Impact of Age on Patient Reported Outcome Measures in Total Knee Arthroplasty Impact of Age on Patient Reported Outcome Measures in Total Knee Arthroplasty Ryan Roubion, Luke Townsend, Grant Pollock, Devin Bourgeois, Claudia Leonardi, PhD, Rabun Fox MD, Vinod Dasa, MD Abstract. In this retrospective, single surgeon database, we showed that patients in our older cohorts had significantly greater improvement in Oxford and WOMAC scores following TKA compared to younger cohorts, when controlling for pre-operative scores. These relative improvements were maintained throughout the study follow up period of six months. Analysis of the pain and function Oxford subscores demonstrated a similar trend of better outcomes for the older cohort, but no relative change over time existed between the two cohorts. Our main finding is in contrast to existing literature, which indicates that younger patients may have greater improvements in subjective scores post-operatively(6,7). It is possible that our findings could be related several key differences to other studies, which may include a single vs multiple surgeon database, follow up time, and unavailable patient information including differing patient demographics, pre-operative range of motion and stability, and radiographic findings. Further studies are warranted to better elucidate the correlation between age and post-TKA outcomes. A more thorough understanding of this relationship will likely require further stratification of patients within age cohorts. The clinical outcomes after TKA have been demonstrated to be affected by BMI, cause and level of arthritis, prior surgeries, etc...(9,10). To date, no study has matched their cohorts for each of the parameters that have been shown to affect outcomes. Thus, we feel that our study illustrates the need for further study into this relationship due to the variability and complexity of the correlation between age and total knee arthroplasty outcomes. Patient Demographics WOMAC and Oxford Scores Introduction Post-surgical Oxford Scores Conclusion Arthroplasty surgeons possess an in-depth understanding of the technical factors related to total knee arthroplasty that affect patient satisfaction, outcomes, and revision rates. In recent years, literature has greatly improved the understanding of which patient demographic factors impact their post-operative course(1). There has been growing focus on defining the relationship between patient age and outcomes. Literature has demonstrated that pre-operatively, expectations following TKA are higher for younger patients(2,3). This finding is intuitive, based on higher activity levels and expected ability to return to sport activity(4,5). Measuring post-operative outcomes, multiple studies have demonstrated significantly greater WOMAC and KSS improvements in younger patients (under 55) following TKA when compared to older cohorts(6,7). However, further analysis of existing studies indicates the complexity of the age-outcome correlation. Despite the improved outcome measures, studies show lower total knee arthroplasty survivability at 5 and 10 years for younger patient(6). Outcome measures analyses have demonstrated worse outcomes on mental components, and are equivalent on pain and function. Understanding this relationship is important to create realistic post-operative expectations, a process which has been demonstrated to improve post-TKA outcomes(2,8). However, the senior author has noticed a clinical difference in patient outcomes between younger and older patients. Older patients seemed to be more satisfied and happier compared to younger patients following TKA, especially during the early post-operative period. We, therefore, hypothesize that younger patients would have significantly worse pain and functional outcomes compared to older patients. References 1. Polkowski, G. G., Ruh, E. L., Barrack, T. N., Nunley, R. M., & Barrack, R. L. (2013). Is pain and dissatisfaction after TKA related to early-grade preoperative osteoarthritis? Clinical Orthopaedics and Related Research, 471, Baker, P., van der Meulen, J. H., Lewsey, J., & Gregg, P. J. (2007). The role of pain and function in determining patient satisfaction after total knee replacement. The Journal of Bone and Joint Surgery, 89-B(7), Hassan M. K. Ghomrawi, C. A. (2013, January). Discordance in TKA Expectations Between Patients and Surgeons. Clinical Orthopaedics and Related Research, 471, Garratt, A., Brealey, S., & Gillespie, W. (2004). Patient assessed health instruments for the knee: a structured review. Rheumatology, 43, Bourne, R. B., Chesworth, B. M., Davis, A. M., Mahomed, N. N., & Charron, K. D. (2010). Patient satisfaction after total knee arthroplasty: who is satisfied and who is not? Clinical Orthopaedics and Related Research, 468, Mannion, A. F., Kampfen, S., Munzinger, U., & Kramers-de Quervain, I. (2009). The role of patient expectations in predicting outcome after total knee arthroplasty. Arthritis Research and Therapy, 11, Mancuso, C., Salvati, E., Johanson, N., Peterson, M., & Charlson, M. (1997). Patient's expectations and satisfaction with total hip arthroplasty. Journal of Arthroplasty, 12, Crowninshield, R. D., Rosenberg, A. G., & Sporer, S. M. (2006). Changing demographics of patients with total joint replacement. Clinical Orthopaedics and Related Research, 443, Mancuso C, Sculco T, Wickiewicz T, Jones E, Robbins L, Warren R, Williams-Russo P. Patients’ Expectations of Knee Surgery. J Bone Joint Surg Am, 2001 Jul; 83 (7): Dahm, Diane L. et al. Patient-Reported Activity Level After Total Knee Arthroplasty. J Arthroplasty, Volume 23, Issue 3, 401 – 407. Introduction: Patient expectations and demographics are vital factors in determining patient satisfaction and outcomes from TKA. This study was a retrospective chart review that analyzed data from TKA patients to determine the impact of age on patient reported outcomes measures following TKA. Methods: WOMAC and Oxford knee scores were collected as primary outcome measures from 356 consecutive patients who underwent TKA. Oxford knee scores were further divided into pain and function subscores. Patients were age categorized as 79. Scores collected post-operative (approximately 10, 30, 90 and 180 days post-operation) were analyzed as repeated measures, day and their interaction, gender, BMI, length of stay and pre-operative score. Pre-operative scores were also compared among age categories including age category, gender, BMI, and length of stay in the model. Results: Pre-operative OXFORD scores significantly differed among age categories (P < 0.05) and were numerically higher for the ≥60 age group (Table 2). After adjusting for pre-operative scores, post-operative WOMAC and OXFORD scores significantly differed among the age groups (P < ). No significant age group by day interaction was observed for any of the scores. Discussion: Prior to TKA, patients aged <60 years old reported worst overall, pain, and functional outcomes scores than patients ≥60 years old. Furthermore, after adjusting for the pre-operative score, patients <60 years old reported the worst overall, pain, and functional outcome scores in the post-operative measures. From the present results, older patients reported better pre-operative overall, pain, and function scores and exhibited better outcomes post TKA than younger patients. Significance: Risk adjustment for age may thus be important in future pay for performance formulas. A better understanding of factors that influence patient reported outcomes can help providers to better counsel patients. Age categories (years) Age Category Effect < > P-value---- N Male, % (n)28.1 (9)27.9 (19)31.2 (43)38.3 (36)45.8 (11) Length of stay, days, mean (SD)1.6 (1.2)1.9 (1.7)1.5 (1.4)1.7 (1.7)2.0 (2.1) Body mass index, kg/m 2, mean (SD) 35.9 (8.8) A 35.7 (6.2) A 34.6 (6.4) A 31.6 (5.7) B 29.0 (4.1) B < Table 1. Patient characteristics by age category (N = 356). Age categories (years)Fixed effect 1 < > 79SEMAge cat.DayAge*Day Pre-surgery WOMAC OXFORD Overall13.4 B 14.9 B 17.4 AB 19.3 A 17.6 AB Pain5.1 AB 5.2 B 6.3 AB 7.3 A 6.6 AB Function8.4 B 9.5 AB 11.1 AB 12.1 A 11.2 AB Post-surgery WOMAC50.0 B 49.9 B 62.9 A 64.0 A 65.3 A 3.6< OXFORD Overall23.0 BC 21.2 C 27.8 AB 28.3 A 29.1 AB 1.8< Pain8.8 AB 8.1 B 10.4 A 11.1 A 11.3 A 0.8< Function14.3 BC 13.0 C 17.3 A 17.2 AB 1.1< Table 2. Least square means of WOMAC and OXFORD (overall, pain and functional) scores by age category ( 79 years old) pre and post TKA surgery. A,B,C Least square means within a row with different letters are significantly different at P < 0.05 Tukey multiple comparison adjustment. 1 Fixed effect model also included outcome score measured pre-surgery (only for post-surgery models), gender, BMI and length of hospital stay as covariates. A Figure 1. Least square means (± SEM) of function (A), pain (B) and overall (C) OXFORD scores by age category ( 79 years, dotted grey) measured post TKA surgery adjusted for pre-surgery scores. Differences in OXFORD scores among age categories did not significantly differ over time (P > 0.05). Functional, pain and overall OXFORD scores significantly differed among age categories (P < ).