Validation of the Oxford Knee Score and Lower Extremity Functional Score questionnaires for use in Slovenia



With the increasing prevalence of total knee replacement (TKR) due to knee osteoarthritis, the absence of patient-reported outcome measures in Slovenia must be addressed.


(1) We cross-culturally adapted Oxford Knee Score (OKS) and Lower Extremity Functional Scale (LEFS) questionnaires to the Slovenian-speaking community. (2) We evaluated OKS and LEFS psychometric characteristics.

Patients and methods

In the first assessment (Time 1) Slovenian versions of both questionnaires (OKS-Slo and LEFS-Slo), knee pain, timed-up to go (TUG) and sit to stand (STS) tests were completed by 123 subjects (55% females), of which 78 were patients scheduled for TKR and 45 were healthy age-matched controls. The questionnaires were assessed one week apart (Time 2) to investigate the test–retest reliability, with 121 subjects (98.4%) completing second measurements.


Significant differences were observed between the two groups. Where patients had greater body mass index, they were slower in TUG, weaker in STS, had greater knee pain in both knees and scored lower on both questionnaires. Additionally, correlation analysis showed that OKS-Slo and LEFS-Slo correlated almost perfectly (correlation coefficient [CC] = .968, p < 0.001). Excellent negative correlations were observed with TUG (OKS-Slo/CC = − 0.679, p < 0.001; LEFS-Slo/CC = − 0.692, p < 0.001) and STS (OKS-Slo/CC = 0.790, p < 0.001; LEFS-Slo/CC = 0.815, p < 0.001) tests, while knee pain of affected leg correlated the most (OKS-Slo/CC = − 0.923, p < 0.001; LEFS-Slo/CC = − 0.915, p < 0.001). The Cronbach’s alpha coefficient for both the OKS-Slo and LEFS-Slo ranged between 0.87 and 0.99, while the interclass correlation coefficient was excellent; i.e., 0.99. Finally, both questionnaires proved to be unidimensional measures.


The Slovenian version of both questionnaires is feasible, valid and reliable for use in clinical studies including the older adult population in Slovenia.

Level of evidence

Level III, Diagnostic—case-control study.

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  1. 1.

    Hunter DJ, Bierma-zeinstra S (2019) Osteoarthritis. Lancet 393:1745–1759

    Article  Google Scholar 

  2. 2.

    Woolf AD, Pfleger B (2003) Burden of major musculoskeletal conditions. Bull World Health Organ 81(9):646–656

    PubMed  PubMed Central  Google Scholar 

  3. 3.

    Cross M, Smith E, Hoy D, Nolte S, Ackerman I, Fransen M et al (2014) The global burden of hip and knee osteoarthritis: estimates from the Global Burden of Disease 2010 study. Ann Rheum Dis 73:1323–1330

    Article  Google Scholar 

  4. 4.

    Srikanth VK, Fryer JL, Zhai G, Winzenberg TM, Hosmer D, Jones G (2005) A meta-analysis of sex differences prevalence, incidence and severity of osteoarthritis. Osteoarthr Cartil 13(9):769–781

    Article  Google Scholar 

  5. 5.

    Kurtz S, Ong K, Lau E, Mowat F, Halpern M (2007) Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Jt Surg Ser A 89(4):780–785

    Article  Google Scholar 

  6. 6.

    Vogrin M, Naranđa J (2010) Artroza in Endorpotetika sklepov. In: Vogrin M, Kuhta M, Naranđa J (eds) Artroza in endoprotetika sklepov. Medicinska fakulteta Univerze v Mariboru, Maribor

    Google Scholar 

  7. 7.

    Mizner PSC, Clements KE, Zeni JA, Irrgang JJ, Snyder-Mackler L (2011) Measuring functional improvement after total knee arthroplasty requires both performance-based and patient-report assessments. A longitudinal analysis of outcomes. J Arthroplasty 26(5):728–737

    Article  Google Scholar 

  8. 8.

    Paravlić, Pisot R, Simunic B (2020) Muscle-specific changes of lower extremities in the early period after total knee arthroplasty: Insight from tensiomyography. J Musculoskelet Neuronal Interact.

  9. 9.

    Ramkumar PN, Harris JD, Noble PC (2015) Patient-reported outcome measures after total knee arthroplasty: a systematic review. Bone Jt Res 4(7):120–127

    Article  Google Scholar 

  10. 10.

    Dowsey MM, Choong PFM (2013) The utility of outcome measures in total knee replacement surgery. Int J Rheumatol 2013:506518

    Article  Google Scholar 

  11. 11.

    Mehta S, Fulton A, Quach C, Thistle M, Toledo C, Evans N (2016) Measurement properties of the lower extremity functional scale: a systematic review. J Orthop Sport Phys Ther 46(3):200–216

    Article  Google Scholar 

  12. 12.

    Liow MHL, Goh GS, Pang H-N, Tay DK-J, Chia S-L, Lo N-N, et al. (2020) Should patients aged 75 years or older undergo medial unicompartmental knee arthroplasty? A propensity score-matched study. Arch Orthop Trauma Surg.

  13. 13.

    Jessing IR, Mikkelsen M, Gromov K, Husted H, Kallemose T, Troelsen A (2020) Patients with anteromedial osteoarthritis achieve the greatest improvement in patient reported outcome after total knee arthroplasty. Arch Orthop Trauma Surg 140(4):517–525

    Article  Google Scholar 

  14. 14.

    Binkley JM, Stratford PW, Lott SA, Riddle DL (1999) The Lower Extremity Functional Scale (LEFS): Scale development, measurement properties, and clinical application. Phys Ther 79(4):371–383

    PubMed  Google Scholar 

  15. 15.

    de Yébenes Prous MJG, Salvanés FR, Ortells LC (2009) Validation of questionnaires. Reumatol Clínica 5(4):171–177 (English Ed.)

    Article  Google Scholar 

  16. 16.

    Paravlić A, Pišot S, Mitić P (2018) Validation of the Slovenian version of motor imagery questionnaire 3 (MIQ-3): promising tool in modern comprehensive rehabilitation practice. Slov J Public Heal 57(4):201–210

    Article  Google Scholar 

  17. 17.

    Altman R, Asch E, Bloch D, Bole G, Borenstein D, Brandt K et al (1986) Development of criteria for the classification and reporting of osteoarthritis: classification of osteoarthritis of the knee. Arthritis Rheum 29(8):1039–1049

    Article  Google Scholar 

  18. 18.

    Jenny JY, Diesinger Y (2012) The Oxford Knee Score: compared performance before and after knee replacement. Orthop Traumatol Surg Res 98(4):409–412

    Article  Google Scholar 

  19. 19.

    Paravlic, Maffulli N, Kovac S, Pisot R. (2020). Home-based motor imagery intervention improves functional performance following total knee arthroplasty: randomized controlled trial. Manuscript submitted for publication

  20. 20.

    Paravlic PR, Marusic U (2019) Specific and general adaptations following motor imagery practice focused on muscle strength in total knee arthroplasty rehabilitation: a randomized controlled trial. PLoS ONE 14(8):1–19

    Article  Google Scholar 

  21. 21.

    Podsiadlo D, Richardson S (1991) The timed “up & go”: a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc 39(2):142–148

    Article  Google Scholar 

  22. 22.

    Boonstra MC, De Waal Malefijt MC, Verdonschot N (2008) How to quantify knee function after total knee arthroplasty? Knee 15(5):390–395

    Article  Google Scholar 

  23. 23.

    Paravlić A, Marušič U, Gerževič M, Urzi F, Šimunič B (2016) The effects of different exercise-based interventions on functional fitness of older adults. Annales Kinesiologiae 7:117–137

    Google Scholar 

  24. 24.

    Hopkins (2000) Measures of reliability in sports medicine and science. Sport Med 30(1):1–15

    Article  Google Scholar 

  25. 25.

    Landis JR, Koch GG (1977) Landis amd Koch1977_agreement of categorical data. Biometrics 33(1):159–174

    Article  Google Scholar 

  26. 26.

    Tuğay BU, Tuğay N, Güney H, Kinikli GI, Yüksel I, Atilla B (2016) Oxford knee score: cross-cultural adaptation and validation of the turkish version in patients with osteoarthritis of the knee. Acta Orthop Traumatol Turc 50(2):198–206

    PubMed  Google Scholar 

  27. 27.

    Xie F, Li SC, Lo NN, Yeo SJ, Yang KY, Yeo W et al (2007) Cross-cultural adaptation and validation of Singapore English and Chinese Versions of the Oxford Knee Score (OKS) in knee osteoarthritis patients undergoing total knee replacement. Osteoarthr Cartil 15(9):1019–1024

    Article  Google Scholar 

  28. 28.

    Reito A, Järvistö A, Jämsen E, Skyttä E, Remes V, Huhtala H et al (2017) Translation and validation of the 12-item Oxford knee score for use in Finland. BMC Musculoskelet Disord 18(1):1–6

    Article  Google Scholar 

  29. 29.

    Eun IS, Kim OG, Kim CK, Lee HS, Lee JS (2013) Validation of the korean version of the oxford knee score in patients undergoing total knee arthroplasty knee. Clin Orthop Relat Res 471(2):600–605

    Article  Google Scholar 

  30. 30.

    Cruz-Díaz D, Lomas-Vega R, Osuna-Pérez MC, Hita-Contreras F, Fernández ÁD, Martínez-Amat A (2014) The Spanish lower extremity functional scale: a reliable, valid and responsive questionnaire to assess musculoskeletal disorders in the lower extremity. Disabil Rehabil 36(23):2005–2011

    Article  Google Scholar 

  31. 31.

    Jenny JY, Diesinger Y (2011) Validation of a French version of the Oxford knee questionnaire. Orthop Traumatol Surg Res 97(3):267–271

    Article  Google Scholar 

  32. 32.

    Haverkamp D, Breugem SJM, Sierevelt IN, Blankevoort L, Van Dijk CN (2005) Translation and validation of the Dutch version of the Oxford 12-item knee questionnaire for knee arthroplasty. Acta Orthop 76(3):347–352

    Article  Google Scholar 

  33. 33.

    Naal FD, Impellizzeri FM, Sieverding M, Loibl M, von Knoch F, Mannion AF et al (2009) The 12-item Oxford Knee Score: cross-cultural adaptation into German and assessment of its psychometric properties in patients with osteoarthritis of the knee. Osteoarthr Cartil 17(1):49–52

    Article  Google Scholar 

  34. 34.

    Citaker S, Kafa N, Hazar Kanik Z, Ugurlu M, Kafa B, Tuna Z (2016) Translation, cross-cultural adaptation and validation of the Turkish version of the Lower Extremity Functional Scale on patients with knee injuries. Arch Orthop Trauma Surg 136(3):389–395

    Article  Google Scholar 

  35. 35.

    Takeuchi R, Sawaguchi T, Nakamura N, Ishikawa H, Saito T, Goldhahn S (2011) Cross-cultural adaptation and validation of the Oxford 12-item knee score in Japanese. Arch Orthop Trauma Surg 131(2):247–254

    Article  Google Scholar 

  36. 36.

    Dunbar MJ, Robertsson O, Ryd L, Lidgren L (2000) Translation and validation of the Oxford-12 Item Knee Score for use in Sweden. Acta Orthop Scand 71(3):268–274

    Article  Google Scholar 

  37. 37.

    Gonçalves RS, Tomás AM, Martins DI (2012) Cross-cultural adaptation and validation of the Portuguese version of the Oxford Knee Score (OKS). Knee 19(4):344–347

    Article  Google Scholar 

  38. 38.

    Padua R, Zanoli G, Ceccarelli E, Romanini E, Bondì R, Campi A (2003) The Italian version of the Oxford 12-item knee questionnaire—cross-cultural adaptation and validation. Int Orthop 27(4):214–216

    Article  Google Scholar 

  39. 39.

    Brenninkmeijer V, Van Yperen N (2003) How to conduct research on burnout: advantages and disadvantages of a unidimensional approach in burnout research. Occup Environ Med 60(Suppl 1):i54–61

    Google Scholar 

  40. 40.

    Dawson J, Fitzpatrick R, Murray D, Carr A (1996) Questionnaire on the perceptions of patients about total hip replacement. J Bone Jt Surg 78(5):856

    Google Scholar 

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The authors would like to thank the participants in the study. The authors also thank orthopaedic surgeon Dr Simon Kovač for organising and managing the daily and initial screenings of the patients and all other involved orthopaedic specialists and staff of Valdoltra Orthopaedic Hospital.

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Correspondence to Armin H. Paravlic.

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Paravlic, A.H., Pisot, S., Mitic, P. et al. Validation of the Oxford Knee Score and Lower Extremity Functional Score questionnaires for use in Slovenia. Arch Orthop Trauma Surg (2020).

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  • Psychometric properties
  • Self-reported measures
  • Osteoarthritis
  • Quality of life
  • Physical function