Reliability parameters of the Timed 25-Foot-Walk (T25FW) in patients with Multiple Sclerosis: Lower walking speed is associated with greater Smallest Detectable Change.

BACKGROUND: Reliability parameters of clinical measures should be sufficient in order to adequately monitor disease course and evaluate treatment in patients with Multiple Sclerosis (MS). The aim of this study was to assess the reliability of the Timed 25-Foot-Walk (T25FW) in patients with MS. METHODS: MS patients performed the T25FW twice with approximately one year in between. After the second measurement, they answered an anchor question using a three-point Likert scale. Taking the non-normal distribution of the T25FW into account, intraclass correlation coefficient (ICCagreement), standard error of the mean (SEMagreement) and smallest detectable change (SDC) were computed. RESULTS: 118 MS patients (76.3 % females, mean age 48.2 years) were included. Of these patients, 73 reported no change on the anchor question. They completed the T25FW at baseline in 4.7s (IQR 4.3-5.4s, n = 72) and at follow-up in 4.9s (IQR 4.3-5.9s, n = 73). The ICCagreement was 0.895, the SEMagreement was 0.037. The SDC was higher for higher mean T25FW and can be computed for each mean T25FW by 0.23*mean T25FW. CONCLUSION: Overall, in patients with MS, the T25FW has a sufficient reliability as measured with the ICC, however the SDC of the T25FW increased when patients perform worse on the T25FW (i.e. have a lower walking speed). Because this test is often used in MS patients with limited walking ability, these findings are important to keep in mind when interpreting the re-test scores of the T25FW.

Effect of Context Specificity on Response to the Shortened WOMAC Function Scale in Patients Undergoing Total Knee Arthroplasty.

OBJECTIVE: To determine, in patients undergoing total knee arthroplasty (TKA), whether increasing context specificity of selected items of the shortened version of the Western Ontario and McMaster Universities Osteoarthritis Index function (WOMAC-F) scale (ShortMAC-F) (1) enhanced the convergent validity of the ShortMAC-F with performance-based mobility measures (ii) affected mean scale score, structural validity, reliability, and interpretability. DESIGN: Secondary analysis of randomized clinical trial data. SETTING: A tertiary teaching hospital. PARTICIPANTS: Patients undergoing TKA (N=114). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The ShortMAC-F was modified by specifying the "ascending stairs" and "rising from sitting" items to enquire about difficulty in performing the tasks without reliance on compensatory strategies, whereas the modified "level walking" item enquired about difficulty in walking 400 m. Before and 12 weeks after TKA, patients completed the WOMAC-F questionnaire, modified ShortMAC-F questionnaire, knee pain scale questionnaire, sit-to-stand test, fast gait speed test, and stair climb test. Interpretability was evaluated by calculating anchor-based substantial clinical benefit estimates. RESULTS: The modified ShortMAC-F correlated significantly more strongly than ShortMAC-F or WOMAC-F with pooled performance measures (differences in correlation values, 0.12-0.14). Increasing item context specificity of the ShortMAC-F did not influence its psychometric properties of unidimensionality (comparative fit and Tucker-Lewis indices, >0.95; root mean square error of approximation, 0.05-0.08), reliability (Cronbach's α, 0.75-0.83), correlation with pain intensity (correlation values, 0.48-0.52), and substantial clinical benefit estimates (16 percentage points); however, it resulted in lower mean score (4.5-4.8 points lower). CONCLUSIONS: The modified ShortMAC-F showed sufficient measurement properties for clinical application, and it seemed more adept than WOMAC-F at correlating with performance-based measures in TKA.

Distinguishing emotional distress from mental disorder in primary care: a qualitative exploration of the Four-Dimensional Symptom Questionnaire.

BACKGROUND: Primary care clinicians see people experiencing the full range of mental health problems. Determining when symptoms reflect disorder is complex. The Four-Dimensional Symptom Questionnaire (4DSQ) uniquely distinguishes general distress from depressive and anxiety disorders. It may support diagnostic conversations and targeting of treatment. AIM: To explore peoples' experiences of completing the 4DSQ and their perceptions of their resulting score profile across distress, depression, anxiety, and physical symptoms. DESIGN AND SETTING: A qualitative study was conducted in the UK with people recruited from primary care and community settings. METHOD: Participants completed the 4DSQ then took part in semi-structured telephone interviews. They were interviewed about their experience of completing the 4DSQ, their perceptions of their scores across four dimensions, and the perceived utility if used with a clinician. Interviews were transcribed verbatim and data were analysed thematically. RESULTS: Twenty-four interviews were conducted. Most participants found the 4DSQ easy to complete and reported that scores across the four dimensions aligned well with their symptom experience. Distinct scores for distress, depression, and anxiety appeared to support improved self-understanding. Some valued the opportunity to discuss their scores and provide relevant context. Many felt the use of the 4DSQ with clinicians would be helpful and likely to support treatment decisions, although some were concerned about time-limited consultations. CONCLUSION: Distinguishing general distress from depressive and anxiety disorders aligned well with people's experience of symptoms. Use of the 4DSQ as part of mental health consultations may support targeting of treatment and personalisation of care.

Minimal important change thresholds change over time after knee and hip arthroplasty.

OBJECTIVES: The minimal important change (MIC) reflects what patients, on average, consider the smallest improvement in a score that is important to them. MIC thresholds may vary across patient populations, interventions used, posttreatment time points and derivation methods. We determine and compare MIC thresholds for the Oxford Knee Score and Oxford Hip Score (OKS/OHS) at 3 months postoperatively to 12- and 24-month thresholds in patients undergoing knee or hip arthroplasty. STUDY DESIGN AND SETTING: This cohort study used data from patients undergoing total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), or total hip arthroplasty (THA) at a public hospital between February 2016 and February 2023. At 3, 12, and 24 months postoperatively, patients responded to the OKS/OHS and a 7-point anchor question determining experienced changes in knee or hip pain and functional limitations. We used the adjusted predictive modeling method that accounts for the proportion improved and the reliability of the anchor question to determine MIC thresholds and their mean differences between time points. RESULTS: Complete data were obtained from 695/957 (73%), 1179/1703 (69%), and 1080/1607 (67%) patients undergoing TKA, 474/610 (78%), 438/603 (73%), and 355/507 (70%) patients undergoing UKA, and 965/1315 (73%), 978/1409 (69%), and 1059/1536 (69%) patients undergoing THA at 3, 12, and 24 months, respectively. The median age ranged from 68 to 70 years and 55% to 60% were females. The proportions improved ranged between 83% and 95%. The OKS/OHS MIC thresholds were 0.1, 4.2, and 5.1 for TKA, 1.8, 5.6, and 3.4 for UKA, and 1.3, 6.1, and 6.0 for THA at 3, 12, and 24 months postoperatively, respectively. The reliability ranged between 0.64 and 0.82, and the MIC values increased between three and 12 months but not between 12 and 24 months. CONCLUSION: Any absence of deterioration in pain and function is considered important at 3 months after knee or hip arthroplasty. Increasing thresholds over time suggest patients raise their standards for what constitutes a minimal important improvement over the first postoperative year. Besides improving our understanding of patients' views on postoperative outcomes, these clinical thresholds may aid in interpreting registry-based treatment outcome evaluations.

Using item response theory to estimate interpretation threshold values for the Frailty Index in community dwelling older adults.

BACKGROUND: Although the frailty index (FI) is designed as a continuous measure of frailty, thresholds are often needed to guide its interpretation. This study aimed to introduce and demonstrate the utility of an item response theory (IRT) method in estimating FI interpretation thresholds in community-dwelling adults and to compare them with cutoffs estimated using the receiver operating characteristics (ROC) method. METHODS: A sample of 1,149 community-dwelling adults (mean[SD], 68[7] years) participated in this cross-sectional study. Participants completed a multi-domain geriatric screen from which the 40-item FI and 3 clinical anchors were computed - namely, (i)self-reported mobility limitations (SRML), (ii)"fair" or "poor" self-rated health (SRH), and (iii) restricted life-space mobility (RLSM). Participants were classified as having SRML-1 if they responded "Yes" to either of the 2 questions regarding walking and stair climbing difficulty and SRML-2 if they reported having walking and stair climbing difficulty. Participants with a Life Space Assessment score <60 points were classified as having RLSM. Threshold values for all anchor questions were estimated using the IRT method and ROC analysis with Youden criterion. RESULTS: The proportions of participants with SRML-1, SRML-2, Fair/Poor SRH, and RLSM were 21 %, 8 %, 22 %, and 9 %, respectively. The IRT-based thresholds for SRML-2 (0.26), fair/poor SRH (0.29), and RLSM (0.32) were significantly higher than those for SRML-1 (0.18). ROC-based FI cutoffs were significantly lower than IRT-based values for SRML-2, SRH, and RLSM (0.12 to 0.17), and they varied minimally and non-systematically across the anchors. CONCLUSIONS: The IRT method identifies biologically plausible FI thresholds that could meaningfully complement and contextualize existing thresholds for defining frailty.

Estimating anchor-based minimal important change using longitudinal confirmatory factor analysis.

PURPOSE: The minimal important change (MIC) is defined as the smallest within-individual change in a patient-reported outcome measure (PROM) that patients on average perceive as important. We describe a method to estimate this value based on longitudinal confirmatory factor analysis (LCFA). The method is evaluated and compared with a recently published method based on longitudinal item response theory (LIRT) in simulated and real data. We also examined the effect of sample size on bias and precision of the estimate. METHODS: We simulated 108 samples with various characteristics in which the true MIC was simulated as the mean of individual MICs, and estimated MICs based on LCFA and LIRT. Additionally, both MICs were estimated in existing PROMIS Pain Behavior data from 909 patients. In another set of 3888 simulated samples with sample sizes of 125, 250, 500, and 1000, we estimated LCFA-based MICs. RESULTS: The MIC was equally well recovered with the LCFA-method as using the LIRT-method, but the LCFA analyses were more than 50 times faster. In the Pain Behavior data (with higher scores indicating more pain behavior), an LCFA-based MIC for improvement was estimated to be 2.85 points (on a simple sum scale ranging 14-42), whereas the LIRT-based MIC was estimated to be 2.60. The sample size simulations showed that smaller sample sizes decreased the precision of the LCFA-based MIC and increased the risk of model non-convergence. CONCLUSION: The MIC can accurately be estimated using LCFA, but sample sizes need to be preferably greater than 125.

Knee Injury and Osteoarthritis Outcome Score Interpretation Thresholds at 3 and 12 Months After Arthroscopic Meniscal Surgery. What Changes, and What Stays the Same?

OBJECTIVE: To evaluate the change in minimal important change (MIC), patient acceptable symptom state (PASS), and treatment failure (TF) thresholds for the Knee injury and Osteoarthritis Outcome Score (KOOS) from 3 to 12 months following arthroscopic meniscus surgery. DESIGN: Retrospective cohort study. METHODS: We included patients from the Knee Arthroscopy Cohort Southern Denmark who had meniscus surgery between 2013 and 2015. We calculated the interpretation threshold values for MIC, PASS, and TF using an anchor-based adjusted predictive modeling method. Thresholds at 3 and 12 months postoperatively were compared to evaluate changes over time. RESULTS: The proportions of people who reported a clinically relevant improvement, or their symptoms being acceptable, increased by 10% to 15% points from 3 to 12 months after surgery. MIC thresholds for the 5 KOOS subscales remained stable from 3 to 12 months with statistically nonsignificant differences (95% confidence intervals) ranging from -0.3 (-3.0, 2.6) to -2.4 (-6.1, 1.3). All PASS thresholds except for quality of life (QOL) decreased by -6.5 (-11.8, -1.5) to -3.7 (-7.1, -0.4) points, indicating that higher symptom levels were accepted at 12 months. In contrast, the proportion reporting their treatment to have failed remained stable over time (19% and 17%). For QOL, a 7.4 (2.0, 13.2) higher TF threshold at 12 months suggested that improved QOL was required to not consider that the treatment had failed. CONCLUSION: More patients reported being improved at 1 year compared to at 3 months following meniscus surgery. The KOOS MIC thresholds were stable over time, whereas time-specific PASS values should be applied after meniscus surgery. J Orthop Sports Phys Ther 2023;53(11):685-702. Epub 3 October 2023. doi:10.2519/jospt.2023.11993.

Estimating cutpoints of gait speed and sit-to-stand test values for self-reported mobility limitations in a cohort of community-dwelling older adults from Singapore: comparing receiver operating characteristic (ROC) analysis with adjusted predictive modelling.

OBJECTIVES: Clinical interpretability of the gait speed and 5-times sit-to-stand (5-STS) tests is commonly established by comparing older adults with and without self-reported mobility limitations (SRML) on gait speed and 5-STS performance, and estimating clinical cutpoints for SRML using the receiver operating characteristics (ROC) method. Accumulating evidence, however, suggests that the adjusted predictive modeling (APM) method may be more appropriate to estimate these interpretational cutpoints. Thus, we aimed to compare, in community-dwelling older adults, gait speed and 5-STS cutpoints estimated using the ROC and APM methods. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: This study analyzed data from 955 community-dwelling independently walking older adults (73%women) aged ≥60 years (mean, 68; range, 60-88). METHODS: Participants completed the 10-metre gait speed and 5-STS tests. Participants were classified as having SRML if they responded "Yes" to either of the 2 questions regarding walking and stair climbing difficulty. Cutpoints for SRML and its component questions were estimated using ROC analysis with Youden criterion and the APM method. RESULTS: The proportions of participants with self-reported walking difficulty, self-reported stair climbing difficulty, and SRML were 10%, 19%, and 22%, respectively. Gait speed and 5-STS time were moderately correlated with each other (r=-0.56) and with the self-reported measures (absolute r-values, 0.39-0.44). ROC-based gait speed cutpoints were 0.14 to 0.16 m/s greater than APM-based cutpoints (P < 0.05) whilst ROC-based 5-STS time cutpoints were 0.8 to 3.3 s lower than APM-based cutpoints (P < 0.05 for walking difficulty). Compared with ROC-based cutpoints, APM-based cutptoints were more precise and they varied monotonically with self-reported walking difficulty, self-reported stair climbing difficulty, and SRML. CONCLUSIONS AND IMPLICATIONS: In a sample of 955 older adults, our findings of precise and biologically plausible gait speed and 5-STS cutpoints for SRML estimated using the APM method indicate that this promising method could potentially complement or even replace traditional ROC methods.

Interpretation Threshold Values for the Oxford Hip Score in Patients Undergoing Total Hip Arthroplasty: Advancing Their Clinical Use.

BACKGROUND: Patient-reported outcome measures such as the Oxford Hip Score (OHS) can capture patient-centered perspectives on outcomes after total hip arthroplasty (THA). The OHS assesses hip pain and functional limitations, but defining interpretation threshold values for the OHS is warranted so that numerical OHS values can be translated into whether patients have experienced clinically meaningful changes. Therefore, we determined the minimal important change (MIC), patient acceptable symptom state (PASS), and treatment failure (TF) threshold values for the OHS at 12 and 24-month follow-up in patients undergoing THA. METHODS: This cohort study used data from patients undergoing THA at 1 public hospital between July 2016 and April 2021. At 12 and 24 months postoperatively, patients provided responses for the OHS and for 3 anchor questions about whether they had experienced changes in hip pain and function, whether they considered their symptom state to be satisfactory, and if it was not satisfactory, whether they considered the treatment to have failed. The anchor-based adjusted predictive modeling method was used to determine interpretation threshold values. Baseline dependency was evaluated using a new item-split method. Nonparametric bootstrapping was used to determine 95% confidence intervals (CIs). RESULTS: Complete data were obtained for 706 (69%) of 1,027 and 728 (66%) of 1,101 patients at 12 and 24 months postoperatively, respectively. These patients had a median age of 70 years, and 55% to 56% were female. Adjusted OHS MIC values were 6.3 (CI, 4.6 to 8.1) and 5.2 (CI, 3.6 to 6.7), adjusted OHS PASS values were 30.6 (CI, 29.0 to 32.2) and 30.5 (CI, 29.3 to 31.8), and adjusted OHS TF values were 25.5 (CI, 22.9 to 27.7) and 27.0 (CI, 25.2 to 28.8) at 12 and 24 months postoperatively, respectively. MIC values were 5.4 (CI, 2.1 to 9.1) and 5.0 (CI, 1.9 to 8.7) higher at 12 and 24 months, respectively, in patients with a more severe preoperative state. CONCLUSIONS: The established interpretation threshold values advance the interpretation and clinical use of the OHS, and may prove especially beneficial for registry-based evaluations of treatment quality. LEVEL OF EVIDENCE: Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

An extension minimal important difference credibility item addressing construct proximity is a reliable alternative to the correlation item.

OBJECTIVES: Minimal important difference (MID), the smallest change or difference that patients perceive as important, aids interpretation of change in patient-reported outcome measure (PROM) scores. A credibility instrument that assesses the methodological rigor of an anchor-based MID includes one core item addressing the correlation between the PROM and the anchor. However, the majority of MID studies in the literature fail to report the correlation. To address this issue, we extended the anchor-based MID credibility instrument by adding an item addressing construct proximity as an alternative to the correlation item. STUDY DESIGN AND SETTING: Informed by an MID methodological survey, we added an alternative item-a subjective assessment of similarity of the constructs (i.e., construct proximity) between PROM and anchor-to the correlation item and generated principles for the assessment. We sampled 101 MIDs and analyzed the assessments performed by each pair of raters. By calculating weighted Cohen's kappa, we assessed the reliability of the assessments. RESULTS: Construct proximity assessment is based on the anticipated association between the anchor and PROM constructs: the closer the anticipated association, the higher the rating. Our detailed principles address the most frequently used anchors: transition ratings, measures of satisfaction, other PROMs, and clinical measures. The assessments showed acceptable agreement (weighted kappa 0.74, 95% CI 0.55-0.94) between raters. CONCLUSION: In the absence of a reported correlation coefficient, construct proximity assessment provides a useful alternative in the credibility assessment of anchor-based MID estimates.

Estimating meaningful thresholds for multi-item questionnaires using item response theory.

PURPOSE: Meaningful thresholds are needed to interpret patient-reported outcome measure (PROM) results. This paper introduces a new method, based on item response theory (IRT), to estimate such thresholds. The performance of the method is examined in simulated datasets and two real datasets, and compared with other methods. METHODS: The IRT method involves fitting an IRT model to the PROM items and an anchor item indicating the criterion state of interest. The difficulty parameter of the anchor item represents the meaningful threshold on the latent trait. The latent threshold is then linked to the corresponding expected PROM score. We simulated 4500 item response datasets to a 10-item PROM, and an anchor item. The datasets varied with respect to the mean and standard deviation of the latent trait, and the reliability of the anchor item. The real datasets consisted of a depression scale with a clinical depression diagnosis as anchor variable and a pain scale with a patient acceptable symptom state (PASS) question as anchor variable. RESULTS: The new IRT method recovered the true thresholds accurately across the simulated datasets. The other methods, except one, produced biased threshold estimates if the state prevalence was smaller or greater than 0.5. The adjusted predictive modeling method matched the new IRT method (also in the real datasets) but showed some residual bias if the prevalence was smaller than 0.3 or greater than 0.7. CONCLUSIONS: The new IRT method perfectly recovers meaningful (interpretational) thresholds for multi-item questionnaires, provided that the data satisfy the assumptions for IRT analysis.

Establishing thresholds for meaningful within-individual change using longitudinal item response theory.

PURPOSE: Thresholds for meaningful within-individual change (MWIC) are useful for interpreting patient-reported outcome measures (PROM). Transition ratings (TR) have been recommended as anchors to establish MWIC. Traditional statistical methods for analyzing MWIC such as mean change analysis, receiver operating characteristic (ROC) analysis, and predictive modeling ignore problems of floor/ceiling effects and measurement error in the PROM scores and the TR item. We present a novel approach to MWIC estimation for multi-item scales using longitudinal item response theory (LIRT). METHODS: A Graded Response LIRT model for baseline and follow-up PROM data was expanded to include a TR item measuring latent change. The LIRT threshold parameter for the TR established the MWIC threshold on the latent metric, from which the observed PROM score MWIC threshold was estimated. We compared the LIRT approach and traditional methods using an example data set with baseline and three follow-up assessments differing by magnitude of score improvement, variance of score improvement, and baseline-follow-up score correlation. RESULTS: The LIRT model provided good fit to the data. LIRT estimates of observed PROM MWIC varied between 3 and 4 points score improvement. In contrast, results from traditional methods varied from 2 to 10 points-strongly associated with proportion of self-rated improvement. Best agreement between methods was seen when approximately 50% rated their health as improved. CONCLUSION: Results from traditional analyses of anchor-based MWIC are impacted by study conditions. LIRT constitutes a promising and more robust analytic approach to identifying thresholds for MWIC.

Responsiveness and Minimal Important Change of the PROMIS Pain Interference Item Bank in Patients Presented in Musculoskeletal Practice.

We evaluated the responsiveness of the Patient Reported Outcome Information System Pain Interference item bank in patients with musculoskeletal pain by testing predefined hypotheses about the relationship between the change scores on the item bank, change scores on legacy instruments and Global Ratings of Change (GRoC), and we estimated Minimal Important Change (MIC). Patients answered the full Dutch-Flemish V1.1 item bank. From the responses we derived scores for the standard 8-item short form (SF8a) and a CAT-score was simulated. Correlations between the change scores on the item bank, GRoC and legacy instruments were calculated, together with Effect Sizes, Standardized Response Means, and Area Under the Curve. GRoC were used as an anchor for estimating the MIC with (adjusted) predictive modeling. Of 1,677 patients answering baseline questionnaires 960 completed follow-up questionnaires at 3 months. The item bank correlated moderately high with the GRoC (Spearman's rho 0.63) and with the legacy instruments (Pearson's R ranging from .45 to .68). It showed a high ES (.97) and Standardized Response Means (.71), and could distinguish well between improved and not improved patients based on the GRoC (Area Under the Curve .77). Comparable results were found for the derived SF8a and CAT-scores. The MIC was estimated to be 3.2 (CI 2.6-3.7) T-score points. PERSPECTIVE: Our study supports the responsiveness of the PROMIS-PI item bank in patients with musculoskeletal complaints. Almost all predefined hypotheses were met (94%). The PROMIS-PI item bank correlated well with several legacy instruments which supports generic use of the item bank. MIC for PROMIS-PI was estimated to be 3.2 T-score points.

Head-to-head comparison of somatic symptom scales: The Patient Health Questionnaire (PHQ-15) and the somatization scale of the Four-Dimensional Symptom Questionnaire (4DSQ-S).

OBJECTIVE: The goal of this study was to compare the 15-item Patient Health Questionnaire (PHQ-15) and the somatization subscale of the Four-Dimensional Symptoms Questionnaire (4DSQ-S) with respect to their latent structure and reliability, and to examine whether their scores are affected by age and gender, and whether the scales measure the same construct(s). METHODS: The study population consisted of individuals with a tendency to experience persistent somatic symptoms, recruited in multiple healthcare settings, who completed the PHQ-15 and 4DSQ-S concurrently. We analyzed the scales' latent factor structure using confirmatory factor analysis (CFA), the scales' reliability, and differential item functioning (DIF) due to age and gender. We performed a head-to-head comparison by fitting structural equation models of the questionnaires' factors. RESULTS: We included 234 participants. CFA showed that both questionnaires fitted a bifactor model with a general factor and four specific factors, three of which (labeled "musculoskeletal", "gastrointestinal", and "cardiopulmonary") were substantively similar. Both scales were essentially unidimensional. The reliability of the PHQ-15 and 4DSQ-S was equally high (omega 0.933 and 0.942, respectively). DIF-analysis showed minor DIF for age in one item of each questionnaire, with negligible impact on the scale score. Head-to-head comparison showed that the PHQ-15 and 4DSQ-S measured the same constructs. We present PHQ-15 - 4DSQ-S cross-walk tables. CONCLUSIONS: Both questionnaires mainly measure a single somatic symptom burden dimension of which all symptoms (covered by the questionnaires) are adequate indicators. They do so equally accurately and they behave the same across gender and age categories.

Meaningful thresholds for patient-reported outcomes following interventions for anterior cruciate ligament tear or traumatic meniscus injury: a systematic review for the OPTIKNEE consensus.

OBJECTIVE: We synthesised and assessed credibility (ie, trustworthiness) of thresholds that define meaningful scores for patient-reported outcome measures (PROMs) following interventions for anterior cruciate ligament (ACL) tear or traumatic meniscus injury. DESIGN: Systematic review, narrative synthesis. DATA SOURCES: We searched five databases, handsearched references of included studies and tracked citations. ELIGIBILITY: Included studies investigated: individuals with ACL tear or meniscus injury; mean age <35 years; and PROM thresholds calculated using any method to define a minimal important change (MIC) or a meaningful post-treatment score (Patient Acceptable Symptom State (PASS) or Treatment Failure). RESULTS: We included 18 studies (15 ACL, 3 meniscus). Three different methods were used to calculate anchor-based MICs across 9 PROMs, PASS thresholds across 4 PROMs and treatment failure for 1 PROM. Credibility was rated 'high' for only one study-an MIC of 18 for the Knee injury and Osteoarthritis Outcome Score Quality-of-life (KOOS-QOL) subscale (using the MID Credibility Assessment Tool). Where multiple thresholds were calculated among 'low' credibility thresholds in ACL studies, MICs converged to within a 10-point range for KOOS-Symptoms (-1.2 to 5.4) and function in daily living (activities of daily living, ADL 0.5-8.1) subscales, and the International Knee Documentation Committee Subjective Knee Form (7.1-16.2). Other PROM thresholds differed up to 30 points. PASS thresholds converged to within a 10-point range in KOOS-ADL for ACL tears (92.3-100), and KOOS-Symptoms (73-78) and KOOS-QOL (53-57) in meniscus injuries. CONCLUSION: Meaningful PROM thresholds were highly susceptible to study heterogeneity. While PROM thresholds can aid interpretability in research and clinical practice, they should be cautiously interpreted.

Experiences of general practitioners explaining central sensitisation to patients with persistent physical symptoms: a focus group study.

OBJECTIVE: Patients with persistent physical symptoms (PPS) require an explanation that is acceptable and comprehensible to them. Central sensitisation (CS) is an explanatory model for PPS and chronic pain that has been broadly applied in the context of pain medicine, but, until recently, not by general practitioners (GPs). We explored how GPs used the CS model in their consultations with patients with PPS. DESIGN AND SETTING: A qualitative focus group study among GPs in the Netherlands. METHODS: We instructed 33 GPs on how to explain CS to patients with PPS. After 0.5-1.5 years of using the CS model, 26 GPs participated in focus groups and interviews to report and discuss their experiences with CS as an explanatory model. Audio recordings were transcribed and two researchers independently analysed the data. The text was coded, codes were organised into themes and discussed until consensus was reached. RESULTS: We identified eleven themes and grouped these into four categories.The GPs regarded the CS model as evidence-based, credible and giving recognition to the patient. On the other hand, they found explaining the CS model difficult and time-consuming. They tailored the CS model to their patients' needs and used multiple consultations to explain the model. The GPs reported that the use of the CS model seemed to improve the understanding and acceptance of the symptoms by the patients and seemed to reduce their need for more diagnostic tests. Furthermore, patients seemed to become more motivated to accept appropriate therapy. CONCLUSION: GPs reported that they were able to provide explanations with the CS model to their patients with PPS. They regarded the model as evidence-based, credible and giving recognition to the patient, but explaining it difficult and time-consuming.

Interpretation threshold values for the Oxford Knee Score in patients undergoing unicompartmental knee arthroplasty.

BACKGROUND AND PURPOSE: Developing meaningful thresholds for the Oxford Knee Score (OKS) advances its clinical use. We determined the minimal important change (MIC), patient acceptable symptom state (PASS), and treatment failure (TF) values as meaningful thresholds for the OKS at 3-, 12-, and 24-month follow-up in patients undergoing unicompartmental knee arthroplasty (UKA). PATIENTS AND METHODS: This is a cohort study with data from patients undergoing UKA collected at a hospital in Denmark between February 2016 and September 2021. The OKS was completed preoperatively and at 3, 12, and 24 months postoperatively. Interpretation threshold values were calculated with the anchor-based adjusted predictive modeling method. Non-parametric bootstrapping was used to derive 95% confidence intervals (CI). RESULTS: Complete 3-, 12-, and 24-month postoperative data was obtained for 331 of 423 (78%), 340 of 479 (71%), and 235 of 338 (70%) patients, median age of 68-69 years (58-59% females). Adjusted OKS MIC values were 4.7 (CI 3.3-6.0), 7.1 (CI 5.2-8.6), and 5.4 (CI 3.4- 7.3), adjusted OKS PASS values were 28.9 (CI 27.6-30.3), 32.7 (CI 31.5-33.9), and 31.3 (CI 29.1-33.3), and adjusted OKS TF values were 24.4 (CI 20.7-27.4), 29.3 (CI 27.3-31.1), and 28.5 (CI 26.0-30.5) at 3, 12, and 24 months postoperatively, respectively. All values statistically significantly increased from 3 to 12 months but not from 12 to 24 months. INTERPRETATION: The UKA-specific measurement properties and clinical thresholds for the OKS can improve the interpretation of UKA outcome and assist quality assessment in institutional and national registries.