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1 Reliability and Responsiveness of the Lower Extremity Functional Scale and the Anterior Knee Pain Scale in Patients With Anterior Knee Pain Cynthia J. Watson, PT, OCS 1 Micah Propps, PT 2 Jennifer Ratner, PT 3 David L. Zeigler, PT, MS, ATC, FAAOMPT 4 Patricia Horton, PT 5 Susan S. Smith, PT, PhD 6 Study Design: Prospective methodological study of repeated measures using a sample of consecutive patients. Objective: To determine the test-retest reliability and responsiveness of the Anterior Knee Pain Scale (AKPS) and the Lower Extremity Functional Scale (LEFS) in patients with anterior knee pain. Background: Anterior knee pain is one of the most common orthopedic complaints affecting the knee. Yet there is currently no self-report outcome measure that has well-established reliability and responsiveness, specifically for this population. As a result, clinicians and researchers may be making inappropriate conclusions regarding patient outcomes by using questionnaires that are misleading. Methods and Measures: This multisite study involved 30 patients from 4 outpatient physical therapy clinics in Dallas, TX (24 women, 6 men; age range, years; mean ± SD age, 35.2 ± 9.1 years). Patients receiving physical therapy for a chief complaint of anterior knee pain completed the AKPS and LEFS at their initial appointment and again 2 to 3 days later. Upon completion of physical therapy, the patients completed the AKPS, LEFS, and a global rating of change form. The treating therapist also completed a global rating of change form at the patient s final visit. The mean of the patient s and therapist s global rating of change was used as the criterion measure of change. Results: Test-retest reliability was high for both questionnaires (ICC 2,1 = 0.95 for the AKPS and 0.98 for the LEFS). A significant correlation was found between the criterion measure of change and both questionnaires. Receiver-operating characteristic curve analysis revealed that both questionnaires were moderately responsive with the area under the curve slightly higher for the LEFS (0.77) than the AKPS (0.69). 1 Graduate Student, School of Physical Therapy, Texas Woman s University, Dallas, TX. 2 Senior Therapist, Parkland Memorial Health & Hospital System, Dallas, TX. 3 Senior Therapist, University of Texas Department of Physical Medicine & Rehabilitation, Dallas, TX. 4 Owner/Partner, The Institute for Sports and Spine Rehabilitation, Plano, TX. 5 Outpatient Coordinator, St Paul Medical Center, Dallas, TX. 6 Associate Professor, Programs in Rehabilitation Sciences, Drexel University, Philadelphia, PA. This project was funded in part by the Orthopedic Section of the American Physical Therapy Association. This study received approval from the following Institutional Review Boards: St. Paul Medical Center, The University of Texas Southwestern Medical Center, and Texas Woman s University. Address correspondence to Cynthia Watson, 101 Wood Spring Road, Gwynedd Valley, PA Watson_Cynthia@hotmail.com Conclusion: The LEFS and the AKPS both demonstrated high test-retest reliability and appear to be moderately responsive to clinical change in patients with anterior knee pain. Reliability and responsiveness were slightly higher in the LEFS than the AKPS. Further research is needed to determine if these measures could be modified, or new measures created, to produce an even more sensitive tool for this population. J Orthop Sports Phys Ther 2005;35: Key Words: iliotibial band syndrome, outcome measures, patellofemoral pain syndrome, patellar tendinitis Anterior knee pain is one of the most common musculoskeletal complaints affecting the knee. 1,16,23 Despite the high prevalence of this condition, there is currently no self-report functional outcome measure with well-established reliability and responsiveness specifically for this population. 10 Clinicians and researchers are currently using a variety of conditionspecific questionnaires (eg, the Lysholm Knee Rating Scale, Cin- 136 Journal of Orthopaedic & Sports Physical Therapy

2 cinnati Knee Rating System) 6,12-14,18 and/or questionnaires that are broad in scope (eg, The Medical Outcome Study 36-Item Short Form). 4,11 However, these were not designed specifically for patients with anterior knee pain. Without a valid self-report measure of function, not only is it difficult to compare results, but it is possible that inappropriate conclusions are being made about the efficacy of treatment. 3 A reliable and responsive self-report outcome measure is needed for patients with anterior knee pain to guide clinical treatment and to determine treatment efficacy in clinical trials, which may ultimately lead to determining the most cost-effective care for these individuals. Several questionnaires have been described in the literature as designed to measure function in the individual with anterior knee pain. 6,10,12-14,18,22 Unfortunately, the measurement properties of these instruments in patients with anterior knee pain have not been reported. Although all of these questionnaires have been purportedly designed for patients with anterior knee pain, their content is highly variable. Harrison et al 10 surveyed physical therapists and sports medicine physicians to determine the content validity of patellofemoral pain syndrome outcome measures. Those clinicians recommended measurement of pain and disability during the following activities: walking, running, ascending and descending stairs, kneeling, squatting, jumping, and prolonged sitting. 10 The first questionnaire we tested was the Anterior Knee Pain Scale (AKPS), a self-report measure that was introduced by Kujala et al 14 in The AKPS contains all but 1 of the functional activities (kneeling) recommended by Harrison et al 10 (Appendix 1). Kujala et al 14 tested their questionnaire on 4 groups of female subjects with the following conditions: control (n = 17), anterior knee pain (n = 16), patellar subluxation (n = 16), and patellar dislocation (n = 19). Their results indicated a significant difference between the AKPS scores of all the patient groups compared to the control group. 14 They also concluded that certain questions distinguished the study groups from one another. 14 While these authors suggested that some of the questions were effective in determining differences among the groups, they did not describe the responsiveness or reliability of the AKPS. Because the AKPS had good content validity and demonstrated the ability to differentiate controls from patients with anterior knee pain, we hypothesized that it would be reliable and responsive in patients with anterior knee pain. The second questionnaire we tested in a population of patients with anterior knee pain was the Lower Extremity Functional Scale (LEFS), which was introduced in 1999 by Binkley et al 4 (Appendix 2). The LEFS also contains all of the functional activities recommended by Harrison et al, 10 with the exception of kneeling. In the study by Binkley et al 4 the LEFS was administered to 107 patients with a wide variety of lower extremity dysfunctions (hip osteoarthritis, ankle fracture, total knee replacement, etc). Testretest reliability was measured by having the patients complete the questionnaire at their initial appointment and again 24 to 48 hours later. 4 Responsiveness of the LEFS was measured by comparing actual scores on the questionnaire with a criterion measure of external prognostic ratings. 4 The LEFS was found to have excellent reliability (r =.94). The construct validity and responsiveness were supported by correlations with the SF-36 and prognostic scores, respectively. 4 The authors concluded that the LEFS was reliable, valid, and responsive for use in patients with lower extremity musculoskeletal dysfunction. 4 It is possible that a questionnaire designed specifically to measure functional limitations in individuals with anterior knee pain would be more sensitive to clinical changes than the LEFS in patients with anterior knee pain. We chose to study the LEFS because it has good content validity for persons with anterior knee pain and does not include extraneous questions on symptoms such as giving way, locking, or effusion. It is also easy to administer and score. The purpose of our study was to determine the test-retest reliability and responsiveness of the LEFS and AKPS in patients with anterior knee pain. Our hypothesis was that the AKPS and LEFS would both demonstrate high test-retest reliability. We also hypothesized that the AKPS, which was developed specifically for individuals with anterior knee pain, would be a superior measure of clinical change in this population. METHODS Subjects Thirty patients (24 women, 6 men) with a physician referral to physical therapy were selected consecutively. The data were collected from November 2000 through May 2003 at 4 separate outpatient clinics in Dallas, TX. Subjects ranged in age from 16 to 50 years, with a mean ± SD age of 35.2 ± 9.1 years. All patients completed a signed informed consent prior to participation in the study. This study received Institutional Review Board approval from all of the participating institutions, which were The University of Texas Southwestern Medical Center, St Paul Medical Center, and Texas Woman s University. To be included in the study, subjects had a chief complaint of anterior knee pain for which they were referred to physical therapy. We defined anterior knee pain as pain in the anterior region of the knee related to patellofemoral and/or peripatellar pathology. 17 Reid suggests that peripatellar conditions (eg, patellar tendinitis, iliotibial band syndrome, RESEARCH REPORT J Orthop Sports Phys Ther Volume 35 Number 3 March

3 quadriceps tendinitis, and Osgood Schlatter s disease) are types of anterior knee pain that are similarly aggravated by repeated knee flexion and extension activity. 17 Not only are these peripatellar conditions aggravated by similar functional activities, but they are not typically associated with intra-articular signs and symptoms such as locking, giving way, or effusion. 17 In our study, therapists were instructed that patients with any of the following pathoanatomical diagnoses could be included in the study: patellofemoral pain syndrome, patellar tendinitis, plica syndrome, patellar subluxation/dislocation, iliotibial band syndrome, Osgood Schlatter s disease, distal quadriceps femoris muscle strain/contusion, or patellar fat pad inflammation. Various etiologies of anterior knee pain were included because a questionnaire with broader application is more likely to be employed regularly by clinicians. 3 Subjects over 50 years old were excluded to reduce the likelihood of osteoarthritis, which the authors felt might present with clinical symptoms that were not addressed by the anterior knee pain questionnaires. Subjects were excluded from the study if they did not speak English or were unable to read the questionnaires. Subjects were also excluded if there was evidence of ligamentous instability, internal derangement, or bony pathology in the knee within the last year. Based on the above criteria, 8 subjects were excluded from participation in this study. All subjects were referred by a physician with a chief complaint of anterior knee pain related to patellofemoral pain syndrome and/or peripatellar dysfunction. To stratify our subjects further, we asked the treating therapists to provide their clinical impressions of the specific pathoanatomical cause of pain using a nonstandardized physical examination, patient history, and review of available medical and/or radiological records. Of the subjects who did participate, the therapists described 21 with patellofemoral pain syndrome, 3 with iliotibial band syndrome, 2 with patellar tendinitis, and 1 with each of the following conditions: distal quadriceps strain, distal quadriceps contusion, fat pad inflammation, and plica syndrome (Table 1). Out of the 30 subjects, 15 reported that they were taking nonsteroidal antiinflammatory medication during the study, 13 reported that they were not, and 2 subjects left that question blank. TABLE 1. Subject characteristics. Subject Age (y) Sex Diagnosis Duration of Symptoms (mo) Involved Limb (Right, Left) 1 34 F PFPS 2 N 2 38 F PFPS 24 R Y 3 42 F PFPS 11 L Y 4 36 F Quadriceps strain 2 L Y 5 49 F PFPS 2 L N 6 32 F ITB R N 7 16 M PFPS 12 R N 8 23 F PFPS 1 L N 9 48 F Patellar tendinitis 4 R Y F Plica 1 R Y F PFPS 5 R Y F Quadriceps contusion 4 L N M ITB 4 L N F Patellar tendinitis 3 R M PFPS 18 L N M ITB 2 L Y F PFPS L M PFPS 24 R N M PFPS Y F PFPS 6 L N F PFPS 6 R Y F PFPS 12 R N F PFPS 3 R Y F FP Infl 7 R N F PFPS 4 R Y F PFPS 24 R Y F PFPS 12 R Y F PFPS 6 L Y F PFPS 3 R N F PFPS 24 R Y NSAIDs* Abbreviations: F, female; FP Infl, fat pad inflammation; ITB, iliotibial band syndrome; L, left; N, no; PFPS, patellofemoral pain syndrome; R, right; Y, yes. * Nonsteroidal anti-inflammatory drugs. 138 J Orthop Sports Phys Ther Volume 35 Number 3 March 2005

4 The duration of the patients conditions ranged from 1 to 24 months, with a mean of 8.4 months. Of the 28 subjects who indicated the involved side of their knee pain, 14 reported right, 8 reported left, and 6 reported bilateral symptoms. In the cases of bilateral knee pain, only 1 side was used so that subjects could more easily differentiate between the 2 knees when answering questions related to functional limitations. The more involved knee, which was determined by taking the 1 with the lowest mean score on the initial AKPS and LEFS, was used in our study. Of the 30 subjects who started the study, 6 subjects did not complete the final set of questionnaires due to attrition. This left 24 knees for analysis of the responsiveness of the questionnaires. The reliability of the questionnaires was judged using a sample of 22 knees. Out of the initial 30 knees included in the study, 8 did not have accurate completion of the follow-up questionnaire (2 to 3 days after the initial evaluation). Typically, the subjects had too much time between the initial and follow-up questionnaire (greater than 3 days), making the data ineligible based on our procedures (see below). Procedures The absence or presence of the inclusion and exclusion criteria was ascertained by the treating physical therapist via patient interview, review of the medical and/or radiological records, and by physical examination at the initial physical therapy evaluation. Participating subjects completed the AKPS and LEFS in random order at the initial physical therapy evaluation and again 2 to 3 days later. Subjects completed the AKPS and LEFS again at their final visit to physical therapy. The AKPS contains 13 questions (some weighted more heavily than others) for a total possible score of 100 points (Appendix 1). The LEFS contains 20 equally weighted questions for a total possible score of 80 points (Appendix 2). Subjects were not given any assistance in completing the questionnaires. Physical therapy intervention was not controlled, because the purpose of this study was solely to examine the measurement properties of the questionnaires. At the final physical therapy visit, the treating physical therapist and the subject independently completed a global rating of change form 20 (Appendix 3). The global rating of change form asks 2 basic questions: (1) How would you say you are doing today compared with your first visit to physical therapy? and (2) How important would you say this change is? The therapist s version of question 1 substituted the patient in place of you. On the global rating form, the subject/therapist may select no change, better, or worse. If he/she selects better or worse, a 15-point ( 7 to 7) scale is provided to indicate the degree of improvement or worsening (eg, from a tiny bit to a very great deal ). 20 The therapist s and the subject s global rating of change scores are then averaged to give an overall change score, which was used in this study as the criterion standard of change 20 (Figure 1). Data Analysis An intraclass correlation coefficient (ICC 2,1 ) was used to calculate test-retest reliability using the initial and follow-up (2 to 3 days later) questionnaire scores. 4,5,9 The minimal detectable change (MDC) was calculated using the test-retest reliability coefficient to estimate the standard error of measurement (SEM) for the difference score. The SEM was the baseline SD multiplied by the square root of 1 R, where R is the test-retest reliability. 2 Christensen and Mendoza 7 recommend multiplying the 1 R by 2, because when analyzing a change score, 2 samples are used (initial and follow-up questionnaires), each with inherent measurement error. The formula to calculate the MDC is given below, where 1.96 represents the appropriate z value for the 95% confidence interval 2 : MDC 95 = 1.96 SD base 2(1 R). Responsiveness of the questionnaires was analyzed 2 ways. First we employed a Spearman rank-order correlation coefficient between the questionnaire change score (final minus initial questionnaire score) and the criterion score, which are both considered ordinal data. Alpha was set at the.05 level (2-tailed). Second, we calculated receiver-operating characteristic (ROC) curves also using the questionnaire change score and the criterion score. In both of these statistical procedures, the average of the patient s and clinician s ratings of change and importance of change was used as the criterion standard of change 21 (Table 2). In plotting the ROC curve, the criterion Number Change in Overall Global Rating Scores FIGURE 1. Sampling distribution of global rating of change (GRC) scores. RESEARCH REPORT J Orthop Sports Phys Ther Volume 35 Number 3 March

5 TABLE 2. Global ratings of change scores. Subject Therapist Rating of Change Therapist Importance of Change Subject Rating of Change Subject Importance of Change Overall Global Rating of Change* * Criterion score obtained by averaging the patient s and clinician s ratings of change and the importance of change. scores were dichotomized to identify those subjects who experienced a clinically meaningful reduction of symptoms. 20,21 Based on previous research, we chose global change scores of less than or equal to 5 to represent unimportant change and scores of greater than 5 to represent important change. 21 Confidence intervals (CI) for the sensitivity and specificity values were estimated using the procedure described by Simel et al 19 (Table 4). RESULTS Test-retest reliability was ICC 2,1 = 0.95 for the AKPS and ICC 2,1 = 0.98 for the LEFS. A significant correlation was found between the criterion score and both the LEFS change score (r s = 0.44, P.03) and the AKPS change score (r s = 0.42, P.04). ROC curve analysis revealed that the area under the curve was 0.77 (95% CI = ) for the LEFS and 0.69 (95% CI = ) for the AKPS (Figure 2). The standard error values were 0.10 for the LEFS and 0.11 for the AKPS (Table 3). The minimal detectable change (MDC) for the LEFS was 8 and the MDC for the AKPS was 13 (CI = 95%). DISCUSSION Reliability is a critical characteristic of an outcome questionnaire. 3,9,20 A questionnaire must exhibit stability, rendering similar scores when taken repeatedly over time, provided that a patient s condition has not changed. Another critical characteristic of a functional questionnaire is responsiveness 3,9,20 (sensitivity to change), which is the ability of the score to reflect meaningful changes in a patient s condition over time. 15 Responsiveness is a component of test validity. 15 Test-retest reliability was high for both the AKPS and the LEFS, indicating that these measures provide stable scores when given to patients over a short period of time and little to no change is expected in their condition. Both the correlational and ROC analyses indicate that the LEFS and AKPS were responsive to changes in a patient s condition over time. The ROC analysis requires that subjects be dichotomized to distinguish between those who experienced a clinically meaningful change and those who did not (we used a global-rating cut point of greater than 5). Setting the cut point is largely based on clinical judgment of what represents meaningful 140 J Orthop Sports Phys Ther Volume 35 Number 3 March 2005

6 change. Stratford et al 20 suggest that a cut point on the ROC curve that produces similar findings to those of the correlational analysis is favored because the correlational analysis preserves a higher level of measurement on the criterion standard. Our correlational analyses and ROC curves both indicated that the questionnaires were responsive, suggesting that the use of a cut point greater than 5 on the ROC curve is appropriate for this population. The area under the ROC curve can be interpreted as an indication of both the sensitivity and specificity of a given measure. 9,15,20,21 The larger the area under the curve, the better the questionnaire s ability to distinguish between those patients who underwent a clinically important change from those who did not. 21 Sensitivity and specificity coefficients for selected points on the ROC curve are provided in Table 4. Clinicians should also consider the MDC, which conveys the number of points a particular questionnaire must change to be confident that a true change has occurred in the patient s functional status. 3 The AKPS (100-point scale) has an MDC of 14, which means that a change of 14 points or greater is required to reflect a true change in the patient s condition. The LEFS (80-point scale) has an MDC of 8. Thus, a more subtle change in the LEFS score is indicative of a true change in the patient s condition. The LEFS was slightly more responsive than the AKPS. The better responsiveness of the LEFS may be related to both the number and nature of the questions on the questionnaire. There are 13 questions on the AKPS and 20 on the LEFS. While both the AKPS and the LEFS ask patients to describe their ability during walking, stair climbing, squatting, running, prolonged sitting, and hopping/jumping, the LEFS goes on to include other functional activities such as housework/work activities, getting in and out of the bath and a car, etc. Neither questionnaire includes a question related to kneeling, which was recommended by clinical experts in the study by Harrison et al. 10 The AKPS includes a few questions that may be considered less meaningful to most patients with anterior knee pain, such as limp, support, swelling, flexion deficiency, and patellar subluxations. The LEFS also includes a few questions that may not be as pertinent to this population, such as rolling over in bed, putting on shoes and socks, and walking between rooms. The directions given to the patient at the beginning of each questionnaire may also lead the patient to focus their responses differently. The AKPS instructs the patient to circle the latest choice which corresponds to your knee symptoms, while the LEFS instructs the patient to describe the amount of difficulty they are having with each activity. The focus of the AKPS on symptoms may lead the patient to emphasize pain rather than function. Another feature that may increase responsiveness of the LEFS is that each question has 5 possible responses ranging from extreme difficulty or unable to perform activity to no difficulty. A wider range of choices may lend itself to detecting more subtle increases or decreases in the patient s function. In contrast, the AKPS offers only 3 to 4 possible responses on the majority of questions. Another feature of a questionnaire that should be considered is ease of usage. 3,8 A questionnaire should be easy to administer, requiring little explanation by the therapist and minimal time to complete by the patient. In our study, the patient was simply handed the questionnaires with no further instruction given by the therapist. We were surprised to find that even under those conditions, there were no instances of blank answers or written comments on the LEFS. Alternately, 4.4% of questions on the AKPS were either left blank or had comments written in the adjacent margins. The questions on the AKPS that most frequently posed a problem for patients were those that included wording such as atrophy of thigh, flexion deficiency, and abnormal kneecap movements (subluxations). In addition to ease of Sensitivity FIGURE 2. Receiver-operating characteristic (ROC) curve for the anterior knee pain scale (AKPS) and the lower extremity functional scale (LEFS). TABLE 3. Summary statistics for the lower extremity functional scale (LEFS) and the anterior knee pain scale (AKPS). Questionnaire Intraclass Correlation Confident (ICC 2,1 ) AKPS Change Score Correlation LEFS Specifity Receiver- Operating Characteristic (ROC) Curve area LEFS AKPS RESEARCH REPORT J Orthop Sports Phys Ther Volume 35 Number 3 March

7 TABLE 4. Selected coordinates of the receiver-operating characteristic curves. LEFS Change Score (Discharge-Initial) Sensitivity 95% CI Specificity 95% CI AKPS Change Score (Discharge-Initial) Sensitivity 95% CI Specificity 95% CI Abbreviations: AKPS, Anterior Knee Pain Scale; CI, confidence interval; LEFS, Lower Extremity Functional Scale. administration, we felt that the LEFS was easier to score than the AKPS, which may enhance utilization in clinical practice. 3 Both questionnaires demonstrated high reliability and were moderately responsive in our population of patients with anterior knee pain. Binkley et al 4 also determined that the LEFS was reliable and responsive; however, their subjects were older (mean age, 44 years) and had more acute conditions (mean duration, 6 weeks) throughout the lower extremity. In generalizing our results, clinicians should consider that our sample was comprised primarily of patients with a clinical diagnosis of patellofemoral pain syndrome and a smaller number of subjects with peripatellar conditions, including iliotibial band syndrome, patellar tendinitis, plica, fat pad inflammation, and distal quadriceps strain. Our results are also primarily applicable to a population of subjects with chronic anterior knee pain, as the mean duration of symptoms for the patients in this study was 8.4 months. In deciding which existing questionnaires to test in this study, we placed a lot of emphasis on whether or not the questionnaires included functional questions meaningful to persons with anterior knee pain (eg, stair climbing, prolonged sitting, etc). In hindsight, it is probably equally important that the questionnaire not have superfluous questions. A questionnaire that is specifically designed for anterior knee pain should not include questions that are rarely applicable to this population (eg, use of assistive device, effusion, locking, limping, etc). It is a challenge to develop a questionnaire that not only contains focused, pertinent questions to ensure responsiveness, but also has broad application. A questionnaire that can be used on multiple diagnoses is more likely to be used in the clinic because clinicians do not want to keep up with a multitude of questionnaires for the different patients they treat. Thus, it is important that a questionnaire designed specifically for patients with anterior knee pain be applied to homogeneous conditions that produce similar functional losses. In this study we originally defined anterior knee pain to include patellofemoral pain syndrome, patellar subluxation/dislocation, iliotibial band syndrome, patellar tendinitis, patellar fat pad inflammation, distal quadriceps femoris contusion/strain, and plica syndrome. In retrospect, patellar subluxation/ dislocation should probably not be included because these conditions may be associated with effusion, giving way, and/or locking. (Our sample actually did not include any patients with patellar dislocation/ subluxation). In an effort to further preserve the homogeneity among our patients, we excluded subjects over 50 years old. Subjects over 50 years old have a higher incidence of intra-articular degenerative changes, which we felt would present with different functional limitations than those of the typical patient with patellofemoral or peripatellar conditions. The sample in this study was relatively small and composed primarily of patients with the diagnosis of patellofemoral pain syndrome. Further research is warranted to determine if existing questionnaires could be modified or new questionnaires developed that would be even more responsive to clinical changes in this population. Ultimately, physical therapists will provide more cost-effective care to patients with anterior knee pain if they have a valid and reliable questionnaire to gauge treatment efficacy. 142 J Orthop Sports Phys Ther Volume 35 Number 3 March 2005

8 CONCLUSION A variety of self-report outcome measures for patients with anterior knee pain have been described in the medical literature. Thus far, the measurement properties of these questionnaires, specifically on patients with anterior knee pain, were largely unknown. Our data indicate that the LEFS and AKPS have high test-retest reliability and appear to be moderately responsive to clinical change in patients with anterior knee pain. The LEFS was slightly more reliable and responsive than the AKPS. Further studies are indicated to determine if these or other existing questionnaires could be modified to produce an even more sensitive tool for this population. REFERENCES 1. Arroll B, Ellis-Pegler E, Edwards A, Sutcliffe G. Patellofemoral pain syndrome. A critical review of the clinical trials on nonoperative therapy. Am J Sports Med. 1997;25: Beaton DE, Katz JN, Fossel AH, Wright JG, Tarasuk V, Bombardier C. Measuring the whole or the parts? Validity, reliability, and responsiveness of the Disabilities of the Arm, Shoulder and Hand outcome measure in different regions of the upper extremity. J Hand Ther. 2001;14: Binkley FM. Measurement of functional status, progress and outcome in orthopedic clinical practice. Orthop Div Rev. 1999;Sept/Oct: Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. North American Orthopaedic Rehabilitation Research Network. Phys Ther. 1999;79: Chatman AB, Hyams SP, Neel JM, et al. The Patient- Specific Functional Scale: measurement properties in patients with knee dysfunction. Phys Ther. 1997;77: Chesworth BM, Culham EG, Tata GE, Peat M. Validation of outcome measures in patients with patellofemoral syndrome. J Orthop Sports Phys Ther. 1989;11: Christensen L, Mendoza JL. A method of assessing change in a single subject: an alteration of the RC index. Behav Ther. 1986;17: Delitto A. Subjective measures and clinical decision making. Phys Ther. 1989;69: Deyo RA, Diehr P, Patrick DL. Reproducibility and responsiveness of health status measures. Statistics and strategies for evaluation. Control Clin Trials. 1991;12:142S-158S. 10. Harrison E, Magee D, Quinney H. Development of a clinical tool and patient questionnaire for evaluation of patellofemoral pain syndrome patients. Clin J Sport Med. 1996;6: Jette DU, Jette AM. Physical therapy and health outcomes in patients with knee impairments. Phys Ther. 1996;76: Kannus P, Niittymaki S. Which factors predict outcome in the nonoperative treatment of patellofemoral pain syndrome? A prospective follow-up study. Med Sci Sports Exerc. 1994;26: Karlsson J, Thomee R, Sward L. Eleven year follow-up of patello-femoral pain syndrome. Clin J Sport Med. 1996;6: Kujala UM, Jaakkola LH, Koskinen SK, Taimela S, Hurme M, Nelimarkka O. Scoring of patellofemoral disorders. Arthroscopy. 1993;9: Portney KG, Watkins MP. Foundations of Clinical Research: Applications to Practice. Upper Saddle River, NJ: Prentice Hall Health; Powers CM. Rehabilitation of patellofemoral joint disorders: a critical review. J Orthop Sports Phys Ther. 1998;28: Reid D. The myth, mystic, and frustration of anterior knee pain. Clin J Sport Med. 1993;3: Shea KP, Fulkerson JP. Preoperative computed tomography scanning and arthroscopy in predicting outcome after lateral retinacular release. Arthroscopy. 1992;8: Simel DL, Samsa GP, Matchar DB. Likelihood ratios with confidence: sample size estimation for diagnostic test studies. J Clin Epidemiol. 1991;44: Stratford PW, Binkley FM, Riddle DL. Health status measures: strategies and analytic methods for assessing change scores. Phys Ther. 1996;76: Stratford PW, Binkley J, Solomon P, Gill C, Finch E. Assessing change over time in patients with low back pain. Phys Ther. 1994;74: Thomee R, Renstrom P, Karlsson J, Grimby G. Patellofemoral pain syndrome in young women. I. A clinical analysis of alignment, pain parameters, common symptoms and functional activity level. Scand J Med Sci Sports. 1995;5: Wilk KE, Davies GJ, Mangine RE, Malone TR. Patellofemoral disorders: a classification system and clinical guidelines for nonoperative rehabilitation. J Orthop Sports Phys Ther. 1998;28: RESEARCH REPORT J Orthop Sports Phys Ther Volume 35 Number 3 March

9 Appendix APPENDIX 1 Anterior Knee Pain Scale For each question, circle the latest choice (letter) which corresponds to your knee symptoms. 1. Limp (a) None (5) (b) Slight or periodical (3) (c) Constant (0) 2. Support (a) Full support without pain (5) (b) Painful (3) (c) Weight bearing impossible(0) 3. Walking (a) Unlimited (5) (b) More than 2 km* (3) (c) 1-2 km* (2) (d) Unable (0) 4. Stairs (a) No difficulty (10) (b) Slight pain when descending (8) (c) Pain both when descending and ascending (5) (d) Unable (0) 5. Squatting (a) No difficulty (5) (b) Repeated squatting painful (4) (c) Painful each time (3) (d) Possible with partial weight bearing (2) (e) Unable (0) 6. Running (a) No difficulty (10) (b) Pain after more than 2 km* (8) (c) Slight pain from start (6) (d) Severe pain (3) (e) Unable (0) 7. Jumping (a) No difficulty (10) (b) Slight difficulty (7) (c) Constant pain (2) (d) Unable (0) 8. Prolonged sitting with the knees flexed (a) No difficulty (10) (b) Pain after exercise (8) (c) Constant pain (6) (d) Pain forces to extend knees temporarily (4) (e) Unable (0) 9. Pain (a) None (10) (b) Slight and occasional (8) (c) Interferes with sleep (6) (d) Occasionally severe (4) (e) Constant and severe (0) 10. Swelling (a) None (10) (b) After severe exertion (8) (c) After daily activities (6) (d) Every evening (4) (e) Constant (0) 11. Abnormal kneecap (patellar) movements (subluxations) (a) None (10) (b) Occasionally in sports activities (6) (c) Occasionally in daily activities (4) (d) At least one documented dislocation (2) (e) More than two dislocations (0) 12. Atrophy of thigh (a) None (5) (b) Slight (3) (c) Severe (0) 13. Flexion deficiency (a) None (5) (b) Slight (3) (c) Severe (0) * 1 km = 5/8 mile. To score, sum the circled responses. Reprinted from Kujala et al, The Journal of Arthroscopic and Related Surgery, Vol 9(2), Scoring of Patellofemoral Disorders, pp , 1993, with permission from Arthroscopy Association of North America. 144 J Orthop Sports Phys Ther Volume 35 Number 3 March 2005

10 APPENDIX 2 Lower Extremity Functional Scale We are interested in knowing whether you are having difficulty at all with the activities listed below because of your lower limb problem for which you are currently seeking attention. Please provide an answer for each activity. Today, do you or would you have any difficulty at all with: (Circle one number on each line) Extreme Difficulty or Unable to Perform Quite a Bit of Difficulty Moderate Difficulty A Little Bit of Difficulty No Difficulty Activities a. Any of your usual work, housework or school activities b. Your usual hobbies, recreational or sporting activities c. Getting into or out of the bath d. Walking between rooms e. Putting on your shoes or socks f. Squatting g. Lifting an object, like a bag of groceries from the floor h. Performing light activities around your home i. Performing heavy activities around your home j. Getting into or out of a car k. Walking 2 blocks l. Walking a mile m. Going up or down 10 stairs (about one flight) n. Standing for 1 hour o. Sitting for 1 hour p. Running on even ground q. Running on uneven ground r. Making sharp turns while running s. Hopping u. Rolling over in bed Column Totals: Score: /80 To score, sum the circled responses. Reprinted from Binkley et al. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. North American Orthopaedic Rehabilitation Research Network. Physical Therapy. 1999;79: With permission of the American Physical Therapy Association. This material is copyrighted, and any further reproduction or distribution is prohibited. RESEARCH REPORT J Orthop Sports Phys Ther Volume 35 Number 3 March

11 APPENDIX 3 Global Rating of Change Form (Therapist) 1. How would you say the patient is today compared with the visit when he/she first completed the knee pain questionnaires? (circle your choice) No Change Worse Better 1 A tiny bit, almost the same 1 2 A little bit 2 3 Somewhat 3 4 Moderately 4 5 Quite a bit 5 6 A great deal 6 7 A very great deal 7 2. How important would you say this change is? (circle your choice) No Change Worse Better 1 A tiny bit, almost the same 1 2 A little bit 2 3 Somewhat 3 4 Moderately 4 5 Quite a bit 5 6 A great deal 6 7 A very great deal 7 (The patient s version is the same as above except that the words this patient is are replaced with the words you are. To score, sum the circled responses.) Reprinted from Stratford, PW et al. Assessing Change Over Time in Patients with Low Back Pain, Physical Therapy, 1994, 74(6): With permission of the American Physical Therapy Association. This material is copyrighted, and any further reproduction or distribution is prohibited. 146 J Orthop Sports Phys Ther Volume 35 Number 3 March 2005