Robot-assisted unicompartmental knee arthroplasty can reduce radiologic outliers compared to conventional techniques

Autoři: Kwan Kyu Park aff001;  Chang Dong Han aff001;  Ick-Hwan Yang aff001;  Woo-Suk Lee aff001;  Joo Hyung Han aff001;  Hyuck Min Kwon aff001
Působiště autorů: Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea aff001
Vyšlo v časopise: PLoS ONE 14(12)
Kategorie: Research Article
prolekare.web.journal.doi_sk: 10.1371/journal.pone.0225941



The aim of this study was to compare the clinical and radiologic outcomes of robot-assisted unicompartmental knee arthroplasty (UKA) to those of conventional UKA in Asian patients.


Fifty-five patients underwent robot-assisted UKA and 57 patients underwent conventional UKA were assessed in this study. Preoperative and postoperative range of motion (ROM), American Knee Society (AKS) score, Western Ontario McMaster University Osteoarthritis Index scale score (WOMAC), and patellofemoral (PF) score values were compared between the two groups. The mechanical femorotibial angle (mFTA) and Kennedy zone were also measured. Coronal alignments of the femoral and tibial components and posterior slopes of the tibial component were compared. Additionally, polyethylene (PE) liner thicknesses were compared.


There was no significant difference between the two groups regarding postoperative ROM, AKS, WOMAC and PF score. Robot group showed fewer radiologic outliers in terms of mFTA and coronal alignment of tibial and femoral components (p = 0.022, 0.037, 0.003). The two groups showed significantly different PE liner thicknesses (8.4 ± 0.8 versus 8.8 ± 0.9, p = 0.035). Robot group was the only influencing factor for reducing radiologic outlier (postoperative mFTA) in multivariate model (odds ratio: 2.833, p = 0.037).


In this study, robot-assisted UKA had many advantages over conventional UKA, such as its ability to achieve precise implant insertion and reduce radiologic outliers. Although the clinical outcomes of robot-assisted UKA over a short-term follow-up period were not significantly different compared to those of conventional UKA, longer follow-up period is needed to determine whether the improved radiologic accuracy of the components in robotic-assisted UKA will lead to better clinical outcomes and improved long-term survival.

Klíčová slova:

Computed axial tomography – Knees – Medical implants – Orthopedic surgery – Osteoarthritis – Robotics – Surgical and invasive medical procedures


1. Suggs JF, Li G, Park SE, Sultan PG, Rubash HE, Freiberg AA. Knee biomechanics after UKA and its relation to the ACL—a robotic investigation. J Orthop Res. 2006;24: 588–594. doi: 10.1002/jor.20082 16514655

2. Pongcharoen B, Chanalithichai N. Clinical outcomes of patients with residual medial osteophytes following mobile bearing unicompartmental knee arthroplasty. PLoS One. 2018;13: e0205469. doi: 10.1371/journal.pone.0205469 30308011

3. Kwon HM, Yang IH, Lee WS, Yu ARL, Oh SY, Park KK. Reliability of Intraoperative Knee Range of Motion Measurements by Goniometer Compared with Robot-Assisted Arthroplasty. J Knee Surg. 2019;32: 233–238. doi: 10.1055/s-0038-1641140 29618145

4. Price AJ, Webb J, Topf H, Dodd CA, Goodfellow JW, Murray DW, et al. Rapid recovery after oxford unicompartmental arthroplasty through a short incision. J Arthroplasty. 2001;16: 970–976 doi: 10.1054/arth.2001.25552 11740750

5. Gunston FH. Polycentric knee arthroplasty. Prosthetic simulation of normal knee movement. J Bone Joint Surg Br. 1971;53: 272–277 5578223

6. Bin Abd Razak HR, Acharyya S, Tan SM, Pang HN, Tay KD, Chia SL, et al. Predictors of Midterm Outcomes after Medial Unicompartmental Knee Arthroplasty in Asians. Clin Orthop Surg. 2017;9: 432–438. doi: 10.4055/cios.2017.9.4.432 29201296

7. Kwon HM, Kang KT, Kim JH, Park KK. Medial unicompartmental knee arthroplasty to patients with a ligamentous deficiency can cause biomechanically poor outcomes. Knee Surg Sports Traumatol Arthrosc. 2019. doi: 10.1007/s00167-019-05636-7 31346669

8. Insall J, Aglietti P. A five to seven-year follow-up of unicondylar arthroplasty. J Bone Joint Surg Am. 1980;62: 1329–1337 7440612

9. Maduekwe UI, Zywiel MG, Bonutti PM, Johnson AJ, Delanois RE, Mont MA. Scientific evidence for the use of modern unicompartmental knee arthroplasty. Expert Rev Med Devices. 2010;7: 219–239. doi: 10.1586/erd.09.65 20214428

10. Kayani B, Konan S, Pietrzak JRT, Huq SS, Tahmassebi J, Haddad FS. The learning curve associated with robotic-arm assisted unicompartmental knee arthroplasty: a prospective cohort study. Bone Joint J. 2018;100-B: 1033–1042. doi: 10.1302/0301-620X.100B8.BJJ-2018-0040.R1 30062950

11. Hernigou P, Deschamps G. Alignment influences wear in the knee after medial unicompartmental arthroplasty. Clin Orthop Relat Res. 2004: 161–165 doi: 10.1097/01.blo.0000128285.90459.12 15232443

12. Lyons MC, MacDonald SJ, Somerville LE, Naudie DD, McCalden RW. Unicompartmental versus total knee arthroplasty database analysis: is there a winner? Clin Orthop Relat Res. 2012;470: 84–90. doi: 10.1007/s11999-011-2144-z 22038173

13. A WD, Robertsson O, Lidgren L, Miller L, Davidson D, Graves S. Unicompartmental knee arthroplasty in patients aged less than 65. Acta Orthop. 2010;81: 90–94. doi: 10.3109/17453671003587150 20175656

14. Riddle DL, Jiranek WA, McGlynn FJ. Yearly incidence of unicompartmental knee arthroplasty in the United States. J Arthroplasty. 2008;23: 408–412. doi: 10.1016/j.arth.2007.04.012 18358380

15. Banks SA. Haptic robotics enable a systems approach to design of a minimally invasive modular knee arthroplasty. Am J Orthop (Belle Mead NJ). 2009;38: 23–27 19340380

16. Buckup K, Linke LC, Hahne V. Minimally invasive implantation and computer navigation for a unicondylar knee system. Orthopedics. 2007;30: 66–69 17824338

17. Citak M, Suero EM, Citak M, Dunbar NJ, Branch SH, Conditt MA, et al. Unicompartmental knee arthroplasty: is robotic technology more accurate than conventional technique? Knee. 2013;20: 268–271. doi: 10.1016/j.knee.2012.11.001 23201147

18. Mofidi A, Plate JF, Lu B, Conditt MA, Lang JE, Poehling GG, et al. Assessment of accuracy of robotically assisted unicompartmental arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2014;22: 1918–1925. doi: 10.1007/s00167-014-2969-6 24744171

19. Song EK, N M, Lee SH, Na BR, Seon JK. Comparison of Outcome and Survival After Unicompartmental Knee Arthroplasty Between Navigation and Conventional Techniques With an Average 9-Year Follow-Up. J Arthroplasty. 2016;31: 395–400. doi: 10.1016/j.arth.2015.09.012 26454570

20. Lonner JH. Robotically Assisted Unicompartmental Knee Arthroplasty with a Handheld Image-Free Sculpting Tool. Orthop Clin North Am. 2016;47: 29–40. doi: 10.1016/j.ocl.2015.08.024 26614918

21. Bell SW, Anthony I, Jones B, MacLean A, Rowe P, Blyth M. Improved Accuracy of Component Positioning with Robotic-Assisted Unicompartmental Knee Arthroplasty: Data from a Prospective, Randomized Controlled Study. J Bone Joint Surg Am. 2016;98: 627–635. doi: 10.2106/JBJS.15.00664 27098321

22. Batailler C, White N, Ranaldi FM, Neyret P, Servien E, Lustig S. Improved implant position and lower revision rate with robotic-assisted unicompartmental knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2019;27: 1232–1240. doi: 10.1007/s00167-018-5081-5 30066017

23. Blyth MJG, Anthony I, Rowe P, Banger MS, MacLean A, Jones B. Robotic arm-assisted versus conventional unicompartmental knee arthroplasty: Exploratory secondary analysis of a randomised controlled trial. Bone Joint Res. 2017;6: 631–639. doi: 10.1302/2046-3758.611.BJR-2017-0060.R1 29162608

24. Motesharei A, Rowe P, Blyth M, Jones B, Maclean A. A comparison of gait one year post operation in an RCT of robotic UKA versus traditional Oxford UKA. Gait Posture. 2018;62: 41–45. doi: 10.1016/j.gaitpost.2018.02.029 29524796

25. Dretakis K, Igoumenou VG. Outcomes of robotic-arm-assisted medial unicompartmental knee arthroplasty: minimum 3-year follow-up. Eur J Orthop Surg Traumatol. 2019;29: 1305–1311. doi: 10.1007/s00590-019-02424-4 30915553

26. Deese JM, Gratto-Cox G, Carter DA, Sasser TM Jr., Brown KL. Patient reported and clinical outcomes of robotic-arm assisted unicondylar knee arthroplasty: Minimum two year follow-up. J Orthop. 2018;15: 847–853. doi: 10.1016/j.jor.2018.08.018 30140132

27. Plate JF, Mofidi A, Mannava S, Smith BP, Lang JE, Poehling GG, et al. Achieving accurate ligament balancing using robotic-assisted unicompartmental knee arthroplasty. Adv Orthop. 2013;2013: 837167. doi: 10.1155/2013/837167 23634304

28. Kim TK, Phillips M, Bhandari M, Watson J, Malhotra R. What Differences in Morphologic Features of the Knee Exist Among Patients of Various Races? A Systematic Review. Clin Orthop Relat Res. 2017;475: 170–182. doi: 10.1007/s11999-016-5097-4 27704318

29. Ho JPY, Merican AM, Hashim MS, Abbas AA, Chan CK, Mohamad JA. Three-Dimensional Computed Tomography Analysis of the Posterior Tibial Slope in 100 Knees. J Arthroplasty. 2017;32: 3176–3183. doi: 10.1016/j.arth.2017.04.060 28579444

30. Chiu KY, Zhang SD, Zhang GH. Posterior slope of tibial plateau in Chinese. J Arthroplasty. 2000;15: 224–227 doi: 10.1016/s0883-5403(00)90330-9 10708090

31. Khattak MJ, Umer M, Davis ET, Habib M, Ahmed M. Lower-limb alignment and posterior tibial slope in Pakistanis: a radiographic study. J Orthop Surg (Hong Kong). 2010;18: 22–25. doi: 10.1177/230949901001800105 20427828

32. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the Knee Society clinical rating system. Clin Orthop Relat Res. 1989: 13–14 2805470

33. Laupacis A, Bourne R, Rorabeck C, Feeny D, Wong C, Tugwell P, et al. The effect of elective total hip replacement on health-related quality of life. J Bone Joint Surg Am. 1993;75: 1619–1626 doi: 10.2106/00004623-199311000-00006 8245054

34. Feller JA, Bartlett RJ, Lang DM. Patellar resurfacing versus retention in total knee arthroplasty. J Bone Joint Surg Br. 1996;78: 226–228 8666630

35. Kennedy WR, White RP. Unicompartmental arthroplasty of the knee. Postoperative alignment and its influence on overall results. Clin Orthop Relat Res. 1987: 278–285 3608312

36. Murray DW, Liddle AD, Dodd CA, Pandit H. Unicompartmental knee arthroplasty: is the glass half full or half empty? Bone Joint J. 2015;97-B: 3–8. doi: 10.1302/0301-620X.97B10.36542 26430080

37. Lim JW, Cousins GR, Clift BA, Ridley D, Johnston LR. Oxford unicompartmental knee arthroplasty versus age and gender matched total knee arthroplasty—functional outcome and survivorship analysis. J Arthroplasty. 2014;29: 1779–1783. doi: 10.1016/j.arth.2014.03.043 24805827

38. Sarraf KM, Konan S, Pastides PS, Haddad FS, Oussedik S. Bone loss during revision of unicompartmental to total knee arthroplasty: an analysis of implanted polyethylene thickness from the National Joint Registry data. J Arthroplasty. 2013;28: 1571–1574. doi: 10.1016/j.arth.2013.02.003 23538124

39. Bruni D, Akkawi I, Iacono F, Raspugli GF, Gagliardi M, Nitri M, et al. Minimum thickness of all-poly tibial component unicompartmental knee arthroplasty in patients younger than 60 years does not increase revision rate for aseptic loosening. Knee Surg Sports Traumatol Arthrosc. 2013;21: 2462–2467. doi: 10.1007/s00167-013-2578-9 23812439

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