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A regional registry study of 216 patients investigating if patient satisfaction after total knee arthroplasty changes over a time period of five to 20 years
The Knee 24 (2017) 824–828
Contents lists available at ScienceDirect
The Knee
A regional registry study of 216 patients investigating if patient satisfaction after total knee arthroplasty changes over a time period of five to 20 years Odei Shannak ⁎, Jeya Palan, Colin Esler Division of Orthopaedic Surgery, The Undercroft, University Hospitals of Leicester, LE5 4PW Leicester, United Kingdom
a r t i c l e
i n f o
Article history: Received 6 October 2016 Received in revised form 5 February 2017 Accepted 13 March 2017 Keywords: Satisfaction Knee arthroplasty PROMS
a b s t r a c t Aims: To determine the temporal changes in patient dissatisfaction following primary knee arthroplasty surgery (TKA). Patients and methods: Three hundred and ninety patients that had previously indicated they were either dissatisfied or unsure with their TKA at one-year post-surgery in our region were mailed a simple questionnaire in addition to the Oxford Knee Score and EQ-5D. Results: A 55% response rate was achieved. The mean follow-up time period was 9.1 years. Of the 120 patients who were initially dissatisfied, 46.7% remained so. Of the 96 patients who were initially unsure, 20.8% remained so, 21.9% and 57.3% became dissatisfied and satisfied, respectively. The primary reason for continued dissatisfaction was persistent pain. Of the 19.4% of patients who had revision surgery, 47.6% remained dissatisfied. 54.2% of patients stated that they would be happy to have a primary TKA again and 55.6% indicated that they would recommend one to a friend. Patients who had concurrent hip pain were six times more likely to remain unsure or dissatisfied over time (OR 6.7, p-value 0.0000). Patients who had back pain or contralateral knee pain were two or three times as likely to remain unsure or dissatisfied. Conclusion: In time half of the patients who stated that they were not satisfied with their arthroplasty, at one year, go on to be satisfied with their knee. © 2017 Elsevier B.V. All rights reserved.
1. Introduction It has become apparent that surgeons' perception of the outcome of their primary knee arthroplasty surgery is at variance with a significant number of their patients. Robertsson et al. [1] reported that eight percent of primary knee arthroplasties registered on the Swedish Knee Register from 1981 to 1995 were dissatisfied with their outcome. Furthermore, studies from national and regional arthroplasty registers have shown that up to 20% of patients remain dissatisfied at one year following TKA [2–6]. The reasons for patient dissatisfaction are multifactorial [2,5–7] and the rates of dissatisfaction have remained the same over time [3–6] and despite advances in TKA implant designs and surgical techniques [8]. Significant factors affecting satisfaction rates include unrealistic patient expectations [3,7], psychological factors [9–11] and the presence of postoperative complications [3]. Patients with post-traumatic osteoarthritis (OA), avascular necrosis (AVN) or primary OA have been found to have higher dissatisfaction rates compared to patients with rheumatoid arthritis of the knee [2,12]. Younger patients (under 55 years of age) and patients with early OA who have a TKR are more likely to have unrealistic expectations
⁎ Corresponding author at: The Undercroft, University Hospitals of Leicester, LE5 4PW Leicester, United Kingdom. E-mail address: [email protected] (O. Shannak).
http://dx.doi.org/10.1016/j.knee.2017.03.005 0968-0160/© 2017 Elsevier B.V. All rights reserved.
O. Shannak et al. / The Knee 24 (2017) 824–828
825
which is strongly predictive of 'dissatisfaction [12]. What is unclear is whether dissatisfaction rates improve over the mid to longer-term period. The aim of this study was to determine the mid to long-term outcome (five years to 20 years) for those patients who were dissatisfied and unsure at one year post-TKA in our region. To date, this study is the first to evaluate if patient satisfaction changes over the long term following TKA, using data from a regional arthroplasty register. 2. Patients and methods The Trent (& Wales) Arthroplasty Register was established to assess the outcome of hip and knee arthroplasty surgery in these regions of the United Kingdom. It was established in 1990, with agreement of all consultant orthopaedic surgeons in the region, all primary hip and knee arthroplasties have been registered prospectively, and the details registered on the database, hosted by the University of Leicester. The information recorded by the surgeon at the time of surgery included demographic, medical and operative details for each patient and implant. Data was fed back to contributing units for validation. All patients were mailed a validated self-administered postal questionnaire one year after their surgery. Non-responders to the questionnaire were sent a further questionnaire. In the period 1990–2007 questionnaires were sent relating to 43,708 knee arthroplasties, 91% for osteoarthritis, 8.7% for rheumatoid arthritis and 0.4% for trauma. The patients were asked ‘are you pleased with the result of your knee surgery?’ They could respond Yes, No or Unsure. For this study we accessed the data from patients who had had their knee arthroplasty surgery between the years 2000 and 2007. Three thousand four hundred eighty three patients were sent questionnaires in this period. Three hundred forty nine (10%) were displeased and 185 (5.3%) were unsure about their outcome. We verified that patients were still alive and had up to date addresses using the National Health Service (NHS) Strategic Tracing Service. This left 390 patients that had previously indicated they were either displeased or unsure with their TKA at one-year post-surgery. This included patients who had subsequently undergone revision surgery also. These patients were mailed a simple questionnaire in addition to the Oxford Knee Score and EQ-5D. Patients were asked whether they were satisfied with their TKA (Dissatisfied/Satisfied/Unsure) and if not satisfied whether this was due to (pain/stiffness/lack of bend/inability to straighten/numbness/instability). They were also asked if they would have the surgery again, would they recommend it to a friend, whether they felt better, worse or the same and if they had concurrent hip or back or contralateral knee pain. Finally, they were asked if they had had revision surgery. Non-responders to the initial mailed questionnaires were sent a reminder questionnaire after six weeks, in order to improve the response rate. Following this, the remaining non-responders were contacted by phone. Incidentally, some of the 390 questionnaires were sent in error to patients whom had had their surgery prior to the year 2000. Given that these questionnaires were sent to people who were also displeased or unsure at one-year post-surgery, we included the 30 responses received in our analysis. Whereas the original questionnaire sent out at one year post-surgery asked patients whether they were pleased or not, the follow-up questionnaire asked about satisfaction. We have assumed that the two terms are comparable and present our findings accordingly. All statistical analyses were performed with StataCorp. 2013 (Stata Statistical Software: Release 13. College Station, TX: StataCorp LP). Descriptive statistics were performed on all study data. ANOVA was used to compare the difference between group means. A p-value b 0.05 was considered significant. Univariate logistic regression analysis was performed looking at independent variables for predicting final satisfaction results. The unsure and dissatisfied patients in the final satisfaction variable were grouped together for this analysis and compared to the satisfied group of patients. 3. Results Two hundred and sixteen (55% response rate) patients completed the questionnaire. There were 93 (43%) males and 123 (57%) females with a mean age of 67.1 (SD 8.6). Table 1 shows the change in satisfaction at a mean follow-up time period of 9.1 years (SD 3.3; five to 20 years). The primary reason for dissatisfaction was persistent pain. One hundred and seventeen (54.2%) patients stated that they would be happy to have a primary TKA again and 120 (55.6%) patients would recommend a primary TKA to a friend. One hundred and fourteen patients (52.8%) felt better, 34 (15.7%) felt the same and 68 (31.5%) felt worse. Forty-two (19.4%) patients had revision surgery of which 20 (47.6%) were dissatisfied. Table 2 demonstrates the responses in relation to satisfaction. Table 3 shows the predictive factors for being unsure or dissatisfied over time. Patients who initially were unsure were much less likely to remain unsure or dissatisfied over time (odds ratio (OR) 0.2, p-value 0.0000). Patients who had concurrent hip pain were six times more likely to remain unsure or dissatisfied over time (OR 6.7, p-value 0.0000). Patients who had back pain or contralateral knee pain were two or three times as likely to remain unsure or dissatisfied.
Table 1 Change in satisfaction at a mean follow-up of 9.1 years (SD 3.3; five to 20 years).
Dissatisfied 1 year post-TKA n = 120 Unsure 1 year post-TKA n = 96
Dissatisfied
Satisfied
Unsure
56 (46.7%) 21 (21.9%)
27 (22.5%) 55 (57.3%)
37 (30.9%) 20 (20.8%)
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Table 2 Responses in relation to satisfaction at a mean follow-up of 9.1 years (SD 3.3; five to 20 years).
N (%) Age, mean (SD) Gender (female), n (%) Follow-up, mean (SD) Overall: n (%) Better Same Worse Reason for dissatisfaction: n (%) Pain Stiffness Lack of bend Inability to straighten leg Numbness on the lateral aspect of the knee Instability Would you have surgery again (yes), n (%) Would you recommend to a friend (yes), n (%) Have you had revision surgery (yes), n (%) Total Oxford score (0–48), mean (SD) EQ Health status (0–100), mean (SD)
Dissatisfied
Satisfied
Unsure
77 (35.6%) 67.8 (8.1) 50 (64.9%) 8.7 (2.9)
82 (38%) 68.4 (7.9) 41 (50%) 9.5 (3.8)
57 (26.4%) 64.3 (9.4) 32 (56%) 8.9 (2.9)
3 (3.9%) 16 (20.8%) 58 (75.3%)
80 (97.6%) 2 (2.4%) 0 (0%)
31 (54.4%) 16 (28.1%) 10 (17.5%)
63 (81.8%) 35 (77%) 40 (51.9%) 15 (19.5%) 26 (33.8%) 34 (44.2%) 14 (18.2%) 15 (19.5%) 20 (26%) 17.1 (8.1) 60.5 (68)
6 (7.3%) 4 (4.9%) 7 (8.5%) 1 (1.2%) 4 (4.9%) 2 (2.4%) 69 (84.1%) 75 (91.5%) 14 (17.1%) 33.4 (11.2) 66.8 (25)
35 (61.4%) 24 (42.1%) 17 (29.8%) 4 (7%) 14 (24.6%) 17 (29.8%) 24 (59.6%) 30 (52.6%) 8 (14%) 25.8 (9.3) 61 (20.8)
p b 0.005, ANOVA p = 0.628, ANOVA
Figure 1 shows that the Oxford Knee Score (OKS) is significantly better (p b 0.005) with patients who became satisfied compared to those who remained unsure or dissatisfied. Figure 2 shows that the overall EuroQoL health score was generally better for patients who were satisfied compared to those who remained unsure or dissatisfied.
4. Discussion In our study of 216 patients who were originally either unsure or dissatisfied, 38% of patients became satisfied, 35.6% remained dissatisfied and 26.4% were unsure at a mean follow-up of 9.1 years. This is in contrast to a study by Ali et al. in which 55 patients who were dissatisfied, as identified by the Swedish Knee Arthroplasty Register (SKAR), were reviewed and these patients continued to be dissatisfied eight to 13 years after surgery [11]. Our study is the first to quantify what proportion of patients show an improvement in satisfaction post-operatively following TKA. Since only two questionnaires were mailed (at one year and at a mean of 9.1 years), with a large interval, it is difficult to establish when this change occurred. Similar to findings by Baker et al. [5,7,13] our study showed a significant relationship between satisfaction and the post-operative OKS with a mean score of 33.4 in the satisfied group. Williams et al. [14,15] in a review of 5600 individual OKS questionnaires, showed that the maximum post-operative OKS was observed at two years following which a gradual but significant decline was observed through to the ten year assessment. Based on this, it is likely that the change in our study participants' satisfaction most probably occurred within the first two years following their TKA. Residual pain is considered one of the factors associated with dissatisfaction [16], and patients with the worst possible pain score being 23% less likely to be satisfied than those with the best possible score [7,11]. The study by Williams et al. [15] found that more than two thirds of patients complained of residual pain following surgery. In our study, 83% of patients who remained dissatisfied stated that pain was the primary reason for this dissatisfaction. On this basis we feel that it is important to warn patients that a TKA might not fully resolve their knee pain. In the study by Brander et al., at five years of follow-up, nearly all of their patients who initially had unexplained pain in their knee at one year postoperatively, were satisfied with their TKA and their pain had resolved [17].
Table 3 Predictive independent factors for patients remaining unsure or dissatisfied over time.
Age (mean, SD) Gender (female) Initial satisfaction (unsure) Would you have surgery again Concurrent back pain Concurrent hip pain Contralateral knee pain Oxford Knee Score EuroQoL health score CI = confidence interval.
Number
Odds ratio
95% CI
p-Value
211 211 210 201 154 121 168 211 206
1.04 1.66 0.20 0.07 2.77 6.55 2.19 1.10 1.02
1.01–1.03 0.95–2.91 0.11–0.36 0.03–0.16 1.41–5.43 2.76–15.54 1.11–4.31 1.07–1.13 1.01–1.03
0.0028 0.0769 0.0000 0.0000 0.0027 0.0000 0.0232 0.0000 0.0028
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Figure 1. Box and Whisker plot showing mean OKS for Dissatisfied, Satisfied and Unsure groups.
Patients in our study reported stiffness and lack of bend as another cause of dissatisfaction. This has a direct effect on the ability to squat and kneel, both essential movements for activities in this age group such as gardening and dancing [18,19]. The patients who were satisfied over time had much lower rates of persistent pain, stiffness and lack of bend. There were a number of factors that influence the likelihood of a patient remaining unsure or dissatisfied over time. The presence of hip, back or contralateral knee pain increased the risk of being either unsure or dissatisfied with the outcome of the knee replacement. In a large registry based study of 1217 patients, Scott et al. identified back pain and multiple joint pains as significant predictors of dissatisfaction at one year follow-up [6]. If a patient was unsure initially, there was a strong likelihood that over time, they would become satisfied with their knee replacement. Age and gender appear to have little significant effect on the final satisfaction outcome although the study by Scott et al. demonstrated that patients aged 55 or less were more likely to be dissatisfied after TKA [12]. There are some limitations with this study. Despite our efforts to maximize the response rate, this study had a response rate 55%. This carries the risk of our dissatisfaction rates being higher as studies have shown that non-respondents to satisfaction surveys either suffer with ill health or are unwilling to discuss their negative experience [20,21]. A response rate as low as 30% has been proposed as ‘reasonable’ for patient satisfaction surveys, while 80% is seen as ‘very high’ [6,7]. The average response rate for mailed questionnaires is 61% [8]. Other published studies evaluating patient satisfaction show a similar response rate to our study of between 50% and 58% [8,11]. Furthermore, given that the length of time for follow-up in our study is up to 20 years, a response rate of 55% in this primarily elderly group of patients with a mean age of 67 years would seem reasonable. Reasons for revision surgery in our cohort were not available for a more in-depth analysis. Our study has demonstrated that having any revision surgery is associated with higher dissatisfaction rates, despite the passage of time. The reason for revision, however, may influence
Figure 2. Box and Whisker plot showing EuroQol health scores and satisfaction.
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the level of dissatisfaction post-operatively [22]. The absence of preoperative data on patients' disease factors and their severity is another limitation. Preoperative outcome scores such as the Oxford Knee Scores have been shown to influence post-operative OKS [23]. However, a large study from Oxford involving over 3000 patients showed no correlation between pre-operatively OKS and post-operative patient satisfaction [24]. Finally, the original questionnaire sent to patients asked them to respond to whether or not they were pleased, displeased or unsure regarding their surgery. The follow-up questionnaire asked them about satisfaction. While the wording of the questionnaire varied from being pleased to being satisfied, we have assumed that the two terms are comparable and that being pleased with surgery was equivalent to being satisfied with surgery. In conclusion, it is evident that over time, dissatisfaction rates decrease in more than half of the cases and this is reassuring for patients and surgeons. However, a not insignificant proportion of patients remain dissatisfied and there are certain factors such as concurrent back, hip or knee pain, which influences the likelihood of dissatisfaction even with the passage of time. Also, patients who have revision surgery are more likely to remain dissatisfied despite the passage of time. This study highlights the need to select patients appropriately, carefully counsel them and manage their expectations accordingly. What is required is the development of a screening tool allowing surgeons to predict which patients are likely to be dissatisfied after their TKA.
Conflict of interest None of the above listed authors have any conflicts of interest to declare.
References [1] Robertsson O, Dunbar M, Pehrsson T, Knutson K, Lidgren L. Patient satisfaction after knee arthroplasty: a report on 27,372 knees operated on between 1981 and 1995 in Sweden, 71; 2000 262–7. http://dx.doi.org/10.1080/000164700317411852. [2] Dunbar MJ, Richardson G, Robertsson O. I can't get no satisfaction after my total knee replacement: rhymes and reasons. Bone Joint J 2013;95-B:148–52. http://dx.doi.org/10.1302/0301-620X.95B11.32767. [3] Bourne RB, Chesworth BM, Davis AM, Mahomed NN, Charron KDJ. Patient satisfaction after total knee arthroplasty: who is satisfied and who is not? Clin Orthop Relat Res 2009;468:57–63. http://dx.doi.org/10.1007/s11999-009-1119-9. [4] Baker PN, van der Meulen JH, Lewsey J, Gregg PJ. National Joint Registry for England and Wales. The role of pain and function in determining patient satisfaction after total knee replacement. Data from the National Joint Registry for England and Wales. J Bone Joint Surg 2007;89:893–900. http://dx.doi.org/10.1302/0301620X.89B7.19091. [5] Robertsson O, Dunbar M, Pehrsson T, Knutson K, Lidgren L. Patient satisfaction after knee arthroplasty — a report on 27,372 knees operated on between 1981 and 1995 in Sweden. Acta Orthop Scand 2000;71:262–7. http://dx.doi.org/10.1080/000164700317411852. [6] Scott CEH, Howie CR, MacDonald D, Biant LC. Predicting dissatisfaction following total knee replacement: a prospective study of 1217 patients. J Bone Joint Surg Br 2010;92:1253–8. http://dx.doi.org/10.1302/0301-620X.92B9.24394. [7] Baker PN, van der Meulen JH, Lewsey J, Gregg PJ. National Joint Registry for England and Wales. The role of pain and function in determining patient satisfaction after total knee replacement. Data from the National Joint Registry for England and Wales. J Bone Joint Surg Br 2007;89:893–900. http://dx.doi.org/10.1302/0301620X.89B7.19091. [8] Nam D, Nunley RM, Barrack RL. Patient dissatisfaction following total knee replacement: a growing concern? Bone Joint J 2014;96-B:96–100. http://dx.doi.org/ 10.1302/0301-620X.96B11.34152. [9] Brander VA, Stulberg SD, Adams AD, Harden RN, Bruehl S, Stanos SP, et al. Ranawat Award paper: predicting total knee replacement pain. Clin Orthop Relat Res 2003;416:27–36. http://dx.doi.org/10.1097/01.blo.0000092983.12414.e9. [10] Blackburn J, Qureshi A, Amirfeyz R, Bannister G. Does preoperative anxiety and depression predict satisfaction after total knee replacement? Knee 2012;19: 522–4. http://dx.doi.org/10.1016/j.knee.2011.07.008. [11] Ali A, Sundberg M, Robertsson O, Dahlberg LE, Thorstensson CA, Redlund-Johnell I, et al. Dissatisfied patients after total knee arthroplasty: a registry study involving 114 patients with 8–13 years of followup. Acta Orthop 2014;85:229–33. http://dx.doi.org/10.3109/17453674.2014.916487. [12] Scott C, Oliver WM, MacDonald D, Wade FA. Predicting dissatisfaction following total knee arthroplasty in patients under 55 years of age. Bone Joint J 2016. http://dx.doi.org/10.1302/0301-620X.98B12. [13] Scott CEH, Howie CR, MacDonald D, Biant LC. Predicting dissatisfaction following total knee replacement: a prospective study of 1217 patients. J Bone Joint Surg Br 2010;92:1253–8. http://dx.doi.org/10.1302/0301-620X.92B9.24394. [14] Roberts VI, Esler CNA, Harper WM. A 15-year follow-up study of 4606 primary total knee replacements. J Bone Joint Surg Br 2007;89B:1452–6. http://dx.doi.org/ 10.1302/0301-620X.89B11.19783. [15] Williams DP, Blakey CM, Hadfield SG, Murray DW, Price AJ, Field RE. Long-term trends in the Oxford knee score following total knee replacement. Bone Joint J 2013;95-B:45–51. http://dx.doi.org/10.1302/0301-620X.95B1.28573. [16] Lavand'homme P, Thienpont E. Pain after total knee arthroplasty: a narrative review focusing on the stratification of patients at risk for persistent pain. Bone Joint J 2015;97-B:45–8. http://dx.doi.org/10.1302/0301-620X.97B10.36524. [17] Brander V, Gondek S, Martin E, Stulberg SD. The John Insall Award. Clin Orthop Relat Res 2007:PAP. http://dx.doi.org/10.1097/BLO.0b013e318126c032. [18] Scott CEH, Bugler KE, Clement ND, MacDonald D, Howie CR, Biant LC. Patient expectations of arthroplasty of the hip and knee. J Bone Joint Surg Br 2012;94: 974–81. http://dx.doi.org/10.1302/0301-620X.94B7.28219. [19] Weiss JM, Noble PC, Conditt MA, Kohl HW, Roberts S, Cook KF, et al. What functional activities are important to patients with knee replacements? Clin Orthop Relat Res 2002:172–88. http://dx.doi.org/10.1097/01.blo.0000036536.46246.d9. [20] Kim J, Lonner JH, Nelson CL, Lotke PA. Response bias: effect on outcomes evaluation by mail surveys after total knee arthroplasty. J Bone Joint Surg Am 2004;86A: 15–21. [21] Hopton JL, Howie JG, Porter AM. The need for another look at the patient in general practice satisfaction surveys. Fam Pract 1993;10:82–7. [22] Barrack RL, Engh G, Rorabeck C, Sawhney J, Woolfrey M. Patient satisfaction and outcome after septic versus aseptic revision total knee arthroplasty. J Arthroplasty 2000;15:990–3. http://dx.doi.org/10.1054/arth.2000.16504. [23] Hamilton DF, Lane JV, Gaston P, Patton JT, MacDonald D, Simpson AHRW, et al. What determines patient satisfaction with surgery? A prospective cohort study of 4709 patients following total joint replacement. BMJ Open 2013;3:e002525. http://dx.doi.org/10.1136/bmjopen-2012-002525. [24] Judge A, Arden NK, Price A, Glyn-Jones S, Beard D, Carr AJ, et al. Assessing patients for joint replacement can pre-operative Oxford hip and knee scores be used to predict patient satisfaction following joint replacement surgery and to guide patient selection? J Bone Joint Surg Br 2011;93B:1660–4. http://dx.doi.org/10.1302/ 0301-620X.93B12.27046.
Contents lists available at ScienceDirect
The Knee
A regional registry study of 216 patients investigating if patient satisfaction after total knee arthroplasty changes over a time period of five to 20 years Odei Shannak ⁎, Jeya Palan, Colin Esler Division of Orthopaedic Surgery, The Undercroft, University Hospitals of Leicester, LE5 4PW Leicester, United Kingdom
a r t i c l e
i n f o
Article history: Received 6 October 2016 Received in revised form 5 February 2017 Accepted 13 March 2017 Keywords: Satisfaction Knee arthroplasty PROMS
a b s t r a c t Aims: To determine the temporal changes in patient dissatisfaction following primary knee arthroplasty surgery (TKA). Patients and methods: Three hundred and ninety patients that had previously indicated they were either dissatisfied or unsure with their TKA at one-year post-surgery in our region were mailed a simple questionnaire in addition to the Oxford Knee Score and EQ-5D. Results: A 55% response rate was achieved. The mean follow-up time period was 9.1 years. Of the 120 patients who were initially dissatisfied, 46.7% remained so. Of the 96 patients who were initially unsure, 20.8% remained so, 21.9% and 57.3% became dissatisfied and satisfied, respectively. The primary reason for continued dissatisfaction was persistent pain. Of the 19.4% of patients who had revision surgery, 47.6% remained dissatisfied. 54.2% of patients stated that they would be happy to have a primary TKA again and 55.6% indicated that they would recommend one to a friend. Patients who had concurrent hip pain were six times more likely to remain unsure or dissatisfied over time (OR 6.7, p-value 0.0000). Patients who had back pain or contralateral knee pain were two or three times as likely to remain unsure or dissatisfied. Conclusion: In time half of the patients who stated that they were not satisfied with their arthroplasty, at one year, go on to be satisfied with their knee. © 2017 Elsevier B.V. All rights reserved.
1. Introduction It has become apparent that surgeons' perception of the outcome of their primary knee arthroplasty surgery is at variance with a significant number of their patients. Robertsson et al. [1] reported that eight percent of primary knee arthroplasties registered on the Swedish Knee Register from 1981 to 1995 were dissatisfied with their outcome. Furthermore, studies from national and regional arthroplasty registers have shown that up to 20% of patients remain dissatisfied at one year following TKA [2–6]. The reasons for patient dissatisfaction are multifactorial [2,5–7] and the rates of dissatisfaction have remained the same over time [3–6] and despite advances in TKA implant designs and surgical techniques [8]. Significant factors affecting satisfaction rates include unrealistic patient expectations [3,7], psychological factors [9–11] and the presence of postoperative complications [3]. Patients with post-traumatic osteoarthritis (OA), avascular necrosis (AVN) or primary OA have been found to have higher dissatisfaction rates compared to patients with rheumatoid arthritis of the knee [2,12]. Younger patients (under 55 years of age) and patients with early OA who have a TKR are more likely to have unrealistic expectations
⁎ Corresponding author at: The Undercroft, University Hospitals of Leicester, LE5 4PW Leicester, United Kingdom. E-mail address: [email protected] (O. Shannak).
http://dx.doi.org/10.1016/j.knee.2017.03.005 0968-0160/© 2017 Elsevier B.V. All rights reserved.
O. Shannak et al. / The Knee 24 (2017) 824–828
825
which is strongly predictive of 'dissatisfaction [12]. What is unclear is whether dissatisfaction rates improve over the mid to longer-term period. The aim of this study was to determine the mid to long-term outcome (five years to 20 years) for those patients who were dissatisfied and unsure at one year post-TKA in our region. To date, this study is the first to evaluate if patient satisfaction changes over the long term following TKA, using data from a regional arthroplasty register. 2. Patients and methods The Trent (& Wales) Arthroplasty Register was established to assess the outcome of hip and knee arthroplasty surgery in these regions of the United Kingdom. It was established in 1990, with agreement of all consultant orthopaedic surgeons in the region, all primary hip and knee arthroplasties have been registered prospectively, and the details registered on the database, hosted by the University of Leicester. The information recorded by the surgeon at the time of surgery included demographic, medical and operative details for each patient and implant. Data was fed back to contributing units for validation. All patients were mailed a validated self-administered postal questionnaire one year after their surgery. Non-responders to the questionnaire were sent a further questionnaire. In the period 1990–2007 questionnaires were sent relating to 43,708 knee arthroplasties, 91% for osteoarthritis, 8.7% for rheumatoid arthritis and 0.4% for trauma. The patients were asked ‘are you pleased with the result of your knee surgery?’ They could respond Yes, No or Unsure. For this study we accessed the data from patients who had had their knee arthroplasty surgery between the years 2000 and 2007. Three thousand four hundred eighty three patients were sent questionnaires in this period. Three hundred forty nine (10%) were displeased and 185 (5.3%) were unsure about their outcome. We verified that patients were still alive and had up to date addresses using the National Health Service (NHS) Strategic Tracing Service. This left 390 patients that had previously indicated they were either displeased or unsure with their TKA at one-year post-surgery. This included patients who had subsequently undergone revision surgery also. These patients were mailed a simple questionnaire in addition to the Oxford Knee Score and EQ-5D. Patients were asked whether they were satisfied with their TKA (Dissatisfied/Satisfied/Unsure) and if not satisfied whether this was due to (pain/stiffness/lack of bend/inability to straighten/numbness/instability). They were also asked if they would have the surgery again, would they recommend it to a friend, whether they felt better, worse or the same and if they had concurrent hip or back or contralateral knee pain. Finally, they were asked if they had had revision surgery. Non-responders to the initial mailed questionnaires were sent a reminder questionnaire after six weeks, in order to improve the response rate. Following this, the remaining non-responders were contacted by phone. Incidentally, some of the 390 questionnaires were sent in error to patients whom had had their surgery prior to the year 2000. Given that these questionnaires were sent to people who were also displeased or unsure at one-year post-surgery, we included the 30 responses received in our analysis. Whereas the original questionnaire sent out at one year post-surgery asked patients whether they were pleased or not, the follow-up questionnaire asked about satisfaction. We have assumed that the two terms are comparable and present our findings accordingly. All statistical analyses were performed with StataCorp. 2013 (Stata Statistical Software: Release 13. College Station, TX: StataCorp LP). Descriptive statistics were performed on all study data. ANOVA was used to compare the difference between group means. A p-value b 0.05 was considered significant. Univariate logistic regression analysis was performed looking at independent variables for predicting final satisfaction results. The unsure and dissatisfied patients in the final satisfaction variable were grouped together for this analysis and compared to the satisfied group of patients. 3. Results Two hundred and sixteen (55% response rate) patients completed the questionnaire. There were 93 (43%) males and 123 (57%) females with a mean age of 67.1 (SD 8.6). Table 1 shows the change in satisfaction at a mean follow-up time period of 9.1 years (SD 3.3; five to 20 years). The primary reason for dissatisfaction was persistent pain. One hundred and seventeen (54.2%) patients stated that they would be happy to have a primary TKA again and 120 (55.6%) patients would recommend a primary TKA to a friend. One hundred and fourteen patients (52.8%) felt better, 34 (15.7%) felt the same and 68 (31.5%) felt worse. Forty-two (19.4%) patients had revision surgery of which 20 (47.6%) were dissatisfied. Table 2 demonstrates the responses in relation to satisfaction. Table 3 shows the predictive factors for being unsure or dissatisfied over time. Patients who initially were unsure were much less likely to remain unsure or dissatisfied over time (odds ratio (OR) 0.2, p-value 0.0000). Patients who had concurrent hip pain were six times more likely to remain unsure or dissatisfied over time (OR 6.7, p-value 0.0000). Patients who had back pain or contralateral knee pain were two or three times as likely to remain unsure or dissatisfied.
Table 1 Change in satisfaction at a mean follow-up of 9.1 years (SD 3.3; five to 20 years).
Dissatisfied 1 year post-TKA n = 120 Unsure 1 year post-TKA n = 96
Dissatisfied
Satisfied
Unsure
56 (46.7%) 21 (21.9%)
27 (22.5%) 55 (57.3%)
37 (30.9%) 20 (20.8%)
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Table 2 Responses in relation to satisfaction at a mean follow-up of 9.1 years (SD 3.3; five to 20 years).
N (%) Age, mean (SD) Gender (female), n (%) Follow-up, mean (SD) Overall: n (%) Better Same Worse Reason for dissatisfaction: n (%) Pain Stiffness Lack of bend Inability to straighten leg Numbness on the lateral aspect of the knee Instability Would you have surgery again (yes), n (%) Would you recommend to a friend (yes), n (%) Have you had revision surgery (yes), n (%) Total Oxford score (0–48), mean (SD) EQ Health status (0–100), mean (SD)
Dissatisfied
Satisfied
Unsure
77 (35.6%) 67.8 (8.1) 50 (64.9%) 8.7 (2.9)
82 (38%) 68.4 (7.9) 41 (50%) 9.5 (3.8)
57 (26.4%) 64.3 (9.4) 32 (56%) 8.9 (2.9)
3 (3.9%) 16 (20.8%) 58 (75.3%)
80 (97.6%) 2 (2.4%) 0 (0%)
31 (54.4%) 16 (28.1%) 10 (17.5%)
63 (81.8%) 35 (77%) 40 (51.9%) 15 (19.5%) 26 (33.8%) 34 (44.2%) 14 (18.2%) 15 (19.5%) 20 (26%) 17.1 (8.1) 60.5 (68)
6 (7.3%) 4 (4.9%) 7 (8.5%) 1 (1.2%) 4 (4.9%) 2 (2.4%) 69 (84.1%) 75 (91.5%) 14 (17.1%) 33.4 (11.2) 66.8 (25)
35 (61.4%) 24 (42.1%) 17 (29.8%) 4 (7%) 14 (24.6%) 17 (29.8%) 24 (59.6%) 30 (52.6%) 8 (14%) 25.8 (9.3) 61 (20.8)
p b 0.005, ANOVA p = 0.628, ANOVA
Figure 1 shows that the Oxford Knee Score (OKS) is significantly better (p b 0.005) with patients who became satisfied compared to those who remained unsure or dissatisfied. Figure 2 shows that the overall EuroQoL health score was generally better for patients who were satisfied compared to those who remained unsure or dissatisfied.
4. Discussion In our study of 216 patients who were originally either unsure or dissatisfied, 38% of patients became satisfied, 35.6% remained dissatisfied and 26.4% were unsure at a mean follow-up of 9.1 years. This is in contrast to a study by Ali et al. in which 55 patients who were dissatisfied, as identified by the Swedish Knee Arthroplasty Register (SKAR), were reviewed and these patients continued to be dissatisfied eight to 13 years after surgery [11]. Our study is the first to quantify what proportion of patients show an improvement in satisfaction post-operatively following TKA. Since only two questionnaires were mailed (at one year and at a mean of 9.1 years), with a large interval, it is difficult to establish when this change occurred. Similar to findings by Baker et al. [5,7,13] our study showed a significant relationship between satisfaction and the post-operative OKS with a mean score of 33.4 in the satisfied group. Williams et al. [14,15] in a review of 5600 individual OKS questionnaires, showed that the maximum post-operative OKS was observed at two years following which a gradual but significant decline was observed through to the ten year assessment. Based on this, it is likely that the change in our study participants' satisfaction most probably occurred within the first two years following their TKA. Residual pain is considered one of the factors associated with dissatisfaction [16], and patients with the worst possible pain score being 23% less likely to be satisfied than those with the best possible score [7,11]. The study by Williams et al. [15] found that more than two thirds of patients complained of residual pain following surgery. In our study, 83% of patients who remained dissatisfied stated that pain was the primary reason for this dissatisfaction. On this basis we feel that it is important to warn patients that a TKA might not fully resolve their knee pain. In the study by Brander et al., at five years of follow-up, nearly all of their patients who initially had unexplained pain in their knee at one year postoperatively, were satisfied with their TKA and their pain had resolved [17].
Table 3 Predictive independent factors for patients remaining unsure or dissatisfied over time.
Age (mean, SD) Gender (female) Initial satisfaction (unsure) Would you have surgery again Concurrent back pain Concurrent hip pain Contralateral knee pain Oxford Knee Score EuroQoL health score CI = confidence interval.
Number
Odds ratio
95% CI
p-Value
211 211 210 201 154 121 168 211 206
1.04 1.66 0.20 0.07 2.77 6.55 2.19 1.10 1.02
1.01–1.03 0.95–2.91 0.11–0.36 0.03–0.16 1.41–5.43 2.76–15.54 1.11–4.31 1.07–1.13 1.01–1.03
0.0028 0.0769 0.0000 0.0000 0.0027 0.0000 0.0232 0.0000 0.0028
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Figure 1. Box and Whisker plot showing mean OKS for Dissatisfied, Satisfied and Unsure groups.
Patients in our study reported stiffness and lack of bend as another cause of dissatisfaction. This has a direct effect on the ability to squat and kneel, both essential movements for activities in this age group such as gardening and dancing [18,19]. The patients who were satisfied over time had much lower rates of persistent pain, stiffness and lack of bend. There were a number of factors that influence the likelihood of a patient remaining unsure or dissatisfied over time. The presence of hip, back or contralateral knee pain increased the risk of being either unsure or dissatisfied with the outcome of the knee replacement. In a large registry based study of 1217 patients, Scott et al. identified back pain and multiple joint pains as significant predictors of dissatisfaction at one year follow-up [6]. If a patient was unsure initially, there was a strong likelihood that over time, they would become satisfied with their knee replacement. Age and gender appear to have little significant effect on the final satisfaction outcome although the study by Scott et al. demonstrated that patients aged 55 or less were more likely to be dissatisfied after TKA [12]. There are some limitations with this study. Despite our efforts to maximize the response rate, this study had a response rate 55%. This carries the risk of our dissatisfaction rates being higher as studies have shown that non-respondents to satisfaction surveys either suffer with ill health or are unwilling to discuss their negative experience [20,21]. A response rate as low as 30% has been proposed as ‘reasonable’ for patient satisfaction surveys, while 80% is seen as ‘very high’ [6,7]. The average response rate for mailed questionnaires is 61% [8]. Other published studies evaluating patient satisfaction show a similar response rate to our study of between 50% and 58% [8,11]. Furthermore, given that the length of time for follow-up in our study is up to 20 years, a response rate of 55% in this primarily elderly group of patients with a mean age of 67 years would seem reasonable. Reasons for revision surgery in our cohort were not available for a more in-depth analysis. Our study has demonstrated that having any revision surgery is associated with higher dissatisfaction rates, despite the passage of time. The reason for revision, however, may influence
Figure 2. Box and Whisker plot showing EuroQol health scores and satisfaction.
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the level of dissatisfaction post-operatively [22]. The absence of preoperative data on patients' disease factors and their severity is another limitation. Preoperative outcome scores such as the Oxford Knee Scores have been shown to influence post-operative OKS [23]. However, a large study from Oxford involving over 3000 patients showed no correlation between pre-operatively OKS and post-operative patient satisfaction [24]. Finally, the original questionnaire sent to patients asked them to respond to whether or not they were pleased, displeased or unsure regarding their surgery. The follow-up questionnaire asked them about satisfaction. While the wording of the questionnaire varied from being pleased to being satisfied, we have assumed that the two terms are comparable and that being pleased with surgery was equivalent to being satisfied with surgery. In conclusion, it is evident that over time, dissatisfaction rates decrease in more than half of the cases and this is reassuring for patients and surgeons. However, a not insignificant proportion of patients remain dissatisfied and there are certain factors such as concurrent back, hip or knee pain, which influences the likelihood of dissatisfaction even with the passage of time. Also, patients who have revision surgery are more likely to remain dissatisfied despite the passage of time. This study highlights the need to select patients appropriately, carefully counsel them and manage their expectations accordingly. What is required is the development of a screening tool allowing surgeons to predict which patients are likely to be dissatisfied after their TKA.
Conflict of interest None of the above listed authors have any conflicts of interest to declare.
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