9%) had CR implants (P\u0026thinsp;=\u0026thinsp;0.0002) with robotic TKAs having a significantly higher proportion of CR components. These data are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eImplant data for all patients. Significant data between the manual and robotic groups are in bold.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll (n\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eManual (n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRobotic (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP Value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCement\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20 (64.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (78.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.095\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAugments\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.45%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (8.70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.544\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTibial augments\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.45%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (8.70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.544\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemur augments\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSize of poly (mm +/- SD)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e11.9 +/- 2.60\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e12.2 +/- 2.48\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e10.2 +/- 1.64\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.017\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeed for Stems\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (38.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (43.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.315\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemoral stem\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.45%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (8.70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.544\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTibial stem\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (38.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (43.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.315\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHinged implant\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (4.35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.742\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCR implant\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e13 (41.9%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e5 (21.7%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e8 (100%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.000163\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn the postoperative followup, of all 31 TKAs, there was one (3.22%) complication which was in the manual group, comprised arthrofibrosis, and was managed by MUA. There were no revisions among all patients. Mean range of motion was 117.8 +/- 11.4 degrees (P\u0026thinsp;=\u0026thinsp;0.927), mean extension was 0.17 +/- 0.91 degrees (P\u0026thinsp;=\u0026thinsp;0.351), and mean flexion was 118 +/- 11.4 degrees (P\u0026thinsp;=\u0026thinsp;0.973). These data are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePostoperative data for all patients.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll (n\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eManual (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRobotic (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP Value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComplications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (4.35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.742\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (4.35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.742\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeed for Revision\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRange of motion at 1 year (degrees +/- SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e117.8 +/- 11.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e117.5 +/- 11.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e118 +/- 12.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.927\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExtension at 1 year (degrees +/- SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.17 +/- 0.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 +/- 0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.63 +/- 1.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.351\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFlexion at 1 year (degrees +/- SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e118 +/- 11.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e117.95 +/- 11.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e118.125 +/- 11.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.973\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003ePatients with retained hardware around the knee joint are more likely to develop arthritis and, in that case, may require a removal of some or all of the hardware to allow for proper positioning of the implants, making TKA more difficult. The decision to remove vs. retain hardware in a staged or simultaneous procedure may be a challenging clinical decision to make. Robotic assisted TKA has not been utilized previously for patients with retained hardware requiring a simultaneous ROH and TKA. Benefits include not only being able to accurately position the implants around the retained hardware, but to pre-operatively plan whether some or all of the hardware even needs to be removed. While there are concerns that CT preoperative planning may be obscured due to hardware, there have been several studies showing successful surgery with prior UKA, PFA or TKA (\u003cspan additionalcitationids=\"CR15 CR16 CR17 CR18 CR19\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). The successful outcomes of RA-TKA with prior hardware further supports CT guided RA-TKA with hardware around the knee is feasible.\u003c/p\u003e \u003cp\u003eIn this study, RA-TKA allowed for significantly smaller poly sizes and a trend towards fewer cases requiring revision components for adequate fixation. These results suggest that RA may allow for less bony resection in these areas with previous hardware while balancing the knee. CT guided preoperative and intraoperative planning may in fact allow for more bone retention as the location of the ORIF hardware is precisely known. These results are similar to Yun et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) who found robotic assisted conversion of UKA to TKA required significantly fewer augments, fewer revision components and a non-significant decrease in polyethylene thickness compared to manual conversion. Notably this was not replicated in a similar study by Lachance et al.(\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e) comparing robotic vs. manual conversion UKA to TKA. As thicker polyethylene sizes are associated with increased poly wear and need for revision(\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e), the use of robotic assistance to predictably place smaller polyethylene components may benefit patients in long term follow up.\u003c/p\u003e \u003cp\u003eOne concern for concurrent ROH and TKA is bone loss from the ROH, which may require increased fixation methods including stems and augments. In this series, there were no patients with early loosening, suggesting good fixation with primary and revision components. While not statistically, significant, there were more patients in the manual TKA group requiring stemmed implants, augments and cementation. Stemmed components may provide some benefit for patients after ROH through increased stability and reduced micromotion at the bone-implant interface, especially in patients with bone loss from prior hardware (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e). Stems are commonly used as a means to try to reduce tibial loosening in patients at high risk of this complication(\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). However, if a patient already has a stem and revision is required for loosening or infection, there may be decreased bone stock in the subsequent surgery, making revision more difficult and requiring longer stemmed implants(\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). Patients may also suffer from stem tip pain and have a higher risk for fracture around the stem(\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). When compared to shorter stems, long stems have increased stress shielding on the the surrounding bone. (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e), (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). Utilization of stems in a primary TKA also increases cost of surgical intervention(\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). These findings suggest there may be some clinical benefit in utilizing RA-TKA for patients with previous hardware around the knee. Our study is likely underpowered to detect a true statistical significance due to the rarity of the case.\u003c/p\u003e \u003cp\u003eBetween manual and RA-TKA, similar range of motion was seen postoperatively at one year. One patient in the manual TKA group with limited ROM required an MUA which did not result in significantly improved function. ROM has been a problem with hardware around the knee(\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e) likely secondary to scarring and thickening of the joint capsule and previous injury around the knee. The goal of postoperative ROM is generally around 110 degrees of flexion for symmetrical stair gait (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e), which was reached by all but one patient in the RA-TKA group and two manual patients. Several studies have shown improved ROM in RA-TKA when compared to manual TKA(\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e). RA-TKA has been found to have a reduction in the early postoperative local inflammatory response and pains scores (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e). In theory, decreased pain and inflammation is thought to lead to faster recovery and shorter length of stay(\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e). Notably, robotic patients were able to be discharged at 48 vs. 75 hours, suggesting potentially better early recovery directly after surgery, although there are a plethora of patient factors affecting this. Further study is required to determine differences in ROM for manual vs. robotic TKA in patients with ROH.\u003c/p\u003e \u003cp\u003eAt one-year post-op, no patients in either group had a significant complication requiring revision surgery. However, our study was underpowered to pick up differences in infection risk. A recent retrospective review by Baker et al. evaluated a total of 16,099 cases and found a statistically significant increase in prosthetic joint infection in patients undergoing concomitant removal of hardware and TKA compared to staged removal of hardware, at 3 months and 1-year post-op, with an infection rate of 3.95% in the concomitant group at 1-year[39]. It was also found that patients who had their ROH performed greater than three months prior to their TKA had a decreased risk of infection. Interestingly, another study demonstrated that concomitant ROH and TKA is more likely to be done through one incision whereas staged ROH and TKA is likely to be done through multiple incisions(\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e). Despite the theoretical risk of infection or wound complications with multiple incisions, there was no difference in the rate of reoperation, complication, or revision between the concomitant or staged groups. While there may be a decreased infection rate in staged ROH and TKA, for select patients wishing or who may be better served by one surgery, our data suggests a similar rate of infection between RA-TKA and manual. These findings are limited by our small sample size.\u003c/p\u003e \u003cp\u003eNotable limitations include the significant heterogeneity in the type of retained hardware that was in place about the knee prior to TKA. Most notably, there was no standardization for patients that had all their retained hardware removed or had some hardware retained. In addition, different preoperative hardware may change how much bone is able to be retained vs. resected. The sample size is limited to the unique nature of patients with previous hardware prior to TKA. Surgeries were performed by six different surgeons which may slightly change instrumentation utilized. Range of motion was performed by several practitioners which is also an additional variable. Additionally, long term follow up is required to make definitive claims.\u003c/p\u003e \u003cp\u003eTaken together, our results suggest that simultaneous removal of hardware with TKA is a safe and effective procedure. RA-TKA may allow for the use of smaller polyethylene sizes with a decreased need for revision components, suggesting improved bone preservation. Similar range of motion and revision rates were documented at 1 year. Longer term outcomes are required to determine the efficacy and safety of RA vs. manual TKA with simultaneous hardware removal.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eA.L, A.E and S.S. wrote the mansucriptS.S. prepared the statistics and collected dataR.S. editted the manuscriptM.S. and J.L. were responsible for the creation of the projectAll authors reviewed the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eDavis JT, Rudloff MI. Posttraumatic Arthritis After Intra-Articular Distal Femur and Proximal Tibia Fractures. Orthop Clin North Am. 2019;50(4):445-59.\u003c/li\u003e\n \u003cli\u003eJagdev SS, Pathak S, Kanani H, Salunke A. Functional outcome and incidence of osteoarthritis in operated tibial plateau fractures. Archives of Bone and Joint Surgery. 2018;6(6):508.\u003c/li\u003e\n \u003cli\u003eBoureau F, Benad K, Putman S, Dereudre G, Kern G, Chantelot C. Does primary total knee arthroplasty for acute knee joint fracture maintain autonomy in the elderly? A retrospective study of 21 cases. Orthopaedics \u0026amp; Traumatology: Surgery \u0026amp; Research. 2015;101(8):947-51.\u003c/li\u003e\n \u003cli\u003eWeiss NG, Parvizi J, Trousdale RT, Bryce RD, Lewallen DG. Total knee arthroplasty in patients with a prior fracture of the tibial plateau. JBJS. 2003;85(2):218-21.\u003c/li\u003e\n \u003cli\u003eSaleh KJ, Sherman P, Katkin P, Windsor R, Haas S, Laskin R, et al. Total knee arthroplasty after open reduction and internal fixation of fractures of the tibial plateau: a minimum five-year follow-up study. JBJS. 2001;83(8):1144-8.\u003c/li\u003e\n \u003cli\u003eScott C, Davidson E, MacDonald D, White T, Keating J. Total knee arthroplasty following tibial plateau fracture: a matched cohort study. The Bone \u0026amp; Joint Journal. 2015;97(4):532-8.\u003c/li\u003e\n \u003cli\u003eLizaur-Utrilla A, Collados-Maestre I, Miralles-Mu\u0026ntilde;oz FA, Lopez-Prats FA. Total Knee Arthroplasty for Osteoarthritis Secondary to Fracture of the Tibial Plateau. A Prospective Matched Cohort Study. J Arthroplasty. 2015;30(8):1328-32.\u003c/li\u003e\n \u003cli\u003eManrique J, Rasouli MR, Restrepo C, Maltenfort MG, Beri J, Oliver J, et al. Total Knee Arthroplasty in Patients with Retention of Prior Hardware Material: What is the Outcome? Arch Bone Jt Surg. 2018;6(1):23-6.\u003c/li\u003e\n \u003cli\u003eApinyankul R, Hui AY, Hwang K, Segovia NA, Amanatullah DF, Huddleston JI, et al. Complications, Implant Survivorships, and Functional Outcomes of Conversion Total Knee Arthroplasty With Prior Hardware. J Arthroplasty. 2023;38(6s):S66-S70.e2.\u003c/li\u003e\n \u003cli\u003eZhang J, Ndou WS, Ng N, Gaston P, Simpson PM, Macpherson GJ, et al. Robotic-arm assisted total knee arthroplasty is associated with improved accuracy and patient reported outcomes: a systematic review and meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2021:1-19.\u003c/li\u003e\n \u003cli\u003eLei K, Liu L, Chen X, Feng Q, Yang L, Guo L. Navigation and robotics improved alignment compared with PSI and conventional instrument, while clinical outcomes were similar in TKA: a network meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2021:1-13.\u003c/li\u003e\n \u003cli\u003eSong E-K, Seon J-K, Yim J-H, Netravali NA, Bargar WL. Robotic-assisted TKA reduces postoperative alignment outliers and improves gap balance compared to conventional TKA. Clinical Orthopaedics and Related Research\u0026reg;. 2013;471:118-26.\u003c/li\u003e\n \u003cli\u003eKayani B, Konan S, Ayuob A, Onochie E, Al-Jabri T, Haddad FS. Robotic technology in total knee arthroplasty: a systematic review. EFORT open reviews. 2019;4(10):611.\u003c/li\u003e\n \u003cli\u003eKalavrytinos D, Koutserimpas C, Kalavrytinos I, Dretakis K. Expanding Robotic Arm-Assisted Knee Surgery: The First Attempt to Use the System for Knee Revision Arthroplasty. Case Reports in Orthopedics. 2020;2020:4806987.\u003c/li\u003e\n \u003cli\u003eYun AG, Qutami M, Chen C-HM, Pasko KBD. Management of failed UKA to TKA: conventional versus robotic-assisted conversion technique. Knee Surgery \u0026amp; Related Research. 2020;32(1):1-8.\u003c/li\u003e\n \u003cli\u003eMacAskill M, Blickenstaff B, Caughran A, Bullock M. Revision total knee arthroplasty using robotic arm technology. Arthroplasty Today. 2022;13:35-42.\u003c/li\u003e\n \u003cli\u003eSteelman K, Carlson K, Ketner A. Utilization of robotic arm assistance for revision of primary total knee arthroplasty: a case report. Journal of Orthopaedic Case Reports. 2021;11(8):50.\u003c/li\u003e\n \u003cli\u003eNgim H, Tang AW. Robotic assisted Revision Total Knee Arthroplasty: The future of Arthroplasty.\u003c/li\u003e\n \u003cli\u003eLachance AD, Edelstein A, Stilwell M, Lutton J. No Difference in Range of Motion, Components, or Complications Following Conversion of Robotic-Assisted Total Knee Arthroplasty Compared to Manual TKA After Undergoing Manual or Robotic-Assisted Unicompartmental Knee Arthroplasty. Arthroplasty Today. 2023;24:101269.\u003c/li\u003e\n \u003cli\u003eLachance AD, Steika R, Lutton J, Austin D. Conversion of Patellofemoral Arthroplasty to Robotic-Assisted Total Knee Arthroplasty. Arthroplasty Today. 2023;23:101215.\u003c/li\u003e\n \u003cli\u003ePijls BG, Van der Linden-Van der Zwaag HM, Nelissen RG. Polyethylene thickness is a risk factor for wear necessitating insert exchange. Int Orthop. 2012;36:1175-80.\u003c/li\u003e\n \u003cli\u003eRajam\u0026auml;ki A, Niemel\u0026auml;inen M, Junnila M, Lehtovirta L, Karsikas M, Ponkilainen V, et al. Thicker polyethylene inserts (\u0026ge; 13 mm) increase the risk for early failure after primary cruciate‐retaining total knee arthroplasty (TKA): a single‐centre study of 7643 TKAs. Knee Surgery, Sports Traumatology, Arthroscopy. 2023;31(3):1018-25.\u003c/li\u003e\n \u003cli\u003eWalsh CP, Han S, Canham CD, Gonzalez JL, Noble P, Incavo SJ. Total knee arthroplasty in the osteoporotic tibia: a biomechanical evaluation of the role of stem extensions and cementing techniques. JAAOS-Journal of the American Academy of Orthopaedic Surgeons. 2019;27(10):370-4.\u003c/li\u003e\n \u003cli\u003eAu AG, Raso VJ, Liggins A, Amirfazli A. Contribution of loading conditions and material properties to stress shielding near the tibial component of total knee replacements. Journal of biomechanics. 2007;40(6):1410-6.\u003c/li\u003e\n \u003cli\u003eHinman AD, Prentice HA, Paxton EW, Kelly MP. Modular tibial stem use and risk of revision for aseptic loosening in cemented primary total knee arthroplasty. The Journal of Arthroplasty. 2021;36(5):1577-83.\u003c/li\u003e\n \u003cli\u003ePasquier GJM, Huten D, Common H, Migaud H, Putman S. Extraction of total knee arthroplasty intramedullary stem extensions. Orthopaedics \u0026amp; Traumatology: Surgery \u0026amp; Research. 2020;106(1):S135-S47.\u003c/li\u003e\n \u003cli\u003eMihalko WM, Whiteside LA. Stem pain after cementless revision total knee arthroplasty. Journal of Surgical Orthopaedic Advances. 2015;24(2):137-9.\u003c/li\u003e\n \u003cli\u003eCipriano CA, Brown NM, Della Valle CJ, Moric M, Sporer SM. Intra-operative periprosthetic fractures associated with press fit stems in revision total knee arthroplasty: incidence, management, and outcomes. The Journal of Arthroplasty. 2013;28(8):1310-3.\u003c/li\u003e\n \u003cli\u003eBarlow BT, Oi KK, Lee YY, Joseph AD, Alexiades MM. Incidence, indications, outcomes, and survivorship of stems in primary total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2017;25(11):3611-9.\u003c/li\u003e\n \u003cli\u003eXie S, Conlisk N, Hamilton D, Scott C, Burnett R, Pankaj P. Metaphyseal cones in revision total knee arthroplasty: the role of stems. Bone \u0026amp; joint research. 2020;9(4):162-72.\u003c/li\u003e\n \u003cli\u003eLonner JH, Klotz M, Levitz C, Lotke PA. Changes in bone density after cemented total knee arthroplasty: influence of stem design. The Journal of arthroplasty. 2001;16(1):107-11.\u003c/li\u003e\n \u003cli\u003eSun X, Su Z. A meta-analysis of unicompartmental knee arthroplasty revised to total knee arthroplasty versus primary total knee arthroplasty. Journal of orthopaedic surgery and research. 2018;13(1):1-9.\u003c/li\u003e\n \u003cli\u003eRowe P, Myles C, Walker C, Nutton R. Knee joint kinematics in gait and other functional activities measured using flexible electrogoniometry: how much knee motion is sufficient for normal daily life? Gait \u0026amp; posture. 2000;12(2):143-55.\u003c/li\u003e\n \u003cli\u003eFary C, Cholewa J, Ren AN, Abshagen S, Anderson MB, Tripuraneni K. Multicenter, prospective cohort study: immediate postoperative gains in active range of motion following robotic-assisted total knee replacement compared to a propensity-matched control using manual instrumentation. Arthroplasty. 2023;5(1):62.\u003c/li\u003e\n \u003cli\u003eAlrajeb R, Zarti M, Shuia Z, Alzobi O, Ahmed G, Elmhiregh A. Robotic-assisted versus conventional total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials. European Journal of Orthopaedic Surgery \u0026amp; Traumatology. 2023:1-11.\u003c/li\u003e\n \u003cli\u003eFontalis A, Kayani B, Asokan A, Haddad IC, Tahmassebi J, Konan S, et al. Inflammatory Response in Robotic-Arm-Assisted Versus Conventional Jig-Based TKA and the Correlation with Early Functional Outcomes: Results of a Prospective Randomized Controlled Trial. J Bone Joint Surg Am. 2022;104(21):1905-14.\u003c/li\u003e\n \u003cli\u003eArcher A, Salem HS, Coppolecchia A, Mont MA. Lengths of Stay and Discharge Dispositions after Total Knee Arthroplasty: A Comparison of Robotic-Assisted and Manual Techniques. J Knee Surg. 2023;36(4):404-10.\u003c/li\u003e\n \u003cli\u003eMitchell J, Wang J, Bukowski B, Greiner J, Wolford B, Oyer M, et al. Relative Clinical Outcomes Comparing Manual and Robotic-Assisted Total Knee Arthroplasty at Minimum 1-Year Follow-up. Hss j. 2021;17(3):267-73.\u003c/li\u003e\n \u003cli\u003eSmith EJ, Katakam A, Box HN, Healy WL, Bedair HS, Melnic CM. Staged vs concurrent hardware removal during conversion total knee arthroplasty. The Journal of Arthroplasty. 2020;35(12):3569-74.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the Supplementary Files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-robotic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jors","sideBox":"Learn more about [Journal of Robotic Surgery](http://link.springer.com/journal/11701)","snPcode":"11701","submissionUrl":"https://submission.nature.com/new-submission/11701/3","title":"Journal of Robotic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4896732/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4896732/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction: \u003c/strong\u003eTKA after previous hardware around the knee is a challenge to preserve bone while boney landmarks are distorted. Robotic assisted (RA) TKA may assist in simultaneous hardware removal and TKA due to preoperative planning and retention of bone. The aim of this study is to identify if there are differences in component and functional outcomes dependent during simultaneous removal of hardware around the knee and TKA.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eA retrospective chart review was performed on patients undergoing simultaneous ROH and TKA over a 10-year period at a single institution. Patients were required to have at least 6 months of follow up. Data extracted included surgical technique, demographics, range of motion (ROM) at 1 year, complications, need for augments and utilization of revision components.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eThere were a total of 31 simultaneous ROH and TKA found in the EMR that met inclusion criteria including 23 manual and 8 RA-TKA with ROH. RA-TKA patients had significantly smaller poly sizes (p=0.017). There was a trend for decreased need for augments (p=0.544) and stems (p=0.315) in the RA-TKA group although this was not statistically significant. Postoperative flexion (p=0.973) or extension (p=0.351) at 1 year did not vary. Notably, one patient in the manual revision group required a hinged knee, and one manual patient required an MUA.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e Patients undergoing ROH and RA-TKA had a statistically significant decrease in poly size with a trend of less revision component utilization. RA may allow for more boney preservation via CT guided preoperative planning and precise boney cuts.\u003c/p\u003e","manuscriptTitle":"Robotic Assisted TKA May Allow for Smaller Poly Sizes compared to Manual TKA with Simultaneous Removal of Hardware","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-11 13:44:39","doi":"10.21203/rs.3.rs-4896732/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorAssigned","content":"","date":"2024-08-14T16:22:52+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-08-14T07:18:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Robotic Surgery","date":"2024-08-11T22:46:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-robotic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jors","sideBox":"Learn more about [Journal of Robotic Surgery](http://link.springer.com/journal/11701)","snPcode":"11701","submissionUrl":"https://submission.nature.com/new-submission/11701/3","title":"Journal of Robotic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"2774975d-eea5-49c2-b424-f1e308ee6917","owner":[],"postedDate":"September 11th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2024-09-11T13:44:39+00:00","versionOfRecord":[],"versionCreatedAt":"2024-09-11 13:44:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4896732","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4896732","identity":"rs-4896732","version":["v1"]},"buildId":"rHA-KDH7Qsr4HCuvH75dn","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}