Abstract
Introduction
Higher preoperative patient expectations correlate with better early postoperative outcomes and satisfaction after orthopaedic surgery. However, it is unclear if this association is maintained past one year after knee surgery. It was hypothesized that greater preoperative expectations would be predictive of better patient-reported pain and function two years after knee surgery.
Materials and methods
460 patients undergoing knee surgery between June 2015 and April 2018 were reviewed retrospectively. Baseline and two-year follow-up questionnaires were administered consisting of six Patient-Reported Outcomes Measurement Information System (PROMIS) computer adaptive testing domains, the International Knee Documentation Committee (IKDC) score, a numeric pain scale (NPS), the Tegner Activity Scale (TAS), and the Marx Activity Rating Scale (MARS). Preoperative expectations were measured using the Musculoskeletal Outcomes and Data Evaluation Management System (MODEMS) preoperative expectations domain, and satisfaction was measured via the Surgical Satisfaction Questionnaire (SSQ-8). Statistical analysis was performed to identify associations between preoperative expectations and patient-reported outcomes at two years postoperatively.
Results
The mean (SD) preoperative expectations score was 91.0 (17.9). Greater preoperative expectations were associated with various demographic factors as well as baseline PROMIS Social Satisfaction, NPS body, and MARS lower extremity scores. Greater preoperative expectations were associated with both significantly better two-year and improvement in PROMIS Physical Function, PROMIS Pain Interference, and IKDC. Additionally, greater preoperative expectations were associated with better two-year PROMIS Fatigue, PROMIS Anxiety, whole body NPS, and Met Expectations, as well as greater improvement in PROMIS Social Satisfaction. Multivariable analysis found that greater preoperative expectations were predictive of improvement in PROMIS Pain Interference and IKDC.
Conclusion
Greater preoperative expectations are independently predictive of improvement in pain and function two years after knee surgery. The impact of patient expectations on outcomes after knee surgery appear to be long-lasting; therefore, optimization of expectations prior to surgery may help maximize postoperative outcomes.
Keywords: Patient expectations, Patient-reported outcomes, PROMIS, Knee surgery
1. Introduction
Knee surgeries, including total knee arthroplasty and arthroscopic knee surgery, are among the most common orthopaedic procedures performed in the United States.1 These procedures offer pain relief and functional improvement for patients suffering from a wide variety of knee pathologies including knee osteoarthritis, anterior cruciate ligament injuries, and meniscal injuries, which have a reported annual incidence in the United States of 130 per 10,000 person-years, 68.6 per 100,000 person-years, and 61 per 100,000 person-years, respectively.2, 3, 4 Orthopaedic patients utilize a wide range of resources to gather information about their injuries, including up to 54 % of patients who access online resources to obtain this information.5,6 Increasing access to digital information surrounding common knee injuries may facilitate patients’ development of their own expectations regarding surgery before ever seeing a healthcare provider.
Importantly, there is some evidence that preoperative education can alter patient expectations, thereby impacting postoperative outcomes.7,8 Studies in several orthopaedic cohorts have demonstrated that expectations may influence short-term outcomes postoperatively.9, 10, 11, 12, 13, 14 However, the long-term impact of preoperative expectations on outcomes after knee surgery is not fully understood. Prior studies have demonstrated a positive association between higher preoperative patient expectations and improved pain and functional outcomes at 3 months,15 6 months,11,16,17 and 1 year after knee surgery.12,18 However, it is unclear if this association persists past one year.19 Additionally, current literature investigating outcomes at two years after knee surgery has largely focused on general outcomes, such as satisfaction, rather than joint-specific or domain-specific measures.19,20 Examining these factors independently could be useful for identifying specific areas of intervention to improve postoperative outcomes.
The purpose of this study was to define the relationship between preoperative patient expectations and patient-reported outcomes at two years following knee surgery. It was hypothesized that greater preoperative expectations would predict better patient-reported pain and function two years postoperatively.
2. Methods
After Institutional Review Board approval, a prospective, orthopaedic registry at a single, academic institution was retrospectively reviewed to identify patients that underwent knee surgery from June 2015 to April 2017.21 A cohort of 697 patients who completed a baseline survey for the registry was identified. All knee procedures were included except for irrigation and debridement, hardware removal, foreign body removal, external fixation, mass excision, or biopsy. Data was collected and stored using Research Electronic Data Capture (REDCap); a secure, web-based data collection system designed for research studies.22,23 The electronic medical record was reviewed for patient factors such as age, patient comorbidities, and Current Procedural Terminology (CPT) codes. Sociodemographic data was self-reported in the baseline survey and included gender, ethnicity, race, income, education level, insurance status, employment status, marital status, alcohol consumption, smoking status, recreational drug use, surgical history, workers’ compensation status and other legal claims. Surveys assessing patient-reported outcomes (PROs) were emailed to patients prior to surgery and two years postoperatively. Patients were considered lost to follow-up if they did not complete their 2-year survey by three years postoperatively.
Preoperative expectations were measured using the Musculoskeletal Outcomes Data Evaluation and Management System (MODEMS) expectations domain.24 Patients answered the prompt, “What results do you expect from your treatment?” in six different categories ranging from likelihood to provide “relief from symptoms” to likelihood to “prevent future disability”. Responses were provided on a five-point Likert scale ranging from “not at all likely” to “extremely likely”. Each patient's mean score across all expectations questions was normalized to a 100-point scale, with 100 representing the highest possible expectations.
Patients completed surveys at baseline and two years postoperatively. Surveys included Patient-Reported Outcomes Measurement Information System (PROMIS) computer adaptive testing (CAT) in six domains: Physical Function, Pain Interference, Social Satisfaction, Fatigue, Anxiety, and Depression.25 Surveys also included the International Knee Documentation Committee (IKDC) Subjective Knee Form.26 Patients’ activity levels were measured using the Tegner Activity Scale,27 Marx Activity Rating Scale (MARS) for the lower extremity,28 and International Physical Activity Questionnaire (IPAQ).29 Pain was assessed using a numeric pain scale (NPS) for the operative knee and body.30 To evaluate postoperative satisfaction and fulfillment of expectations, patients completed the Surgical Satisfaction Questionnaire (SSQ-8)31 and the MODEMS Met Expectations domain at two years postoperatively.
Patients with complete baseline and 2-year follow-up surveys were included for analysis. Categorical variables were presented as cell counts and percentages, while continuous variables were reported as means and standard deviations. A goodness-of-fit test was performed to assess for normality. A majority of outcomes were not normally distributed, therefore, non-parametric testing was performed. Wilcoxon rank-sum tests and Kruskal-Wallis tests were used to compare expectations between categorical variables. Post-hoc pairwise comparisons were utilized when a significant group effect was observed. Spearman's correlation coefficient (rs) was used to describe relationships between preoperative expectations and continuous variables. Backwards, stepwise, linear regression was performed to identify predictors of two-year outcomes. Variables that were significantly associated with preoperative expectations were included as candidate variables for regression analysis, along with preoperative expectations. Variables were removed in a step-wise fashion based on contribution to the R2, and the minimum BIC was used to determine the final model. All tests were two-sided and statistical significance was set at p < .05. The analysis was performed using JMP Pro, Version 13 software (JMP®, Version 13 SAS Institute Inc., Cary, North Carolina).
3. Results
460 (66 %) of the 697 patients who completed their baseline questionnaires also completed the two-year PRO questionnaire. The median time to follow-up was 25.1 months (Range 24–36 months). The median preoperative expectations score was 92.7 (IQR = 75–100). More than 65 % of patients answered either “Very likely” or “Extremely likely” for each of the six expectations domains.
The most common primary procedures performed in the cohort were arthroscopic anterior cruciate ligament repair or reconstruction (CPT 29888, n = 143 [31 %]), arthroscopic partial meniscectomy (CPT 29881, n = 82 [19 %]), and total knee arthroplasty (CPT 27447, n = 43 [9 %]) (Table 1). Expectations were similar across all primary CPT codes (p = .57).
Table 1.
Preoperative expectations score by primary CPT code.
| Primary CPT Code | N | Surgical Procedure | Preoperative Expectations Mean (SD) | P-Valuea |
|---|---|---|---|---|
| 29888 | 143 (31 %) | Arthroscopically aided anterior cruciate ligament repair/augmentation or reconstruction | 87.1 (16.9) | 0.57 |
| 29881 | 82 (19 %) | Arthroscopy, knee, surgical; with meniscectomy (medial OR lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty), same or separate compartment(s), when performed | 90.8 (11.1) | |
| 27447 | 43 (9 %) | Arthroplasty, knee, condyle and plateau; medial AND lateral compartments with or without patella resurfacing (total knee arthroplasty) | 86.1 (16.7) | |
| 29882 | 33 (7 %) | Arthroscopy, knee, surgical; with meniscus repair (medial OR lateral) | 87.6 (15.8) | |
| 27446 | 24 (5 %) | Arthroplasty, knee, condyle and plateau; medial OR lateral compartment | 87 (14.5) | |
| 29876 | 23 (5 %) | Arthroscopy, knee, surgical; synovectomy, major, 2 or more compartments (eg, medial or lateral) | 80.8 (23.3) | |
| 29877 | 17 (4 %) | Arthroscopy, knee, surgical; debridement/shaving of articular cartilage (chondroplasty) | 90 (10.8) | |
| 29879 | 14 (3 %) | Arthroscopy, knee, surgical; abrasion arthroplasty (includes chondroplasty where necessary) or multiple drilling or microfracture | 84.6 (15) | |
| 29870 | 13 (3 %) | Arthroscopy, knee, diagnostic, with or without synovial biopsy (separate procedure) | 84.7 (25.3) | |
| 29880 | 8 (2 %) | Arthroscopy, knee, surgical; with meniscectomy (medial AND lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty), same or separate compartment(s), when performed | 76.2 (15.8) |
Abbreviations: CPT, Current Procedural Terminology; SD, standard deviation.
Wilcoxon rank-sum test.
On bivariate analysis, higher expectations were correlated with a lower Charlson Comorbidity Index (CCI, rs = −0.12, p = .013), fewer prior anesthesia events (rs = −0.09, p = .046), fewer prior knee surgeries (rs = −0.17, p = .002), and fewer prior orthopaedic surgeries (rs = −0.12, p = .013, Table 2). Expectations were also significantly higher based on female sex (female 88.0 vs male 85.5, p = .032), lower education level (less than high-school graduate 91.8 vs high-school graduate 82.5, p = .002), employment status (employed/retired 87.6 or student 87.5 vs unable to work 76.3, p = .021) and history of ipsilateral knee surgery (prior surgery 88.8 vs no prior surgery 82, p < .001). Finally, higher expectations were correlated with worse baseline PROMIS Social Satisfaction (rs = −0.10, p = .033), better baseline whole body NPS (rs = −0.10, p = .03), and better baseline MARS lower extremity (rs = 0.11, p = .027, Table 3).
Table 2.
Association between preoperative expectations and patient demographics.
| Continuous Variables | Mean (SD) | rs | P-Value |
|---|---|---|---|
| Age (years) | 44.1 (17.2) | −0.25 | 0.60 |
| BMI (kg/m2) | 29.0 (6.2) | −0.02 | 0.64 |
| CCI | 1.2 (1.5) | −0.12 | 0.013 |
| Surgical History | |||
| No. of prior anesthesia events | 3.2 (3.9) | −0.09 | 0.046 |
| No. of all prior surgeries | 2.7 (3.8) | −0.08 | 0.10 |
| No. of prior knee surgeries | 0.5 (0.9) | −0.17 | 0.002 |
| No. of prior orthopaedic surgeries | 1.3 (2.1) | −0.12 | 0.013 |
| Categorical Variables | N (%) | Preoperative Expectations Mean (SD) | P-Value |
|---|---|---|---|
| Gender | |||
| Female | 207 (45 %) | 88.0 (17.2) | 0.032 |
| Male | 253 (55 %) | 85.5 (17.2) | |
| Race | |||
| Asian | 18 (4.1 %) | 87.5 (17.4) | 0.47 |
| Black | 139 (31.3 %) | 84.3 (19.8) | |
| Other | 14 (3.2 %) | 92.4 (8.5) | |
| White | 273 (61.5 %) | 88.0 (15.3) | |
| Ethnicity | |||
| Not Hispanic or Latino | 423 (94.2 %) | 86.6 (17.1) | 0.70 |
| Hispanic or Latino | 26 (5.8 %) | 86.9 (21.10 | |
| Education level | |||
| College education | 316 (70.5 %) | 86.9 (16.7) | 0.002a |
| High-school graduate | 83 (18.5 %) | 82.5 (18.7) | |
| Less than high-school | 49 (11 %) | 91.8 (12.5) | |
| Employment status | |||
| Employed/Retired | 278 (62.2 %) | 87.6 (15.8) | 0.021a |
| Unemployed | 29 (6.5 %) | 87.1 (14.5) | |
| Unable to work | 43 (9.6 %) | 76.3 (23.7) | |
| Student | 97 (21.7 %) | 87.5 (17.1) | |
| Income | |||
| <$70,000 | 149 (44.9 %) | 84.0 (21.2) | 0.09 |
| >$70,000 | 182 (55.1 %) | 89.4 (14.5) | |
| Insurance status | |||
| Government | 85 (18.8 %) | 83.9 (19.1) | 0.10 |
| Private | 366 (81.1 %) | 87.4 (16.7) | |
| Marital status | |||
| Single | 266 (59.1 %) | 87.0 (17.3) | 0.63 |
| Married or domestic partnership | 184 (40.9 %) | 86.3 (17.1) | |
| Smoking | |||
| Daily smoker | 36 (8.0 %) | 81.0 (20.8) | 0.11 |
| Never smoked | 341 (75.6 %) | 86.8 (17.0) | |
| Quit Smoking | 74 (16.4 %) | 88.3 (15.5) | |
| Alcohol | |||
| Greater than four times a month | 101 (22.5 %) | 87.5 (15.0) | 0.85 |
| Four times a month or fewer | 208 (46.4 %) | 85.8 (18.5) | |
| Never | 139 (31.0 %) | 86.8 (16.7) | |
| Recreational drug use | |||
| No | 424 (94.4 %) | 86.7 (16.9) | 0.40 |
| Yes | 25 (5.6 %) | 83.8 (21.4) | |
| ASA score | |||
| I | 195 (42.5 %) | 87.8 (16.9) | 0.18 |
| II | 243 (52.9 %) | 86.1 (17.5) | |
| III | 21 (4.6 %) | 81.0 (17.7) | |
| Clinical history of depression or anxiety | |||
| No | 413 (89.8 %) | 87.4 (16.3) | 0.06 |
| Yes | 47 (10.2 %) | 80.1 (23.3) | |
| Prior surgery on knee | |||
| No | 303 (66.6 %) | 88.8 (15.4) | <0.001 |
| Yes | 152 (33.4 %) | 82.0 (20.0) | |
| Injury prior to surgery | |||
| No | 157 (35.0 %) | 85.2 (18.6) | 0.22 |
| Yes | 291 (65.0 %) | 87.4 (16.3) | |
| Workers' compensation | |||
| No | 429 (96.8 %) | 86.8 (16.9) | 0.34 |
| Yes | 14 (3.2 %) | 79.9 (24.3) | |
| Legal claim | |||
| No | 415 (93.7 %) | 86.7 (17.0) | 0.81 |
| Yes | 28 (6.3 %) | 84.8 (19.4) | |
Abbreviations: rs, Spearman's Correlation Coefficient; ASA, American Society of Anesthesiologists; BMI, body mass index; CCI, Charlson Comorbidity Index; SD, Standard Deviation.
Boldface p-values indicate a statistically significant difference (p < .05).
Post-hoc pairwise comparisons using the Bonferroni correction demonstrated statistical significance in the “less than high-school” group compared to the “high-school graduate” group, as well as in the “unable to work” group compared to the “employed/retired” and “student” groups.
Table 3.
Correlations between preoperative expectations and baseline patient-reported outcomes.
| Baseline Score |
|||
|---|---|---|---|
| Outcome Measurement | Mean (SD) | rs | P-Value |
| PROMIS Physical Function | 41.5 (8.3) | −0.05 | 0.33 |
| PROMIS Pain Interference | 59.8 (7.4) | 0.07 | 0.11 |
| PROMIS Social Satisfaction | 43.4 (8.9) | −0.10 | 0.033 |
| PROMIS Fatigue | 51.3 (10.4) | <-0.01 | 0.95 |
| PROMIS Anxiety | 55.3 (8.9) | −0.05 | 0.27 |
| PROMIS Depression | 49.1 (9) | −0.08 | 0.10 |
| Numeric Pain Scale, operative knee | 44.5 (29.7) | 0.04 | 0.41 |
| Numeric Pain Scale, whole body | 13.7 (22.3) | −0.10 | 0.030 |
| Tegner Activity Scale | 2.3 (1.8) | −0.01 | 0.85 |
| IKDC | 41.6 (16.7) | −0.06 | 0.24 |
| MARS lower extremity | 46.0 (38.0) | 0.11 | 0.027 |
| IPAQ, MET-min/week | 2502 (2219) | 0.06 | 0.28 |
Abbreviations: rs, Spearman's Correlation Coefficient; IKDC, International Knee Documentation Committee; IPAQ, International Physical Activity Questionnaire; MARS, Marx Activity Rating Scale; MET, Metabolic Equivalent of Task; PROMIS, Patient-Reported Outcomes Measurement Information System; SD, standard deviation.
Boldface p-values indicate a statistically significant difference (p < .05).
Greater preoperative expectations correlated with better two-year PROMIS Physical Function (rs = 0.12, p = .01), PROMIS Pain Interference (rs = −0.11, p = .02), PROMIS Fatigue (rs = −0.11, p = .024), PROMIS Anxiety (rs = −0.10, p = .03), IKDC (rs = 0.13, p = .006), and NPS whole body (rs = −0.11, p = .023) (Table 4). Greater preoperative expectations also correlated with greater improvement in PROMIS Physical Function (rs = 0.13, p = .005), PROMIS Pain Interference (rs = −0.16, p < .001), PROMIS Social Satisfaction (rs = 0.11, p = .017), and IKDC (rs = 0.15, p = .002). Finally, greater preoperative expectations correlated with greater met expectations (rs = 0.12, p = .016) but not satisfaction (rs = 0.07, p = .16).
Table 4.
Correlations between preoperative expectations and 2-year patient-reported outcomes.
| 2-Year Score |
Change in Score |
|||||
|---|---|---|---|---|---|---|
| Outcome Measurement | Mean (SD) | rs | P-Value | Mean (SD) | rs | P-Value |
| PROMIS Physical Function | 51.3 (10.8) | 0.12 | 0.010 | 9.8 (11.4) | 0.13 | 0.005 |
| PROMIS Pain Interference | 50.8 (9.9) | −0.11 | 0.020 | −9.0 (9.5) | −0.16 | <0.001 |
| PROMIS Social Satisfaction | 53.2 (11.6) | 0.06 | 0.25 | 9.9 (12.6) | 0.11 | 0.017 |
| PROMIS Fatigue | 46.9 (10.8) | −0.11 | 0.024 | −4.4 (11.3) | −0.07 | 0.15 |
| PROMIS Anxiety | 49.6 (10.4) | −0.10 | 0.030 | −5.8 (10.5) | −0.01 | 0.81 |
| PROMIS Depression | 46.8 (9.5) | −0.08 | 0.09 | −2.4 (9.6) | 0.04 | 0.46 |
| Numeric Pain Scale, operative knee | 23.6 (26.6) | −0.09 | 0.07 | −9.0 (32.2) | −0.05 | 0.35 |
| Numeric Pain Scale, whole body | 21.0 (24.8) | −0.11 | 0.023 | 7.5 (23.6) | 0.03 | 0.59 |
| Tegner Activity Scale | 4.9 (2.8) | 0.07 | 0.15 | 2.6 (2.8) | 0.05 | 0.37 |
| IKDC | 67.5 (23.6) | 0.13 | 0.006 | 26.3 (22.5) | 0.15 | 0.002 |
| MARS lower extremity | 37.6 (33.6) | 0.09 | 0.07 | −20.9 (34.8) | −0.05 | 0.26 |
| IPAQ, MET-min/week | 3720 (2657) | 0.01 | 0.89 | 1342 (3021) | −0.91 | 0.18 |
| MODEMS met expectations | 73.1 (29.8) | 0.12 | 0.016 | |||
| SSQ-8 | 77.4 (21.4) | 0.07 | 0.16 | |||
Abbreviations: rs, Spearman's Correlation Coefficient; IKDC, International Knee Documentation Committee; IPAQ, International Physical Activity Questionnaire; MARS, Marx Activity Rating Scale; MET, Metabolic Equivalent of Task; MODEMS, Musculoskeletal Outcomes Data Evaluation and Management System; PROMIS, Patient-Reported Outcomes Measurement Information System; SD, standard deviation; SSQ-8, Surgical Satisfaction Questionnaire.
Boldface p-values indicate a statistically significant difference (p < .05).
On multivariable regression analysis, preoperative expectations was identified as a predictor of greater improvement in PROMIS Pain Interference and IKDC (Table 5). Over the range of preoperative expectations from 0 to 100, expectations predicted a 7-point improvement in PROMIS Pain Interference and a 17-point improvement in IKDC. Preoperative expectations did not emerge as a predictor of two-year PROMIS Physical Function, NPS, Tegner Activity Scale, MARS, or IPAQ.
Table 5.
Multivariable linear regression models for preoperative predictors of 2-year change in PROMIS pain interference and IKDC.a
| 2-Year Change in PROMIS Pain Interference |
2-Year Change in IKDC |
|||
|---|---|---|---|---|
| Term | Estimate (SE) | P-Value | Estimate (SE) | P-Value |
| Preoperative expectations | −0.07 (0.03) | 0.006 | 0.17 (0.06) | 0.008 |
| PROMIS Social Satisfaction (baseline) | 0.22 (0.05) | <0.001 | −0.46 (0.12) | <0.001 |
| MARS lower extremity (baseline) | −0.04 (0.01) | <0.001 | 0.15 (0.03) | <0.001 |
Abbreviations: IKDC, International Knee Documentation Committee; MARS, Marx Activity Rating Scale; PROMIS, Patient-Reported Outcome Measurement Information System; SE, standard error.
Variables included in the multivariable linear regression analysis: normalized preoperative expectations score, gender, history of prior knee surgery, number of prior orthopaedic procedures, number of anesthesia events, education status, employment status, Charlson Comorbidity Index, baseline PROMIS Social Satisfaction, baseline numeric pain scale whole body, baseline Marx Activity Rating Scale lower body.
4. Discussion
This study partially supports the hypothesis that greater preoperative expectations are predictive of better two-year patient-reported pain and function scores. There was a significant correlation between greater preoperative expectations and both two-year and change in scores in PROMIS Physical Function, PROMIS Pain Interference, and IKDC. Additionally, greater expectations were associated with better two-year scores for PROMIS Fatigue, PROMIS Anxiety, whole body NPS, and improvement in PROMIS Social Satisfaction. Furthermore, when controlling for potential confounding variables through multivariable analysis, preoperative expectations were independently predictive of greater improvement in PROMIS Pain Interference and IKDC scores. Strengths of this study include a large, diverse population of various knee surgery patients, minimum follow-up of two years, and comprehensive multivariable analyses that broadly controlled for potential confounders.
While the relationship between preoperative expectations and short-term PROs is well-established, there is a scarcity of literature exploring this relationship in the knee surgery population at two years. Existing studies with two-year follow-up have primarily examined satisfaction as an outcome measure. In a large cohort of patients undergoing total knee arthroplasty, Ghomrawi et al. demonstrated that some, but not all, preoperative expectations domains were associated with overall satisfaction at a minimum two-year follow-up.32 Mannion et al. found that higher preoperative expectations were correlated with satisfaction at two years, but were not a significant predictor on multivariable analysis.33 The results of the present study are similar, demonstrating no correlation between preoperative expectations and satisfaction at two years. One prior study assessed functional outcomes at two years in patients undergoing total knee arthroplasty using the Oxford Knee Score and found an association with preoperative expectations regarding pain, but not function.34 Additionally, there was no difference in satisfaction based on level of preoperative expectations. The present study provides evidence that greater preoperative expectations are correlated with better pain and functional PROs in both arthroplasty and non-arthroplasty patients. It is important to note that the correlations found in this study were weak, however, it is noteworthy that these correlations persist even at two years postoperatively. Additionally, the results of the multivariable analysis demonstrate that preoperative expectations are independently predictive of the overall change in PROMIS Pain Interference and IKDC scores when controlling for other confounders. Lastly, the predicted change in PROMIS Pain Interference and IKDC over the range of preoperative expectations scores meets the reported minimal clinically important difference (MCID) values for each respective measure.35,36
Studies examining the relationship between expectations and satisfaction as the primary outcome measure potentially overlook other crucial aspects such as function, pain, and mental health. Importantly, this study found a significant relationship between preoperative expectations and postoperative pain and function in knee surgery patients at two years using PROMIS Pain Interference and IKDC. PROMIS Pain Interference domain has been shown to be a superior assessment of pain in orthopaedic patients with minimal floor or ceiling effects.37 The IKDC questionnaire effectively assesses patients' perceived knee function and is particularly effective at measuring outcomes from two to nine years postoperatively.38 This questionnaire has also been shown to be effective in evaluating change in functioning of patients aged 45–70 years following meniscus tear,39 which is relevant to this study given the average age was approximately 44 years old and two of the top four CPT codes in the cohort were meniscus surgery. This study demonstrates that improved preoperative expectations independently predict better postoperative scores in both of these outcome measures. While other studies have previously demonstrated that preoperative expectations predict postoperative satisfaction, this study indicates that greater preoperative expectations are also associated with improvements in pain and knee function at the two-year time point, as measured by PROMIS and legacy PROs. Notably, no such association was found with other PROs such as social satisfaction, depression, or activity levels, suggesting that the long-term effect of preoperative expectations may be domain specific.
The results of this study suggest that preoperative interventions and education aimed at modifying patients’ expectations before surgery may be important. Studies by Rief et al.,40 McDonald et al.,41 and Mancuso et al.42 have shown that interventions and education can alter preoperative expectations, leading to enhanced postoperative outcomes. By educating patients and shaping their expectations, it may be possible to impact the long-term results of knee surgery, however, more research is needed in this area. Future research should be directed at effective education strategies in these patient populations to support these longer-term outcomes.
This study has several limitations. Firstly, this is a single-center retrospective study and is therefore susceptible to all the limitations of such a study design, including selection bias and missing data. The use of surveys to assess PROs limits the study to individuals capable of responding to email-administered survey questions. It is possible that patients who do not maintain an active email address form different expectations than those that do and are not represented in this sample. Furthermore, as an observational study, causation between preoperative expectations and postoperative outcomes cannot be established. The overall high preoperative expectations observed in the study could reflect a ceiling effect in the measurement tool, which would affect the reported mean scores and limit the ability to detect differences between groups. Additionally, this cohort includes a wide variety of knee surgeries, which improves the generalizability of results, but may reduce the clinical specificity. Lastly, the 34.0 % loss to follow-up rate may affect the interpretation of the two-year outcome scores.
5. Conclusion
In patients undergoing knee surgery, greater preoperative expectations are independently associated with improvement in pain and function at two years postoperatively. These findings suggest that assessment and optimization of expectations prior to knee surgery may be important to improving postoperative outcomes. Future prospective studies are needed in this population to determine if preoperative educational strategies can alter preoperative expectations and ultimately postoperative outcomes.
CRediT authorship contribution statement
Brandon Leon: Investigation, Methodology, Writing – original draft. Evan L. Honig: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Writing – review & editing. Samir Kaveeshwar: project administration, Methodology, Writing – review & editing. Dominic J. Ventimiglia: Investigation, Formal analysis, Methodology, Writing – review & editing. Leah E. Henry: Investigation, Writing – review & editing. Alexandra Baker Lutz: Investigation, Writing – review & editing. Natalie L. Leong: project administration, Writing – review & editing. Sean J. Meredith: project administration, Writing – review & editing. Jonathan D. Packer: project administration, Writing – review & editing. R. Frank Henn: Conceptualization, Project administration, Supervision, Writing – review & editing.
Declaration of interest
None.
Consent
Informed consent was obtained from all patients for participation in the study.
Ethics approval
This study was approved by the Institutional Review Board (IRB) Committee at the University of Maryland, Baltimore (HP-00062261).
Funding
This work was supported by a grant from The James Lawrence Kernan Hospital Endowment Fund, Incorporated (BL1941007WS). This work was also supported in part by Career Development Award Number IK2 BX004879 from the United States (U.S.) Department of Veterans Affairs Biomedical Laboratory R&D (BLRD) Service.
Conflict of interest statement
The authors have no conflicts of interest to disclose.
Acknowledgements
The authors would like to thank J. Kathleen Tracy, Ph.D.; Andrew G. Dubina, MD; Julio J. Jauregui, MD; Michael P. Smuda; Vidushan Nadarajah, MD; Ali Aneizi, MD; Patrick M.J. Sajak MD; Tina Zhang, MD; Matheus B. Schneider; Joshua M. Abzug, MD; Farshad Adib, MD, Craig H. Bennett, MD; Vincent Ng, MD; Cameran I. Burt; Zachary Clark; Shaun H. Medina; Daniel Rivkin; Keyan Shasti; and Alexander J. Wahl for their assistance with data collection.
References
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