- Top of page
- PATIENTS AND METHODS
Osteoarthritis (OA) is a major cause of disability (1), and the knee is the second most commonly affected joint (2). In the US population, 16.3% of 24–75-year-olds have some form of arthritis or rheumatism and 75% (12.3% of the US population) have OA (3, 4), whereas in Canada 4 million individuals are living with OA. It is estimated that in Canada there will be a 45% increase in the prevalence and an 88% increase in the number of persons affected by arthritis-associated disability between 1985 and 2020 (5). The World Health Organization suggests similar increasing rates in Europe and developing countries as longevity increases (1). For individuals with moderate to severe OA of the knee, total knee replacement (TKR) is a cost-effective treatment because it reduces pain and disability (6). However, as primary joint implants loosen and fail, revision surgery is required.
Patients' expectations that a treatment or behavior will achieve its desired effect are a key factor in understanding health treatments and outcomes (7, 8). For example, patient expectations have been linked to requests for elective treatments, compliance with medical regimens, prediction of functional outcomes, and satisfaction with outcomes (9–14). However, only a few studies (largely retrospective) have reported on the expectations of patients undergoing primary total joint replacement (15–17). Moreover, although Haddad et al (18) and Eisler et al (10) evaluated expectations in persons undergoing revision total hip replacement, no reports exist of expectations of patients undergoing revision TKR.
Previous research has focused on a single dimension of expectations, most often expectations of satisfaction or expectations of returning to a previous level of functioning (13, 17, 18). We do not know to what extent patients' expectations form a global evaluation of TKR or are varied and multidimensional in nature. If patients have different types of expectations regarding TKR, this has implications for targeting areas that may need to be addressed to better educate patients and to assist them in decision making.
Theories of social cognition have posited that factors such as perceived vulnerability, previous experience, and individual differences may shape individuals' expectations (7, 8). Therefore, examining expectations in revision TKR may be particularly important because patients have previous (unsuccessful) experience with the procedure and may report greater vulnerability or concerns. This, ultimately, may affect the outcome of surgery. As a first step in uncovering the role of expectations in revision TKR, we examined personal factors, patient functioning, previous experiences with knee replacement surgery, concerns about surgery and general health, and the relationship of these factors to patients' expectations prior to receiving revision TKR.
- Top of page
- PATIENTS AND METHODS
The sample consisted of 184 patients who were undergoing revision TKR. A total of 99 (53.8%) patients were women. The mean age was 69 years, the youngest patient being 32 years of age and the oldest patient being 89 years of age. A total of 120 (65.6%) were married or with a partner; 48 (26.2%) lived alone; and the remainder lived with family members, friends, or in a residential institution. For education level, 8.7% had a bachelor's degree or higher. On average, patients had 1.9 previous knee replacement surgeries with a maximum of 8 prior surgeries on index and nonindex knees combined (Table 1).
Table 1. Description of the sample (n = 184)*
|Married or with a partner||120 (65.6)|
|Living alone||48 (26.2)|
|Bachelor's degree or higher||16 (8.7)|
|Other medical problems||136 (75.1)|
|Help around the house||140 (76.1)|
|Using walking aid||144 (79.1)|
|Taking pain medication||28 (15.4)|
|Age, mean ± SD years (range)||69.1 ± 11.3 (31.9–89.4)|
|Number of previous replacement surgeries, mean ± SD (range)||1.9 ± 1.1 (1–8)|
|Arthritis Helplessness Score, mean ± SD (range)||15.0 ± 4.0 (5.0–25.0)|
|Life Orientation Test, mean ± SD (range)||17.7 ± 4.9 (8.0–34.0)|
|Concerns About Surgery scale, mean ± SD (range)||15.0 ± 4.0 (5.0–25.0)|
|Past Experience scale, mean ± SD (range)||12.8 ± 4.1 (5.0–21.0)|
|WOMAC pain subscale, mean ± SD (range)||11.1 ± 3.9 (3.0–20.0)|
|WOMAC physical subscale, mean ± SD (range)||38.6 ± 12.8 (14.3–52.5)|
|General health rating by patient, mean ± SD (range)||73.5 ± 18.7 (10–100)|
|General health with respect to knee, mean ± SD (range)||39.2 ± 22.1 (0–90)|
The mean ± SD score on the AHS was 15.0 ± 4.0, suggesting that most patients were in the middle range of the scale in reporting helplessness in dealing with their arthritis. The LOT scores revealed that patients were generally optimistic (mean ± SD score 17.7 ± 4.9). The Concerns Scale had a mean ± SD score of 15.0 ± 4.0, indicating that patients were only somewhat concerned about surgery. Patients' past experience with knee revision surgery was unremarkable as suggested by the mid-range scores (mean ± SD score 12.8 ± 4.1). The WOMAC pain and physical subscales had mean ± SD scores of 11.1 ± 3.9 and 38.6 ± 12.8, respectively. Patients regarded their overall general health as being good (mean ± SD 73.5 ± 18.7) but rated their health as poor with respect to their knee (mean ± SD 39.2 ± 22.1).
Most patients had relatively high expectations (Table 2). A total of 54.9% believed the upcoming surgery would be extremely beneficial in helping them resume their everyday activities (group mean ± SD 1.7 ± 0.8). Half of the patients undergoing revision TKR (51.1%) expected to recover in <6 months after surgery, whereas a slightly lower number of patients (45.1%) thought they would recover between 6 months and 1 year. The remainder believed that it would take longer than 1 year or that they would never fully recover. In terms of expecting complications, more than half the patients (59%) did not expect to experience any complications. A total of 59.3% expected the recovery to be somewhat painful. Expectation of difficulty with respect to everyday activities during recovery was similar to expectation of pain, with 64.3% expecting a somewhat difficult recovery, 14.3% expecting between somewhat and extreme difficulty, and 12.1% expecting extreme difficulty. The others thought it would be somewhat or not at all difficult.
Table 2. Percentage of response, number of patients, and mean ± SD for each of the 5 expectations
|Expectation/response options||Mean ± SD||No. (%)|
|Global benefit||1.7 ± 0.8|| |
| 1 (extremely)|| ||100 (54.9)|
| 2|| ||43 (23.6)|
| 3 (somewhat)|| ||37 (20.3)|
| 4|| ||1 (0.5)|
| 5 (not at all)|| ||1 (0.5)|
|Pain||3.4 ± 0.9|| |
| 1 (extremely)|| ||27 (14.8)|
| 2|| ||35 (19.2)|
| 3 (somewhat)|| ||108 (59.3)|
| 4|| ||8 (4.4)|
| 5 (not at all)|| ||4 (2.2)|
|Difficulty||3.2 ± 0.9|| |
| 1 (extremely)|| ||22 (12.1)|
| 2|| ||26 (14.3)|
| 3 (somewhat)|| ||117 (64.3)|
| 4|| ||9 (4.9)|
| 5 (not at all)|| ||8 (4.4)|
|Recovery time, months||1.5 ± 0.6|| |
| <6|| ||93 (51.1)|
| 6–12|| ||82 (45.1)|
| >12|| ||6 (3.3)|
| Do not expect to recover|| ||1 (0.5)|
|Complications||1.4 ± 0.6|| |
| No|| ||108 (59.0)|
| Not sure|| ||68 (37.2)|
| Yes|| ||7 (3.8)|
Predictor variables were not highly correlated, with the correlation values ranging from 0.01 to 0.59. WOMAC pain and physical subscales had the highest correlation (r = 0.59).
Expectations of benefit.
Univariate regression analyses revealed that low concerns about surgery (P < 0.0001), optimism (P = 0.001), positive past experience (P = 0.005), perceiving overall health as good (P = 0.01), older age (P = 0.02), and seeing one's self as being responsible for the decision to have surgery (P = 0.037) were associated with perceptions of increased benefits of surgery. However, when the above variables were entered into a multiple linear regression model (Table 3), only low concerns about surgery (P = 0.02) was predictive of perceived beneficial effects from surgery, with a trend for age (P = 0.08).
Table 3. Predictor variables (P < 0.10) in multivariable regression models*
|Expectation of benefit (R2 = 0.17; n = 162)|| || || || |
| Concerns about surgery||0.037||0.015||2.435||0.016|
| Life Orientation Test||0.018||0.014||1.316||0.190|
| Past Experience Scale||0.015||0.018||0.841||0.402|
| General health||−0.003||0.004||−0.928||0.355|
| Responsible for decision||0.079||0.049||1.612||0.109|
|Expected recovery time (R2 = 0.27; n = 164)|| || || || |
| Concerns about surgery||0.029||0.010||2.970||0.003|
| Past Experience Scale||0.022||0.011||1.910||0.058|
| WOMAC pain subscale||0.030||0.019||1.568||0.119|
| WOMAC physical subscale||0.002||0.006||0.336||0.737|
| Arthritis Helplessness Scale||−0.010||0.014||−0.743||0.459|
| Life Orientation Test||0.015||0.009||1.646||0.102|
|Expectation of complications (R2 = 0.16; n = 162)|| || || || |
| Concerns about surgery||0.029||0.010||2.952||0.004|
| Past Experience Scale||0.008||0.012||0.733||0.465|
| Life Orientation Test||0.012||0.009||1.291||0.199|
| General health||0.000||0.002||0.020||0.984|
| Arthritis Helplessness Scale||0.000||0.012||0.019||0.985|
|Expectation of pain (R2 = 0.16; n = 160)|| || || || |
| Concerns about surgery||0.064||0.016||4.085||< 0.0001|
| Past Experience Scale||0.020||0.018||1.100||0.273|
| WOMAC pain subscale||0.039||0.030||1.281||0.202|
| WOMAC physical subscale||−0.008||0.009||−0.926||0.356|
| Arthritis Helplessness Scale||−0.0013||0.022||−0.598||0.551|
| General health||−0.001||0.004||−0.301||0.764|
| Previous surgeries||−0.038||0.061||−0.613||0.541|
|Expectation of difficulty (R2 = 0.22; n = 170)|| || || || |
| Concerns about surgery||0.032||0.015||2.144||0.034|
| Past Experience Scale||0.032||0.018||1.781||0.077|
| Arthritis Helplessness Scale||0.007||0.018||0.389||0.698|
Expectations of recovery time.
Expectation of a shorter recovery time was associated with having low concerns about the upcoming surgery (P < 0.0001), a positive past experience with surgery (P < 0.0001), experiencing pain (P < 0.0001), having difficulty with physical functioning (P < 0.0001), low feelings of helplessness (P = 0.001), optimism (P = 0.001), and higher education (P = 0.04), as was evident from univariate regression analyses. Expectation of a faster recovery was predicted by low concerns about surgery (P = 0.003), with a trend for positive past surgical experiences (P = 0.06) and higher education (P = 0.06) when the variables from the above univariate analyses were entered into a multiple linear regression model.
Expectations of complications.
Univariate regression analyses revealed that being less concerned about surgery (P < 0.0001), having a positive past surgery experience (P = 0.001), optimism (P = 0.002), and not feeling helpless (P = 0.04) were all associated with low expectations of complications, whereas older patients (P = 0.006) and those who did not rate their general health as high (P = 0.02) expected complications to arise while recovering from surgery. Multiple regression analysis revealed that concerns about surgery (P = 0.004) and age (P = 0.05) were the only independent predictors of expectation of complications during recovery from surgery.
Expectations of pain.
Univariate regression analyses demonstrated that expectations of pain were low for women (P = 0.08), when concerns about surgery were low (P < 0.0001), when patients had a positive past experience with surgery (P < 0.0001), when current pain was low (P = 0.01), when patients did not feel helpless (P = 0.03), and when physical functioning was higher (P = 0.04). Expectations of pain were high when the patients were older (P = 0.04), had fewer numbers of previous replacement surgeries (P = 0.10), or perceived themselves to have poorer overall health (P = 0.04). The only significant predictor of expectations of pain was concerns about surgery (P < 0.0001) when the above variables were entered into the multiple regression analysis.
Expectations of difficulty with everyday activities.
Univariate regression analyses showed that patients expected less difficulty with everyday activities after surgery when they were less concerned about surgery (P < 0.0001), female (P = 0.08), had a positive past experience with surgery (P = 0.002), and did not feel helpless (P = 0.02). Upon entering the above variables into a multiple linear regression model, expectation of experiencing fewer difficulties with everyday activities after surgery was predicted by low concerns about surgery (P = 0.03). There was a trend toward significance for past experience with surgery (P = 0.07).
An interaction between concerns about surgery and general health as perceived by the patient was entered into the above multivariate models to understand if patients with lower levels of health status had more concerns and if the interaction of the 2 variables was, in turn, related to expectations. This interaction was significant in the model with expected recovery time as the outcome variable. Including this interaction term in the multivariable model resulted in optimism (P = 0.03), experiencing pain (P = 0.03), and the interaction between concerns about surgery and perceived general health (P = 0.03) becoming significant predictors, along with having a good past experience with surgery (P = 0.05). However, concerns about surgery were no longer a significant predictor, indicating that concerns about surgery were moderated by patients' perceptions of their general overall health in predicting expectations about recovery time from surgery (Figure 1). Specifically, the interaction revealed that at low levels of general health, patients' concerns about surgery did not influence their expectations of recovery. Most of these individuals believed they would recover within a year. Among those with higher ratings of general health, a different pattern emerged. Despite having better reported health, patients with high ratings of general health who reported greater concerns about surgery reported the longest expected recovery times compared with all other groups.
Figure 1. Interaction between general health rating and concerns about surgery in relation to expected recovery time. 1 = recover in <6 months; 2 = recover in 6 months to a year; 3 = recover in more than a year; 4 = do not expect to ever recover.
Download figure to PowerPoint
When the interaction between concerns for surgery and general health as rated by the patient was replaced with the interaction between concerns about surgery and WOMAC physical subscale score, no significant change was noted in any model except for the expected recovery time model. Patients' previous experiences with surgery (P = 0.08), optimism (P = 0.09), higher education (P = 0.06), and the interaction between concerns about surgery and WOMAC physical functioning scores (P = 0.07) predicted patients' expectation of a faster recovery. When the interaction variable in the above models for the 5 expectations was replaced with the interaction between concerns about surgery and WOMAC pain subscale score, no significant change was found in any of the models.
- Top of page
- PATIENTS AND METHODS
Revision total joint replacement is more complex than primary replacement, and with increased volume of primary total joint replacement, revision total joint replacement rates are also increasing (29). Currently, there are little data available on the outcomes of revision TKR (30) with which to guide patients, and there are no data on what patients expect after revision TKR. Previous work has evaluated expectations of patients undergoing primary hip or knee replacement or revision hip replacement with the intent of evaluating how expectations relate to functional outcome and satisfaction with outcome (13, 15–18). To our knowledge, this is the first study that has evaluated expectations of patients undergoing revision TKR and that has attempted to understand factors that shape patients' expectations about their recovery from surgery.
In capturing expectations, we included an overall question of expected benefit as well as several questions related to specific benefits expected in terms of symptoms and function. When tested, these items were not homogeneous based on a low Cronbach's alpha, suggesting that expectations about recovery following revision TKR are formed from distinct components. If expectations were a homogeneous concept, we would also expect similar factors to predict expectations. However, our modeling of various factors demonstrated that the predictors varied depending on which expectation question was the dependent variable. In the total joint replacement literature, expectations have been evaluated by individual questions similar to our study and by summing the responses to individual items (13, 15–18). It is unclear if these summed scales reflect a homogeneous concept. The multidimensional nature of expectations revealed in this study suggests that studies need to evaluate multiple aspects of expectations and ultimately look at how these different expectations relate to outcome. Also, further work needs to be done to determine if individuals have additional expectations that have not been evaluated.
Despite the fact that their knee replacement failed, patients expected the overall benefit from their revision TKR to be high (mean 1.68); however, their expectations of specific benefits in pain relief and disability were less positive (mean 3.40 and 3.25, respectively). (For these questions, 1 indicated a higher level of expectation.) In this study, the indications for revision TKR included pain, functional deficit, instability, and radiographic loosening or bone loss. It is rare that radiographic loosening, bone loss, or instability would occur without the patient experiencing pain and/or functional compromise. It is, therefore, unexpected that patients would have high global expectations with much lower expectations for pain relief and functional recovery. This suggests that global expectations may represent additional specific expectations that were not evaluated by our questions.
In this study, most patients reported relatively high expectations from their surgery. Although there is a fair amount of variability in patients' expectations of recovery, complications, pain, and potential interference with daily activities, on average patients expect the recovery to be without complications, the surgery to be extremely beneficial, some pain, and some amount of difficulty with daily activities. Patients expect to be fully recovered or to be near full recovery in 6 months. Similar results of high expectations have been reported in studies on patients who underwent primary total joint replacement and revision total hip replacement (10, 16–18). Saleh et al concluded that revision TKR is a beneficial procedure (30). However, their meta-analysis was based on a clinician's global ratings of pain, function, and range of motion rather than the patients' perceptions of their function, and the data provide no indication of the timeline of recovery. Only through a longitudinal study of recovery will we be able to determine if these expectations match true recovery and predict outcome.
Although research shows that past experience may shape individuals' expectations (7, 8), there seems to be no known scale measuring past experience of patients, especially in relation to surgery outcomes. To determine the relevant domains of interest, we drew extensively from research on total joint replacements, consequently suggesting the outcomes, namely pain, recovery, difficulty resuming daily activities, complication, and benefit to be the most relevant to surgery (10, 12, 15–17, 30, 31). Our preliminary analyses of the scale indicate an acceptable internal reliability (Cronbach's α = 0.80). Past experience was only predictive of expectation of recovery time. There may be other aspects of past experience that might be relevant to the other domains of expectation. More research is needed to assess how patients' previous experiences might be a factor associated with outcomes of surgery, and also to validate the domains of expectation in other samples.
Sex and individual differences in optimism and perceptions of helplessness related to arthritis were not related to the expectations that patients have about revision TKR. However, patients' concerns about surgery were a significant factor in shaping their expectations of global benefit, complications, pain relief, and difficulty with daily activities. Even considering that we had multiple expectation outcomes, these findings are consistent, with the exception of expectations of difficulty with daily activities, had a Bonferroni correction been used where a significant P value would be 0.01. In a study of patients undergoing primary total knee and total hip arthroplasty, Trousdale et al also found patients to be concerned about pain after surgery and the length of recovery (31). These results suggest that individual, relatively stable characteristics such as sex and optimism may not be as important in determining expectations as situational or specific contextual factors such as concerns or worries about different aspects of surgery.
Concerns about surgery interacted with general health status to predict expected time to recovery. When patients rated their overall health as low, there was little variability in the recovery time, irrespective of concerns about surgery. This expectation of a relatively short recovery time regardless of concerns about surgery may mean that, at low levels of general health, patients are focused primarily on their current health and are motivated to do something to alleviate their pain and disability. As a result, they expect that surgery will allow them some degree of recovery in a relatively short time. The implications for this expectation warrant further study, particularly because older patients with more comorbidities are undergoing revision surgery (29) and their expectations of recovery time may not be realized. When general health is higher, the focus may not only be on improving health status but also on the costs and benefits of the surgery itself. Individuals with concerns may be more likely to question their decision to go ahead with surgery and more likely to expect a longer recovery time. It is unclear whether these expectations will be more realistic in terms of actual outcomes than the expectations of individuals in other groups. Future research would benefit from examining the concordance of patients' expectations of recovery with outcomes.
In summary, most of the patients undergoing revision TKR in this study expected their surgery to be extremely beneficial. Most expected to recover within a year of surgery, and more than half expected not to experience complications after surgery but to have a somewhat painful and difficult recovery period with respect to performing everyday activities. Concerns about surgery are the most significant factor influencing expectations about revision TKR surgery. In addition, past experience also influenced expectation of recovery time, while age seemed to influence expectation of complications. Understanding these individual expectations has implications for targeting areas that may need to be addressed to better educate patients and to assist them in understanding their recovery and the extent of recovery following revision TKR, particularly as work in primary joint replacement has shown that expectations are a predictor of outcome (17).
- Top of page
- PATIENTS AND METHODS
We would like to acknowledge the contributions of the lead surgeons at each of the centers where patients were accrued to this study: Dr. Michael Dunbar, Queen Elizabeth II, Halifax, Nova Scotia; Dr. Steve MacDonald, London Health Sciences Center, London, Ontario; Dr. Nizar Mahomed, Toronto Western Hospital, Toronto, Ontario; Dr. Allan Gross, Mount Sinai Hospital, Toronto, Ontario; Dr. Jeffrey Gollish, Sunnybrook and Women's College Health Science Center, Toronto, Ontario; Dr. Emil Schemitsch, St. Michael's Hospital, Toronto, Ontario; Dr. David Hedden, St. Boniface General Hospital, Winnipeg, Manitoba; Dr. Donald Garbuz, Vancouver General Hospital, Vancouver, British Columbia.