Defining Patient-relevant Thresholds and Change Scores for the HOOS JR and KOOS JR Anchored on the Patient-acceptable Symptom State Question.

BACKGROUND: When evaluating the results of clinical research studies, readers need to know that patients perceive effect sizes, not p values. Knowing the minimum clinically important difference (MCID) and the patient-acceptable symptom state (PASS) threshold for patient-reported outcome measures helps us to ascertain whether our interventions result in improvements that are large enough for patients to care about, and whether our treatments alleviate patient symptoms sufficiently. Prior studies have developed the MCID and PASS threshold for the Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) anchored on satisfaction with surgery, but to our knowledge, neither the MCID nor the PASS thresholds for these instruments anchored on a single-item PASS question have been described. QUESTIONS/PURPOSES: (1) What are the MCID (defined here as the HOOS/KOOS JR change score associated with achieving PASS) and PASS threshold for the HOOS JR and KOOS JR anchored on patient responses to the single-item PASS instrument? (2) How do patient demographic factors such as age, gender, and BMI correlate with MCID and PASS thresholds using the single-item PASS instrument? METHODS: Between July 2020 and September 2021, a total of 10,970 patients underwent one primary unilateral THA or TKA and completed at least one of the three surveys (preoperative HOOS or KOOS JR, 1-year postoperative HOOS or KOOS JR, and 1-year postoperative single-item anchor) at one large, academic medical center. Of those, only patients with data for all three surveys were eligible, leaving 13% (1465 total; 783 THAs and 682 TKAs) for analysis. Despite this low percentage, the overall sample size was large, and there was little difference between completers and noncompleters in terms of demographics or baseline patient-reported outcome measure scores. Patients undergoing bilateral total joint arthroplasty or revision total joint arthroplasty and those without all three surveys at 1 year of follow-up were excluded. A receiver operating characteristic curve analysis, leveraging a 1-year, single-item PASS (that is, "Do you consider that your current state is satisfactory?" with possible answers of "yes" or "no") as the anchor was then used to establish the MCID and PASS thresholds among the 783 included patients who underwent primary unilateral THA and 682 patients who underwent primary unilateral TKA. We also explored the associations of age at the time of surgery (younger than 65 years or 65 years and older), gender (men or women), BMI (< 30 or ≥ 30 kg/m 2 ), and baseline Patient-Reported Outcome Measure Information System-10 physical and mental component scores (< 50 or ≥ 50) for each of the MCID and PASS thresholds through stratified analyses. RESULTS: For the HOOS JR, the MCID associated with the PASS was 23 (95% CI 18 to 31), with an area under the receiver operating characteristic curve of 0.75, and the PASS threshold was 81 (95% CI 77 to 85), with an area under the receiver operating characteristic curve of 0.81. For the KOOS JR, the MCID was 16 (95% CI 14 to 18), with an area under the receiver operating characteristic curve of 0.75, and the PASS threshold was 71 (95% CI 66 to 73) with an area under the receiver operating characteristic curve of 0.84. Stratified analyses indicated higher change scores and PASS threshold for younger men undergoing THA and higher PASS thresholds for older women undergoing TKA. CONCLUSION: Here, we demonstrated the utility of a single patient-centered anchor question, raising the question as to whether simply collecting a postoperative PASS is an easier way to measure success than collecting preoperative and postoperative patient-reported outcome measures and then calculating MCIDs and the substantial clinical benefit. LEVEL OF EVIDENCE: Level III, therapeutic study.

Does Computer Navigation or Robotic Assistance Affect the Risk of Periprosthetic Joint Infection in Primary Total Knee Arthroplasty? A Propensity Score-Matched Cohort Analysis.

BACKGROUND: The use of technology during total knee arthroplasty (TKA) has been associated with more accurate component position and less blood loss. Yet to date, the risk of developing prosthetic joint infection (PJI) associated with computer navigation (CN) or robotic assistance (RA) has not been thoroughly evaluated. This study used propensity score-matching (PSM) in a large cohort of primary TKA patients to compare the rate of PJI following conventional TKA (TKA) versus CN-TKA and RA-TKA. METHODS: We retrospectively reviewed 13,015 knees in 11,727 patients who underwent primary TKA at a single institution from 2018 to 2021. The cohort was stratified into TKA, CN-TKA, and RA-TKA groups. 1:1 PSM was applied to 11,834 patients. Propensity score-matching was performed using logistic regression accounting for age, sex, body mass index, Charlson Comorbidity Index (CCI) score, CCI components, and smoking status. Univariate and multivariable analyses were performed to evaluate differences in surgical time and PJI rate. RESULTS: Significantly longer median operating times were noted in the RA-TKA group (14 minutes) compared to TKA (P < .001). The PJI rates among matched cohorts were similar among RA-TKA (0.3%), CN-TKA (0.3%), and conventional TKA (0.5%). Multivariable logistic regressions demonstrated that the use of robotic assistance (odds ratio (OR) = 0.5, P = .423) or computer navigation (OR = 0.61, P = .128) was not associated with increased risk of PJI when compared to conventional TKA. CONCLUSIONS: Use of computer navigation and robotic assistance during primary TKA are associated with longer surgical times, but no difference in PJI frequency within 90 days of surgery.

Dislocation Following Anterior and Posterior Total Hip Arthroplasty in the Setting of Spinal Deformity and Stiffness: Evolving Trends Using a High-Risk Protocol at a Single Tertiary Center.

BACKGROUND: Patients who have spinal stiffness and deformity are at the highest risk for dislocation after total hip arthroplasty (THA). Previous reports of this cohort are limited to antero-lateral and postero-lateral (PL) approaches. We investigated the dislocation rate after direct anterior (DA) and PL approach THA with a contemporary high-risk protocol to optimize stability. METHODS: We investigated patients undergoing THA who had preoperative biplanar imaging from January-December 2019. Patients were identified using radiographic criteria of spinal-stiffness (<10-degree change in sacral slope from standing to seated) and deformity (flatback deformity with >10-degree difference in pelvic incidence and lumbar lordosis). There were 367 patients identified (181 DA, 186 PL). The primary outcome was dislocation rate at 2-years postoperatively. Risk-factors for dislocation were evaluated using logistic regressions (significance level of 0.05). RESULTS: There were 6 (1.6%) dislocations in the entire cohort, with low dislocation rates for both DA (0.6%) and PL-THA (2.7%). We observed increased utilization of dual mobility with larger outer head bearings (>38 mm) with PL-THA (34.4 versus 5.0%, P < .01) and conversely increased utilization of 32-mm femoral-heads with DA-THA (39.4 versus 7.0%, P < .001). Surgical approach (PL) was not a significant risk-factor for dislocation (odds ratio: 5.03, P = .15). Patients who had a history of lumbar-fusion had 8-times higher odds for dislocation (OR: 8.20, P = .020). CONCLUSIONS: To the best of our knowledge, this is the largest series to date evaluating DA and PL-THA in the hip-spine 2B-group. Our results demonstrate lower dislocation rate than expected with either surgical approach using a high-risk protocol.

Is Preoperative Weight Reduction in Patients Who Have Body Mass Index ≥ 40 Associated With Lower Complication Rates After Primary Total Hip Arthroplasty?

BACKGROUND: Given the heightened risk of postoperative complications associated with obesity, delaying total hip arthroplasty (THA) in patients who have a body mass index (BMI) > 40 to maximize preoperative weight loss has been advocated by professional societies and orthopaedic surgeons. While the benefits of this strategy are not well-understood, previous studies have suggested that a 5% reduction in weight or BMI may be associated with reduced complications after THA. METHODS: We identified 613 patients who underwent primary THA in a single institution during a 7-year period and who had a BMI >40 recorded from 9 to 12 months prior to surgery. Subjects were stratified into 3 cohorts based on whether their baseline BMI decreased by >5% (147 patients, 24%), was unchanged ( ± 5%) (336 patients, 55%), or increased by >5% (130 patients, 21%) on the day of surgery. The frequency of 90-days Hip Society and Centers for Medicare & Medicaid Services complications was compared between these cohorts. There were significant baseline differences between the cohorts with respect to baseline American Society of Anesthesiologists class (P < .001) and hemoglobin A1C (P = .011), which were accounted for in a multivariate regression analysis. RESULTS: In univariate analysis, there was a lower incidence of readmission (P = .025) and total complications (P = .005) in the increased BMI cohort. The overall complication rate was 18.4% in the decreased BMI cohort, 17.6% in the unchanged cohort, and 6.2% in the increased cohort. However, multivariable regression analysis controlling for potential confounders did not find that preoperative change in BMI was associated with differences in 90-days complications between cohorts (P > .05). CONCLUSIONS: Patients who have a BMI >40 and achieved a clinically significant (>5%) BMI reduction prior to THA did not have a lower risk of 90-days complications or readmissions. Thus, delaying THA in these patients to encourage weight loss may result in restricting access to a beneficial surgery without an appreciable safety benefit.

Substantial Weight Loss May Not Improve Early Outcomes of Total Knee Arthroplasty in the Morbidly Obese.

BACKGROUND: Body mass index (BMI) cutoffs for morbidly obese patients otherwise indicated for total knee arthroplasty (TKA) have been widely proposed and implemented, though they remain controversial. Previous studies suggested that a 5% reduction in BMI may be associated with fewer postoperative complications. Thus, the purpose of this study was to determine whether a substantial reduction in preoperative BMI in morbidly obese patients improved 90-day outcomes after TKA. METHODS: There were 1,270 patients who underwent primary TKA at a single institution and had a BMI > 40 recorded during the year prior to surgery. Patients were stratified into three cohorts based on whether their BMI within 3 months to 1 year preoperatively had decreased by ≥ 5% (228 patients [18%]); increased by ≥ 5% (310 [24%]); or remained unchanged (within 5%) (732 [58%]) on the day of surgery. There were several baseline differences between the cohorts with respect to medical comorbidities. The rate of 90-day complications and six-week patient-reported outcome measures were compared via univariate and multivariable analyses. RESULTS: On univariate analysis, individual and total complication rates were similar between the cohorts (P > .05). On multivariable logistic regression, the risk of complications was similar in patients who had decreased versus unchanged BMI (OR [odds ratio] 1.0; P = .898). However, there was a higher risk of complications in the increased BMI cohort compared to those patients who had an unchanged BMI (OR 1.5; P = .039). The six-week patient-reported outcome measures were similar between the cohorts. CONCLUSIONS: Patients who have a BMI > 40 who achieved a meaningful reduction in BMI prior to TKA did not have a lower rate of 90-day complications than those whose BMI remained unchanged. Furthermore, considering that nearly one in four patients experienced a significant increase in BMI while awaiting surgery, postponing TKA may actually be detrimental.

Machine Learning on Medicare Claims Poorly Predicts the Individual Risk of 30-Day Unplanned Readmission After Total Joint Arthroplasty, Yet Uncovers Interesting Population-level Associations With Annual Procedure Volumes.

BACKGROUND: Unplanned hospital readmissions after total joint arthroplasty (TJA) represent potentially serious adverse events and remain a critical measure of hospital quality. Predicting the risk of readmission after TJA may provide patients and clinicians with valuable information for preoperative decision-making. QUESTIONS/PURPOSES: (1) Can nonlinear machine-learning models integrating preoperatively available patient, surgeon, hospital, and county-level information predict 30-day unplanned hospital readmissions in a large cohort of nationwide Medicare beneficiaries undergoing TJA? (2) Which predictors are the most important in predicting 30-day unplanned hospital readmissions? (3) What specific information regarding population-level associations can we obtain from interpreting partial dependency plots (plots describing, given our modeling choice, the potentially nonlinear shape of associations between predictors and readmissions) of the most important predictors of 30-day readmission? METHODS: National Medicare claims data (chosen because this database represents a large proportion of patients undergoing TJA annually) were analyzed for patients undergoing inpatient TJA between October 2016 and September 2018. A total of 679,041 TJAs (239,391 THAs [61.3% women, 91.9% White, 52.6% between 70 and 79 years old] and 439,650 TKAs [63.3% women, 90% White, 55.2% between 70 and 79 years old]) were included. Model features included demographics, county-level social determinants of health, prior-year (365-day) hospital and surgeon TJA procedure volumes, and clinical classification software-refined diagnosis and procedure categories summarizing each patient's Medicare claims 365 days before TJA. Machine-learning models, namely generalized additive models with pairwise interactions (prediction models consisting of both univariate predictions and pairwise interaction terms that allow for nonlinear effects), were trained and evaluated for predictive performance using area under the receiver operating characteristic (AUROC; 1.0 = perfect discrimination, 0.5 = no better than random chance) and precision-recall curves (AUPRC; equivalent to the average positive predictive value, which does not give credit for guessing "no readmission" when this is true most of the time, interpretable relative to the base rate of readmissions) on two holdout samples. All admissions (except the last 2 months' worth) were collected and split randomly 80%/20%. The training cohort was formed with the random 80% sample, which was downsampled (so it included all readmissions and a random, equal number of nonreadmissions). The random 20% sample served as the first test cohort ("random holdout"). The last 2 months of admissions (originally held aside) served as the second test cohort ("2-month holdout"). Finally, feature importances (the degree to which each variable contributed to the predictions) and partial dependency plots were investigated to answer the second and third research questions. RESULTS: For the random holdout sample, model performance values in terms of AUROC and AUPRC were 0.65 and 0.087, respectively, for THA and 0.66 and 0.077, respectively, for TKA. For the 2-month holdout sample, these numbers were 0.66 and 0.087 and 0.65 and 0.075. Thus, our nonlinear models incorporating a wide variety of preoperative features from Medicare claims data could not well-predict the individual likelihood of readmissions (that is, the models performed poorly and are not appropriate for clinical use). The most predictive features (in terms of mean absolute scores) and their partial dependency graphs still confer information about population-level associations with increased risk of readmission, namely with older patient age, low prior 365-day surgeon and hospital TJA procedure volumes, being a man, patient history of cardiac diagnoses and lack of oncologic diagnoses, and higher county-level rates of hospitalizations for ambulatory-care sensitive conditions. Further inspection of partial dependency plots revealed nonlinear population-level associations specifically for surgeon and hospital procedure volumes. The readmission risk for THA and TKA decreased as surgeons performed more procedures in the prior 365 days, up to approximately 75 TJAs (odds ratio [OR] = 1.2 for TKA and 1.3 for THA), but no further risk reduction was observed for higher annual surgeon procedure volumes. For THA, the readmission risk decreased as hospitals performed more procedures, up to approximately 600 TJAs (OR = 1.2), but no further risk reduction was observed for higher annual hospital procedure volumes. CONCLUSION: A large dataset of Medicare claims and machine learning were inadequate to provide a clinically useful individual prediction model for 30-day unplanned readmissions after TKA or THA, suggesting that other factors that are not routinely collected in claims databases are needed for predicting readmissions. Nonlinear population-level associations between low surgeon and hospital procedure volumes and increased readmission risk were identified, including specific volume thresholds above which the readmission risk no longer decreases, which may still be indirectly clinically useful in guiding policy as well as patient decision-making when selecting a hospital or surgeon for treatment. LEVEL OF EVIDENCE: Level III, therapeutic study.

Hip arthroscopy for femoroacetabular impingement is associated with significant improvement in early patient reported outcomes: analysis of 4963 cases from the UK non-arthroplasty registry (NAHR) dataset.

PURPOSE: Results from recent randomised controlled trials demonstrate the superiority of surgery over physiotherapy in patients with femoroacetabular impingement (FAI) of the hip in early follow-up. However, there is paucity of evidence regarding which factors influence outcomes of FAI surgery, particularly notable is the lack of information on the effect of impingement subtype (cam or pincer or mixed) on patient reported outcomes measures (PROMs). This study aims to evaluate the early outcomes of hip arthroscopy for FAI, and their determinants. METHODS: This is a retrospective analysis of prospectively collected data from the UK Non-Arthroplasty Hip Registry (NAHR) of patients undergoing arthroscopic intervention for FAI between 2012 and 2019. The null hypothesis was that there is no difference in PROMs, based on morphological subtype of FAI treated or patient characteristics, at each follow-up timepoint. The outcome measures used for the study were the iHOT-12 score and the EQ5D Index and VAS 6- and 12-month follow-up. RESULTS: A cohort of 4963 patients who underwent arthroscopic treatment of FAI were identified on the NAHR database. For all FAI pathology groups, there was significant improvement from pre-operative PROMs when compared to those at 6 and 12 months. Overall, two-thirds of patients achieved the minimum clinically important difference (MCID), and almost half achieved substantial clinical benefit (SCB) for iHOT-12 by 12 months. Pre-operatively, and at 12-month follow-up, iHOT-12 scores were significantly poorer in the pincer group compared to the cam and mixed pathology groups (p < 0.01). Multivariable analysis revealed PROMS improvement in the setting of a higher-grade cartilage lesion. CONCLUSION: This registry study demonstrates that hip arthroscopy is an effective surgical treatment for patients with symptomatic FAI and results in a statistically significant improvement in PROMs which are maintained through 12 months follow-up. LEVEL OF EVIDENCE: III.

Freeze-dried noncoagulating platelet-derived factor concentrate is a safe and effective treatment for early knee osteoarthritis.

PURPOSE: While a wide variety of platelet-rich plasma (PRP) solutions has been developed, innovation continues. In this case, the freeze-dried platelet factor concentrate (PFC-FD) represents another step in PRP refinement. The preparation of PFC-FD at a central laboratory with freeze drying for shelf stabilization should provide additional quality improvements if clinical effectiveness can be demonstrated. Therefore, this study was undertaken to assess the safety and effectiveness of PFC-FD in a prospective open-label trial of patients suffering from knee osteoarthritis (OA). METHODS: 312 consecutive knee OA patients (67% female, mean age 63 ± 10 years), were prospectively recruited in an outpatient knee clinic in Japan. Of these, 10 (3.2%) were lost to follow-up at < 12 months and 17 (5.5%) sought additional knee therapy during the follow-up period. The primary outcome of interest was achievement of the OMERACT-OARSI responder criteria with secondary outcomes of adverse events and PROMs scores 1, 3, 6, 12 months following a single PFC-FD injection. RESULTS: 285 patients (91%) completed 12 month PROMs. The 17 who sought additional therapy were considered failures leaving an effective sample size of 302 for our primary outcome in which 62% of patients achieved OMERACT-OARSI responder status by 12 months. This varied by OA class with Kellgren-Lawrence grade 4 patients 3.6 times less likely to be responders than grade 1-2 patients. 6% of patients experienced a non-serious adverse event, primarily pain or swelling at the injection site. CONCLUSIONS: PFC-FD provides an observable clinical improvement in 62% of knee OA patients at 12 months post-injection with very little risk of any clinically relevant adverse event. Of course, nearly 40% of patients did not experience an observable clinical improvement, primarily among those with worse KL grades. LEVEL OF EVIDENCE: Therapeutic, Level II.

Cross-cultural adaptation and validation of the KOOS, JR questionnaire for assessing knee osteoarthritis in Spanish-speaking patients.

PURPOSE: The present study aims to translate, adapt and validate a Spanish version of the Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS, JR), including a reliability and validity analysis in patients with knee osteoarthritis (OA). METHODS: This study conducted a prospective validation study following the six stages of the "Guidelines for the Process of Cross-Cultural Adaptation of Self-Report Measures". Psychometric testing was conducted in patients with knee osteoarthritis. Subjects answered the Spanish KOOS, JR (S-KOOS, JR) and a validated Spanish Oxford Knee Score (S-OKS). Retest was conducted at 10 days. Acceptability, floor and ceiling effect, internal consistency (Cronbach's α), reproducibility (mixed-effect model coefficient [MEMC]) and construct validity (Spearman's correlation; p = 0.05) were assessed. RESULTS: Forty-one patients (mean age: 65.6 ± 5.39; 48.8% female) participated in the study. All patients (100%) answered both scores during the first assessment and 38 (92.7%) during the second assessment. All patient-reported outcomes measures were answered completely (100%). The S-KOOS, JR resulted in 100% acceptability when answered. There were no ceiling or floor effects detected. The Cronbach's α for the S-KOOS, JR was 0.927 and its MEMC was 0.852 (CI 95% 0.636-1.078). The Spearman's correlation between the S-KOOS, JR and the S-OKS was 0.711 (CI 0.345-0.608; p < 0.001) and 0.870 (CI 0.444-0.651; p < 0.001) for the first and second assessments, respectively. CONCLUSION: The S-KOOS, JR has very high internal consistency and reproducibility, with a high correlation with the S-OKS; it is a reliable and valid instrument for characterising Spanish-speaking patients suffering from knee OA. LEVEL OF EVIDENCE: IV.

Identifying Aseptic Revision Total Knee Arthroplasty Diagnoses That Achieve Minimal Clinically Important Difference and Patient Acceptable Symptom State.

BACKGROUND: Minimal clinically important difference (MCID) defines a meaningful clinical change in patient-reported outcome measures. Patient acceptable symptom state (PASS) provides a patient-reported outcome measures threshold value to indicate a satisfactory clinical state. MCID and PASS for revision total knee arthroplasty (rTKA) are ill-defined. Moreover, it is unknown whether diagnosis influences the likelihood of achieving MCID or PASS. The purpose of this study was to calculate MCID for aseptic rTKA and compare the percentage of patients achieving MCID and PASS per diagnosis. METHODS: An institutional registry of rTKA was used. First-time aseptic rTKA were included. Demographics, revision diagnosis, preoperative Knee Injury and Osteoarthritis Outcome Score, Jr (KOOS Jr), and 1-year postoperative KOOS Jr were recorded. The 1-year postoperative KOOS Jr PASS score was available. MCID was calculated using distribution-based methods. Three hundred fifty eight first-time aseptic rTKAs were analyzed. The 3 most common diagnoses were aseptic loosening (n = 156), instability (n = 109), and stiffness (n = 37). RESULTS: The mean KOOS Jr 1-year postoperative MCID for rTKA was 10.3. Overall, 75.4% achieved MCID and 56.9% achieved PASS. The percentage of patients per diagnosis achieving MCID and PASS, respectively, were periprosthetic fracture (100, 44), aseptic loosening (94, 60), implant fracture (88, 63), stiffness (60, 38), instability (59, 61), polyethylene wear/osteolysis (57, 57), and metal allergy (44, 33). CONCLUSION: Aseptic rTKA MCID is 10.3 for KOOS Jr at 1 year postoperatively. rTKA outcomes vary depending on preoperative diagnosis. Even in diagnoses with a high proportion of MCID achieved, less than 2/3 of patients achieved PASS, suggesting rTKA provides noticeable improvement but may not return patients to a satisfactory state.

Predicting Postoperative Anemia and Blood Transfusion Following Total Knee Arthroplasty.

BACKGROUND: While transfusion and clinically relevant anemia after elective primary total knee arthroplasty (TKA) are uncommon, there remains a question of who needs postoperative hemoglobin monitoring, especially in the setting of increasing incidence of outpatient TKA. The purpose of this study was to create predictive models for postoperative anemia and blood transfusion to guide clinical decision-making. METHODS: The records of consecutive TKA patients were reviewed from February 2016 to December 2020 at a single institution. Two multivariable logistic regression models, for postoperative anemia (hemoglobin < 10 g/dL) and allogeneic blood transfusion included 8 variables: age, sex, body mass index, preoperative hemoglobin level, tranexamic acid total dose, American Society of Anesthesiologists level, operative time, and drain use. Model performance was assessed using accuracy, area under the curve (AUC), sensitivity, and specificity. RESULTS: The records of 14,901 patients were included in this study. Patients had a mean (± standard deviation) age of 67.9 ± 9.2 years and mean body mass index of 31.3 ± 6.5 kg/m2. The postoperative anemia model had an accuracy of 88% (95% confidence interval [CI], 87%-89%) and AUC of 0.88 (95% CI, 0.87-0.89). The blood transfusion model had an accuracy of 97% (95% CI, 96%-97%) and AUC of 0.90 (95% CI, 0.87-0.93). CONCLUSION: The postoperative anemia and blood transfusion model accurately predicted each outcome. Patients with less than a 5% probability of postoperative anemia may not benefit from a complete blood count at postoperative day 1. Application of these criteria may save the healthcare system hundreds of millions of dollars. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Risk Assessment and Prediction Tool (RAPT) Score Predicts Discharge Destination, Length of Stay, and Postoperative Mobility After Total Joint Arthroplasty.

BACKGROUND: Predicting an arthroplasty patient's discharge disposition, length of stay (LOS), and physical function is helpful because it allows for preoperative patient optimization, expectation management, and discharge planning. The goal of this study was to evaluate the ability of the Risk Assessment and Prediction Tool (RAPT) score to predict discharge destination, LOS, and postoperative mobility in patients undergoing primary total knee arthroplasty (TKA) and total hip arthroplasty (THA). METHODS: Primary unilateral TKAs (n = 9,064) and THAs (n = 8,649) performed for primary osteoarthritis at our institution from 2018 to 2021 (excluding March to June 2020) were identified using a prospectively maintained institutional registry. We evaluated the associations between preoperative RAPT score and (1) discharge destination, (2) LOS, and postoperative mobility as measured by (3) successful ambulation on the day of surgery and (4) Activity Measure for Post-Acute Care (AM-PAC) "6-Clicks" score. RESULTS: On multivariable analyses adjusting for multiple covariates, every one-point increase in RAPT score among TKA patients was associated with a 1.82-fold increased odds of home discharge (P < .001), 0.22 days shorter LOS (P < .001), 1.13-fold increased odds of ambulating on postoperative day 0 (P < .001), and 0.25-point higher Activity Measure for Post-Acute Care score (P < .001). Similar findings were seen among THAs. A RAPT score of 8 or higher was the most sensitive and specific cutoff to predict home discharge. CONCLUSION: Among nearly 18,000 TKA and THA patients, RAPT score was predictive of discharge disposition, LOS, and postoperative mobility. A RAPT score of 8 or higher was the most sensitive and specific cutoff to predict discharge to home. In contrast to prior studies of the RAPT score which have grouped TKAs and THAs together, this study ran separate analyses for TKAs and THAs and found that THA patients seemed to perform better than TKA patients with equal RAPT scores, suggesting that RAPT may behave differently between TKAs and THAs, particularly in the intermediate risk RAPT range.

Improved responsiveness for JKOOS+ compared to KOOS in Japanese patients undergoing total knee arthroplasty.

BACKGROUND: Existing knee related patient reported outcome measurements (PROMs) have overwhelmingly been developed and validated in western chair-based societies, suggesting a potential for a western bias in PROMs evaluation of patients with knee conditions. We, therefore, endeavor to evaluate the responsiveness of the previously developed culturally relevant Japanese version of the knee injury and osteoarthritis outcome score (JKOOS+). METHODS: We enrolled 114 patients scheduled for total knee arthroplasty (TKA) across 8 knee clinics in Japan. Patients completed the Oxford Knee Score (OKS) and JKOOS + both at the time of enrollment and again 1-year post-TKA. Responsiveness was evaluated using effect size and standardized response mean (SRM). An effect size or SRM >0.8 is considered adequately responsive. We further tested the difference in responsiveness between the original Japanese language KOOS activities of daily living (ADL) domain and the novel Japanese ADL (JADL) domain using the modified Jacknife test. RESULTS: All domains were adequately responsive with the exception of the KOOS sports and recreation domain, which has previously been ignored by TKA researchers due to its lack of applicability to elderly patients undergoing TKA. The JADL domain outperformed the ADL domain in both effect size (1.51 v. 1.45) and SRM (1.67 v. 1.57) (p < 0.001). The novel Knee Flexion (KF) domain was adequately responsive, though less responsive than other domains except sports and recreation (p < 0.01 v. all other PROMs domains). CONCLUSIONS: The JKOOS+ JADL domain is significantly more responsive than the Europe-developed ADL domain to TKA in Japanese knee patients suffering from knee osteoarthritis (OA). The KF domain, unique to the JKOOS+ and intended to assess difficulty with knee flexion, is adequately responsive to TKA in Japanese patients suffering from OA.

Improved total knee arthroplasty pain outcome when joint gap targets are achieved throughout flexion.

PURPOSE: Achieving a balanced knee is accepted as an important goal in total knee arthroplasty; however, the definition of ideal balance remains controversial. This study therefore endeavoured to determine: (1) whether medio-lateral gap balance in extension, midflexion, and flexion are associated with improved outcome scores at one-year post-operatively and (2) whether these relationships can be used to identify windows of optimal gap balance throughout flexion. METHODS: 135 patients were enrolled in a multicenter, multi-surgeon, prospective investigation using a robot-assisted surgical platform and posterior cruciate ligament sacrificing gap balancing technique. Joint gaps were measured under a controlled tension of 70-90 N from 10°-90° flexion. Linear correlations between joint gaps and one-year KOOS outcomes were investigated. KOOS Pain and Activities of Daily Living sub-scores were used to define clinically relevant joint gap target thresholds in extension, midflexion, and flexion. Gap thresholds were then combined to investigate the synergistic effects of satisfying multiple targets. RESULTS: Significant linear correlations were found throughout extension, midflexion, and flexion. Joint gap thresholds of an equally balanced or tighter medial compartment in extension, medial laxity ± 1 mm compared to the final insert thickness in midflexion, and a medio-lateral imbalance of less than 1.5 mm in flexion generated subgroups that reported significantly improved KOOS pain scores at one year (median ∆ = 8.3, 5.6 and 2.8 points, respectively). Combining any two targets resulted in further improved outcomes, with the greatest improvement observed when all three targets were satisfied (median ∆ = 11.2, p = 0.002). CONCLUSION: Gap thresholds identified in this study provide clinically relevant and achievable targets for optimising soft tissue balance in posterior cruciate ligament sacrificing gap balancing total knee arthroplasty. When all three balance windows were achieved, clinically meaningful pain improvement was observed. LEVEL OF EVIDENCE: Level II.

Minimal Clinically Important Difference (MCID) at One Year Postoperatively in Aseptic Revision Total Hip Arthroplasty.

BACKGROUND: Outcomes after aseptic revision total hip arthroplasty (THA) are variable, and it is unknown whether the indication for aseptic revision THA influences postoperative clinical improvement. The minimal clinically important difference (MCID) assesses if changes in patient-reported outcome measure result in meaningful clinical benefit to patients. The purpose of this study was to quantify the 1-year postoperative MCID for aseptic revision THA and to assess the percentage of patients achieving the MCID for each revision diagnosis. METHODS: A prospective, single-institution registry of revision total joint arthroplasties was used. Retrospective review of 413 first-time aseptic revision THAs was performed. Demographics, revision diagnosis, preoperative Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS Jr.), and 1-year postoperative HOOS Jr. were recorded. The MCID for the HOOS Jr. at one year postoperatively was calculated for each revision diagnosis using a distribution-based method. The percentage of patients exceeding the MCID with each diagnosis was determined. RESULTS: There were 9 aseptic revision diagnoses, all with n ≥ 5. The 3 most common revision diagnosis were aseptic loosening (n = 114), dislocation or instability (n = 103), and polyethylene wear or osteolysis (n = 73). The MCID for all the aseptic revision THAs was 10.9. Seven of the nine revision diagnoses achieved the MCID. The highest percentage of patients achieving the MCID was for aseptic loosening (84.2%) and implant fracture (81.3%), whereas lowest was for adverse local tissue reaction (35.3%) and implant recall (20.0%). CONCLUSION: The one-year revision THA MCID is 10.9 for the HOOS Jr. There is variability in the percentage of patients achieving the MCID based on diagnosis. Our data can be used to counsel patients undergoing revision THA for noninfectious etiologies.

Development and Validation of Crosswalks Between the Western Ontario & McMaster Universities Osteoarthritis Index and Hip Disability and Osteoarthritis Outcome Score Joint Replacement/Knee Injury and Osteoarthritis Outcome Score Joint Replacement.

BACKGROUND: The wide variety of patient-reported outcome measures used to assess outcomes following total joint arthroplasty can present a substantial methodological obstacle when attempting to compare information across studies or between institutions. A simple solution is to create crosswalks that reliably convert scores between patient-reported outcome measures. Our goal is to create and validate crosswalks between the commonly used Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) and short-form versions of the Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR)/Knee Injury and Osteoarthritis Outcome Score (KOOS JR.). METHODS: Patients in our joint replacement registry were included if they underwent primary total hip arthroplasty (n = 4649) or total knee arthroplasty (n = 3750) for osteoarthritis between May 2007 and February 2012. We used their preoperative and 2-year postoperative HOOS scores (n = 6351) or KOOS scores (n = 4688) to generate the patients' WOMAC and HOOS JR/KOOS JR scores. The equipercentile equating method was applied to create 10 crosswalks: HOOS JR/KOOS JR to WOMAC Total (WOMAC-T), and WOMAC-T, WOMAC Pain (WOMAC-P), WOMAC Stiffness (WOMAC-S), and WOMAC Function (WOMAC-F) to HOOS JR/KOOS JR. Crosswalk validity was assessed by comparing actual and derived scores using Spearman's rank correlation coefficients in a bootstrapped cohort. RESULTS: All 10 crosswalks showed strong positive correlations ranging from 0.846 (WOMAC-S to KOOS JR) to 0.981 (HOOS JR to WOMAC-T). CONCLUSION: We created and validated 10 crosswalks between WOMAC and HOOS JR/KOOS JR. We recommend using the crosswalks between WOMAC-T and HOOS JR/KOOS JR when possible, as they demonstrated the highest correlation. WOMAC-F or WOMAC-P should be used in favor of WOMAC-S if only subscores are available. The HOOS JR/KOOS JR should only be converted to a WOMAC-T. LEVEL OF EVIDENCE: Level III.

Predicting Post-Discharge Opioid Consumption After Total Hip and Knee Arthroplasty in the Opioid-Naïve Patient.

BACKGROUND: Pain catastrophizing, anxiety, and depression are associated with poor outcomes after total hip (THA) and total knee (TKA) arthroplasty. The goal of this study is to determine the relationship between post-operative pain scores and opioid consumption; and the association among pre-operative measures of anxiety, depression, and pain catastrophizing and post-operative opioid consumption in patients undergoing THA and TKA. METHODS: This is a single-institution prospective cohort study of 243 opioid-naïve patients undergoing elective, primary THA (n = 123) or TKA (n = 120) for osteoarthritis. Pre-operatively, patients completed the PROMIS-29 (Patient-Reported Outcomes Measures Information System; physical function/anxiety/depression/fatigue/sleep disturbance/social activities/pain interference/pain intensity) and Pain Catastrophizing Scale. Post-operatively, patients completed a weekly survey for 12 weeks determining morphine-milligram-equivalent (MME) opioid consumption, opioid cessation, and visual analog scale pain scores. Multivariable regression models determined the association between pre-operative scores and post-operative opioid consumption. RESULTS: Mean (±standard deviation) total opioid consumption and duration was 75.1 ± 112.0 MME and 1.7 ± 1.7 weeks in THA and 384.7 ± 473.3 MME and 4.3 ± 3.5 weeks in TKA. Visual analog scale pain scores (0-100) after opioid cessation were 28.0 ± 22.9 in THA and 30.7 ± 25.8 in TKA. Multivariable regression showed that each unit increase in PROMIS-29 fatigue T-score was associated with 8.4 hours longer opioid usage in THA (P = .008) and 15.1 hours longer in TKA (P = .036), as well as 12.7 MME additional opioids in TKA (P = .027). There were no significant associations with other PROMIS-29 domains or the Pain Catastrophizing Scale. CONCLUSION: Opioid use duration is different for THA and TKA and may correlate with pain scores. Only pre-operative fatigue was associated with post-operative opioid consumption. These findings should inform THA and TKA post-operative pain management pathways.

Hip resurfacing and posterior approach total hip arthroplasty have equivalent blood loss when tranexamic acid is used: a propensity score matched cohort analysis.

INTRODUCTION: Hip resurfacing (HR) requires a larger approach and soft tissue dissection and might therefore be associated with increased blood loss compared to total hip arthroplasty (THA). However, the effect of the adoption of tranexamic acid (TXA) in this setting is unknown. Therefore, the current study compares the blood loss and transfusion requirements between HR and posterior THA in patients receiving TXA. MATERIALS AND METHODS: This retrospective cohort study included patients undergoing primary, unilateral THA or HR using a posterior approach between February 2016 and 2020 in which TXA was administered. THA and HR patients were propensity score matched using nearest neighbor greedy matching accounting for demographic, health and surgical variables. Postoperative hemoglobin (Hgb) levels and Hgb drop from preoperative to post-operative day (POD) 1 were compared using t-tests and associated risk factors were assessed using linear mixed modelling. RESULTS: After matching, each cohort consisted of 1395 patients. Cohorts were similar regarding age, sex, BMI, and Charlson Comorbidity Index. No significant differences were found for Hgb levels on POD 1 (12.3 g/dl; p = 0.90) or Hgb drop (2.3 g/dl; p = 0.87). Duration of surgery was significantly longer for HR patients (82 vs 77 min; p < 0.01). Transfusion rate was 0.1% in both cohorts (p = 1.00). Hospital stay was significantly shorter for HR patients (1 vs 2 days; p < 0.01). CONCLUSION: HR using a standard TXA regimen is not associated with greater perioperative blood loss than posterior THA and does not result in increased transfusion requirements. Both surgical procedures can be considered equally safe in terms of perioperative blood management when TXA is used.

Collection and Reporting of Patient-reported Outcome Measures in Arthroplasty Registries: Multinational Survey and Recommendations.

BACKGROUND: Patient-reported outcome measures (PROMs) are validated questionnaires that are completed by patients. Arthroplasty registries vary in PROM collection and use. Current information about registry collection and use of PROMs is important to help improve methods of PROM data analysis, reporting, comparison, and use toward improving clinical practice. QUESTIONS/PURPOSES: To characterize PROM collection and use by registries, we asked: (1) What is the current practice of PROM collection by arthroplasty registries that are current or former members of the International Society of Arthroplasty Registries, and are there sufficient similarities in PROM collection between registries to enable useful international comparisons that could inform the improvement of arthroplasty care? (2) How do registries differ in PROM administration and demographic, clinical, and comorbidity index variables collected for case-mix adjustment in data analysis and reporting? (3) What quality assurance methods are used for PROMs, and how are PROM results reported and used by registries? (4) What recommendations to arthroplasty registries may improve PROM reporting and facilitate international comparisons? METHODS: An electronic survey was developed with questions about registry structure and collection, analysis, reporting, and use of PROM data and distributed to directors or senior administrators of 39 arthroplasty registries that were current or former members of the International Society of Arthroplasty Registries. In all, 64% (25 of 39) of registries responded and completed the survey. Missing responses from incomplete surveys were captured by contacting the registries, and up to three reminder emails were sent to nonresponding registries. Recommendations about PROM collection were drafted, revised, and approved by the International Society of Arthroplasty Registries PROMs Working Group members. RESULTS: Of the 25 registries that completed the survey, 15 collected generic PROMs, most frequently the EuroQol-5 Dimension survey; 16 collected joint-specific PROMs, most frequently the Knee Injury and Osteoarthritis Outcome Score and Hip Disability and Osteoarthritis Outcome Score; and 11 registries collected a satisfaction item. Most registries administered PROM questionnaires within 3 months before and 1 year after surgery. All 16 registries that collected PROM data collected patient age, sex or gender, BMI, indication for the primary arthroplasty, reason for revision arthroplasty, and a comorbidity index, most often the American Society of Anesthesiologists classification. All 16 registries performed regular auditing and reporting of data quality, and most registries reported PROM results to hospitals and linked PROM data to other data sets such as hospital, medication, billing, and emergency care databases. Recommendations for transparent reporting of PROMs were grouped into four categories: demographic and clinical, survey administration, data analysis, and results. CONCLUSION: Although registries differed in PROM collection and use, there were sufficient similarities that may enable useful data comparisons. The International Society of Arthroplasty Registries PROMs Working Group recommendations identify issues that may be important to most registries such as the need to make decisions about survey times and collection methods, as well as how to select generic and joint-specific surveys, handle missing data and attrition, report data, and ensure representativeness of the sample. CLINICAL RELEVANCE: By collecting PROMs, registries can provide patient-centered data to surgeons, hospitals, and national entities to improve arthroplasty care.

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

BACKGROUND: Total 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. METHODS: Using 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. RESULTS: Significantly 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. CONCLUSION: At 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 EVIDENCE: III.