Regional differences between the US, Scandinavia, and South Korea in patient demographics and patient-reported outcomes for primary total knee arthroplasty

  • Nicholas SauderEmail author
  • Vincent P. Galea
  • Pakdee Rojanasopondist
  • Yhan E. Colon Iban
  • Isabella Soares Florissi
  • Christian S. Nielsen
  • Andreas Kappel
  • Charles R. Bragdon
  • Henrik Malchau
  • Anders Troelsen
Knee Arthroplasty



Differences in total knee arthroplasty (TKA) patient demographics and clinical outcomes may exist between international regions, yet research is limited. The aim of this study was, therefore, to compare TKA patient demographics and patient-reported outcome measure (PROM) scores between the US, Scandinavia, and South Korea.

Materials and methods

A total of 398 TKA patients from three regions were assessed: 169 in Scandinavia (3 centers), 129 in the US (3 centers), and 100 patients in South Korea (2 centers). Regional variation in patient demographics was assessed using Kruskal–Wallis H tests. Regional variation in PROM scores from preoperative, 1-, 3- and 5-year visits was assessed using piecewise linear mixed effect models. The PROMs analyzed were a numerical rating scale for satisfaction and the Knee Osteoarthritis Outcome Score.


South Korean patients were the oldest (p < 0.001) and had the highest Charnley class (p < 0.001); US patients had the highest BMI (p < 0.001); Scandinavian patients had the lowest preoperative KL grade (p < 0.001). Scandinavian patients were associated with better preoperative and worse postoperative PROM scores. Scandinavian patients were also associated with moderately lower levels of satisfaction. These differences were lessened but remained significant after controlling for relevant demographic and surgical factors.


Regional differences were found in TKA patient demographics and PROMs between the US, Scandinavia, and South Korea. The regional differences in patient demographics support the need for more research and clear guidelines related to TKA appropriateness criteria. The better preoperative and worse postoperative Scandinavian PROM scores may have been related to their less severe KL grade but might also reflect cultural differences in how patients reflect on their health state when answering PROMs. Clinicians should be aware of these international differences in PROM scores when interpreting studies conducted in different international regions. Future studies should investigate TKA variation between more international regions and assess intraregional variation.

Level of evidence

Level III.


Total knee arthroplasty Total knee replacement Osteoarthritis Regional differences Patient-reported outcome measures Satisfaction 



We received no funding for this specific analysis. Data collection for the cohort of patients included in this study has been supported with funding from Zimmer Biomet. The institutions and Zimmer Biomet signed a standard legal study agreement whereby economic support was granted unconditionally and the manufacturer would have no influence on study design, data analysis, or publication.

Compliance with ethical standards

Conflict of interest

Authors NS, VPG, PR, YECI, ISF, CSN, AK, and CRB report no conflicts of interest. Author HM reports board membership for and stock membership in RSA Biomedical, research support from Biomet, Smith & Nephew, DePuy, Zimmer, and MAKO, and royalties from Zimmer, Biomet, Corin, and RSA Biomedical. Author AT reports paid speakership, paid consultancy, and research support from Zimmer Biomet, as well as board membership or committee appointment for the European Knee Society (EKS).

Ethical approval

Institutional review board or local ethics committee approval was obtained at each center, and at the Academic Coordinating Research Organization.

Informed consent

Informed consent was obtained from all individual participants included in the study in accordance with the declaration of Helsinki.


  1. 1.
    Healthcare Cost and Utilization Project (HCUP): Nationwide Inpatient Sample (NIS)Google Scholar
  2. 2.
    Koh IJ, Kim TK, Chang CB et al (2013) Trends in use of total knee arthroplasty in Korea from 2001 to 2010. Clin Orthop Relat Res 471:1441–1450. CrossRefPubMedGoogle Scholar
  3. 3.
    NiemeläInen MJ, MäKelä KT, Robertsson O et al (2017) Different incidences of knee arthroplasty in the Nordic countries. Acta Orthop 88:173–178. CrossRefPubMedPubMedCentralGoogle Scholar
  4. 4.
    Katz JN, Winter AR, Hawker G (2017) Measures of the appropriateness of elective orthopaedic joint and spine procedures. J Bone Jt Surg Am 99:e15. CrossRefGoogle Scholar
  5. 5.
    Escobar A, Quintana JM, Aróstegui I et al (2003) Development of explicit criteria for total knee replacement. Int J Technol Assess Health Care 19:57–70CrossRefGoogle Scholar
  6. 6.
    Escobar A, Quintana JM, Bilbao A et al (2007) Development of explicit criteria for prioritization of hip and knee replacement. J Eval Clin Pract 13:429–434CrossRefGoogle Scholar
  7. 7.
    Riddle DL, Perera RA (2017) Appropriateness and total knee arthroplasty: an examination of the American Academy of Orthopaedic Surgeons appropriateness rating system. Osteoarthr Cartil 25:1994–1998. CrossRefPubMedGoogle Scholar
  8. 8.
    Riddle DL, Ghomrawi H, Jiranek WA et al (2018) Appropriateness criteria for total knee arthroplasty: additional comments and considerations. J Bone Jt Surg Am 100:e22. CrossRefGoogle Scholar
  9. 9.
    Baumann F, Krutsch W, Worlicek M et al (2018) Reduced joint-awareness in bicruciate-retaining total knee arthroplasty compared to cruciate-sacrificing total knee arthroplasty. Arch Orthop Trauma Surg 138:273–279. CrossRefPubMedGoogle Scholar
  10. 10.
    McLean JM, Brumby-Rendell O, Lisle R et al (2018) Asymptomatic population reference values for three knee patient-reported outcomes measures: evaluation of an electronic data collection system and implications for future international, multi-centre cohort studies. Arch Orthop Trauma Surg 138:611–621. CrossRefPubMedGoogle Scholar
  11. 11.
    Scott CEH, Wade FA, MacDonald D, Nutton RW (2018) Ten-year survival and patient-reported outcomes of a medial unicompartmental knee arthroplasty incorporating an all-polyethylene tibial component. Arch Orthop Trauma Surg 138:719–729. CrossRefPubMedPubMedCentralGoogle Scholar
  12. 12.
    Gromov K, Greene ME, Sillesen NH et al (2014) Regional differences between US and Europe in radiological osteoarthritis and self assessed quality of life in patients undergoing total hip arthroplasty surgery. J Arthroplasty 29:2078–2083CrossRefGoogle Scholar
  13. 13.
    Gagnier JJ, Mullins M, Huang H et al (2017) Review: a systematic review of measurement properties of patient-reported outcome measures used in patients undergoing total knee arthroplasty. J Arthroplast 32:1688.e7–1697.e7CrossRefGoogle Scholar
  14. 14.
    Dowsey MM, Nikpour M, Dieppe P, Choong PFM (2012) Associations between pre-operative radiographic changes and outcomes after total knee joint replacement for osteoarthritis. Osteoarthr Cartil 20:1095–1102. CrossRefPubMedGoogle Scholar
  15. 15.
    den Hertog A, Gliesche K, Timm J et al (2012) Pathway-controlled fast-track rehabilitation after total knee arthroplasty: a randomized prospective clinical study evaluating the recovery pattern, drug consumption, and length of stay. Arch Orthop Trauma Surg 132:1153–1163. CrossRefGoogle Scholar
  16. 16.
    Giesinger JM, Loth FL, MacDonald DJ et al (2018) Patient-reported outcome metrics following total knee arthroplasty are influenced differently by patients’ body mass index. Knee Surg Sport Traumatol Arthrosc VO 26:3257. CrossRefGoogle Scholar
  17. 17.
    Jiang Y, Sanchez-Santos MT, Judge AD et al (2017) Primary arthroplasty: predictors of patient-reported pain and functional outcomes over 10 years after primary total knee arthroplasty: a prospective cohort study. J Arthroplast 32:92.e2–100.e2Google Scholar
  18. 18.
    Haynes J, Sassoon A, Nam D et al (2017) Younger patients have less severe radiographic disease and lower reported outcome scores than older patients undergoing total knee arthroplasty. Knee 24:663–669CrossRefGoogle Scholar
  19. 19.
    Charnley J, Halley DK (1975) Rate of wear in total hip replacement. Clin Orthop Relat Res 112:170–179CrossRefGoogle Scholar
  20. 20.
    Mj D, Robertsson O, Ryd L (2004) What’s all that noise? The effect of co-morbidity on health outcome questionnaire results after knee arthroplasty. Acta Orthop Scand 75:119–126CrossRefGoogle Scholar
  21. 21.
    Kellgren JH, Lawrence JS (1957) Radiological assessment of osteo-arthrosis. Ann Rheum Dis 16:494–502CrossRefGoogle Scholar
  22. 22.
    Abdelaziz H, Balde OM, Citak M et al (2019) Kellgren–Lawrence scoring system underestimates cartilage damage when indicating TKA: preoperative radiograph versus intraoperative photograph. Arch Orthop Trauma Surg 139:1287–1292. CrossRefPubMedGoogle Scholar
  23. 23.
    Gromov K, Korchi M, Thomsen MG et al (2014) What is the optimal alignment of the tibial and femoral components in knee arthroplasty? Acta Orthop 85:480–487. CrossRefPubMedPubMedCentralGoogle Scholar
  24. 24.
    Zalzal P, Backstein D, Gross AE, Papini M (2006) Notching of the anterior femoral cortex during total knee arthroplasty: characteristics that increase local stresses. J Arthroplast 21:737–743. CrossRefGoogle Scholar
  25. 25.
    Roos EM, Toksvig-Larsen S (2003) Knee injury and Osteoarthritis Outcome Score (KOOS)—validation and comparison to the WOMAC in total knee replacement. Health Qual Life Outcomes 1:17. CrossRefPubMedPubMedCentralGoogle Scholar
  26. 26.
    Roos EM, Roos HP, Ekdahl C, Lohmander LS (1998) Knee injury and Osteoarthritis Outcome Score (KOOS)—validation of a Swedish version. Scand J Med Sci Sports 8:439CrossRefGoogle Scholar
  27. 27.
    Guillemin F, Bombardier C, Beaton D (1993) Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol 46:1417–1432CrossRefGoogle Scholar
  28. 28.
    Fitzmaurice G, Laird N, Ware J (2011) Applied longitudinal analysis, 2nd edn. Wiley, HobokenCrossRefGoogle Scholar
  29. 29.
    Kennedy DM, Hanna SE, Stratford PW et al (2006) Preoperative function and gender predict pattern of functional recovery after hip and knee arthroplasty. J Arthroplast 21:559–566CrossRefGoogle Scholar
  30. 30.
    Kennedy DM, Stratford PW, Riddle DL et al (2008) Assessing recovery and establishing prognosis following total knee arthroplasty. Phys Ther 88:22–32. CrossRefPubMedGoogle Scholar
  31. 31.
    Nielsen CS, Nebergall A, Huddleston J et al (2018) medial overhang of the tibial component is associated with higher risk of inferior knee injury and osteoarthritis outcome score pain after knee replacement. J Arthroplast VO . CrossRefGoogle Scholar
  32. 32.
    Momoli A, Giarretta S, Modena M, Micheloni GM (2017) The painful knee after total knee arthroplasty: evaluation and management. Acta Biomed Atenei Parm 88:60–67. CrossRefGoogle Scholar
  33. 33.
    Lesh ML, Schneider DJ, Deol G et al (2000) The consequences of anterior femoral notching in total knee arthroplasty. A biomechanical study. J Bone Jt Surg Am 82-A:1096–1101CrossRefGoogle Scholar
  34. 34.
    Seon JK, Park JK, Jeong MS et al (2011) Correlation between preoperative and postoperative knee kinematics in total knee arthroplasty using cruciate retaining designs. Int Orthop 35:515–520. CrossRefPubMedGoogle Scholar
  35. 35.
    King SW, Lamb JN, Cage ES, Pandit H (2018) Periprosthetic femoral fractures following total hip and total knee arthroplasty. Maturitas 117:1–5CrossRefGoogle Scholar
  36. 36.
    Sugitani K, Arai Y, Takamiya H et al (2015) Factors affecting range of motion after total knee arthroplasty in patients with more than 120 degrees of preoperative flexion angle. Int Orthop VO 39:1535. CrossRefGoogle Scholar
  37. 37.
    Sarmah SS, Patel S, Reading G et al (2012) Periprosthetic fractures around total knee arthroplasty. Ann R Coll Surg Engl 94:302–307. CrossRefPubMedPubMedCentralGoogle Scholar
  38. 38.
    Hoorntje A, Witjes S, Koenraadt KLM et al (2018) More severe preoperative Kellgren–Lawrence grades of knee osteoarthritis were partially associated with better postoperative patient-reported outcomes in TKA patients. J Knee Surg. CrossRefPubMedGoogle Scholar
  39. 39.
    Verra WC, van den Boom LGH, Jacobs WCH et al (2015) Similar outcome after retention or sacrifice of the posterior cruciate ligament in total knee arthroplasty. Acta Orthop 86:195–201. CrossRefPubMedPubMedCentralGoogle Scholar
  40. 40.
    American Academy of Orthopaedic Surgeons (2019) American Joint Replacement Registry annual report 2018Google Scholar
  41. 41.
    Dowsey MM, Choong PFM, Paxton EW et al (2018) Body mass index is associated with all-cause mortality after THA and TKA. Clin Orthop Relat Res 476:1139–1148. CrossRefPubMedPubMedCentralGoogle Scholar
  42. 42.
    Lübbeke A, Silman AJ, Barea C et al (2018) Mapping existing hip and knee replacement registries in Europe. Health Policy (New York) 122:548–557. CrossRefGoogle Scholar
  43. 43.
    Deshpande BR, Katz JN, Solomon DH et al (2016) Number of persons with symptomatic knee osteoarthritis in the US: impact of race and ethnicity, age, sex, and obesity. Arthritis Care Res (Hoboken) 68:1743–1750. CrossRefGoogle Scholar
  44. 44.
    Ackerman IN, Osborne RH (2012) Obesity and increased burden of hip and knee joint disease in Australia: results from a national survey. BMC Musculoskelet Disord 13:254. CrossRefPubMedPubMedCentralGoogle Scholar
  45. 45.
    Hame SL, Alexander RA (2013) Knee osteoarthritis in women. Curr Rev Musculoskelet Med 6:182–187. CrossRefPubMedPubMedCentralGoogle Scholar
  46. 46.
    McCrae RR, Terracciano A (2005) Personality profiles of cultures: aggregate personality traits. J Personal Soc Psychol VO 89:407CrossRefGoogle Scholar
  47. 47.
    Karlsdottìr A, Rispling L, Norlén G et al (2018) State of the Nordic Region 2018: immigration and integration editionGoogle Scholar
  48. 48.
    Blackwell DL, Lucas JW, Clarke TC (2014) Summary health statistics for U.S. adults: national health interview survey, 2012. Vital Health Stat 10:1–161Google Scholar
  49. 49.
    Dunlop DD, Manheim LM, Song J et al (2008) Age and racial/ethnic disparities in arthritis-related hip and knee surgeries. Med Care VO 46:200CrossRefGoogle Scholar
  50. 50.
    Robertsson O, Bizjajeva S, Fenstad AM et al (2010) Knee arthroplasty in Denmark, Norway and Sweden. A pilot study from the Nordic Arthroplasty Register Association. Acta Orthop 81:82–89. CrossRefPubMedPubMedCentralGoogle Scholar
  51. 51.
    Statistics Korea Korean Statistical Information ServiceGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Nicholas Sauder
    • 1
    Email author
  • Vincent P. Galea
    • 1
  • Pakdee Rojanasopondist
    • 1
  • Yhan E. Colon Iban
    • 1
  • Isabella Soares Florissi
    • 1
  • Christian S. Nielsen
    • 2
  • Andreas Kappel
    • 3
  • Charles R. Bragdon
    • 1
    • 4
  • Henrik Malchau
    • 1
    • 4
  • Anders Troelsen
    • 2
  1. 1.Harris Orthopaedic LaboratoryMassachusetts General HospitalBostonUSA
  2. 2.Department of Orthopedic SurgeryCopenhagen University HospitalHvidovreDenmark
  3. 3.Department of Orthopaedic SurgeryAalborg University HospitalAalborgDenmark
  4. 4.Department of Orthopaedic SurgeryHarvard Medical SchoolBostonUSA

Personalised recommendations