BRIEF REPORT 610 / Brewer, Cornelius, Van Raalte, et al. JOURNAL OF SPORT & EXERCISE PSYCHOLOGY, 2004, 26, 610-615 2004 Human Kinetics Publishers, Inc. Comparison of Concurrent and Retrospective Pain Ratings During Rehabilitation Following Anterior Cruciate Ligament Reconstruction Britton W. Brewer 1, Allen E. Cornelius 1, Judy Van Raalte 1, John C. Brickner 1, Howard Tennen 2, Joseph H. Sklar 3, John R. Corsetti 3, and Mark H. Pohlman 3 1 Springfield College; 2 University of Connecticut Health Center; 3 New England Orthopedic Surgeons The accuracy of retrospective ratings of pain intensity was examined in a sample of 72 men and 36 women undergoing rehabilitation following anterior cruciate ligament (ACL) reconstructive surgery. Participants completed daily ratings of current, worst, and average pain intensity for the first 42 days of rehabilitation. Participants provided retrospective ratings of worst and average pain intensity twice for a 7-day period (on Days 7 and 21) and once for a 30-day period (on Day 30). Correlations between concurrent and retrospective pain ranged from.74 to.88. Retrospective pain ratings consistently overestimated concurrent pain ratings, but were generally not biased by current pain. The results suggest that retrospective pain ratings can substitute for concurrent pain ratings if the tendency toward overestimation is taken into account. Key Words: bias, recall, injury, knee, symptoms Physical injury is common among sport participants (Caine, Caine, & Lindner, 1996). Sport injury is often accompanied by pain (Heil & Fine, 1999). An acute rupture of the anterior cruciate ligament (ACL) is one of the more prevalent and debilitating sport injuries (Griffin et al., 2000). Athletes sustaining a torn ACL may experience pain not only from the injury itself but also from reconstructive surgery and postoperative rehabilitation (DeCarlo, Sell, Shelbourne, & Klootwyk, 1994). Although measures of pain are generally included in assessments of ACL rehabilitation outcome (Shapiro, Richmond, Rockett, McGrath, & Donaldson, 1996; Treacy, Barron, Brunet, & Barrack, 1997), these indices are typically administered 6 months or more after surgery. Few studies have examined pain processes during ACL rehabilitation. 1 Center for Performance Enhancement and Applied Research, Dept. of Psychology, Springfield College, Springfield, MA 01109; 2 Dept. of Community Medicine and Health Care, Univ. of Connecticut School of Medicine, 263 Farmington Ave., Farmington, CT 06030-6325; 3 New England Orthopedic Surgeons, 300 Birnie Ave., Springfield, MA 01107. 610
Comparison of Pain Ratings / 611 Optimal assessment of pain during ACL rehabilitation would likely involve multiple daily measures of pain over time (Jensen & McFarland, 1993). When practical constraints prevent such an approach to data collection, retrospective pain ratings may be a feasible alternative. There is evidence that retrospective ratings of pain intensity correspond reasonably well with concurrent ratings of pain intensity for a variety of pain phenomena, including acute painful events (Singer, Kowalska, & Thode, 2001), low back pain (McGorry, Webster, Snook, & Hsiang, 1999), general musculoskeletal pain (Brauer, Thomsen, Loft, & Mikkelsen, 2003), and knee pain (Hahn, 2002). Nevertheless, retrospective reports are subject to forgetting, bias, and distortion. Recalled pain overestimated concurrently assessed pain in two studies (Breme, Altmeppen, & Taeger, 2000; Van den Brink, Bandell- Hoekstra, & Abu-Saad, 2001) and underestimated it in one study (Dawson et al., 2002). Current pain level is a factor that can influence the accuracy of retrospective pain ratings, as elevations in current pain are associated with less accurate pain recall (Brauer et al., 2003; Breme et al., 2000; Lefebvre & Keefe, 2002). The purpose of the present study was to compare concurrent and retrospective ratings of pain intensity during postsurgical ACL rehabilitation. Analyses of correspondence (strength of association) and concordance (discrepancy) between concurrent and retrospective pain ratings were conducted. The potential impact of current pain level on the accuracy of retrospectively reported pain was also examined. Method Participants Of the 120 people satisfying eligibility requirements to participate in the study (i.e., scheduled to undergo rehabilitation after ACL surgery performed by one of the three orthopedic surgeons on the project at one of three designated clinic locations), 1 person refused to participate and 11 people were no longer eligible to participate after surgery because they did not need to have an ACL reconstruction. The remaining 108 individuals (72 men and 36 women) served as participants in the study. Their mean age was 29.38 years (SD = 9.93), with a range of 14 to 54 years. With respect to race/ethnicity, 90% of the sample indicated that they were White, 6% reported that they were Hispanic (6%), 4% were Black not of Hispanic origin, and 1% were Asian/Pacific Islander. In terms of sport involvement, 47% of participants identified themselves as competitive athletes, 49% indicated they were recreational athletes, and 4% noted that they were nonathletes. Procedure As part of a larger 2-year longitudinal study on the role of behavioral factors in the postsurgical rehabilitation of ACL injuries, participants completed an informed consent document and a questionnaire requesting demographic information prior to surgery. For a 42-day period beginning on the first day of postsurgical outpatient physical therapy (typically 4 7 days postsurgery), participants completed daily ratings of pain and other variables not pertinent to this report (e.g., home rehabilitation behavior, mood, goal cognition) and returned them to the researchers in postage-paid envelopes. They were instructed to complete their ratings each night before going to bed and to mail their ratings to the researchers the next day. Three types of pain were assessed: (a) current pain; (b) worst pain expe-
612 / Brewer, Cornelius, Van Raalte, et al. rienced during the day; and (c) average pain experienced over the course of the day. All three types of pain were assessed on a scale from 0 = no pain to 10 = pain as bad as it can be, the validity of which is well documented (Jensen & Karoly, 2001). On the 7th and 21st reporting days, participants completed additional items in which they were asked to rate their average levels of worst pain and average pain experienced over the previous 7 days. On the 30th reporting day, participants were asked to rate their average levels of worst pain and average pain experienced over the previous 30 days. The same 0 to 10 scale used for the daily ratings was used for the 7- and 30-day retrospective ratings. To enhance compliance with the data collection protocol, participants were paid $1 for each completed set of daily ratings that was returned, and $7 additional for each week of full (daily) responding. From the daily report data, mean levels of average pain and worst pain were calculated for each of the three reporting periods (Days 1 7, 15 21, and 1 30) for each participant. Results Of the 13,608 possible daily pain ratings, 11,504 (84.5%) were received from participants. In accord with the recommendations of Hopkins (2000) and Uebersax (2000), we performed a series of t-tests and Pearson correlations to examine the concordance and correspondence of concurrent and retrospective ratings of average and worst pain. As shown in Table 1, concurrent pain ratings were significantly lower than the corresponding retrospective pain ratings for all three reporting periods (Days 1 7, 15 21, and 1 30) and both types of pain. Similarly, strong positive correlations (r =.74 to.89) were found between the concurrent and retrospective pain ratings for all three reporting periods and both types of pain. Table 1 Means, Standard Deviations, t-values, η 2 Values, and Correlations of Concurrent and Retrospective Ratings of Average and Worst Pain Concurrent Retrospective Reporting day M SD M SD t η 2 r Day 7 Average 3.48 2.01 4.04 2.36 3.75 **.12.77 ** Worst 5.05 2.49 5.57 2.81 2.99 **.08.80 ** Day 21 Average 1.79 1.84 2.21 2.19 3.83 **.15.89 ** Worst 2.83 2.28 3.35 2.68 3.53 **.13.88 ** Day 30 Average 2.36 1.65 2.99 2.12 4.10 **.17.75 ** Worst 3.62 2.04 4.06 2.47 2.46 *.07.74 ** Note. η 2 values correspond to the t-tests comparing concurrent and retrospective means. N = 81 100. * p <.05; ** p <.005
Comparison of Pain Ratings / 613 To assess the relationship between current pain and the accuracy of retrospectively reported pain, we computed Pearson correlations between current pain ratings and the discrepancy between concurrent and retrospective ratings of average and worst pain for the three reporting periods. The correlations between current pain and the discrepancy between concurrent and retrospective average pain were.09,.14, and.05 for ratings made on reporting Days 7, 21, and 30, respectively. The correlations between current pain and the discrepancy between concurrent and retrospective worst pain were.04,.01, and.10 for ratings made on reporting Days 7, 21, and 30, respectively. None of these correlations were statistically significant at the p <.05 level. The trend in pain ratings over the course of the study was examined in a series of t-tests comparing concurrent and retrospective reporting Day 7 values for average pain and worst pain, respectively, with those of reporting Day 21. Reporting Day 7 pain ratings were significantly higher than reporting Day 21 pain rating values for concurrent average pain, t(84) = 9.30, p <.001, η 2 =.51; concurrent worst pain, t(83) = 10.12, p <.001, η 2 =.55; retrospective average pain, t(84) = 8.22, p <.001, η 2 =.45; and retrospective worst pain, t(83) = 8.29, p <.001, η 2 =.45. Discussion Consistent with research on other types of pain (Brauer et al., 2003; Hahn, 2002; McGorry et al., 1999; Singer et al., 2001), 7- and 30-day retrospective pain ratings were strongly correlated with concurrent pain ratings during ACL rehabilitation. As documented previously (Breme et al., 2000; Van den Brink et al., 2001), however, retrospective reports of pain intensity consistently overestimated concurrent reports of pain intensity by approximately 1/2 point on an 11-point scale. Current pain level was weakly associated with the accuracy of retrospective pain ratings. Although the findings suggest that retrospective reports of pain could be used as a substitute for concurrent reports of pain during ACL rehabilitation as long as the tendency toward overestimation is taken into account, the present study is hampered by a limitation that is unavoidable in this type of research. Specifically, it is possible that the retrospective recall of pain was enhanced by the act of providing pain ratings on a daily basis. Giving daily ratings of pain may have made it easier for participants to remember their responses, and consequently to report 1-week and 1-month retrospective pain in line with the daily reports. On the other hand, the pain ratings constituted only 3 of more than 40 items that participants completed each day as part of a larger study. Considering that participants were not informed in advance regarding the periods for which retrospective ratings would be sought, it seems unlikely that the strong correlation between daily and retrospective pain ratings is due primarily to participants simply remembering their responses over the reporting periods. A limitation should be acknowledged in the manner in which pain data were collected in this study. Although participants were instructed to complete their pain ratings nightly and mail them to the researchers the next day, there was no way to verify that they complied fully with this request. It was typical for participants to send in their daily reports one at a time, but some indicated that they sent in multiple reports on the same day due to factors such as inclement weather, surgery-related restrictions in mobility, and lack of weekend mail service. Elec-
614 / Brewer, Cornelius, Van Raalte, et al. tronic means of data collection should be used in future studies to substantiate the extent to which pain ratings are provided as requested. From a pragmatic standpoint, the results suggest that retrospective pain ratings, for a period of up to 30 days, can be used to substitute for daily pain ratings in studies of rehabilitation after ACL surgery. If retrospective reports of pain are used, however, it is necessary to take into account the tendency toward overestimation in recalled pain. The utility of retrospective pain ratings in capturing the dynamic aspect of pain over the course of the rehabilitation period is determined by the extent that multiple sets of ratings are obtained. More frequent assessments of pain increase the sensitivity of temporal analyses. To assess daily changes in pain, and more important the concomitants of these changes, there is no substitute for obtaining measures of pain on a daily basis. References Brauer, C., Thomsen, J.F., Loft, I.P., & Mikkelsen, S. (2003). Can we rely on retrospective pain assessments? American Journal of Epidemiology, 157, 552-557. Breme, K., Altmeppen, J., & Taeger, K. (2000). Wie zuverlässig ist unser Gedächtnis für akute postoperative Schmerzen? [How reliable is our memory for acute postoperative pain?] Anaesthesist, 49, 18-24. Caine, D.J., Caine, C.G., & Lindner, K.J. (1996). Epidemiology of sports injuries. Champaign, IL: Human Kinetics. Dawson, E.G., Kanim, L.E., Sra, P., Dorey, F.J., Goldstein, T.B., Delamarter, R.B., & Sandhu, H.S. (2002). Low back pain recollection versus concurrent accounts: Outcomes analysis. Spine, 27, 984-993. DeCarlo, M.S., Sell, D.E., Shelbourne, K.D., & Klootwyk, T.E. (1994). Current concepts on accelerated ACL rehabilitation. Journal of Sport Rehabilitation, 3, 304-318. Griffin, L.Y., Agel, J., Albohm, M.J., Arendt, E.A., Dick, R.W., Garrett, W.E., Garrick, J.G., Hewett, T.E., Huston, L., Ireland, M.L., Johnson, R.J., Kibler, W.B., Lephart, S., Lewis, J.L., Lindenfeld, T.N., Mandelbaum, B.R., Marchak, P., Teitz, C.C., & Wojtys, E.M. (2000). Noncontact anterior cruciate ligament injuries: Risk factors and prevention strategies. Journal of the American Academy of Orthopaedic Surgeons, 18, 141-150. Hahn, T. (2002). Criterion related validity of self-reported knee symptoms among athletes. Scandinavian Journal of Medicine and Science in Sports, 12, 282-287. Heil, J., & Fine, P.G. (1999). Pain in sport: A biopsychological perspective. In D. Pargman (Ed.), Psychological bases of sport injuries (2nd ed., pp. 13-28). Morgantown, WV: Fitness Information Technology. Hopkins, W.G. (2000). Calculations for reliability. In A new view of statistics. Retrieved June 30, 2003, from http://www.sportsci.org/resource/stats/newview.html Jensen, M.P., & Karoly, P. (2001). Self-report scales and procedures for assessing pain in adults. In D.C. Turk & R. Melzack (Eds.), Handbook of pain assessment (2nd ed., pp. 15-34). New York: Guilford Press. Jensen, M.P., & McFarland, A. (1993). Increasing the reliability and validity of pain intensity measurement in chronic pain patients. Pain, 55, 195-203. Lefebvre, J.C., & Keefe, F.J. (2002). Memory for pain: The relationship of pain catastrophizing to the recall of daily rheumatoid arthritis pain. Clinical Journal of Pain, 18, 56-63.
Comparison of Pain Ratings / 615 McGorry, R.W., Webster, B.S., Snook, S.H., & Hsiang, S.M. (1999). Accuracy of pain recall in chronic and recurrent low back pain. Journal of Occupational Rehabilitation, 9, 169-178. Shapiro, E.T., Richmond, J.C., Rockett, S.E., McGrath, M.M., & Donaldson, W.R. (1996). The use of a generic, patient-based health assessment (SF-36) for evaluation of patients with anterior cruciate ligament injuries. American Journal of Sports Medicine, 24, 196-200. Singer, A.J., Kowalska, A., & Thode, H.C., Jr. (2001). Ability of patients to accurately recall the severity of acute painful events. Academy of Emergency Medicine, 8, 292-295. Treacy, S.H., Barron, O.A., Brunet, M.E., & Barrack, R. (1997). Assessing the need for extensive supervised rehabilitation following arthroscopic ACL reconstruction. The American Journal of Orthopedics, 26, 25-29. Uebersax, J.S. (2000). Agreement on interval-level ratings. In Statistical methods for rater agreement. Retrieved June 27, 2003, from http://ourworld.compuserve.com/ homepages/jsuebersax/agree.htm Van den Brink, M., Bandell-Hoekstra, E.N., & Abu-Saad, H.H. (2001). The occurrence of recall bias in pediatric headache: A comparison of questionnaire and diary data. Headache, 41, 11-20. Acknowledgment This article was supported in part by grant no. R29 AR44484 from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Its contents are solely the responsibility of the authors and do not represent the official views of the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Manuscript submitted: August 1, 2003 Revision accepted: March 26, 2004