Mesenchymal stem cells for chronic knee pain secondary to osteoarthritis: A systematic review and meta-analysis of randomized trials.

OBJECTIVE: To assess the effectiveness of mesenchymal stem cells (MSCs) for chronic knee pain secondary to osteoarthritis (OA). METHODS: We searched MEDLINE, EMBASE, CINAHL, and Cochrane Central to September 2023 for trials that (1) enrolled patients with chronic pain associated with knee OA, and (2) randomized them to MSC therapy vs. placebo or usual care. We performed random-effects meta-analysis and used Grading of Recommendations, Assessment, Development, and Evaluation to assess the certainty of evidence. RESULTS: We included 16 trials (807 participants). At 3-6 months, MSC therapy probably results in little to no difference in pain relief (weighted mean difference [WMD] -0.74 cm on a 10 cm visual analog scale [VAS], 95% confidence interval [95%CI] -1.16 to -0.33; minimally important difference [MID] 1.5 cm) or physical functioning (WMD 2.23 points on 100-point 36-item Short Form Survey (SF-36) physical functioning subscale, 95%CI -0.97 to 5.43; MID 10-points; both moderate certainty). At 12 months, injection of MSCs probably results in little to no difference in pain (WMD -0.73 cm on a 10 cm VAS, 95%CI -1.69 to 0.24; moderate certainty) and may improve physical functioning (WMD 19.36 points on 100-point SF-36 PF subscale, 95%CI -0.19 to 38.9; low certainty). MSC therapy may increase risk of any adverse events (risk ratio [RR] 2.67, 95%CI 1.19 to 5.99; low certainty) and pain and swelling of the knee joint (RR 1.58, 95%CI 1.04 to 2.38; low certainty). CONCLUSIONS: Intra-articular injection of MSCs for chronic knee pain associated with OA probably provides little to no improvement in pain or physical function.

Are Commonly Used Geographically Based Social Determinant of Health Indices in Orthopaedic Surgery Research Correlated With Each Other and With PROMIS Global-10 Physical and Mental Health Scores?

BACKGROUND: Geographically based social determinants of health (SDoH) measures are useful in research and policy aimed at addressing health disparities. In the United States, the Area Deprivation Index (ADI), Neighborhood Stress Score (NSS), and Social Vulnerability Index (SVI) are frequently used, but often without a clear reason as to why one is chosen over another. There is limited evidence about how strongly correlated these geographically based SDoH measures are with one another. Further, there is a paucity of research examining their relationship with patient-reported outcome measures (PROMs) in orthopaedic patients. Such insights are important in order to determine whether comparisons of policies and care programs using different geographically based SDoH indices to address health disparities in orthopaedic surgery are appropriate. QUESTIONS/PURPOSES: Among new patients seeking care at an orthopaedic surgery clinic, (1) what is the correlation of the NSS, ADI, and SVI with one another? (2) What is the correlation of Patient-Reported Outcomes Measurement Information System (PROMIS) Global-10 physical and mental health scores and the NSS, ADI, and SVI? (3) Which geographically based SDoH index or indices are associated with presenting PROMIS Global-10 physical and mental health scores when accounting for common patient-level sociodemographic factors? METHODS: New adult orthopaedic patient encounters at clinic sites affiliated with a tertiary referral academic medical center between 2016 and 2021 were identified, and the ADI, NSS, and SVI were determined. Patients also completed the PROMIS Global-10 questionnaire as part of routine care. Overall, a total of 75,335 new patient visits were noted. Of these, 62% (46,966 of 75,335) of new patient visits were excluded because of missing PROMIS Global-10 physical and mental health scores. An additional 2.2% of patients (1685 of 75,335) were excluded because they were missing at least one SDoH index at the time of their visit (for example, if a patient only had a Post Office box listed, the SDoH index could not be determined). This left 35% of the eligible new patient visits (26,684 of 75,335) in our final sample. Though only 35% of possible new patient visits were included, the diversity of these individuals across numerous characteristics and the wide range of sociodemographic status-as measured by the SDoH indices-among included patients supports the generalizability of our sample. The mean age of patients in our sample was 55 ± 18 years and a slight majority were women (54% [14,366 of 26,684]). Among the sample, 16% (4381of 26,684) of patients were of non-White race. The mean PROMIS Global-10 physical and mental health scores were 43.4 ± 9.4 and 49.7 ± 10.1, respectively. Spearman correlation coefficients were calculated among the three SDoH indices and between each SDoH index and PROMIS Global-10 physical and mental health scores. In addition, regression analysis was used to assess the association of each SDoH index with presenting functional and mental health, accounting for key patient characteristics. The strength of the association between each SDoH index and PROMIS Global-10 physical and mental health scores was determined using partial r-squared values. Significance was set at p < 0.05. RESULTS: There was a poor correlation between the ADI and the NSS (ρ = 0.34; p < 0.001). There were good correlations between the ADI and SVI (ρ = 0.43; p < 0.001) and between the NSS and SVI (ρ = 0.59; p < 0.001). There was a poor correlation between the PROMIS Global-10 physical health and NSS (ρ = -0.14; p < 0.001), ADI (ρ = -0.24; p < 0.001), and SVI (ρ = -0.17; p < 0.001). There was a poor correlation between PROMIS Global-10 mental health and NSS (ρ = -0.13; p < 0.001), ADI (ρ = -0.22; p < 0.001), and SVI (ρ = -0.17; p < 0.001). When accounting for key sociodemographic factors, the ADI demonstrated the largest association with presenting physical health (regression coefficient: -0.13 [95% CI -0.14 to -0.12]; p < 0.001) and mental health (regression coefficient: -0.13 [95% CI -0.14 to -0.12]; p < 0.001), as confirmed by the partial r-squared values for each SDoH index (physical health: ADI 0.04 versus SVI 0.02 versus NSS 0.01; mental health: ADI 0.04 versus SVI 0.02 versus NSS 0.01). This finding means that as social deprivation increases, physical and mental health scores decrease, representing poorer health. For further context, an increase in ADI score by approximately 36 and 39 suggests a clinically meaningful (determined using distribution-based minimum clinically important difference estimates of one-half SD of each PROMIS score) worsening of physical and mental health, respectively. CONCLUSION: Orthopaedic surgeons, policy makers, and other stakeholders looking to address SDoH factors to help alleviate disparities in musculoskeletal care should try to avoid interchanging the ADI, SVI, and NSS. Because the ADI has the largest association between any of the geographically based SDoH indices and presenting physical and mental health, it may allow for easier clinical and policy application. CLINICAL RELEVANCE: We suggest using the ADI as the geographically based SDoH index in orthopaedic surgery in the United States. Further, we caution against comparing findings in one study that use one geographically based SDoH index to another study's findings that incorporates another geographically based SDoH index. Although the general findings may be the same, the strength of association and clinical relevance could differ and have policy ramifications that are not otherwise appreciated; however, the degree to which this may be true is an area for future inquiry.

Machine Learning Did Not Outperform Conventional Competing Risk Modeling to Predict Revision Arthroplasty.

BACKGROUND: Estimating the risk of revision after arthroplasty could inform patient and surgeon decision-making. However, there is a lack of well-performing prediction models assisting in this task, which may be due to current conventional modeling approaches such as traditional survivorship estimators (such as Kaplan-Meier) or competing risk estimators. Recent advances in machine learning survival analysis might improve decision support tools in this setting. Therefore, this study aimed to assess the performance of machine learning compared with that of conventional modeling to predict revision after arthroplasty. QUESTION/PURPOSE: Does machine learning perform better than traditional regression models for estimating the risk of revision for patients undergoing hip or knee arthroplasty? METHODS: Eleven datasets from published studies from the Dutch Arthroplasty Register reporting on factors associated with revision or survival after partial or total knee and hip arthroplasty between 2018 and 2022 were included in our study. The 11 datasets were observational registry studies, with a sample size ranging from 3038 to 218,214 procedures. We developed a set of time-to-event models for each dataset, leading to 11 comparisons. A set of predictors (factors associated with revision surgery) was identified based on the variables that were selected in the included studies. We assessed the predictive performance of two state-of-the-art statistical time-to-event models for 1-, 2-, and 3-year follow-up: a Fine and Gray model (which models the cumulative incidence of revision) and a cause-specific Cox model (which models the hazard of revision). These were compared with a machine-learning approach (a random survival forest model, which is a decision tree-based machine-learning algorithm for time-to-event analysis). Performance was assessed according to discriminative ability (time-dependent area under the receiver operating curve), calibration (slope and intercept), and overall prediction error (scaled Brier score). Discrimination, known as the area under the receiver operating characteristic curve, measures the model's ability to distinguish patients who achieved the outcomes from those who did not and ranges from 0.5 to 1.0, with 1.0 indicating the highest discrimination score and 0.50 the lowest. Calibration plots the predicted versus the observed probabilities; a perfect plot has an intercept of 0 and a slope of 1. The Brier score calculates a composite of discrimination and calibration, with 0 indicating perfect prediction and 1 the poorest. A scaled version of the Brier score, 1 - (model Brier score/null model Brier score), can be interpreted as the amount of overall prediction error. RESULTS: Using machine learning survivorship analysis, we found no differences between the competing risks estimator and traditional regression models for patients undergoing arthroplasty in terms of discriminative ability (patients who received a revision compared with those who did not). We found no consistent differences between the validated performance (time-dependent area under the receiver operating characteristic curve) of different modeling approaches because these values ranged between -0.04 and 0.03 across the 11 datasets (the time-dependent area under the receiver operating characteristic curve of the models across 11 datasets ranged between 0.52 to 0.68). In addition, the calibration metrics and scaled Brier scores produced comparable estimates, showing no advantage of machine learning over traditional regression models. CONCLUSION: Machine learning did not outperform traditional regression models. CLINICAL RELEVANCE: Neither machine learning modeling nor traditional regression methods were sufficiently accurate in order to offer prognostic information when predicting revision arthroplasty. The benefit of these modeling approaches may be limited in this context.

A simplified, 2-question grading system for evaluating abstracts in orthopedic scientific meetings: a serial randomization study.

BACKGROUND AND PURPOSE: Efficient abstract scoring for congress presentation is important. Given the emergence of new study methodologies, a scoring system that accommodates all study designs is warranted. We aimed to assess the equivalence of a simplified, 2-question abstract grading system with a more complex currently used system in assessing abstracts submitted for orthopedic scientific meetings in a serial randomized study. METHODS: Dutch Orthopedic Association Scientific Committee (DOASC) members were randomized to grade abstracts using either the current grading system, which includes up to 7 scoring categories, or the new grading system, which consists of only 2 questions. Pearson correlation coefficient and mean abstract score with 95% confidence intervals (CI) were calculated. RESULTS: Analysis included the scoring of 195 abstracts by 12-14 DOASC members. The average score for an abstract using the current system was 60 points (CI 58-62), compared with 63 points (CI 62-64) using the new system. By using the new system, abstracts were scored higher by 3.3 points (CI 1.7-5.0). Pearson correlation was poor with coefficient 0.38 (P < 0.001). CONCLUSION: The simplified abstract grading system exhibited a poor correlation with the current scoring system, while the new system offers a more inclusive evaluation of varying study designs and is preferred by almost all DOASC members.

Short versus conventional straight stem in uncemented total hip arthroplasty: functional outcomes up to 5 years and survival up to 12 years: secondary results of a randomized controlled trial.

BACKGROUND AND PURPOSE: To date, the mid- and long-term outcomes of the Collum Femoris Preserving (CFP) stem compared with conventional straight stems are unknown. We aimed to compare physical function at a 5-year follow-up and implant survival at an average of 10-year follow-up in an randomized controlled trial (RCT). METHODS: This is a secondary report of a double-blinded RCT in 2 hospitals. Patients aged 18-70 years with hip osteoarthritis undergoing an uncemented primary THA were randomized to a CFP or a Zweymüller stem. Patient-reported outcomes, clinical tests, and radiographs were collected at baseline, 2, 3, 4, and 5 years postoperatively. Primary outcome was the Hip disability and Osteoarthritis Outcome Score (HOOS) function in activities of daily living (ADL) subscale. Secondary outcomes were other patient-reported outcomes, clinical tests, adverse events, and implant survival. Kaplan-Meier and competing risk survival analyses were performed with data from the Dutch Arthroplasty Registry. RESULTS: We included 150 patients. Mean difference between groups on the HOOS ADL subscale at 5 years was -0.07 (95% confidence interval -5.1 to 4.9). Overall survival was 92% for the CFP and 96% for the Zweymüller stem. No significant difference was found. CONCLUSION: No significant differences were found in physical function at 5-year and implant survival at 10-year follow-up between the CFP and Zweymüller stems. When taking cup revisions into account, the CFP group showed clinically inferior survival.

Are Detailed, Patient-level Social Determinant of Health Factors Associated With Physical Function and Mental Health at Presentation Among New Patients With Orthopaedic Conditions?

BACKGROUND: It is well documented that routinely collected patient sociodemographic characteristics (such as race and insurance type) and geography-based social determinants of health (SDoH) measures (for example, the Area Deprivation Index) are associated with health disparities, including symptom severity at presentation. However, the association of patient-level SDoH factors (such as housing status) on musculoskeletal health disparities is not as well documented. Such insight might help with the development of more-targeted interventions to help address health disparities in orthopaedic surgery. QUESTIONS/PURPOSES: (1) What percentage of patients presenting for new patient visits in an orthopaedic surgery clinic who were unemployed but seeking work reported transportation issues that could limit their ability to attend a medical appointment or acquire medications, reported trouble paying for medications, and/or had no current housing? (2) Accounting for traditional sociodemographic factors and patient-level SDoH measures, what factors are associated with poorer patient-reported outcome physical health scores at presentation? (3) Accounting for traditional sociodemographic factor patient-level SDoH measures, what factors are associated with poorer patient-reported outcome mental health scores at presentation? METHODS: New patient encounters at one Level 1 trauma center clinic visit from March 2018 to December 2020 were identified. Included patients had to meet two criteria: they had completed the Patient-Reported Outcome Measure Information System (PROMIS) Global-10 at their new orthopaedic surgery clinic encounter as part of routine clinical care, and they had visited their primary care physician and completed a series of specific SDoH questions. The SDoH questionnaire was developed in our institution to improve data that drive interventions to address health disparities as part of our accountable care organization work. Over the study period, the SDoH questionnaire was only distributed at primary care provider visits. The SDoH questions focused on transportation, housing, employment, and ability to pay for medications. Because we do not have a way to determine how many patients had both primary care provider office visits and new orthopaedic surgery clinic visits over the study period, we were unable to determine how many patients could have been included; however, 9057 patients were evaluated in this cross-sectional study. The mean age was 61 ± 15 years, and most patients self-reported being of White race (83% [7561 of 9057]). Approximately half the patient sample had commercial insurance (46% [4167 of 9057]). To get a better sense of how this study cohort compared with the overall patient population seen at the participating center during the time in question, we reviewed all new patient clinic encounters (n = 135,223). The demographic information between the full patient sample and our study subgroup appeared similar. Using our study cohort, two multivariable linear regression models were created to determine which traditional metrics (for example, self-reported race or insurance type) and patient-specific SDoH factors (for example, lack of reliable transportation) were associated with worse physical and mental health symptoms (that is, lower PROMIS scores) at new patient encounters. The variance inflation factor was used to assess for multicollinearity. For all analyses, p values < 0.05 designated statistical significance. The concept of minimum clinically important difference (MCID) was used to assess clinical importance. Regression coefficients represent the projected change in PROMIS physical or mental health symptom scores (that is, the dependent variable in our regression analyses) accounting for the other included variables. Thus, a regression coefficient for a given variable at or above a known MCID value suggests a clinical difference between those patients with and without the presence of that given characteristic. In this manuscript, regression coefficients at or above 4.2 (or at and below -4.2) for PROMIS Global Physical Health and at or above 5.1 (or at and below -5.1) for PROMIS Global Mental Health were considered clinically relevant. RESULTS: Among the included patients, 8% (685 of 9057) were unemployed but seeking work, 4% (399 of 9057) reported transportation issues that could limit their ability to attend a medical appointment or acquire medications, 4% (328 of 9057) reported trouble paying for medications, and 2% (181 of 9057) had no current housing. Lack of reliable transportation to attend doctor visits or pick up medications (ß = -4.52 [95% CI -5.45 to -3.59]; p < 0.001), trouble paying for medications (ß = -4.55 [95% CI -5.55 to -3.54]; p < 0.001), Medicaid insurance (ß = -5.81 [95% CI -6.41 to -5.20]; p < 0.001), and workers compensation insurance (ß = -5.99 [95% CI -7.65 to -4.34]; p < 0.001) were associated with clinically worse function at presentation. Trouble paying for medications (ß = -6.01 [95% CI -7.10 to -4.92]; p < 0.001), Medicaid insurance (ß = -5.35 [95% CI -6.00 to -4.69]; p < 0.001), and workers compensation (ß = -6.07 [95% CI -7.86 to -4.28]; p < 0.001) were associated with clinically worse mental health at presentation. CONCLUSION: Although transportation issues and financial hardship were found to be associated with worse presenting physical function and mental health, Medicaid and workers compensation insurance remained associated with worse presenting physical function and mental health as well even after controlling for these more detailed, patient-level SDoH factors. Because of that, interventions to decrease health disparities should focus on not only sociodemographic variables (for example, insurance type) but also tangible patient-specific SDoH characteristics. For example, this may include giving patients taxi vouchers or ride-sharing credits to attend clinic visits for patients demonstrating such a need, initiating financial assistance programs for necessary medications, and/or identifying and connecting certain patient groups with social support services early on in the care cycle. LEVEL OF EVIDENCE: Level III, prognostic study.

Challenges in developing national orthopedic health research agendas in the Netherlands: process overview and recommendations.

Growing demand for clinical research to improve evidence-based medicine in daily medical practice led to healthcare evaluation, which assesses the effectiveness of the existing care. The first step is identifying and prioritizing the most important evidence uncertainties. A health research agenda (HRA) can be valuable and helps determine funding and resource allocation, aiding researchers and policymakers to design successful research programs and implement the results in daily medical practice. We provide an overview of the development process of the first 2 HRAs within orthopedic surgery in the Netherlands and the following research process. In addition, we developed a checklist with recommendations for the future development of an HRA. This perspective guides the development of highquality and widely supported nationwide HRAs, including preparatory actions. This improves the uptake of evidence uncertainties in a successful research program and disseminates evidence-based literature in daily medical practice to improve patient care.

Total Hip Arthroplasty or Hemiarthroplasty for Hip Fracture.

BACKGROUND: Globally, hip fractures are among the top 10 causes of disability in adults. For displaced femoral neck fractures, there remains uncertainty regarding the effect of a total hip arthroplasty as compared with hemiarthroplasty. METHODS: We randomly assigned 1495 patients who were 50 years of age or older and had a displaced femoral neck fracture to undergo either total hip arthroplasty or hemiarthroplasty. All enrolled patients had been able to ambulate without the assistance of another person before the fracture occurred. The trial was conducted in 80 centers in 10 countries. The primary end point was a secondary hip procedure within 24 months of follow-up. Secondary end points included death, serious adverse events, hip-related complications, health-related quality of life, function, and overall health end points. RESULTS: The primary end point occurred in 57 of 718 patients (7.9%) who were randomly assigned to total hip arthroplasty and 60 of 723 patients (8.3%) who were randomly assigned to hemiarthroplasty (hazard ratio, 0.95; 95% confidence interval [CI], 0.64 to 1.40; P = 0.79). Hip instability or dislocation occurred in 34 patients (4.7%) assigned to total hip arthroplasty and 17 patients (2.4%) assigned to hemiarthroplasty (hazard ratio, 2.00; 99% CI, 0.97 to 4.09). Function, as measured with the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score, pain score, stiffness score, and function score, modestly favored total hip arthroplasty over hemiarthroplasty. Mortality was similar in the two treatment groups (14.3% among the patients assigned to total hip arthroplasty and 13.1% among those assigned to hemiarthroplasty, P = 0.48). Serious adverse events occurred in 300 patients (41.8%) assigned to total hip arthroplasty and in 265 patients (36.7%) assigned to hemiarthroplasty. CONCLUSIONS: Among independently ambulating patients with displaced femoral neck fractures, the incidence of secondary procedures did not differ significantly between patients who were randomly assigned to undergo total hip arthroplasty and those who were assigned to undergo hemiarthroplasty, and total hip arthroplasty provided a clinically unimportant improvement over hemiarthroplasty in function and quality of life over 24 months. (Funded by the Canadian Institutes of Health Research and others; ClinicalTrials.gov number, NCT00556842.).

Arthroscopic surgery for degenerative knee disease (osteoarthritis including degenerative meniscal tears).

BACKGROUND: Arthroscopic knee surgery remains a common treatment for symptomatic knee osteoarthritis, including for degenerative meniscal tears, despite guidelines strongly recommending against its use. This Cochrane Review is an update of a non-Cochrane systematic review published in 2017. OBJECTIVES: To assess the benefits and harms of arthroscopic surgery, including debridement, partial menisectomy or both, compared with placebo surgery or non-surgical treatment in people with degenerative knee disease (osteoarthritis, degenerative meniscal tears, or both). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and two trials registers up to 16 April 2021, unrestricted by language. SELECTION CRITERIA: We included randomised controlled trials (RCTs), or trials using quasi-randomised methods of participant allocation, comparing arthroscopic surgery with placebo surgery or non-surgical interventions (e.g. exercise, injections, non-arthroscopic lavage/irrigation, drug therapy, and supplements and complementary therapies) in people with symptomatic degenerative knee disease (osteoarthritis or degenerative meniscal tears or both). Major outcomes were pain, function, participant-reported treatment success, knee-specific quality of life, serious adverse events, total adverse events and knee surgery (replacement or osteotomy). DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies for inclusion, extracted data, and assessed risk of bias and the certainty of evidence using GRADE. The primary comparison was arthroscopic surgery compared to placebo surgery for outcomes that measured benefits of surgery, but we combined data from all control groups to assess harms and knee surgery (replacement or osteotomy). MAIN RESULTS: Sixteen trials (2105 participants) met our inclusion criteria. The average age of participants ranged from 46 to 65 years, and 56% of participants were women. Four trials (380 participants) compared arthroscopic surgery to placebo surgery. For the remaining trials, arthroscopic surgery was compared to exercise (eight trials, 1371 participants), a single intra-articular glucocorticoid injection (one trial, 120 participants), non-arthroscopic lavage (one trial, 34 participants), non-steroidal anti-inflammatory drugs (one trial, 80 participants) and weekly hyaluronic acid injections for five weeks (one trial, 120 participants). The majority of trials without a placebo control were susceptible to bias: in particular, selection (56%), performance (75%), detection (75%), attrition (44%) and selective reporting (75%) biases. The placebo-controlled trials were less susceptible to bias and none were at risk of performance or detection bias. Here we limit reporting to the main comparison, arthroscopic surgery versus placebo surgery. High-certainty evidence indicates arthroscopic surgery leads to little or no difference in pain or function at three months after surgery, moderate-certainty evidence indicates there is probably little or no improvement in knee-specific quality of life three months after surgery, and low-certainty evidence indicates arthroscopic surgery may lead to little or no difference in participant-reported success at up to five years, compared with placebo surgery. Mean post-operative pain in the placebo group was 40.1 points on a 0 to 100 scale (where lower score indicates less pain) compared to 35.5 points in the arthroscopic surgery group, a difference of 4.6 points better (95% confidence interval (CI) 0.02 better to 9 better; I2 = 0%; 4 trials, 309 participants). Mean post-operative function in the placebo group was 75.9 points on a 0 to 100 rating scale (where higher score indicates better function) compared to 76 points in the arthroscopic surgery group, a difference of 0.1 points better (95% CI 3.2 worse to 3.4 better; I2 = 0%; 3 trials, 302 participants). Mean post-operative knee-specific health-related quality of life in the placebo group was 69.7 points on a 0 to 100 rating scale (where higher score indicates better quality of life) compared with 75.3 points in the arthroscopic surgery group, a difference of 5.6 points better (95% CI 0.36 better to 10.68 better; I2 = 0%; 2 trials, 188 participants). We downgraded this evidence to moderate certainty as the 95% confidence interval does not rule in or rule out a clinically important change. After surgery, 74 out of 100 people reported treatment success with placebo and 82 out of 100 people reported treatment success with arthroscopic surgery at up to five years (risk ratio (RR) 1.11, 95% CI 0.66 to 1.86; I2 = 53%; 3 trials, 189 participants). We downgraded this evidence to low certainty due to serious indirectness (diversity in definition and timing of outcome measurement) and serious imprecision (small number of events). We are less certain if the risk of serious or total adverse events increased with arthroscopic surgery compared to placebo or non-surgical interventions. Serious adverse events were reported in 6 out of 100 people in the control groups and 8 out of 100 people in the arthroscopy groups from eight trials (RR 1.35, 95% CI 0.64 to 2.83; I2 = 47%; 8 trials, 1206 participants). Fifteen out of 100 people reported adverse events with control interventions, and 17 out of 100 people with surgery at up to five years (RR 1.15, 95% CI 0.78 to 1.70; I2 = 48%; 9 trials, 1326 participants). The certainty of the evidence was low, downgraded twice due to serious imprecision (small number of events) and possible reporting bias (incomplete reporting of outcome across studies). Serious adverse events included death, pulmonary embolism, acute myocardial infarction, deep vein thrombosis and deep infection. Subsequent knee surgery (replacement or high tibial osteotomy) was reported in 2 out of 100 people in the control groups and 4 out of 100 people in the arthroscopy surgery groups at up to five years in four trials (RR 2.63, 95% CI 0.94 to 7.34; I2 = 11%; 4 trials, 864 participants). The certainty of the evidence was low, downgraded twice due to the small number of events. AUTHORS' CONCLUSIONS: Arthroscopic surgery provides little or no clinically important benefit in pain or function, probably does not provide clinically important benefits in knee-specific quality of life, and may not improve treatment success compared with a placebo procedure. It may lead to little or no difference, or a slight increase, in serious and total adverse events compared to control, but the evidence is of low certainty. Whether or not arthroscopic surgery results in slightly more subsequent knee surgery (replacement or osteotomy) compared to control remains unresolved.

Patients With Femoral Neck Fractures Are at Risk for Conversion to Arthroplasty After Internal Fixation: A Machine-learning Algorithm.

BACKGROUND: Femoral neck fractures are common and are frequently treated with internal fixation. A major disadvantage of internal fixation is the substantially high number of conversions to arthroplasty because of nonunion, malunion, avascular necrosis, or implant failure. A clinical prediction model identifying patients at high risk of conversion to arthroplasty may help clinicians in selecting patients who could have benefited from arthroplasty initially. QUESTION/PURPOSE: What is the predictive performance of a machine-learning (ML) algorithm to predict conversion to arthroplasty within 24 months after internal fixation in patients with femoral neck fractures? METHODS: We included 875 patients from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial. The FAITH trial consisted of patients with low-energy femoral neck fractures who were randomly assigned to receive a sliding hip screw or cancellous screws for internal fixation. Of these patients, 18% (155 of 875) underwent conversion to THA or hemiarthroplasty within the first 24 months. All patients were randomly divided into a training set (80%) and test set (20%). First, we identified 27 potential patient and fracture characteristics that may have been associated with our primary outcome, based on biomechanical rationale and previous studies. Then, random forest algorithms (an ML learning, decision tree-based algorithm that selects variables) identified 10 predictors of conversion: BMI, cardiac disease, Garden classification, use of cardiac medication, use of pulmonary medication, age, lung disease, osteoarthritis, sex, and the level of the fracture line. Based on these variables, five different ML algorithms were trained to identify patterns related to conversion. The predictive performance of these trained ML algorithms was assessed on the training and test sets based on the following performance measures: (1) discrimination (the model's ability to distinguish patients who had conversion from those who did not; expressed with the area under the receiver operating characteristic curve [AUC]), (2) calibration (the plotted estimated versus the observed probabilities; expressed with the calibration curve intercept and slope), and (3) the overall model performance (Brier score: a composite of discrimination and calibration). RESULTS: None of the five ML algorithms performed well in predicting conversion to arthroplasty in the training set and the test set; AUCs of the algorithms in the training set ranged from 0.57 to 0.64, slopes of calibration plots ranged from 0.53 to 0.82, calibration intercepts ranged from -0.04 to 0.05, and Brier scores ranged from 0.14 to 0.15. The algorithms were further evaluated in the test set; AUCs ranged from 0.49 to 0.73, calibration slopes ranged from 0.17 to 1.29, calibration intercepts ranged from -1.28 to 0.34, and Brier scores ranged from 0.13 to 0.15. CONCLUSION: The predictive performance of the trained algorithms was poor, despite the use of one of the best datasets available worldwide on this subject. If the current dataset consisted of different variables or more patients, the performance may have been better. Also, various reasons for conversion to arthroplasty were pooled in this study, but the separate prediction of underlying pathology (such as, avascular necrosis or nonunion) may be more precise. Finally, it may be possible that it is inherently difficult to predict conversion to arthroplasty based on preoperative variables alone. Therefore, future studies should aim to include more variables and to differentiate between the various reasons for arthroplasty. LEVEL OF EVIDENCE: Level III, prognostic study.

An individualized decision between physical therapy or surgery for patients with degenerative meniscal tears cannot be based on continuous treatment selection markers: a marker-by-treatment analysis of the ESCAPE study.

PURPOSE: Marker-by-treatment analyses are promising new methods in internal medicine, but have not yet been implemented in orthopaedics. With this analysis, specific cut-off points may be obtained, that can potentially identify whether meniscal surgery or physical therapy is the superior intervention for an individual patient. This study aimed to introduce a novel approach in orthopaedic research to identify relevant treatment selection markers that affect treatment outcome following meniscal surgery or physical therapy in patients with degenerative meniscal tears. METHODS: Data were analysed from the ESCAPE trial, which assessed the treatment of patients over 45 years old with a degenerative meniscal tear. The treatment outcome of interest was a clinically relevant improvement on the International Knee Documentation Committee Subjective Knee Form at 3, 12, and 24 months follow-up. Logistic regression models were developed to predict the outcome using baseline characteristics (markers), the treatment (meniscal surgery or physical therapy), and a marker-by-treatment interaction term. Interactions with p < 0.10 were considered as potential treatment selection markers and used these to develop predictiveness curves which provide thresholds to identify marker-based differences in clinical outcomes between the two treatments. RESULTS: Potential treatment selection markers included general physical health, pain during activities, knee function, BMI, and age. While some marker-based thresholds could be identified at 3, 12, and 24 months follow-up, none of the baseline characteristics were consistent markers at all three follow-up times. CONCLUSION: This novel in-depth analysis did not result in clear clinical subgroups of patients who are substantially more likely to benefit from either surgery or physical therapy. However, this study may serve as an exemplar for other orthopaedic trials to investigate the heterogeneity in treatment effect. It will help clinicians to quantify the additional benefit of one treatment over another at an individual level, based on the patient's baseline characteristics. LEVEL OF EVIDENCE: II.

The learning curve of the direct anterior approach is 100 cases: an analysis based on 15,875 total hip arthroplasties in the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: In the last decade, the direct anterior approach (DAA) for total hip arthroplasty (THA) has become more popular in the Netherlands. Therefore, we investigated the learning curve and survival rate of the DAA in primary THA, using data from the Dutch Arthroplasty Register (LROI). PATIENTS AND METHODS: We identified all patients who received a primary THA using the DAA in several high-volume centers in the Netherlands between 2007 and 2019 (n = 15,903). Procedures were ordered per surgeon, using date of operation. Using the procedure number, operations were divided into 6 groups based on the number of previous procedures per surgeon (first 25, 26-50, 51-100, 101-150, 151-200, > 200). Data from different surgeons in different hospitals was pooled together. Revision rates were calculated using a multilevel time-to-event analysis. RESULTS: Patients operated on in group 1-25 (hazard ratio [HR] 1.6; 95% CI 1.1-2.4) and 26-50 (HR 1.6; CI 1.1-2.5) had a higher risk for revision compared with patients operated on in group > 200 THAs. Between 50 and 100 procedures the revision risk was increased (HR 1.3; CI 0.9-1.9), albeit not statistically significant. From 100 procedures onwards the HR for revision was respectively 1.0 (CI 0.6-1.6) and 0.8 (CI 0.5-1.4) for patients in operation groups 101-150 and 151-200. Main reasons for revision were loosening of the stem (29%), periprosthetic infection (19%), and dislocation (16%). INTERPRETATION: We found a 64% increased risk of revision for patients undergoing THA using the DAA for the first 50 cases per surgeon. Between 50 and 100 cases, this risk was 30% increased, but not statistically significant. From 100 cases onwards, a steady state had been reached in revision rate. The learning curve for DAA therefore is around 100 cases.

Comparison of early migration patterns between a ceramic and polyethylene liner in uncemented Trabecular Titanium cups: a 2-year randomized controlled trial of 52 hips using radiostereometric analysis.

BACKGROUND AND PURPOSE: Ceramic liners may reduce early stability of uncemented acetabular components due to higher stiffness. However, the bone ingrowth capacities of porous trabecular titanium might compensate for this effect. This prospective randomized trial quantifies migration patterns of the Delta-TT cup, and compares polyethylene and ceramic liners. PATIENTS AND METHODS: Patients undergoing primary uncemented total hip arthroplasty with the Delta-TT cup and femoral stem with ceramic head were randomized to a polyethylene (n = 25) or ceramic (n = 28) liner. Radiostereometric analysis (RSA) radiographs, patient-reported hip function (HOOS-PS, OHS), and quality of life (EQ5D) were collected at baseline and 1.5, 3, 6, 12, and 24 months postoperatively. Model-based RSA was used to calculate 3D cup translation and rotation, and mixed models were used to compare effects over time between groups. RESULTS: At 2 years follow-up, Delta-TT cups showed similar mean proximal translation of 0.56 mm (95% CI 0.38-0.75) in the ceramic (CE) group and 0.54 mm (0.30-0.77) in the polyethylene (PE) group, with a between group effect of 0.02 mm (-0.20-0.23). Most cup migration occurred in the first 1.5 to 3 months, stabilizing within 6 months. Any between-group effects were ≤ 0.30 mm for translation and ≤ 0.45° for rotation. Improvements in patient-reported hip function and quality of life were similar in both groups. INTERPRETATION: Regardless of liner type, Delta-TT cups showed some initial migration and stabilized within 6 months, which seems promising for long-term fixation in both cup-liner constructs.

Posterolateral or direct lateral approach for cemented hemiarthroplasty after femoral neck fracture (APOLLO): protocol for a multicenter randomized controlled trial with economic evaluation and natural experiment alongside.

BACKGROUND AND PURPOSE: The posterolateral and direct lateral surgical approach are the 2 most common surgical approaches for performing a hemiarthroplasty in patients with a hip fracture. It is unknown which surgical approach is preferable in terms of (cost-)effectiveness and quality of life. METHODS AND ANALYSIS: We designed a multicenter randomized controlled trial (RCT) with an economic evaluation and a natural experiment (NE) alongside. We will include 555 patients ≥ 18 years with an acute femoral neck fracture. The primary outcome is patient-reported health-related quality of life assessed with the EQ-5D-5L. Secondary outcomes include healthcare costs, complications, mortality, and balance (including fear of falling, actual falls, and injuries due to falling). An economic evaluation will be performed for quality adjusted life years (QALYs). We will use variable block randomization stratified for hospital. For continuous outcomes, we will use linear mixed-model analysis. Dichotomous secondary outcome measures will be analyzed using chi-square statistics and logistic regression models. Primary analyses are based on the intention-to-treat principle. Additional as treated analyses will be performed to evaluate the effect of protocol deviations. Study summary: (i) Largest RCT addressing the health-related patient outcome of the main surgical approaches of hemiarthroplasty. (ii) Focus on outcomes that are important for the patient. (iii) Pragmatic and inclusive RCT with few exclusion criteria, e.g., patients with dementia can participate. (iv) Natural experiment alongside to amplify the generalizability. (v) The first study conducting a costutility analysis comparing both surgical approaches.

How are you doing in the eyes of your spouse? Level of agreement between the self-completed EQ-5D-5L and two proxy perspectives in an orthopaedic population: a randomized agreement study.

OBJECTIVES: To determine the level of agreement between both proxy versions and the self-completed EQ-5D-5L. DESIGN: A randomized agreement study. SETTING AND PARTICIPANTS: We recruited 120 patients (compos mentis) and their proxies at the orthopaedic outpatient clinic. Patients completed the regular EQ-5D-5L and their proxy completed the proxy version of the EQ-5D-5L and rated the patients' health from their own (proxy-proxy) perspective (i.e. how do you rate the health of the patient), and from the patient's (proxy-patient) perspective (i.e. how do you think the patient would rate their own health if they were able to). MEASURES: The primary outcome was the agreement between patients and their proxy, quantified as the intra class correlation coefficient for the EQ-5D-5L Utility score. RESULTS: Average Utility scores were 0.65 with the self completed EQ-5D-5L, versus 0.60 with the proxy-patient version and 0.58 with the proxy-proxy version. The ICC was 0.66 (95% CI 0.523, 0.753) for the proxy-patient perspective and 0.58 (95% CI 0.411, 0.697) for the proxy-proxy perspective. The mean gold standard score of the VAS-Health was 69.7 whereas the proxy-proxy perspective was 66.5 and the proxy-patient perspective was 66.3. CONCLUSION AND IMPLICATIONS: The proxy-patient perspective yielded substantial agreement with the self completed EQ-5D-5L, while the agreement with the proxy-proxy perspective was moderate. In this study population of patients without cognitive impairment, proxies tended to underestimate the quality of life of their relative.

Is There An Association Between Bundled Payments and "Cherry Picking" and "Lemon Dropping" in Orthopaedic Surgery? A Systematic Review.

BACKGROUND: The goal of bundled payments-lump monetary sums designed to cover the full set of services needed to provide care for a condition or medical event-is to provide a reimbursement structure that incentivizes improved value for patients. There is concern that such a payment mechanism may lead to patient screening and denying or providing orthopaedic care to patients based on the number and severity of comorbid conditions present associated with complications after surgery. Currently, however, there is no clear consensus about whether such an association exists. QUESTIONS/PURPOSES: In this systematic review, we asked: (1) Is the implementation of a bundled payment model associated with a change in the sociodemographic characteristics of patients undergoing an orthopaedic procedure? (2) Is the implementation of a bundled payment model associated with a change in the comorbidities and/or case-complexity characteristics of patients undergoing an orthopaedic procedure? (3) Is the implementation of a bundled payment model associated with a change in the recent use of healthcare resources characteristics of patients undergoing an orthopaedic procedure? METHODS: This systematic review was registered in PROSPERO before data collection (CRD42020189416). Our systematic review included scientific manuscripts published in MEDLINE, Embase, Web of Science, Econlit, Policyfile, and Google Scholar through March 2020. Of the 30 studies undergoing full-text review, 20 were excluded because they did not evaluate the outcome of interest (patient selection) (n = 8); were editorial, commentary, or review articles (n = 5); did not evaluate the appropriate intervention (introduction of a bundled payment program) (n = 4); or assessed the wrong patient population (not orthopaedic surgery patients) (n = 3). This led to 10 studies included in this systematic review. For each study, patient factors analyzed in the included studies were grouped into the following three categories: sociodemographics, comorbidities and/or case complexity, or recent use of healthcare resources characteristics. Next, each patient factor falling into one of these three categories was examined to evaluate for changes from before to after implementation of a bundled payment initiative. In most cases, studies utilized a difference-in-difference (DID) statistical technique to assess for changes. Determination of whether the bundled payment initiative required mandatory participation or not was also noted. Scientific quality using the Adapted Newcastle-Ottawa Scale had a median (range) score of 8 (7 to 8; highest possible score: 9), and the quality of the total body of evidence for each patient characteristic group was found to be low using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool. We could not assess the likelihood of publication using funnel plots because of the variation of patient factors analyzed in each study and the heterogeneity of data precluded a meta-analysis. RESULTS: Of the nine included studies that reported on the sociodemographic characteristics of patients selected for care, seven showed no change with the implementation of bundled payments, and two demonstrated a difference. Most notably, the studies identified a decrease in the percentage of patients undergoing an orthopaedic operative intervention who were dual-eligible (range DID estimate -0.4% [95% CI -0.75% to -0.1%]; p < 0.05 to DID estimate -1.0% [95% CI -1.7% to -0.2%]; p = 0.01), which means they qualified for both Medicare and Medicaid insurance coverage. Of the 10 included studies that reported on comorbidities and case-complexity characteristics, six reported no change in such characteristics with the implementation of bundled payments, and four studies noted differences. Most notably, one study showed a decrease in the number of treated patients with disabilities (DID estimate -0.6% [95% CI -0.97% to -0.18%]; p < 0.05) compared with before bundled payment implementation, while another demonstrated a lower number of Elixhauser comorbidities for those treated as part of a bundled payment program (before: score of 0-1 in 63.6%, 2-3 in 27.9%, > 3 in 8.5% versus after: score of 0-1 in 50.1%, 2-3 in 38.7%, > 3 in 11.2%; p = 0.033). Of the three included studies that reported on the recent use of healthcare resources of patients, one study found no difference in the use of healthcare resources with the implementation of bundled payments, and two studies did find differences. Both studies found a decrease in patients undergoing operative management who recently received care at a skilled nursing facility (range DID estimate -0.50% [95% CI -1.0% to 0.0%]; p = 0.04 to DID estimate: -0.53% [95% CI -0.96% to -0.10%]; p = 0.01), while one of the studies also found a decrease in patients undergoing operative management who recently received care at an acute care hospital (DID estimate -0.8% [95% CI -1.6% to -0.1%]; p = 0.03) or as part of home healthcare (DID estimate -1.3% [95% CI -2.0% to -0.6%]; p < 0.001). CONCLUSION: In six of 10 studies in which differences in patient characteristics were detected among those undergoing operative orthopaedic intervention once a bundled payment program was initiated, the effect was found to be minimal (approximately 1% or less). However, our findings still suggest some level of adverse patient selection, potentially worsening health inequities when considered on a large scale. It is also possible that our findings reflect better care, whereby the financial incentives lead to fewer patients with a high risk of complications undergoing surgical intervention and vice versa for patients with a low risk of complications postoperatively. However, this is a fine line, and it may also be that patients with a high risk of complications postoperatively are not being offered surgery enough, while patients at low risk of complications postoperatively are being offered surgery too frequently. Evaluation of the longer-term effect of these preliminary bundled payment programs on patient selection is warranted to determine whether adverse patient selection changes over time as health systems and orthopaedic surgeons become accustomed to such reimbursement models.

Resident training does not influence the complication risk in total knee and hip arthroplasty.

Background and purpose - Gaining experience in the surgery room during residency is an important part of learning the skills needed to perform arthroplasties. However, in practice, patients are often not fully comfortable with trainee involvement in their own surgery. Therefore, we investigated complications, revision rates, mortality, and operative time of orthopedic surgeons and residents as primary surgeon performing total knee arthroplasties (TKAs) or total hip arthroplasties (THAs).Patients and methods - In this multi-center retrospective cohort study, 3,098 TKAs and 4,027 THAs performed between 2007 and 2013 were analyzed. Complications, revisions, mortality, and operative time were compared for patients operated on by the orthopedic surgeon or a resident as primary surgeon. An additional analysis was performed to determine whether the complication risk was affected by the postgraduate year of the resident.Results - Orthopedic complication rates were similar (TKA: orthopedic surgeon: 10%, resident: 11%; THA: 9% and 8%), revision rates (TKA: 3% and 2%, THA: 3% and 2%), or mortality rates (TKA: 0.1% and 0.3%, THA: 0.2% and 0.3%). For both procedures a higher non-orthopedic complication rate was found in the resident group (TKA: 8% and 10%; p = 0.03, THA: 8% and 10%; p = 0.01) and a slightly longer operative time (TKA: mean difference 9.0 minutes (8%); THA: 11.3 minutes (11%)).Interpretation - Complications, revisions, and mortality were similar in TKAs or THAs performed by the resident as primary surgeon compared with surgeries performed by an orthopedic surgeon. This data can be used in teaching hospitals and may help to reassure patients.

The influence of perioperative interventions targeting psychological distress on clinical outcome after total knee arthroplasty.

Our aim was to assess the effect of perioperative interventions targeting psychological distress on clinical outcome after total knee arthroplasty (TKA). We searched studies on the effect of perioperative interventions focused on psychological distress used in conjunction with TKA on pain, function, and quality of life (QoL) on PubMed, Embase.com, PsycINFO/OVID, CENTRAL, the Cochrane Database of Systematic Reviews, Scopus, and Web of Science. We included 40 studies (22 RCTs, ten cohort studies, and eight quasi-experimental studies) with a total of 3846 patients. We graded the quality of evidence as low for pain and function and as moderate for QoL. Patients receiving music, education, cognitive behavioural therapy, guided imagery, pain coping skills training, Reiki, occupational therapy with self-monitoring, and biofeedback-assisted progressive muscles relaxing training had lower pain scores or declined opioid prescriptions after TKA. Pain coping skills training, audio recording-guided imagery scripts, video promoting self-confidence, psychological therapies by video, Reiki, music, occupational therapy with self-monitoring, education, and psychotherapy improved postoperative functional outcome. Education through an app improved QoL after TKA. The studies in our systematic review show that perioperative interventions targeting psychological distress for patients receiving TKA seem to have a positive effect on postoperative pain, function, and QoL. RCTs with strict methodological safeguards are still needed to determine if perioperative interventions focused on psychological distress should be used in conjunction with TKA. These studies should also assess which type of intervention will be most effective in improving patient-reported outcome measures and declining opioid prescriptions.

Can even experienced orthopaedic surgeons predict who will benefit from surgery when patients present with degenerative meniscal tears? A survey of 194 orthopaedic surgeons who made 3880 predictions.

OBJECTIVES: To examine the ability of surgeons to predict the outcome of treatment for meniscal tears by arthroscopic partial meniscectomy (APM) and exercise therapy in middle-aged patients. DESIGN AND SETTING: Electronic survey. Orthopaedic surgeon survey participants were presented 20 patient profiles. These profiles were derived from a randomised clinical trial comparing APM with exercise therapy in middle-aged patients with symptomatic non-obstructive meniscal tears. From each treatment group (APM and exercise therapy), we selected five patients with the best (responders) and five patients with the worst (non-responders) knee function after treatment. 1111 orthopaedic surgeons and residents in the Netherlands and Australia were invited to participate in the survey. INTERVENTIONS: For each of the 20 patient profiles, surgeons (unaware of treatment allocation) had to choose between APM and exercise therapy as preferred treatment and subsequently had to estimate the expected change in knee function for both treatments on a 5-point Likert Scale. Finally, surgeons were asked which patient characteristics affected their treatment choice. MAIN OUTCOMES: The primary outcome was the surgeons' percentage correct predictions. We also compared this percentage between experienced knee surgeons and other orthopaedic surgeons, and between treatment responders and non-responders. RESULTS: We received 194 (17%) complete responses for all 20 patient profiles, resulting in 3880 predictions. Overall, 50.0% (95% CI 39.6% to 60.4%) of the predictions were correct, which equals the proportion expected by chance. Experienced knee surgeons were not better in predicting outcome than other orthopaedic surgeons (50.4% vs 49.5%, respectively; p=0.29). The percentage correct predictions was lower for patient profiles of non-responders (34%; 95% CI 21.3% to 46.6%) compared with responders (66.0%; 95% CI 57.0% to 75.0%; p=0.01).In general, bucket handle tears, knee locking and failed non-operative treatment directed the surgeons' choice towards APM, while higher level of osteoarthritis, degenerative aetiology and the absence of locking complaints directed the surgeons' choice towards exercise therapy. CONCLUSIONS: Surgeons' criteria for deciding that surgery was indicated did not pass statistical examination. This was true regardless of a surgeon's experience. These results suggest that non-surgical management is appropriate as first-line therapy in middle-aged patients with symptomatic non-obstructive meniscal tears. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03462134.

How do the costs of physical therapy and arthroscopic partial meniscectomy compare? A trial-based economic evaluation of two treatments in patients with meniscal tears alongside the ESCAPE study.

OBJECTIVES: To examine whether physical therapy (PT) is cost-effective compared with arthroscopic partial meniscectomy (APM) in patients with a non-obstructive meniscal tear, we performed a full trial-based economic evaluation from a societal perspective. In a secondary analysis-this paper-we examined whether PT is non-inferior to APM. METHODS: We recruited patients aged 45-70 years with a non-obstructive meniscal tear in nine Dutch hospitals. Resource use was measured using web-based questionnaires. Measures of effectiveness included knee function using the International Knee Documentation Committee (IKDC) and quality-adjusted life-years (QALYs). Follow-up was 24 months. Uncertainty was assessed using bootstrapping techniques. The non-inferiority margins for societal costs, the IKDC and QALYs, were €670, 8 points and 0.057 points, respectively. RESULTS: We randomly assigned 321 patients to PT (n=162) or APM (n=159). PT was associated with significantly lower costs after 24 months compared with APM (-€1803; 95% CI -€3008 to -€838). The probability of PT being cost-effective compared with APM was 1.00 at a willingness to pay of €0/unit of effect for the IKDC (knee function) and QALYs (quality of life) and decreased with increasing values of willingness to pay. The probability that PT is non-inferior to APM was 0.97 for all non-inferiority margins for the IKDC and 0.89 for QALYs. CONCLUSIONS: The probability of PT being cost-effective compared with APM was relatively high at reasonable values of willingness to pay for the IKDC and QALYs. Also, PT had a relatively high probability of being non-inferior to APM for both outcomes. This warrants further deimplementation of APM in patients with non-obstructive meniscal tears. TRIAL REGISTRATION NUMBERS: NCT01850719 and NTR3908.