Validation of the Hip Disability and Osteoarthritis Outcome Score and Knee Injury and Osteoarthritis Outcome Score Pain and Function Subscales for Use in Total Hip Replacement and Total Knee Replacement Clinical Trials

BackgroundTotal hip replacement (THR)/total knee replacement (TKR) studies do not uniformly measure patient centered domains, pain, and function. We aim to validate existing measures of pain and function within subscales of standard instruments to facilitate measurement.MethodsWe evaluated baseline and 2-year pain and function for THR and TKR using Hip disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS), with primary unilateral TKR (4796) and THR (4801). Construct validity was assessed by correlating HOOS/KOOS pain and activities of daily living (ADL), function quality of life (QOL), and satisfaction using Spearman correlation coefficients. Patient relevant thresholds for change in pain and function were anchored to improvement in QOL; minimally clinically important difference (MCID) corresponded to “a little improvement” and a really important difference (RID) to a “moderate improvement.” Pain and ADL function scores were compared by quartiles using Kruskal-Wallis.ResultsTwo-year HOOS/KOOS pain and ADL function correlated with health-related QOL (KOOS pain and Short Form 12 Physical Component Scale ρ = 0.54; function ρ = 0.63). Comparing QOL by pain and function quartiles, the highest levels of pain relief and function were associated with the most improved QOL. MCID for pain was estimated at ≥20, and the RID ≥29; MCID for function ≥14, and the RID ≥23. The measures were responsive to change with large effect sizes (≥1.8).ConclusionWe confirm that HOOS/KOOS pain and ADL function subscales are valid measures of critical patient centered domains after THR/TKR, and achievable thresholds anchored to improved QOL. Cost-free availability and brevity makes them feasible, to be used in a core measurement set in total joint replacement trials.     

Normative Data of the Hip Disability and Osteoarthritis Outcome Score,JR in a Healthy United States Population

BackgroundPatient-reported outcome measures (PROMs) play a vital role in the care we provide our patients. To help understand the application of PROMs in arthroplasty, normative and benchmark data to serve as a comparison to patients presurgery and postsurgery would be extremely valuable. We collected normative data of the Hip Disability and Osteoarthritis Outcome Score (HOOS), JR on a healthy population, greater than 17 years of age, in the United States devoid of hip injury and/or surgery.MethodsThis is a cross-sectional study, where hard copy surveys were administered to 1140 patients, being seen for an orthopedic issue unrelated to their hip, and nonpatient visitors in July 2018 at an outpatient orthopedic clinic in a suburban metropolitan city. Participants were eligible if they self-reported a medical history negative for hip arthroplasty, current hip pain/disability, or hip procedure (surgery or injection) within the past year. Mean, standard deviation, 95% confidence intervals, and ranges on the HOOS, JR interval scores were calculated by sex, age decade, body mass index (BMI), reason for visit, history of orthopedic procedure, and medical history.ResultsWe included 425 men and 575 women in the final study cohort. Women aged between 70+ years reported the lowest mean interval score (mean = 89.8). Overall women scored lower as well (93.3 vs 95.7, P = .001). There was not a statistical difference between the interval scores by tobacco consumption (93.5 vs 94.4, P = .49) and between patients versus nonpatient visitors (94.2 vs 94.5, P = .672). Lower scores were observed in participants with a past nonhip orthopedic procedure (92.6 vs 94.9, P = .016), with a medical history of a chronic illness (92.5 vs 95.9, P = <.001), and classified as obese (BMI > 30) (91.7 vs 95.2, P < .001). On regression analysis, there was a decrease of 0.3 and 0.1 in the interval score for each unit of BMI and age by year, respectively (P < .001).ConclusionThis study provides normative reference values for the HOOS, JR in a US population from a suburban metropolitan city for individuals greater than 17 years of age. These scores can facilitate physician-patient shared decision-making to help patients understand expectations after hip arthroplasty in respect to PROMs.     

Patient Acceptable Symptom State for the Forgotten Joint Score in Primary Total Knee Arthroplasty

BackgroundIn order to better understand the clinical benefits of total knee arthroplasty (TKA) and improve the interpretability of the Forgotten Joint Score (FJS-12), the establishment of a meaningful change in score is necessary. The purpose of this study is to determine the threshold of the FJS-12 for detecting the patient acceptable symptom state (PASS) following primary TKA.MethodsWe retrospectively reviewed all patients who underwent elective, primary TKA and answered both the FJS-12 and the Knee Injury Osteoarthritis Outcome Survey, Joint Replacement KOOS, JR surveys 1-year postoperatively. The questionnaires were administered via a web-based electronic application. KOOS, JR score was used as the anchor. The anchor for PASS calculation should relate pain, physical function, and patient satisfaction. Two statistical methods were employed: (1) the receiver operating characteristic (ROC) curve point; (2) 75^th percentile of the cumulative percentage curve of patients who had the KOOS, JR score difference larger than the cut-off value.ResultsThis study included 457 patients. The mean 1-year FJS-12 score was 42.6 ± 27.8. The mean 1-year KOOS, JR score was 68.0 ± 17.2. A high positive correlation between FJS-12 and KOOS, JR was found (r = 0.72, P < .001) making the KOOS, JR a valid external anchor. The threshold score of the FJS-12 which maximized the sensitivity and specificity for detecting a PASS was 33.3 (AUC = 0.78, 95% CI [0.74, 0.83]). The cut-off value computed with the 75^th percentile approach was 77.1 (95% CI [73.9, 81.5]).ConclusionThe PASS threshold for the FJS-12 was 33.3 and 77.1 at 1-year follow-up after primary TKA using the receiver operating characteristic (ROC) curve and 75^th percentile approaches, respectively. These values can be used to assess the successful achievement of a forgotten joint.Level III EvidenceRetrospective Cohort Study.     

African American Patients Have Improved Functional Gains and Comparable Clinical Outcomes to Caucasian Patients After Total Hip and Knee Arthroplasty

BackgroundWith the increasing popularity of alternative payment models, minorities who use more postacute care resources may face difficulties with access to quality total hip arthroplasty (THA) and total knee arthroplasty (TKA) care. The purpose of this study is to compare differences in perioperative complications and functional outcomes between African American and Caucasian patients undergoing THA and TKA.MethodsWe reviewed a consecutive series of all primary THA and TKA patients at our institution from 2015 to 2018. Demographics, comorbidities, 90-day complications, readmissions, Veterans Rand 12-Item Health Survey (VR-12), Hip disability Osteoarthritis Outcome Score (HOOS), and Knee injury and Osteoarthritis Outcome Scores (KOOS) were compared between African American and Caucasian patients. A multivariate analysis was performed to control for confounding variables.ResultsOf the 5284 patients included in the study, 1041 were African American (24.5%). Although African American patients had lower preoperative HOOS/KOOS (33.5 vs 45.1, P < .001) and mental VR-12 scores (37.8 vs 51.5, P < .001) compared with Caucasian patients, there was no clinical difference at 1 year in HOOS/KOOS (50.2 vs 50.4), mental VR-12 (55.0 vs 52.6), or physical VR-12 scores (39.5 vs 39.8). When controlling for demographics and medical comorbidities, African American race was associated with increased rehabilitation facility discharge (odds ratio, 1.69; P < .001) but no difference in readmissions or complications.ConclusionAlthough African American patients had lower preoperative functional scores, they made improved postoperative gains when compared with Caucasian patients. Although there was no difference in postoperative complications, further studies should assess social causes for the increase in rehabilitation utilization rates in minority patients.     

Preoperative Patient-Reported Outcomes and Clinical Characteristics as Predictors of 90-Day Cost/Utilization and Complications

Background

With the advent of mandatory bundle payments for total joint arthroplasty (TJA), assessing patients’ risk for increased 90-day complications and resource utilization is crucial. This study assesses the degree to which preoperative patient-reported outcomes predict 90-day complications, episode costs, and utilization in TJA patients.

The Short Form KOOS,JR Is Valid for Revision Knee Arthroplasty

BackgroundThe Knee Injury Osteoarthritis Outcome Survey, Joint Replacement (KOOS, JR) is a reliable, responsive, and validated patient-reported outcome measure (PROM) of knee health in patients with knee osteoarthritis undergoing unilateral primary total knee arthroplasty (TKA). The validity of the KOOS, JR for revision TKA remains unknown.MethodsWe identified 314 patients who underwent revision TKA and had completed preoperative and 2-year postoperative PROMs. Validation included assessment of local dependence, unidimensionality, internal consistency, external construct validity, responsiveness, and floor effects preoperatively and ceiling effects at 2 years postoperatively.ResultsAmong patients undergoing revision TKA, the KOOS, JR demonstrated an absence of residual item correlation, adequate unidimensionality, high internal consistency (Person Separation Index: 0.897), and high external construct validity with existing validated PROMs, including KOOS Pain (Spearman’s correlation coefficient 0.89) and KOOS activities of daily living (0.90) domains. The KOOS, JR was more responsive (standardized response means: 1.14) to revision TKA than other common knee PROMs. Three percent of revision TKA patients were at the floor (lowest score) preoperatively and 9% reached the ceiling (highest possible score) postoperatively.ConclusionsKOOS, JR performs well in revision TKA patients with regard to internal consistency, external validity, responsiveness, and floor and ceiling effects. Our results support extending its use to revision TKA in both clinical and research settings.     

Reliability and Validity of the Knee Injury and Osteoarthritis Outcome Score in Patients Undergoing Unicompartmental Knee Arthroplasty

BackgroundThe Knee Injury and Osteoarthritis Outcome Score (KOOS) was developed to document outcomes from knee injury, including the impact of osteoarthritis on knee function. The purpose of this study is to determine the reliability and validity of the KOOS subscales for evaluating outcomes following unicompartmental knee arthroplasty (UKA).MethodsKOOS Pain, Activities of Daily Living (ADL), Sport, Symptoms, and Quality of Life (QoL) scores collected from 172 patients who underwent UKA were used in the analysis. KOOS subscales were tested for reliability and validity of scores through a Rasch model analysis.ResultsKOOS Sport, KOOS ADL, and KOOS QoL had good evidence of reliability with acceptable person reliability, person separation, and item reliability. For overall scale functioning, KOOS Pain, Symptoms, and ADL all had 1 question that did not have an acceptable value for infit or outfit mean square value. Questions in KOOS Sport and QoL all had acceptable values. There was a positive, linear relationship between the Short-Form 12 Physical Component Summary and the KOOS subscales which indicated good evidence of convergent validity. These associations were also seen when the cohort was separated in medial and lateral UKA.ConclusionTwo of the 5 KOOS subscales (KOOS Sport and KOOS QoL) were considered adequate in measuring outcomes, as well as reliability. The KOOS ADL had borderline values; however, it had adequate infit and outfit values. The KOOS Pain and Symptom score performed poorly in this analysis. For documenting outcomes following UKA, this study supports the use of KOOS ADL, Sport, and QoL.     

Monitoring Patient Recovery After THA or TKA Using Mobile Technology

Background

Smartphones offer the possibility of assessing recovery of mobility after total hip or knee arthroplasty (THA or TKA) passively and reliably, as well as facilitating the collection of patient-reported outcome measures (PROMs) with greater frequency.

Questions/Purposes

We investigated the feasibility of using mobile technology to collect daily step data and biweekly PROMs to track recovery after total joint arthroplasty.

Methods

Pre- and post-operative daily steps were recorded in prospectively enrolled patients (128 THA and 139 TKA) via an app, which uses the phone’s accelerometer. During 6-month follow-up, patients also completed PROMs (the pain numeric rating scale, the Hip Disability and Osteoarthritis Outcome Score Joint Replacement [HOOS JR] and the Knee Injury and Osteoarthritis Outcome Score Joint Replacement [KOOS JR]), and HOOS or KOOS JR quality of life domain via a mobile-enabled web link.

Results

At least 6 months of follow-up was completed by 65% for THA and 68% for TKA patients. Reasons for non-completion included time commitment, phone battery, app issues, and health complications. Responses from 78% of requested PROMs were returned with 96% of patients returning at least one post-operative PROM. Step data were available from 92% of days from male patients and 86% of days from female patients. The most robust recovery occurred early, within the first 2 months. The groups with higher pre-operative steps were more likely to recover their maximum daily steps at an earlier time point. Correlations between step counts and PROMs scores were modest.

Conclusion

Assessing large amounts of post-TKA and post-THA step data using mobile technology is feasible. Completion rates were good, making the technology very useful for collecting frequent PROMs. Being unable to ensure that patients always carried their phones limited our analysis of the step counts.

     

Accuracy and Validity of Computer Adaptive Testing for Outcome Assessment in Patients Undergoing Total Hip Arthroplasty

BackgroundProbability-based computer algorithms that reduce patient burden are currently in high demand. These computer adaptive testing (CAT) methods improve workflow and reduce patient frustration, while achieving high measurement precision. In this study, we evaluated the accuracy and validity of the CAT Hip Disability and Osteoarthritis Outcome Score (HOOS) and the Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS-JR) by comparing them to the full version of these scoring systems in a subset of patients who had undergone total hip arthroplasties.MethodsA previously developed CAT HOOS and HOOS-JR was applied to 354 and 1547 HOOS and HOOS-JR patient responses, respectively. Mean, standard deviations, Pearson’s correlation coefficients, interclass correlation coefficients, frequency distribution plots, and Bland-Altman plots were used to compare the precision, validity, and accuracy between CAT scores and full-form scores.ResultsBy modifying the questions to past responses, the CAT HOOS demonstrated a mean reduction of 30% of questions (28 vs 40 questions). There were no significant differences between the full HOOS and CAT HOOS with respect to pain (P = .73), symptoms (P = .94), quality of life (P = .99), activities of daily living (P = .82), and sports (P = .99). There were strong linear relationships between the CAT versions and the standard questionnaires (r > 0.99). The Bland-Altman plot showed that differences between CAT HOOS and full HOOS were independent of the overall scores.ConclusionThe CAT HOOS and HOOS-JR have high correlation and require fewer questions to finish compared to the standard full-form questionnaires. This may represent a reliable and practical alternative that may be less burdensome to patients and may help improve compliance for reporting outcome metrics.     

Does Physical Activity Level Influence Total Hip Arthroplasty Expectations,Satisfaction, and Outcomes?

BackgroundTotal hip arthroplasty (THA) patients expect pain relief and functional improvement, including return to physical activity. Our objective was to determine the impact of patients' physical activity level on preoperative expectations and postoperative satisfaction and clinical outcomes in patients undergoing THA.MethodsUsing an institutional registry of patients undergoing THA between 2007 and 2012, we retrospectively identified patients who underwent unilateral primary THA for osteoarthritis and completed a preoperative Lower Extremity Activity Scale, Hospital for Special Surgery Hip Replacement Expectations Survey, and Hip disability and Osteoarthritis Outcome Score in addition to two-year HOOS and satisfaction evaluations. Active patients (n = 1053) were matched to inactive patients (n = 1053) by age, sex, body mass index, and comorbidities. The cohorts were compared with regard to the association of expectations with Hip disability and Osteoarthritis Outcome Score and satisfaction, the change in Lower Extremity Activity Scale level from baseline to 2 years, complications, and revision surgical procedures.ResultsSignificantly more active patients (74%) expected to be “back to normal” regarding ability to exercise and participate in sports compared with inactive patients (64%, P < .001). Overall satisfaction was similar. Higher expectations with regard to exercise and sports were associated with higher HOOS sports and recreation subdomain scores in active patients. The inactive patient group improved on baseline activity level at 2 years while the active group did not.ConclusionAt 2 years after THA, active and inactive patients were similarly satisfied and achieved comparable outcomes. Inactive patients showed a greater improvement in physical activity level from preoperative baseline than active patients. Complications and revision rates were similar.Level of EvidenceIII.     

Computer-Assisted Kinematic and Mechanical Axis Total Knee Arthroplasty: A Prospective Randomized Controlled Trial of Bilateral Simultaneous Surgery

BackgroundRandomized controlled trials of kinematic alignment (KA) and mechanical alignment (MA) in primary total knee arthroplasty (TKA) have to date demonstrated at least equivalence of KA in terms of clinical outcomes. No trial of bilateral TKA has been conducted so patient preference for one technique over the other is unknown.MethodsForty-one participants underwent computer-assisted bilateral TKA. The outcome measures were as follows: (1) joint range of motion and functional scores including the KOOS, the KOOS JR, Oxford Knee Score, and the Forgotten Joint Score at a minimum of 2 years; (2) preference and perception of limb symmetry; (3) intraoperative alignment data; (4) release and gap balance data; and (5) postoperative radiographic joint angles.ResultsThere were no significant differences with respect to flexion range (P = .970) or functional scores (mean KOOS, P = .941; KOOS JR, P = .685; Oxford Knee Score, P = .578; FJS, P = .542). Significantly more participants who favored one knee preferred their KA TKA (P = .03); however, half of the patients had no preference and the overall numbers were small. Only 3 participants perceived any limb asymmetry (P < .001). More releases were required in the MA group (P = .018). Standing hip-knee-ankle angle means and frequency distributions were similar (P = .097 and P = .097, respectively).ConclusionClinical outcomes were equivalent at 2 years. Significantly more participants preferred their KA joint. Fewer releases were required using a KA technique. Participants were visually insensitive to modest hip-knee-ankle angle asymmetry.Level of EvidenceLevel 1.     

Mapping and Crosswalk of the Oxford Hip Score and Different Versions of the Hip Disability and Osteoarthritis Outcome Score

BackgroundPatient-reported outcome measures such as the Oxford-12 Hip Score and Hip Disability and Osteoarthritis Outcome Score (HOOS) are used in daily orthopaedic practice to evaluate patients. Because different studies use different scores, it would be important to build conversion tables between scores (crosswalk) to compare the results of one study with those of another study. Various mapping methods can be used to develop crosswalk tables that convert Oxford-12 scores to the HOOS (and its derivatives, including the HOOS physical function short form, HOOS joint replacement, and HOOS-12) and vice versa. Although prior studies have investigated this issue, they are limited to short forms of the HOOS score. Consequently, they cannot be applied to hip preservation surgery and do not include quality-of-life items, whereas the Oxford-12 Hip Score is used for all hip evaluations.Questions/purposesWe prospectively studied the Oxford-12 and HOOS and its derivatives to (1) determine which version of the HOOS has the best mapping with the Oxford-12, (2) define the most-appropriate mapping method using selected indicators, and (3) generate crosswalk tables between these two patient-reported outcome measures.MethodsThe study enrolled 500 adult patients before primary THA (59% men [294 of 500 patients]) with hip osteoarthritis or avascular necrosis of the femoral head who completed the HOOS and Oxford-12. Patients were recruited from January 2018 to September 2019 in a tertiary-care university hospital, and we included all primary THAs in patients older than 18 years with a BMI lower than 35 kg/m² and greater than 18 kg/m². After a minimum of 6 months of follow-up, 39% (195 of 500) of the patients were assessed using the same tools. To determine which version of the HOOS mapped best to the Oxford-12 and what the most-appropriate mapping method was, we used preoperative data from all 500 patients. Because there is no consensus on the method to establish crosswalk, various mapping methods (linear regression, tobit regression, and quantile regression) and equating methods (linear equating and equipercentile method) were applied along with cross-validation to determine which method was the most suitable and which form of the HOOS provided the best result according to different criteria (mean absolute error, r², and Kolmogorov-Smirnov distance).To generate crosswalk tables, we created a conversion table (between the Oxford-12 and the HOOS form that was chosen after answering our first research question and the method chosen after answering our second question) using preoperative and postoperative data (n = 695). This table was meant to be simple to use and allows easy conversions from one scoring system to another.ResultsThe Oxford-12 and HOOS were strongly correlated (Pearson correlation coefficient range 0.586-0.842) for the HOOS subcategories and HOOS physical function, HOOS joint replacement, and HOOS-12. The correlation between the HOOS-12 and Oxford-12 was the strongest (r = 0.825). According to the three different criteria and five methods, the HOOS-12 was the best suited for mapping. The goal was to minimize the mean absolute error (perfect model = 0), have a Kolmogorov-Smirnov distance as close as possible to 0, and have the r² as close as possible to 1. Regarding the most-suitable method for the crosswalk mapping (research question 2), the five methods generated similar results for the r² (range 0.63-0.67) and mean absolute error (range 6-6.2). For the Kolmogorov-Smirnov distance, the equipercentile method was the best (Kolmogorov-Smirnov distance 0.04), with distance reduced by 43% relative to the regression methods (Kolmogorov-Smirnov distance 0.07). A graphical comparison of the predicted and observed scores showed that the equipercentile method provided perfect superposition of predicted and observed values after mapping. Finally, crosswalk tables were produced between the HOOS-12 and Oxford-12.ConclusionThe HOOS-12 is the most complete and suitable form of the HOOS for mapping with the Oxford-12, while the equipercentile method is the most suitable for predicting values after mapping. This study provides clinicians with a reliable tool to crosswalk between these scores not only for joint arthroplasty but also for all types of hip surgeries while also assessing quality of life. Our findings should be confirmed in additional studies.Clinical RelevanceThe resulting crosswalk tables can be used in meta-analyses, systematic reviews, or clinical practice to compare clinical studies that did not include both outcome scores. In addition, with these tools, the clinician can collect only one score while still being able to compare his or her results with those obtained in other databases and registries, and to add his or her results to other databases and joint registries.     

Extrapolation of Normative KOOS,JR Data for the Young Patient Population Undergoing Knee Arthroplasty Procedures

Background

The Knee Injury and Osteoarthritis Outcome (KOOS), JR is a patient-reported outcome measure that is validated for patients undergoing total knee arthroplasty. The objective of this study was to provide normative data for the KOOS, JR in a relatively healthy US population visiting an outpatient orthopedic setting. This study is a cross-sectional study.

Changes in Patient Reported Outcome Measure Scores From Initial Presentation to Day-of-Surgery in Patients Undergoing Hip and Knee Arthroplasty

BackgroundIt is not well understood how patient reported outcome measures (PROMs) change from initial presentation to day-of-surgery (DOS). This study sought to quantify preoperative PROM changes for hip and knee arthroplasty patients.MethodsA retrospective review was performed on primary total hip, total knee, and partial knee arthroplasty patients from October 2020 through January 2021. Trends in preoperative Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) scores were compared using scores at initial presentation in the ambulatory clinic and at a time near the date-of-surgery. A total of 497 patients possessed 2 preoperative PROMIS-PF (497/497), HOOS-JR (152/497), or KOOS-JR (258/497) surveys.ResultsThere was no significant statistical difference in mean PROM scores between initial presentation and DOS PROMIS-PF or HOOS-JR scores. Only KOOS-JR demonstrated a significant statistical difference of 2 ± 14 (P = .002) when comparing initial versus preoperative scores. Partial knee arthroplasty patients saw a strong positive correlation (r = 0.77) between initial PROMIS-PF and DOS scores. However, mean absolute value changes on an individual level were 4 ± 4, 11 ± 39, and 11 ± 10 for PROMIS-PF, HOOS-JR, and KOOS-JR, respectively, indicating the presence of meaningful patient-level score changes as based on previously published anchor-based minimal clinically important differences.ConclusionPROMs collected during the preoperative period demonstrated wide variability at an individual level, but not at a population level. Collection at both time points may be necessary in order to understand the clinical impact of surgery on these patients.     

Does Age Influence Patient-Reported Outcomes in Unilateral Primary Total Hip and Knee Arthroplasty?

BackgroundTotal hip arthroplasty (THA) and total knee arthroplasty (TKA) are used to treat patients with end-stage arthritis. Previous studies have not demonstrated a consistent relationship between age and patient-reported outcomes. The purpose of this study is to assess the impact of age on patient-reported outcomes after unilateral primary THA or TKA.MethodsA retrospective review of available data in Alberta Bone and Joint Health Institute (ABJHI) Data Repository was performed. We identified 53,498 unilateral primary THA and TKA between April 2011 and 2017. Patients were divided by age into 3 categories: <55, 55-70, and >70. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and EuroQoL 5-dimension (EQ-5D) Canada scores were obtained at presurgery, 3 and 12 months postoperatively.ResultsFor TKA, younger patients had larger improvements in WOMAC scores at 3 and 12 months (P = <.001-.033), and in EQ-5D scores at 3 months (P < .001). When adjusted, patients <55 had lower WOMAC and EQ-5D scores at 3 months postoperatively compared to those 55-70 or >70 (all P < .01). Outcomes at 12 months did not differ between age-groups.For THA, younger patients had larger improvements in WOMAC at 3 months (P = .03). When adjusted, patients <55 had higher WOMAC scores at 12 months postoperatively compared to those 55-70 or >70, and higher EQ-5D scores compared to those 55-70 (all P < .05).ConclusionWhile a multitude of factors go in to quantifying successful THA or TKA, this study suggests that patient age should not be a deterrent when considering the impact of age on patient-reported outcomes.     

Can Machine Learning Methods Produce Accurate and Easy-to-Use Preoperative Prediction Models of One-Year Improvements in Pain and Functioning After Knee Arthroplasty?

BackgroundApproximately 15%-20% of total knee arthroplasty (TKA) patients do not experience clinically meaningful improvements. We sought to compare the accuracy and parsimony of several machine learning strategies for developing predictive models of failing to experience minimal clinically important differences in patient-reported outcome measures (PROMs) 1 year after TKA.MethodsPatients (N = 587) in 3 large Veteran Health Administration facilities completed PROMs before and 1 year after TKA (92% follow-up). Preoperative PROMs and electronic health record data were used to develop and validate models to predict failing to experience at least a minimal clinically important difference in Knee Injury and Osteoarthritis Outcome Score (KOOS) Total, KOOS JR, and KOOS subscales (Pain, Symptoms, Activities of Daily Living, Quality of Life, and recreation). Several machine learning strategies were used for model development. Ten-fold cross-validation and bootstrapping were used to produce measures of overall accuracy (C-statistic, Brier Score). The sensitivity and specificity of various predicted probability cut-points were examined.ResultsThe most accurate models produced were for the Activities of Daily Living, Pain, Symptoms, and Quality of Life subscales of the KOOS (C-statistics 0.76, 0.72, 0.72, and 0.71, respectively). Strategies varied substantially in terms of the numbers of inputs required to achieve similar accuracy, with none being superior for all outcomes.ConclusionModels produced in this project provide estimates of patient-specific improvements in major outcomes 1 year after TKA. Integrating these models into clinical decision support, informed consent and shared decision making could improve patient selection, education, and satisfaction.Level of EvidenceLevel III, diagnostic study.     

Patient-Reported Outcome Measures are not a Valid Proxy for Patient Satisfaction in Total Joint Arthroplasty

BackgroundPatient-reported outcome measures (PROMs) are increasingly used as quality benchmarks in total joint arthroplasty. The objective of this study is to investigate whether PROMs correlate with patient satisfaction, which is arguably the most important and desired outcome.MethodsOur institutional joint database was queried for patients who underwent primary, elective, unilateral total joint arthroplasty. Eligible patients were asked to complete a satisfaction survey at final follow-up. Correlation coefficients (R) were calculated to quantify the relationship between patient satisfaction and prospectively collected PROMs. We explored a wide range of PROMs including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12, Oxford Hip Score, Knee Society Clinical Rating Score (KSCRS), Single Assessment Numerical Evaluation, and University of California Los Angeles activity level rating.ResultsIn general, there was only weak to moderate correlation between patient satisfaction and PROMs. Querying the absolute postoperative scores had higher correlation with patient satisfaction compared to either preoperative scores or net changes in scores. The correlation was higher with disease-specific PROMs (WOMAC, Oxford Hip Score, KSCRS) compared to general health (Short Form-12), activity level (University of California Los Angeles activity level rating), or perception of normalcy (Single Assessment Numerical Evaluation). Within disease-specific PROMs, the pain domain consistently carried the highest correlation with patient satisfaction (WOMAC pain subscale, R = 0.45, P < .001; KSCRS pain subscale, R = 0.49, P < .001).ConclusionThere is only weak to moderate correlation between PROMs and patient satisfaction. PROMs alone are not the optimal way to evaluate patient satisfaction. We recommend directly querying patients about satisfaction and using shorter PROMs, particularly disease-specific PROMs that assess pain perception to better gauge patient satisfaction.     

The Effects of Bundled Payment Programs for Hip and Knee Arthroplasty on Patient-Reported Outcomes

BackgroundPatient-reported outcomes are essential to demonstrate the value of hip and knee arthroplasty, a common target for payment reforms. We compare patient-reported global and condition-specific outcomes after hip and knee arthroplasty based on hospital participation in Medicare’s bundled payment programs.MethodsWe performed a prospective observational study using the Comparative Effectiveness of Pulmonary Embolism Prevention after Hip and Knee Replacement trial. Differences in patient-reported outcomes through 6 months were compared between bundle and nonbundle hospitals using mixed-effects regression, controlling for baseline patient characteristics. Outcomes were the brief Knee Injury and Osteoarthritis Outcomes Score or the brief Hip Disability and Osteoarthritis Outcomes Score, the Patient-Reported Outcomes Measurement Information System Physical Health Score, and the Numeric Pain Rating Scale, measures of joint function, overall health, and pain, respectively.ResultsRelative to nonbundled hospitals, arthroplasty patients at bundled hospitals had slightly lower improvement in Knee Injury and Osteoarthritis Outcomes Score (−1.8 point relative difference at 6 months; 95% confidence interval −3.2 to −0.4; P = .011) and Hip Disability and Osteoarthritis Outcomes Score (−2.3 point relative difference at 6 months; 95% confidence interval −4.0 to −0.5; P = .010). However, these effects were small, and the proportions of patients who achieved a minimum clinically important difference were similar. Preoperative to postoperative change in the Patient-Reported Outcomes Measurement Information System Physical Health Score and Numeric Pain Rating Scale demonstrated a similar pattern of slightly worse outcomes at bundled hospitals with similar rates of achieving a minimum clinically important difference.ConclusionsPatients receiving care at hospitals participating in Medicare’s bundled payment programs do not have meaningfully worse improvements in patient-reported measures of function, health, or pain after hip or knee arthroplasty.     

Accuracy and Validity of Computer Adaptive Testing for Outcome Assessment in Patients Undergoing Total Knee Arthroplasty

BackgroundComputerized adaptive test (CAT) questionnaires may allow standardization of patient-reported outcome measures and reductions in questionnaire burden. We evaluated the validity, accuracy, and efficacy of a CAT system in patients with end-stage osteoarthritis undergoing total knee arthroplasty.MethodsCAT Knee Osteoarthritis Outcome Scores (KOOS) and CAT KOOS-JR questionnaires were applied to 1871 standard form KOOS and 1493 KOOS-JR patient responses, respectively. Mean, standard deviations, Pearson’s correlation coefficients, interclass correlation coefficients (ICCs), frequency distribution plots, and Bland-Altman plots were used to compare the precision, validity, and accuracy between CAT scores and full-form scores.ResultsThere was a mean reduction of 14 questions (33%) in the CAT KOOS and 1.4 questions (20%) with the CAT KOOS-JR version, compared with the standard KOOS and KOOS-JR surveys, respectively. There were no significant differences between KOOS and CAT KOOS scores with respect to pain (P = .66), symptoms (P = .43), quality of life (P = .99), activities of daily living (P = .68), and sports (P = .84). Similarly, there were no significant differences between the standard form KOOS-JR and CAT KOOS-JR scores (P = .94). There were strong correlations with minimal variability between the CAT KOOS and standard KOOS questionnaires for pain (r = 0.98, ICC: 0.98), symptoms (r = 0.97, ICC: 0.97), quality of life scores (r = 0.99, ICC: 0.99), activities of daily living scores (r = 0.99, ICC: 0.99), and sports scores (r = 0.99, ICC: 0.99). Similarly, there were strong correlations between the KOOS-JR and the CAT KOOS-JR scores (r = 0.99, ICC: 0.99).ConclusionCAT KOOS and the CAT KOOS-JR versions are accurate and reduce questionnaire burden up to one-third compared with standard surveys. CAT versions may improve patient compliance and decrease fatigue.     

Validation of the Dutch version of the Hip disability and Osteoarthritis Outcome Score

INTRODUCTION: The Hip disability and Osteoarthritis Outcome Score (HOOS) was constructed in Sweden; this questionnaire has proved to be valid for persons with hip disability with or without hip osteoarthritis (OA) and with high demands of physical function. OBJECTIVE: The objective of this study was to evaluate the internal consistency, reliability, construct validity, and floor and ceiling effects of the Dutch version of the HOOS questionnaire. PATIENTS AND METHODS: After translation with a forward/backward protocol, 74 hip arthroplasty patients and 88 hip OA patients filled in the Dutch HOOS, as well as a Short Form-36 (SF-36), an Oxford Hip Score (OHS) and a VAS-pain questionnaire. RESULTS: The Dutch version of the HOOS questionnaire achieved excellent scores in all of the clinimetric properties. CONCLUSION: The Dutch HOOS questionnaire has a good internal consistency and reliability. Moreover, the construct validity is good and no floor and ceiling effects were found. The HOOS is a good instrument for patients with different stadia of hip OA.