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Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)

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General Description

Purpose

To assess pain, stiffness, and physical function in patients with hip and / or knee osteoarthritis (OA)1

Content

The WOMAC consists of 24 items divided into 3 subscales:

  • Pain (5 items): during walking, using stairs, in bed, sitting or lying, and standing
  • Stiffness (2 items): after first waking and later in the day
  • Physical Function (17 items): stair use, rising from sitting, standing, bending, walking, getting in / out of a car, shopping, putting on / taking off socks, rising from bed, lying in bed, getting in / out of bath, sitting, getting on / off toilet, heavy household duties, light household duties

Developer/contact information

  • Nicholas Bellamy, Centre of National Research on Disability and Rehabilitation medicine, University of Queensland, Department of Medicine, Level 3, Mayne Medical School, Herston Road, Brisbane Queensland 4006, Australia. Email: n.bellamy@uq.edu.au.
  • Requests to use the WOMAC and for User Guides can be submitted at: www.womac.org

Number of items in scale

24 items

Versions:

  • The WOMAC is available in 5-point Likert-type and 100mm Visual Analog formats1.
  • The WOMAC has been validated for telephone2 and computerized / electronic3, 4 administration.
  • Short forms of the WOMAC function subscale have been developed, but these have not been extensively used or validated5-8. Validation of a proposed WOMAC short form for patients with hip osteoarthritis. Bilbao A, Quintana JM, Escobar A, Las Hayas C, Orive M. Health Qual Life Outcomes. 2011 Sep 21;9:75
  • The WOMAC is available in over 65 alternate language forms, including: Arabic9, Chinese10, Dutch11, Finnish12, French-Canadian13-15, German16-18, Hebrew19, Italian20, Korean21, Moroccan22, Spanish23, 24, Swedish25, 26, Thai27, and Turkish28, 29.

Populations

The WOMAC was developed for use among patients with knee and / or hip OA, but it has been used among patients with different conditions, including: low back pain30, rheumatoid arthritis31, juvenile rheumatoid arthritis32, systemic lupus erythematosus33, and fibromyalgia31. The WOMAC has been extensively used in both observational / epidemiological studies and to examine changes following treatments including pharmacotherapy, arthroplasty, exercise, physical therapy, knee bracing, and acupuncture.

WHO ICF Components34

b28016 (pain in joints), b289 (sensation of pain, other specified and unspecified), b134 (sleep functions), b7603 (supportive functions of arm or leg), b7800 (sensation of muscle stiffness),b7808 (sensations related to muscles and movement functions, other specified), d4100 (lying down), d4101 (squatting), d4103 (sitting), d4105 (bending), d4150 (maintaining a lying position, d4153 (maintaining a sitting position), d4154 (maintaining a standing position), d4400 (picking up), d4102 (transferring oneself while lying), d450 (walking), d4500 (walking short distances),d4501 (walking long distances), d4502 (walking on different surfaces), d4551 (climbing), d4559 (moving around unspecified), d498 (mobility, other specified), d5101 (washing whole body), d530 (toileting), d5402 (putting on footwear), d5403 (taking off footwear), d6200 (shopping), d699 (domestic life, unspecified), d9208 (recreation and leisure, unspecified), d6408 (doing housework)

Administration

Method

Patient report questionnaire can be completed in person, over the telephone, or by computer.

The use of the WOMAC has also been validated for delivery via mobile phone (m-WOMAC). Osteoarthritis Index delivered by mobile phone (m-WOMAC) is valid, reliable, and responsive. Bellamy N, Wilson C, Hendrikz J, Whitehouse SL, Patel B, Dennison S, Davis T; EDC Study Group.J Clin Epidemiol. 2011 Feb;64(2):182-90. Epub 2010 Jul 6.

Training:

Minimal instruction needed. User guide available1.

Time to administer/complete

Approximately 12 minutes.

Equipment needed

Copy of instrument. Ruler, if using Visual Analog format.

Availability/cost

The WOMAC is a proprietary health status questionnaire protected by copyright and trademark. To obtain permission to use the WOMAC for research purposes, a request can be submitted at www.womac .org. Licensing processes and costs are determined on the basis of information specific to each research project.

Scoring

Responses

Scale. The Likert Scale version uses the following descriptors for all items: none, mild moderate, severe, and extreme. These correspond to an ordinal scale of 0-4. The 100mm Visual Analog version uses anchors of no pain/stiffness/difficulty and extreme pain/stiffness/difficulty.

Score Range. On the Likert Scale version, the scores are summed for items in each subscale, with possible ranges as follows: pain=0-20, stiffness=0-8, physical function=0-68. On the Visual Analog version, a ruler is used to measure the distance (in mm) from the left end marker to the patient's mark. For each item, the possible range of scores is therefore 0-100. Items are summed for each subscale, resulting in possible ranges as follows: pain=0-500, stiffness=0-200, physical function=0-1700. Most commonly, a total WOMAC score is created by summing the items for all three subscales. However, other methods of aggregating scores have been used1.

Interpretation of Scores

Higher scores on the WOMAC indicate worse pain, stiffness, and functional limitations.

Method of Scoring

The WOMAC is typically scored by hand, using the conventions described above.

Time to Score

5-10 minutes

Training to score

Minimal. User Guide provides instructions1.

Training to interpret

Minimal.

Norms available

There are no clear norms available.

Psychometric Information

Reliability

Internal consistency. In a small randomized controlled trial of 2 nonsteroidal anti-inflammatory drugs among patients with knee and hip OA (N = 57), Cronbach's alphas for the Likert Scale format of the WOMAC were 0.86-0.89, 0.90-0.91, and 0.95 for the pain, stiffness, and function subscales, respectively35. In the same study, Cronbach's alphas for the Visual Analog format were 0.7.-0.81 for pain and 0.89-0.91 for function (not calculated for the stiffness subscale). Among patients in the Swedish Knee Arthroplasty Registry (n=1,014), Cronbach's alphas were 0.91 for pain and stiffness and 0.98 for physical function36. Overall, results support the internal consistency of the WOMAC subscales37.

Test-retest. In the clinical trial of nonsteroidal anti-inflammatory drugs for patients with hip or knee OA (n=57)35, with a 1-week interval, Kendall's TAU-C for Likert Scale formats were 0.68, 0.48, and 0.68 for pain, stiffness, and function subscales, respectively, and 0.68 for the total score. Corresponding values for the Visual Analog format were 0.64, 0.61, 0.72, and 0.64. Among patients with arthroscopically assessed knee OA (n=52), the test-retest reliability (intraclass correlation coefficients; ICC's) were 0.74, 0.58, and 0.92, for pain, stiffness, and physical function subscales, respectively26. In the Swedish Knee Arthroplasty Registry, Intraclass Correlations (ICC's; n=1,014) over a 3-week period were 0.95, 0.90, and 0.92 for pain, stiffness, and function, respectively36. Adequate test-retest reliability has also been confirmed for the German and Swedish versions of the WOMAC 16, 25. Overall, test-retest reliability of the WOMAC pain subscale has been variable across studies but generally meets the minimum standard; test-retest reliability has been more consistent and stronger for the physical function subscale, but the stiffness subscale has shown low test-retest reliability37.

Rater. In a study of patients undergoing hip arthroplasty (n=78), in which the WOMAC was administered by an interviewer, ICCs for intra-rater reliability ranged from 0.53-0.78 and for inter-rater reliability, 0.62-0.9738.

Validity

Content/face. Development of the WOMAC involved expert opinion (including rheumatologists and epidemiologists), reviews of existing instruments, and surveys of patients with hip and / or knee OA39.

Factorial / domain. The factor structure of the WOMAC has been confirmed in some studies of patients with hip and knee OA31, 40 (n = 317 & 2,205). However, one study of patients with hip and knee OA awaiting arthroplasty (n= 474) failed to support a single-item solution for the pain subscale41. Other studies have shown that items on the physical function subscale did not load unequivocally on that factor, and some items from the pain and physical function subscales tended to load together on a factor13, 42-45 (n =66-474). High correlations and overlapping items between the pain and physical function subscales45-47 may pose measurement problems. Specifically, it has been argued that the ability of the WOMAC physical function scale to detect change may be particularly limited in situations where there is a low correlation or “mismatch” between physical function and pain severity45, 47.

Criterion. Two studies found statistically significant Spearman correlations between patient satisfaction with knee arthroplasty and WOMAC pain (r =0.67, 0.55), stiffness (r =0.63, 0.56), and function (r =0.64, 0.48) subscales48, 49 (n =108 & 1,104). In another study, patients who were satisfied with knee arthroplasty had better WOMAC total, pain, and physical function scores than those who were not satisfied50 (n=1,193).

Construct. The WOMAC has been shown to distinguish well between patients with better vs. worse outcomes from knee arthroplasty50, patients with post-traumatic knee OA vs. normal controls51, and patients with mild / moderate vs. severe knee OA52. Several studies have shown that WOMAC and SF-36 subscales with similar constructs have moderate to high correlations, while lower correlations were observed between subscales with less similar constructs38, 52, 53. The WOMAC has shown significant Spearman correlations with performance scores for walking, stair climbing, rising from a chair, and joint range of motion among older adults with knee and hip OA54.

Sensitivity / Responsiveness. The WOMAC has been extensively used in the context of clinical trials. Prior reviews have summarized the performance of the WOMAC with respect to responsiveness in these trials37, 55.

Overall, studies have shown that the WOMAC pain and function subscales exhibit comparable or greater responsiveness to change than corresponding SF-36 subscales38, 52, 53, 56, 57. Responsiveness varies according to subscales and type of intervention37.

Clinically Important Differences

In a study of patients with hip and knee OA undergoing comprehensive inpatient rehabilitation, the minimal clinically important differences (MCIDs) for WOMAC global and subscale scores ranged from 0.51-1.33 for worsening and 0.67-0.75 for improvement58. In a study of outpatients with knee or hip OA, the MCIDs on the WOMAC VAS format ranged from -7.9mm to -32.6mm59. Based on these two studies, investigators used three definitions of MCID to calculate the frequency of clinically important improvement in function over 30 months in Multicenter Osteoarthritis Study (MOST)participants60. The three definitions were: MCID26% (26% improvement from baseline), MCID17% (17% improvement from baseline), and MCID tertile (low, medium, and high, based on pre-specified criteria). In that study, 24-39% of participants reached MCID based on these criteria60, suggesting that a clinically important improvement is frequent in individuals with or at high risk for knee OA. MCID values must be viewed cautiously because of limitations in methodology for calculating these values and should not be considered absolute thresholds.

Comments and Critique

The WOMAC is one of the most widely utilized self-report measures of lower extremity symptoms and function. It has been studied over a period of almost 30 years in many different contexts and patient populations, and there are abundant data regarding its utility and measurement properties. Overall, studies support the adequacy of the measurement properties of the WOMAC, though two potential weaknesses have been debated. First, there is little evidence regarding the measurement properties of the stiffness subscale, and its test-retest reliability has been low37. Second, some studies have found inadequate factorial validity of the WOMAC pain and physical function subscales, potentially leading to weaknesses in the ability of the physical function subscale to detect change when there is a weak association between pain and function. Pua et al. provide an overview of this argument47, for which further exploration is warranted.

References

  1. Bellamy N. WOMAC Osteoarthritis Index User Guide. Version V. Brisbane, Australia 2002.
  2. Bellamy N, Campbell J, Hill J, Band P. A comparative study of telephone versus onsite completion of the WOMAC 3.0 Osteoarthritis Index. J Rheumatol. 2002; 29:783-786.
  3. Theiler R, Speilberger J, Bischoff HA, Bellamy N, Huber J, Kroesen S. Clinical evaluation of the WOMAC 3.0 OA Index in numeric rating scale format using a computerised touch screen version. Osteoarthritis Cartilage. 2002; 10:479-481.
  4. Bellamy N, Campbell J, Stevens J, Pilcher L, Stewart C, Mahmood Z. Validation study of a computerized version of the Western Ontario and McMaster Universities VA3.0 Osteoarthritis Index J Rheumatol. 1997;24:2413.
  5. Baron G, Tubach F, Ravaud P, Logeart I, Dougados M. Validation of a short form of the Western Ontario and McMaster Universities Osteoarthritis Index function subscale in hip and knee osteoarthritis. Arthritis Care Res. 2007; 57(4):633-638.
  6. Tubach F, Baron G, Falissard B, et al. using patients' and rheumatologists' opinions to specify a short form of the WOMAC function subscale. Ann Rheum Dis. 2005; 64:75-79.
  7. Whitehouse SL, Lingard EA, Katz JN, Learmonth ID. Development and testing of a reduced WOMAC function scale. J Bone Joint Surg Am. 2003;85-B(5):706-711.
  8. Auw Yang KG, Raijmakers NJH, Verbout AJ, Dhert WJA, Saris DBF. Validation of the short-form WOMAC function scale for the evaluation of osteoarthritis of the knee. J Bone Joint Surg Am. 2007; 89-B: 50-56.
  9. Guermazi M, Poiraudeau S, Yahia M, et al. Translation, adaptation, and validation of the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) for an Arab population: the Sfax modified WOMAC. Osteoarthritis Cartilage. 2004;12:459-468.
  10. Xie F, Li SC, Goeree R, et al. Validation of Chinese Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients scheduled for total knee replacement. Qual Life Res. 2008;17:595-601.
  11. Roorda LD, Jones CA, Waltz M, et al. Satisfactory cross cultural equivalence of Dutch WOMAC in patients with hip osteoarthritis waiting for arthroplasty. Ann Rheum Dis. 2004;63:36-42.
  12. Soininen JV, Paavolainen PO, Gronblad MA, Kaapa EH. Validation study of a Finnish version of the Western Ontario and McMasters University osteoarthritis index. Hip International. 2008;18(2):108-111.
  13. Faucher M, Poiraudeau S, Lefevre-Colau M, Rannou F, Fermanian J, Revel M. Algo-functional assessment of knee osteoarthritis: comparison of the test-retest reliability and construct validity of the WOMAC and Lequesne indexes. Osteoarthritis Cartilage. 2002;10:602-610.
  14. Choquette D, Bellamy N, Raynauld JP. A French-Canadian version of the WOMAC Osteoarthritis Index Arthritis Rheum. 1994;37 Suppl 9 S226.
  15. Parent E, Moffet H. Comparative responsiveness of locomotors tests and questionnaires used to follow early recovery after total knee arthroplasty. Arch Phys Med Rehabil. 2002;83:70-80.
  16. Stucki G, Sangha O, Stucki S, et al. Comparison of the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index and a self-report format of the self-administered Lequesne-Algofunctional index in patients with knee and hip osteoarthritis. Osteoarthritis Cartilage. 1998;6(2):79-86.
  17. Stucki G, Stucki S, Michel BA, Tyndall AG, Dick W, Theiler R. Evaluation of a German version of WOMAC (Western Ontario and McMasters Universities) Arthrosis Index. Z. Rheumatol. 1996;55:40-49.
  18. Theiler R, Sangha O, Schaeren S, et al. Superior responsiveness of the pain and function sections of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) as compared to the Lequesne-Algofunctional Index in patients with osteoarthritis of the lower extremities. Osteoarthritis Cartilage. 1999;7(6):515-519.
  19. Wigler I, Neumann L, Yaron M. Validation study of a Hebrew version of WOMAC in patients with osteoarthritis of the knee. Clin Rheumatol. 1999;18:402-405.
  20. Salaffi F, Leardini G, Canesi B, et al. Reliability and validity of the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index in Italian patients with osteoarthritis of the kneed. Osteoarthritis Cartilage. 2003;11:551-560.
  21. Bae S-C, Lee H-S, Yun HR, Kim T-H, Yoo D-H, Kim SY. Cross-cultural adaptation and validation of Korean Western Ontario and McMaster Universities (WOMAC) and Lequesne Osteoarthritis Indices for clinical research. Osteoarthritis Cartilage. 2001;9:746-750.
  22. Falk A, Benbouazza K, Amine B, et al. Translation and validation of Moroccan Western Ontario and McMaster Universities (WOMAC) osteoarthritis index in knee osteoarthritis. Rheumatol Int. 2008;28:677-683.
  23. Escobar A, Quintana JM, Bilbao A, Azkarate J, Guenaga JI. Validation of the Spanish version of the WOMAC questionnaire for patients with hip or knee osteoarthritis. Clin Rheumatol. 2002;21:466-471.
  24. Villanueva I, del Mar Guzman M, Javier Toyos F, Ariza-Ariza R, Navarro F. Relative efficiency and validity properties of a visual analog vs. a categorical scaled version of the Western Ontario and MacMaster Universities Osteoarthritis (WOMAC) Index: Spanish versions. Osteoarthritis Cartilage. 2004;12:225-231.
  25. Soderman P, Malchau H. Validity and reliability of Swedish WOMAC osteoarthritis index: a self-administered disease-specific questionnaire (WOMAC) versus generic instruments (SF-36 and NHP). Acta Orthopaedica Scandinavica 2000;71(1):39-46.
  26. Roos EM, Klassbo M, Lohmander LS. WOMAC osteoarthritis index. Reliability, validity, and responsiveness in patients with arthroscopically assessed osteoarthritis. Western Ontario and MacMaster Universities. Scand J Rheumatol. 1999;28(4):210-215.
  27. Kuptniratsaikul V, Rattanachaiyanont M. Validation of a modified Thai version of the Western Ontario and McMaster (WOMAC) osteoarthritis index for knee osteoarthritis. Clin Rheumatol. 2007;26:1641-1645.
  28. Basaram S, Guzel R, Seydaoglu G, Guler-Uysal F. Validity, reliability, and comparison of the WOMAC osteoarthritis index and Lequesne algofunctional index in Turkish patients with hip or knee osteoarthritis. Clin Rheumatol. 2010;Epub ahead of print.
  29. Tuzun EH, Eker L, Aytar A, Daskapan A, Bayramoglu M. Acceptability, reliability, validity and responsiveness of the Turkish version of WOMAC osteoarthritis index. Osteoarthritis Cartilage. 2005;13:28-33.
  30. Wolfe F. Determinants of WOMAC function, pain and stiffness scores: evidence for the role of low back pain, symptom counts, fatigue and depression in osteoarthritis, rheumatoid arthritis and fibromyalgia. Rheumatology (Oxford). 1999;38(4):355-361.
  31. Wolfe F, Kong SX. Rasch analysis of the Western Ontario MacMaster questionnaire (WOMAC) in 2205 patients with osteoarthritis, rheumatoid arthritis, and fibromyalgia. Ann Rheum Dis. 1999; 58(9):563-568.
  32. Jolles BM, Bogoch ER. Quality of life after TKA for patients with juvenile rheumatoid arthritis. Clin Orthop. 2008; 466(1):167-178.
  33. Ito H, Matsuno T, Hirayama T, Tanino H, Minami A. Health-related quality of life in patients with systemic lupus erythematosus after medium to long-term follow-up of hip arthroplasty. Lupus: 2007; 16(5):318-232.
  34. Weigl M, Cieza A, Harder M, et al. linking osteoarthritis-specific health-status measures to the International Classification of Functioning, Disability, and Health (ICF). Osteoarthritis Cartilage. 2003; 11(7):519-523.
  35. Bellamy N, Buchanan WW, Goldsmith CH, Campbell J, Stitt LW. Validation study of WOMAC: A health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. J Rheumatol. 1988; 15:1833-1840.
  36. Dunbar MJ, Robertsson O, Ryd L, Lindgren L. Appropriate questionnaires for knee arthroplasty: results of a survey of 360 patients from the Swedish knee arthroplasty registry J Bone Joint Surg Am. 2001; 83:339-344.
  37. McConnell S, Kolopack P, Davis AM. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): a review of its utility and measurement properties. Arthritis Rheum. 2001; 45(5):453-461.
  38. Wright JG, Young NL. A comparison of different indices of responsiveness. Journal of Clinical Epidemiology. 1997; 50:239-246.
  39. Bellamy N, Buchanan WW. A preliminary evaluation of the dimensionality and clinical importance of pain and disability in osteoarthrits of the hip and knee. Clin Rheumatol. 1986; 5:231-241.
  40. Angst F, Ewert T, Lehmann S, Aeschlimann A, Stucki G. The factor subdimensions of the Western Ontario and McMaster Universityies Osteoarthritis Index (WOMAC) help to specify hip and knee osteoarthritis. A prospective evaluation and validation study. J Rheumatol. 2005; 32:1324-1330.
  41. Stratford PW, Kennedy DM, Woodhouse LJ, Spadoni GF. Measurement properties of the WOMAC LK 3.1 pain scale. Osteoarthritis Cartilage. 2006; 15:266-272.
  42. Terwee CB, van der Slikke RM, van Lummel RC, Benink RJ, Meijers WG, de Vet HC. Self-reported physical functioning was more influenced by pain than performance-based physical functioning in knee osteoarthritis patients. J Clin Epidemiol. 2006; 59:724-731.
  43. Thumboo J, Chew LH, Soh CH. Validation of the Western Ontario and McMaster University Osteoarthritis Index in Asians with osteoarthritis in Singapore. Osteoarthritis Cartilage. 2001; 9:440-446.
  44. Kennedy D, Stratford PW, Pagura MC, Wessel J, Gollish JD, Woodhouse LJ. Exploring the factorial validity and clinical interpretability of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Physiother Can. 2003;55:160-168.
  45. Stratford PW, Kennedy D. Does parallel item content on WOMAC's pain and function subscales limit its ability to detect change in functional status? BMC Musculoskeletal Disorder. 2004; 5:17.
  46. Ryser L, Wright BD, Aeschlimann A, Mariacher-Gehler S, Stucki G. A new look at the Western Ontario and McMaster Universities Osteoarthritis Index using Rasch analysis. Arthritis Care Res. 1999; 12:331-335.
  47. Pua Y-H, Cowan SM, Wrigley TV, Bennell KL. Discriminant validity of the Western Ontario and McMaster Universities Osteoarthritis Index physical functioning subscale in community samples with hip osteoarthritis. Arch Phys Med Rehabil. 2009; 90:1772-1777.
  48. Bullens PHJ, van Loon CJM, de Waal Malefijt MC, Laan RFJM, Veth RPH. Patient satisfaction after total knee arthroplasty: a comparison between subjective and objective outcome assessments. J Arthroplasty. 2001; 16(6):740-747.
  49. Robertson O, Dunbar MJ. Patient satisfaction compared with general health and disease-specific questionnaires in knee arthroplasty patients. The Journal of Arthroplasty. 2001; 16(4):476-482.
  50. Bombardier C, Melfi CA, Paul J, et al. Comparison of a generic and a disease-specific measure of pain and physical function after knee replacement surgery. Med Care. 1995; 33(4 Suppl):AS131-AS144.
  51. Roos EM, Roos HP, Lohmander LS. WOMAC Osteoarthritis Index: additional dimensions for use in subjects with post-traumatic osteoarthritis of the knee. Osteoarthritis Cartilage. 1999; 7:216-221.
  52. Brazier JE, Harper R, Munro J, Walters SJ, Snaith ML. Generic and condition-specific outcome measures for people with osteoarthritis of the knee. Rheumatology (Oxford). 1999; 38(9):870-877.
  53. Davies GM, Watson DJ, Bellamy N. Comparison of the responsiveness and relative effect size of the Western Ontario and McMaster Universities Osteoarthritis Index and the Short-Form Medical Outcomes Study Survey in a randomized clinical trial of osteoarthritis patients. Arthritis Care Res. 1999; 12:172-179.
  54. Allyson JC, Voaklander DC, Johnston DWC, Suarez-Almazor M. The effect of age on pain, function, and quality of life after total hip and knee arthroplasty. Arch Intern Med. 2001;161:454-460.
  55. Rogers JC, Irrgang JJ. Measures of adult lower extremity function. Arthritis Care Res. 2003;49(5S):S67-S84.
  56. Bachmeier CJ, March LM, Cross MJ, et al. A comparison of outcomes in osteoarthritis patients undergoing total hip and knee replacement surgery. Osteoarthritis Cartilage. 2001; 9(2):137-146.
  57. Angst F, Aeschlimann A, Steiner W, Stucki G. Responsiveness of the WOMAC Osteoarthritis Index as compared with the SF-36 in patients with osteoarthritis of the legs undergoing a comprehensive rehabilitation program. Ann Rheum Dis. 2001;60:834-840.
  58. Angst F, Aeschlimann A, Stucki G. Smallest detectable and minimal clinically important differences of rehabilitation intervention with their implications for required sample sizes using WOMAC and SF-36 quality of life measurement instruments in patients with osteoarthritis of the lower extremities. Arthritis Rheum. Aug 2001; 45(4):384-391.
  59. Tubach F, Ravaud P, Baron G, et al. Evaluation of clinically relevant changes in patient reported outcomes in knee and hip osteoarthritis: the minimal clinically important improvement. Ann Rheum Dis. 2005; 64(1):29-33.
  60. White DK, Keysor JJ, Lavalley MP, et al. Clinically Important Improvement in Function Is Common in People with or at High Risk of Knee OA: The MOST Study. J Rheumatol. 2010; 37(6) 1244-1251.

CREDITS

ARHP Research Committee has reviewed this document in June 2012.

For questions or comments, contact ARHP@rheumatology.org.