Skip to main content
SpringerLink
Log in

Development of a New Knee Society Scoring System

  • Symposium: Papers Presented at the Annual Meetings of The Knee Society
  • Published:
Clinical Orthopaedics and Related Research®

Abstract

Background

The Knee Society Clinical Rating System was developed in 1989 and has been widely adopted. However, with the increased demand for TKA, there is a need for a new, validated scoring system to better characterize the expectations, satisfaction, and physical activities of the younger, more diverse population of TKA patients.

Questions/purposes

We developed and validated a new Knee Society Scoring System.

Methods

We developed the new knee scoring system in two stages. Initially, a comprehensive survey of activities was developed and administered to 101 unilateral TKA patients (53 women, 48 men). A prototype knee scoring instrument was developed from the responses to the survey and administered to 497 patients (204 men, 293 women; 243 postoperatively, 254 preoperatively) at 15 medical institutions within the United States and Canada. Objective and subjective data were analyzed using standard statistical and psychometric procedures and compared to the Knee Injury and Osteoarthritis Score and SF-12 scores for validation. Based on this analysis, minor modifications led to the new Knee Society Scoring System.

Results

We found the new Knee Society Scoring System to be broadly applicable and to accurately characterize patient outcomes after TKA. Statistical analysis confirmed the internal consistency, construct and convergent validity, and reliability of the separate subscale measures.

Conclusions

The new Knee Society Scoring System is a validated instrument based on surgeon- and patient-generated data, adapted to the diverse lifestyles and activities of contemporary patients with TKA. This assessment tool allows surgeons to appreciate differences in the priorities of individual patients and the interplay among function, expectation, symptoms, and satisfaction after TKA.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

References

  1. Anderson JG, Wixson RL, Tsai D, Stulberg SD, Chang RW. Functional outcome and patient satisfaction in total knee patients over the age of 75. J Arthroplasty. 1996;11:831–840.

    Article  PubMed  CAS  Google Scholar 

  2. Ayers DC, Franklin PD, Ploutz-Snyder R, Boisvert CB. Total knee replacement outcome and coexisting physical and emotional illness. Clin Orthop Relat Res. 2005;440:157–161.

    Article  PubMed  Google Scholar 

  3. Bach CM, Nogler M, Steingruber IE, Ogon M, Wimmer C, Göbel G, Krismer M. Scoring systems in total knee arthroplasty. Clin Orthop Relat Res. 2002;399:184–196.

    Article  PubMed  Google Scholar 

  4. Bayley KB, London MR, Grunkemeier GL, Lansky DJ. Measuring the success of treatment in patient terms. Med Care. 1995;33:AS226–AS35.

    PubMed  CAS  Google Scholar 

  5. Benjamini Y, Hochberg Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing. J R Stat Soc B. 1995;57:289–300.

    Google Scholar 

  6. Bourne RB. Measuring tools for functional outcomes in total knee arthroplasty. Clin Orthop Relat Res. 2008;466:2634–2638.

    Article  PubMed  Google Scholar 

  7. Bourne RB, Chesworth BM, Davis AM, Mahomed NN, Charron KD. Patient satisfaction after total knee arthroplasty: who is satisfied and who is not? Clin Orthop Relat Res. 2010;468:57–63.

    Article  PubMed  Google Scholar 

  8. Bourne RB, Maloney WJ, Wright JG. An AOA critical issue: the outcome of the outcomes movement. J Bone Joint Surg Am. 2004;86:633–640.

    PubMed  Google Scholar 

  9. Callahan CM, Drake BG, Heck DA, Dittus RS. Patient outcomes following tricompartmental total knee replacement: a meta-analysis. JAMA. 1994;271:1349–1357.

    Article  PubMed  CAS  Google Scholar 

  10. Chang CH, Reeve BB. Item response theory and its applications to patient-reported outcomes measurement. Eval Health Prof. 2005;28:264–282.

    Article  PubMed  Google Scholar 

  11. Chesworth BM, Mahomed NN, Bourne RB, Davis AM. Willingness to go through surgery again validated WOMAC clinically important difference from THR/TKR surgery. J Clin Epidemiol. 2008;61:907–918.

    Article  PubMed  Google Scholar 

  12. Cronbach L. Coefficient alpha and the internal structure of tests. Psychometrica. 1951;16:297–334.

    Article  Google Scholar 

  13. Davies AP. Rating systems for total knee replacement. Knee. 2002;9:261–266.

    Article  PubMed  Google Scholar 

  14. Dawson J, Fitzpatrick R, Murray D, Carr A. Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br. 1998;80:63–69.

    Article  PubMed  CAS  Google Scholar 

  15. Dunbar MJ, Robertsson O, Ryd L, Lidgren L. Appropriate questionnaires for knee arthroplasty: results of a survey of 3600 patients from The Swedish Knee Arthroplasty Registry. J Bone Joint Surg Br. 2001;83:339–344.

    Article  PubMed  CAS  Google Scholar 

  16. Franklin PD, Li W, Ayers DC. The Chitranjan Ranawat Award. Functional outcome after total knee replacement varies with patient attributes. Clin Orthop Relat Res. 2008;466:2597–2604.

    Google Scholar 

  17. Gandhi R, Davey JR, Mahomed NN. Predicting patient dissatisfaction following joint replacement surgery. J Rheumatol. 2008;35:2415–2418.

    Article  PubMed  Google Scholar 

  18. Hawker G, Wright J, Coyte P, Paul J, Dittus R, Croxford R, Katz B, Bombardier C, Heck D, Freund D. Health-related quality of life after knee replacement. J Bone Joint Surg Am. 1998;80:163–173.

    PubMed  CAS  Google Scholar 

  19. Hays RD, Morales LS, Reise SP. Item response theory and health outcomes measurement in the 21st century. Med Care. 2000;38:II28–II42.

    Article  PubMed  CAS  Google Scholar 

  20. Healy WL, Sharma S, Schwartz B, Iorio R. Athletic activity after total joint arthroplasty. J Bone Joint Surg Am. 2008;90:2245–2252.

    Article  PubMed  Google Scholar 

  21. Heck DA, Robinson RL, Partridge CM, Lubitz RM, Freund DA. Patient outcomes after knee replacement. Clin Orthop Relat Res. 1998;356:93–110.

    Article  PubMed  Google Scholar 

  22. Impellizzeri FM, Mannion AF, Leunig M, Bizzini M, Naal FD. Comparison of the reliability, responsiveness, and construct validity of 4 different questionnaires for evaluating outcomes after total knee arthroplasty. J Arthroplasty. 2011;26:861–869.

    Article  PubMed  Google Scholar 

  23. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the Knee Society Clinical Rating System. Clin Orthop Relat Res. 1989;248:13–14.

    PubMed  Google Scholar 

  24. Insall JN, Ranawat CS, Aglietti P, Shine J. A comparison of four models of total knee-replacement prostheses. J Bone Joint Surg Am. 1976;58:754–765.

    PubMed  CAS  Google Scholar 

  25. Janse AJ, Gemke RJBJ, Uiterwaal CSPM, van der Tweel I, Kimpen JL, Sinnema G. Quality of life: patients and doctors don’t always agree: a meta-analysis. J Clin Epidemiol. 2004;57:653–661.

    Article  PubMed  CAS  Google Scholar 

  26. Kline P, Auld F, Cooper C. Five new personality scales: their location in the factor space of personality measures. J Clin Psychol. 1987;43:328–336.

    Article  PubMed  CAS  Google Scholar 

  27. Kline P, Cooper C. A factorial analysis of the authoritarian personality. Br J Psychol. 1984;75:171–176.

    Article  Google Scholar 

  28. Konig A, Scheidler M, Rader C, Eulert J. The need for a dual rating system in total knee arthroplasty. Clin Orthop Relat Res. 1997;345:161–167.

    PubMed  Google Scholar 

  29. Kreibich DN, Vaz M, Bourne RB, Rorabeck CH, Kim P, Hardie R, Kramer J, Kirkley A. What is the best way of assessing outcome after total knee replacement? Clin Orthop Relat Res. 1996;331:221–225.

    Article  PubMed  Google Scholar 

  30. Kroenke K. Studying symptoms: sampling and measurement issues. Ann Intern Med. 2001;134:844–853.

    PubMed  CAS  Google Scholar 

  31. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007;89:780–785.

    Article  PubMed  Google Scholar 

  32. Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ. Future young patient demand for primary and revision joint replacement: national projections from 2010 to 2030. Clin Orthop Relat Res. 2009;467:2606–2612.

    Article  PubMed  Google Scholar 

  33. Lingard EA, Katz JN, Wright RJ, Wright EA, Sledge CB. Validity and responsiveness of the Knee Society Clinical Rating System in comparison with the SF-36 and WOMAC. J Bone Joint Surg Am. 2001;83:1856–1864.

    PubMed  Google Scholar 

  34. Mahomed NN, Liang MH, Cook EF, Daltroy LH, Fortin PR, Fossel AH, Katz JN. The importance of patient expectations in predicting functional outcomes after total joint arthroplasty. J Rheumatol. 2002;29:1273–1279.

    PubMed  Google Scholar 

  35. Mahomed NN, Sledge CB, Daltroy LH, Fossel AH, Katz JN. Self-administered satisfaction scale for joint replacement arthroplasty. J Bone Joint Surg Br. 1998;80:9.

    Google Scholar 

  36. Mancuso CA, Graziano S, Briskie LM, Peterson MG, Pellicci PM, Salvati EA, Sculco TP. Randomized trials to modify patients’ preoperative expectations of hip and knee arthroplasties. Clin Orthop Relat Res. 2008;466:424–431.

    Article  PubMed  Google Scholar 

  37. Mancuso CA, Sculco TP, Wickiewicz TL, Jones EC, Robbins L, Warren RF, Williams-Russo P. Patients’ expectations of knee surgery. J Bone Joint Surg Am. 2001;83:1005–1012.

    Article  PubMed  Google Scholar 

  38. Mäntyselkä P, Kumpusalo E, Ahonen R, Takala J. Patients’ versus general practitioners’ assessments of pain intensity in primary care patients with non-cancer pain. Br J Gen Pract. 2001;51:995–997.

    PubMed  Google Scholar 

  39. Mont MA, Marker DR, Seyler TM, Jones LC, Kolisek FR, Hungerford DS. High-impact sports after total knee arthroplasty. J Arthroplasty. 2008;23:80–84.

    Article  PubMed  Google Scholar 

  40. Nilsdotter AK, Toksvig-Larsen S, Roos EM. Knee arthroplasty: are patients’ expectations fulfilled? A prospective study of pain and function in 102 patients with 5-year follow-up. Acta Orthop. 2009;80:55–61.

    Article  PubMed  Google Scholar 

  41. Noble PC, Conditt MA, Cook KF, Mathis KB. The John Insall Award. Patient expectations affect satisfaction with total knee arthroplasty. Clin Orthop Relat Res. 2006;452:35–43.

    Google Scholar 

  42. Noble PC, Gordon MJ, Weiss JM, Reddix RN, Conditt MA, Mathis KB. Does total knee replacement restore normal knee function? Clin Orthop Relat Res. 2005;431:157–165.

    Article  PubMed  Google Scholar 

  43. Orlando M, Thissen D. Likelihood-based item-fit indices for dichotomous item response theory models. Appl Psychol Meas. 2002;24:50–64.

    Article  Google Scholar 

  44. Reeve BB, Hays RD, Bjorner J. Psychometric evaluation and calibration of health-related quality of life item banks. Med Care. 2007;45:S22–S31.

    Article  PubMed  Google Scholar 

  45. Robertsson O, Dunbar MJ. Patient satisfaction compared with general health and disease-specific questionnaires in knee arthroplasty patients. J Arthroplasty. 2001;16:476–482.

    Article  PubMed  CAS  Google Scholar 

  46. Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD. Knee Injury and Osteoarthritis Outcome Score (KOOS)—development of a self-administered outcome measure. J Orthop Sports Phys Ther. 1998;28:88–96.

    PubMed  CAS  Google Scholar 

  47. Roos EM, Toksvig-Larsen S. Knee Injury and Osteoarthritis Outcome Score (KOOS)— validation and comparison to the WOMAC in total knee replacement. Health Qual Life Outcomes. 2003;1:17.

    Article  PubMed  Google Scholar 

  48. Samejima F. Handbook of Modern Item Response Theory. New York, NY: Springer; 1997. 49.

    Google Scholar 

  49. Schmalzried TP, Szuszczewicz ES, Northfield MR, Akizuki KH, Frankel RE, Belcher G, Amstutz HC. Quantitative assessment of walking activity after total hip or knee replacement. J Bone Joint Surg Am. 1998;80:54–59.

    Article  PubMed  CAS  Google Scholar 

  50. Scuderi GR, Bourne RB, Noble PC, Benjamin JB, Lonner JH, Scott WN. The New Knee Society Knee Scoring System. Clin Orthop Relat Res. 2011. DOI:10.1007/s11999-011-2135-0.

  51. Swanson EA, Schmalzried TP, Dorey FJ. Activity recommendations after total hip and knee arthroplasty: a survey of the American Association for Hip and Knee Surgeons. J Arthroplasty. 2009;24:120–126.

    Article  PubMed  Google Scholar 

  52. The Knee Society. Outcomes assessment. Available at: https:\\www.kneesociety.org/web/outcomes.html. Accessed October 4, 2011.

  53. US Food and Drug Administration. Patient-reported outcome measures: use in medical product development to support labeling claims. 2009. Available at: http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM071975.pdf. Accessed October 4, 2011.

  54. Ware J Jr, Kosinski M, Keller SD. A 12-Item Short-Form Health Survey: construction of scales and preliminary tests of reliability and validity. Med Care. 1996;34:220–233.

    Article  PubMed  Google Scholar 

  55. Weiss JM, Noble PC, Conditt MA, Kohl HW, Roberts S, Cook KF, Gordon MJ, Mathis KB. What functional activities are important to patients with knee replacements? Clin Orthop Relat Res. 2002;404:172–188.

    Article  PubMed  Google Scholar 

  56. Wright JG. Evaluating the outcome of treatment: shouldn’t we be asking patients if they are better? J Clin Epidemiol. 2000;53:549–553.

    Article  PubMed  CAS  Google Scholar 

  57. Wright JG, Young NL. The patient-specific index: asking patients what they want. J Bone Joint Surg Am. 1997;79:974–983.

    PubMed  CAS  Google Scholar 

  58. Wylde V, Learmonth I, Potter A, Bettinson K, Lingard E. Patient-reported outcomes after fixed- versus mobile-bearing total knee replacement: a multi-centre randomised controlled trial using the Kinemax total knee replacement. J Bone Joint Surg Br. 2008;90:1172–1179.

    PubMed  CAS  Google Scholar 

Download references

Acknowledgments

The authors warmly acknowledge the contributions of Richard S. Laskin MD (deceased) to the work of The Knee Society Task Force. They also acknowledge the technical assistance of Dr Michael Conditt, Mr Uche Osadebe, Dr Maureen Dwyer, Mr Sabir Ismaily, Mr Prem Ramkumar, Mr Paul Newhouse, Mr Eugene Stone, and Ms Denise Leon in preparing the manuscript and in performing background studies in support of this work and Dianne Bryant, PhD, and Bert Chesworth, PhD, for their contributions relating to epidemiologic aspects of the study. The authors acknowledge the work of the following members of The Knee Society in contributing patients to the field evaluation of the new Knee Society Score: Keith Berend, MD; Dan Berry, MD; Kim Bertin, MD; Kevin Bozic, MD; David Dalury, MD; Terence Gioe, MD; Arlen Hanssen, MD; Steve Incavo, MD; Carlos Lavernia, MD; David Lewallen, MD; Adolph Lombardi, MD; Bassam Masri, MD; Michael Mont, MD; Mark Pagnano, MD; Michael Reis, MD; Jay Rodrigo, MD; Tad Vail, MD; and Ray Wasielewski, MD. The authors are also indebted to Dr Gerald Engh, who, as President of The Knee Society, appointed the task force to develop a new Knee Society Score, and Ms Olga Foley for organizing its meetings and activities.

Author information

Authors and Affiliations

  1. Barnhart Department of Orthopedic Surgery, Baylor College of Medicine, 6550 Fannin Street, Houston, TX, 77030, USA

    Philip C. Noble PhD

  2. Institute of Orthopedic Research and Education, Houston, TX, USA

    Adam C. Brekke BA & Daniel A. Daylamani BS

  3. Insall Scott Kelly Institute, New York, NY, USA

    Giles R. Scuderi MD, Priya Chadha MD & W. Norman Scott MD

  4. Department of Statistics and Probability, Michigan State University, East Lansing, MI, USA

    Alla Sikorskii PhD

  5. University Orthopedic Specialists, Tucson, AZ, USA

    James B. Benjamin MD

  6. Rothman Institute, Philadelphia, PA, USA

    Jess H. Lonner MD

  7. Division of Orthopaedic Surgery, University Hospital, London Health Sciences Centre, University of Western Ontario, London, ON, Canada

    Robert B. Bourne MD, FRCSC

Authors
  1. Philip C. Noble PhD
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Giles R. Scuderi MD
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Adam C. Brekke BA
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Alla Sikorskii PhD
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. James B. Benjamin MD
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Jess H. Lonner MD
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Priya Chadha MD
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Daniel A. Daylamani BS
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. W. Norman Scott MD
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Robert B. Bourne MD, FRCSC
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Philip C. Noble PhD.

Additional information

The institution of one or more of the authors (RBB, PCN) has received, in any 1 year, funding from The Knee Society. P. C. Noble certifies that he has consultancies in Zimmer Inc (Warsaw, IN, USA). G. R. Scuderi certifies that he has consultancies in Zimmer Inc and Salient Surgical Technologies (Portsmouth, NH, USA). J. H. Lonner certifies that he has consultancies in Zimmer Inc. W. N. Scott certifies he received royalties from Zimmer Inc.

All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.

This work reflects the efforts of a task force of The Knee Society.

Appendices

Appendix 1

Methodologies for Assessment of the Validity and Reliability of the Subscale Measures

The reliability and validity of the prototype instrument were assessed using classical test theory and item response theory (IRT) methods described below. These analyses were performed for the objective subscale and for each subscale of subjective measures (satisfaction, expectation, and functional activities subscales: walking and standing, standard activities, advanced activities, and discretionary activities).

Classical Test Theory Methods

Validity

The validity assessment aims at the evaluation of the systematic component of the error of measurement, which is the difference between the unobserved true score of an individual and the computed score from the instrument. Content validity reflects the adequacy of the instrument with respect to the trait being measured and is achieved by the involvement of subject matter expert in the generation and refinement of items. Factor analyses establish dimensionality of the underlying trait, that is, determine whether a single subscale score is an adequate summary of the trait. In this study, we employed exploratory factor analysis for categorical indicators since the item responses were categorical and not treated as continuous. The exploratory factor analysis assessed the dimensions into which the prototype items tap and was implemented in Mplus software (Muthen and Muthen, Los Angeles, CA, USA). Convergent validity was established by evaluating the associations between the measure under investigation and other measures of the same or related constructs. In this study, the new Knee Society Score was correlated to the individual subscales of the SF-12 (physical and mental component scores) and the Knee Injury and Osteoarthritis Score (pain, symptoms, activities of daily living, sport/recreation, quality of life).

Reliability

Methods for assessment of reliability deal with random error and include evaluation of the internal consistency reliability (Cronbach’s alpha) [12]. Values above 0.7 or 0.8 are preferred for group level measurement [44].

IRT Model

IRT analyses were used to assess the properties of items and their coverage of the underlying trait. IRT models evaluate whether a set of items can be used to measure, indirectly, a trait of interest, such as expectation, satisfaction, or activities performed by an individual. Each item in the instrument has a set of numerical values called item parameters. Ideally, the items should be chosen so that their range of difficulty covers the potential range of the trait but with small-enough increments to be able to discriminate between different levels of the trait. In other words, if the instrument is designed to measure satisfaction in the population of patients that include those who are highly satisfied and highly unsatisfied, items should be present that capture both ends of the range and the levels in between. Further, when two or more items have approximately the same location parameters, they are redundant. In this case, the item providing the highest discrimination could be kept to minimize the burden placed on respondents while preserving the measurement properties of the instrument itself. For each of the one-dimensional subscales established using factor analyses, the location and discrimination parameters of each item were evaluated using Samejima’s graded response model [10, 19, 48].

Differential Item Functioning (DIF)

In terms of IRT modeling, DIF testing stems from the requirement that item parameters are properties of items and not properties of patients who respond to these items. DIF is also known as item bias, and it occurs when there are no differences in the underlying trait between groups of patients, for example, males and females, but responses to a particular item differ between the two sexes. When this happens, the validity of measurement is jeopardized since the item measures sex and not the underlying trait. The logistic regression method of DIF testing was implemented in this study. Nonuniform DIF (ie, DIF with varying direction across levels of the trait) is present if the interaction term is significant. Comparison of models with summed score only and summed score and group yields a test for uniform DIF. The DIF analyses were carried out in two stages: initially with all items and then after censoring any items exhibiting DIF on the initial run [43]. Logistic regression analyses were performed using SAS® Version 9.2 (SAS Institute Inc, Cary, NC, USA). Since DIF analyses involved running multiple logistic regression models and multiple tests, the Benjamini-Hochberg procedure was used to control the false discovery rate [5].

Appendix 2

The New Knee Society Score: Domains and Point Allocations

Objective Knee Score (seven items; 100 points):

AP alignment (25 points)

Stability (25 points)

  • Medial/lateral (15 points)

  • Anterior/posterior (10 points)

ROM (25 points)

Symptoms (25 points)

Deductions

  • Malalignment (−10 points)

  • Flexion contracture (−2/−5/−10/−15 points)

  • Extensor lag (−5/−10/−15 points)

Satisfaction Score (five items; 40 points):

Pain level while sitting (8 points)

Pain level while lying in bed (8 points)

Knee function while getting out of bed (8 points)

Knee function while performing light household duties (8 points)

Knee function while performing leisure recreational activities (8 points)

Expectation Score (three items; 15 points):

Pain relief (5 points)

Ability to carry out activities of daily living (5 points)

Ability to perform leisure, recreational, or sport activities (5 points)

Functional Activity Score (19 items; 100 points):

Walking and standing (five items; 30 points)

Standard activities (six items; 30 points)

Advanced activities (five items; 25 points)

Discretionary activities (three items; 15 points)

About this article

Cite this article

Noble, P.C., Scuderi, G.R., Brekke, A.C. et al. Development of a New Knee Society Scoring System. Clin Orthop Relat Res 470, 20–32 (2012). https://doi.org/10.1007/s11999-011-2152-z

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11999-011-2152-z

Keywords

Search

Navigation