Patient Expectations and HRQoL After Total Joint Replacement
Our prospective study of a sample of consecutive patients with knee or hip OA undergoing TJR offers insight into the association of patient expectations with HRQoL outcomes and satisfaction at one year post-intervention. We observed that patients with higher expectations improved more in HRQoL, measured by SF-12 and WOMAC questionnaires, and had more likelihood to be satisfied, adjusted for BMI, age, gender, joint, education, previous intervention and HRQoL baseline scores. In spite of the existence of several studies that have measured the association between patients expectations and treatment outcomes in TJR, in general there is limited evidence for this association. Haanstra et al. in a systematic review about it highlighted the need for more research in this field. The strengths of our study include the relatively large sample size, the use of valid and responsive instruments for assessing outcomes in TJR and the use of multivariate analyses adjusting for confounding variables.
Patients in our study had higher expectations for improvements in physical or functional symptoms than in social or psychological capacities. The two areas where patients had the highest expectations were pain relief and ability to walk, which are traditional reasons for performing TJR. Physical and functional expectations are more closely related to the direct effects of the intervention; therefore, patients might look forward to potential benefits that are more closely related to their basal symptoms such as pain or ability to walk.
These expectations were also the ones with the most association with changes in HRQoL at 12 months after surgery, even after adjusting for covariables. This change, besides being statistically significant, was clinically relevant because there was higher percentage of patients who exceeded MCID as expectations increases. Therefore, the areas where patients place more trust in improving, are the ones more associated with change. This could be due to the fact that our patients had realistic expectations of surgery and correctly anticipated the outcome of the intervention. As in previous studies, our findings show that patients with worse baseline HRQoL are more likely to improve, so high expectations of surgery are realistic, and might explain the association, adjusting for covariables.
Another potential explanation about observed association of greater expectations being related with improved outcomes is that patients with higher preintervention expectations interpreted their gains more optimistically and participated more intensely in their rehabilitation process, which in turn may affect their recovery, as suggested by some studies.
Keeping this in mind, it would be important to analyse why some patients have low expectations, which could prevent them from improving. It has been found that unrealistically low expectations may not provide the motivation necessary to progress with the recovery, and thus may result in patients not deriving full benefit from TJR.
There are many studies in TJR about expectations that have pointed out the importance of baseline patients' realistic expectations so they could be sufficiently fulfilled; however, these studies usually do not emphasize the importance of building up patients' expectations. So, an alternative point of view is that patients' higher expectations contributed to outcomes by acting as a psychological factor, which ultimately could have an influence on post-intervention HRQoL. Hence as Judge et al. pointed out, it could be argued that surgeons should explain to patients with low expectations that the TJR will be quite successful, building up appropriate expectations.
To our knowledge, there are a few comparable studies that explore the association between pre-operative expectations and change in HRQoL for TJR. In our study we found that all analyzed baseline patient expectations were associated with change in HRQoL 12 months after surgery. However, in our study, like others, independent expectations associated with improvement in pain and function domains were pain relief and improved ability to walk, measured by WOMAC and SF-36, after adjusting for covariables. So, patients who have higher pain relief or ability to walk expectations may have perceived less pain, less stiffness, and better functional and mental outcomes than patients with less expectations.
Along the same line, Judge et al. in a study of 1327 primary total hip replacement (THR) explored whether pre-operative expectations predict surgical outcomes in terms of pain and function measured by WOMAC 12 months post THR. They found that the more the preoperative expectations of a patient, the more likely they were to improve at 12 months.
On the other hand, one study of 112 patients who underwent total knee replacement (TKR) examined which was the most important unique determinant of global outcome/satisfaction after surgical management: baseline expectations, fulfillment of expectations or current symptoms and function. Bivariate analyses showed that baseline expectations were associated with change in pain and in functional limitations. Similar outcomes were reported by other studies. However, these results did not retain significance in the multivariable model predicting the overall global outcome or satisfaction. A previous study for TKR also found that pain scores were significantly better for patients who had expected to have no pain and/or had expected they would not need a walking aid. However, although it was significant in this large cohort of 598 patients, the magnitude of this difference (5 points) may not be clinically meaningful. Moreover, for TJR a more recent study found that expectations of time to fully recover from surgery and level of function were not predictors of WOMAC change scores. However, having expectations of pain relief was a significant predictor.
Satisfaction is a complex item, which is affected by many factors, especially expectations before the surgery. Like Noble et al. we found that some preoperative expectations were associated with satisfaction after TJR. Having higher pain relief, daily activities and ability to walk expectations seem to be related to more satisfaction than patients with low expectations. However, these differences only persist for daily activities expectations after adjusting for the other covariables. Therefore, in our study, patients who have significant expectations to improve their ability to perform daily activities had more likelihood to be satisfied than patients who had low expectations. Pain and ability to walk could be associated with the ability to perform daily activities. Thus, the less the pain and difficulty in walking the patients have, the greater their ability to perform daily activities; which seems to be associated directly with satisfaction. Patients seem to see more easily the relationship of their ability to perform daily activities with satisfaction, however, this ability could probably be related to pain relief and ability to walk. Following this trend Noble et al. suggest that patient's expectations will strongly influence their interpretation of the outcome of their TJR and their satisfaction. On the other hand, a US study by Mancuso et al. in 180 THR looked at whether preoperative expectations were associated with satisfaction with surgery. They concluded that expectations were not associated with satisfaction. Finally, it should be noted that we would have to take into account that this relationship between expectations and satisfaction is likely to be mediated by a larger improvement in those with high expectations.
A possible limitation of our study is the percentage of non-responders or missing values. Only 53.06% patients completed questionnaires at 12 months. Probably owed to our questionnaire extension, the patient's burden to complete the questionnaire could be important. However our sample keeps on being large enough comparing with others similar studies. Besides, TJRs performed in total during the recruitment period are unknown because there were fifteen hospitals of different autonomous community participating and not all of these hospitals did collect this information. As well as owed to large sample size we found differences between responders and non-reponders, nevertheless this differences despite being statistically significant were not clinically relevant, although could cause a bias in the results. Another limitation is that we did not evaluate patients's knowledge of TJR, coming from their clinical or their social/familiar settings about the procedure, recovery process, complications and so on, as potential covariables associated with functional outcomes and which could strongly influence expectations. Besides, like in other studies in order to estimate the score for satisfaction at one year we used a single anchoring question on patient satisfaction with the surgical outcome. This is a similar concept to widely used Patient Acceptable Symptom State (PASS). The difference is that our item asked about satisfaction with surgery that included aspects of patients' current symptoms, but also their baseline level of symptoms, in addition to their response and expectations of surgery. Furthermore, we did not use a validated expectation questionnaire that could ensure comparability for future research or an open-ended free text question allowing other types of expectations to be identified. However, these kinds of questions may pose problems regarding how to code answers, and differences in verbosity or fluency could affect the findings. Finally, these questions did not measure the importance of different expectations expressed by individual patients. Therefore future studies need other possible factors that influence expectations.
Discussion
Our prospective study of a sample of consecutive patients with knee or hip OA undergoing TJR offers insight into the association of patient expectations with HRQoL outcomes and satisfaction at one year post-intervention. We observed that patients with higher expectations improved more in HRQoL, measured by SF-12 and WOMAC questionnaires, and had more likelihood to be satisfied, adjusted for BMI, age, gender, joint, education, previous intervention and HRQoL baseline scores. In spite of the existence of several studies that have measured the association between patients expectations and treatment outcomes in TJR, in general there is limited evidence for this association. Haanstra et al. in a systematic review about it highlighted the need for more research in this field. The strengths of our study include the relatively large sample size, the use of valid and responsive instruments for assessing outcomes in TJR and the use of multivariate analyses adjusting for confounding variables.
Patients in our study had higher expectations for improvements in physical or functional symptoms than in social or psychological capacities. The two areas where patients had the highest expectations were pain relief and ability to walk, which are traditional reasons for performing TJR. Physical and functional expectations are more closely related to the direct effects of the intervention; therefore, patients might look forward to potential benefits that are more closely related to their basal symptoms such as pain or ability to walk.
These expectations were also the ones with the most association with changes in HRQoL at 12 months after surgery, even after adjusting for covariables. This change, besides being statistically significant, was clinically relevant because there was higher percentage of patients who exceeded MCID as expectations increases. Therefore, the areas where patients place more trust in improving, are the ones more associated with change. This could be due to the fact that our patients had realistic expectations of surgery and correctly anticipated the outcome of the intervention. As in previous studies, our findings show that patients with worse baseline HRQoL are more likely to improve, so high expectations of surgery are realistic, and might explain the association, adjusting for covariables.
Another potential explanation about observed association of greater expectations being related with improved outcomes is that patients with higher preintervention expectations interpreted their gains more optimistically and participated more intensely in their rehabilitation process, which in turn may affect their recovery, as suggested by some studies.
Keeping this in mind, it would be important to analyse why some patients have low expectations, which could prevent them from improving. It has been found that unrealistically low expectations may not provide the motivation necessary to progress with the recovery, and thus may result in patients not deriving full benefit from TJR.
There are many studies in TJR about expectations that have pointed out the importance of baseline patients' realistic expectations so they could be sufficiently fulfilled; however, these studies usually do not emphasize the importance of building up patients' expectations. So, an alternative point of view is that patients' higher expectations contributed to outcomes by acting as a psychological factor, which ultimately could have an influence on post-intervention HRQoL. Hence as Judge et al. pointed out, it could be argued that surgeons should explain to patients with low expectations that the TJR will be quite successful, building up appropriate expectations.
To our knowledge, there are a few comparable studies that explore the association between pre-operative expectations and change in HRQoL for TJR. In our study we found that all analyzed baseline patient expectations were associated with change in HRQoL 12 months after surgery. However, in our study, like others, independent expectations associated with improvement in pain and function domains were pain relief and improved ability to walk, measured by WOMAC and SF-36, after adjusting for covariables. So, patients who have higher pain relief or ability to walk expectations may have perceived less pain, less stiffness, and better functional and mental outcomes than patients with less expectations.
Along the same line, Judge et al. in a study of 1327 primary total hip replacement (THR) explored whether pre-operative expectations predict surgical outcomes in terms of pain and function measured by WOMAC 12 months post THR. They found that the more the preoperative expectations of a patient, the more likely they were to improve at 12 months.
On the other hand, one study of 112 patients who underwent total knee replacement (TKR) examined which was the most important unique determinant of global outcome/satisfaction after surgical management: baseline expectations, fulfillment of expectations or current symptoms and function. Bivariate analyses showed that baseline expectations were associated with change in pain and in functional limitations. Similar outcomes were reported by other studies. However, these results did not retain significance in the multivariable model predicting the overall global outcome or satisfaction. A previous study for TKR also found that pain scores were significantly better for patients who had expected to have no pain and/or had expected they would not need a walking aid. However, although it was significant in this large cohort of 598 patients, the magnitude of this difference (5 points) may not be clinically meaningful. Moreover, for TJR a more recent study found that expectations of time to fully recover from surgery and level of function were not predictors of WOMAC change scores. However, having expectations of pain relief was a significant predictor.
Satisfaction is a complex item, which is affected by many factors, especially expectations before the surgery. Like Noble et al. we found that some preoperative expectations were associated with satisfaction after TJR. Having higher pain relief, daily activities and ability to walk expectations seem to be related to more satisfaction than patients with low expectations. However, these differences only persist for daily activities expectations after adjusting for the other covariables. Therefore, in our study, patients who have significant expectations to improve their ability to perform daily activities had more likelihood to be satisfied than patients who had low expectations. Pain and ability to walk could be associated with the ability to perform daily activities. Thus, the less the pain and difficulty in walking the patients have, the greater their ability to perform daily activities; which seems to be associated directly with satisfaction. Patients seem to see more easily the relationship of their ability to perform daily activities with satisfaction, however, this ability could probably be related to pain relief and ability to walk. Following this trend Noble et al. suggest that patient's expectations will strongly influence their interpretation of the outcome of their TJR and their satisfaction. On the other hand, a US study by Mancuso et al. in 180 THR looked at whether preoperative expectations were associated with satisfaction with surgery. They concluded that expectations were not associated with satisfaction. Finally, it should be noted that we would have to take into account that this relationship between expectations and satisfaction is likely to be mediated by a larger improvement in those with high expectations.
Limitations
A possible limitation of our study is the percentage of non-responders or missing values. Only 53.06% patients completed questionnaires at 12 months. Probably owed to our questionnaire extension, the patient's burden to complete the questionnaire could be important. However our sample keeps on being large enough comparing with others similar studies. Besides, TJRs performed in total during the recruitment period are unknown because there were fifteen hospitals of different autonomous community participating and not all of these hospitals did collect this information. As well as owed to large sample size we found differences between responders and non-reponders, nevertheless this differences despite being statistically significant were not clinically relevant, although could cause a bias in the results. Another limitation is that we did not evaluate patients's knowledge of TJR, coming from their clinical or their social/familiar settings about the procedure, recovery process, complications and so on, as potential covariables associated with functional outcomes and which could strongly influence expectations. Besides, like in other studies in order to estimate the score for satisfaction at one year we used a single anchoring question on patient satisfaction with the surgical outcome. This is a similar concept to widely used Patient Acceptable Symptom State (PASS). The difference is that our item asked about satisfaction with surgery that included aspects of patients' current symptoms, but also their baseline level of symptoms, in addition to their response and expectations of surgery. Furthermore, we did not use a validated expectation questionnaire that could ensure comparability for future research or an open-ended free text question allowing other types of expectations to be identified. However, these kinds of questions may pose problems regarding how to code answers, and differences in verbosity or fluency could affect the findings. Finally, these questions did not measure the importance of different expectations expressed by individual patients. Therefore future studies need other possible factors that influence expectations.
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