The use of patient-reported outcome measures to guide referral for hip and knee arthroplasty

Improvement in Patient-Reported Outcomes After Revision Total Knee Arthroplasty is Comparable to Primaries in Some Diagnoses, but Not Others

BACKGROUND

Patient-reported outcome measures (PROMs) are becoming increasingly important for reimbursement after primary total knee arthroplasty (TKA) and are likely soon to follow for revision TKA. Therefore, as the Centers for Medicare and Medicaid Services (CMS) establish criteria for minimal clinically important differences (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) metrics, it is critical to understand which patients have the greatest propensity for clinical improvement after revision TKA. This study compared PROMs of revision TKAs by diagnosis to a cohort of primary TKAs.

METHODS

A total of 2,308 primary and 340 aseptic revision TKAs using consistent clinical protocols were retrospectively reviewed. Study data were extracted from patient health records. Modern PROMs and their associated MCID, SCB, and PASS thresholds were evaluated with P < 0.05 as significant. The mean follow-up was 27.1 months (range, one to 153).

RESULTS

Primary and revision TKA cohorts did not differ by demographic variables (P ≥ 0.100); however, primaries had slightly longer follow-ups (mean five months, P < 0.001). Satisfaction for cases revised for loosening (81%) and polyethylene wear/osteolysis (72%) was not different compared to primary TKAs (84%, P ≥ 0.190). The mean improvement scores for University of California, Los Angeles (UCLA) Activity Level and pain with level walking were not different when comparing primary TKAs to cases revised for loosening (P ≥ 0.728). Primary TKAs achieved MCID, SCB, and PASS thresholds most often (range, 60 to 90%), followed by revisions for loosening and wear/osteolysis (range, 48 to 81%); and then arthrofibrosis and instability (range, 33 to 70%; P ≤ 0.009).

CONCLUSION

Study results show that revision TKAs for loosening and polyethylene wear/osteolysis may have comparable improvement in outcomes compared to primary TKA. Study results provide data to possibly help CMS set rational metrics for reimbursement and set appropriate expectations.

LEVEL OF EVIDENCE

III.

Primary Total Hip Arthroplasty Achieves Minimal Clinically Important Difference Faster than Revision Total Hip Arthroplasty

BACKGROUND

Despite the prevalence of total hip arthroplasty (THA) as a treatment for hip-related conditions, there is limited research directly comparing the patient-reported outcome measures between primary and revision total hip arthroplasty (rTHA). This study compared the time to achieve minimal clinically important difference (MCID) between primary and rTHA.

METHODS

We conducted a retrospective analysis comparing 6,671 THAs (6,070 primary and 601 all-cause rTHAs) performed between 2016 and 2022. Patient-reported outcomes were evaluated using preoperative and postoperative scores of Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical, PROMIS Physical Function Short Form 10a (PF-10a), and Hip Injury and Osteoarthritis Outcome Score - Physical Function Short Form (HOOS-PS). The time to achieve MCID was assessed using survival curves with and without interval-censoring, and statistical comparisons were performed using log-rank and weighted log-rank tests.

RESULTS

Comparing the time to achieve MCID without interval-censoring, primary total hip arthroplasty (pTHA) demonstrated significantly faster median times than rTHA for PROMIS Global Physical (3.3 versus 3.9 months, P < 0.001), PROMIS PF-10a (3.6 versus 6.2 months, P < 0.001), and HOOS-PS (3.1 versus 4.0 months, P < 0.001). Similarly, when using interval-censoring, pTHA continued to achieve MCID significantly faster than rTHA for PROMIS Global Physical (0.23 to 0.24 versus 0.50 to 0.51 months, P < 0.001), PROMIS PF-10a (1.43 to 1.44 versus 3.03 to 3.04 months, P < 0.001), and HOOS-PS (0.87 to 0.87 versus 1.20 to 1.21 months, P < 0.001).

CONCLUSIONS

Across all patient-reported outcome measures, pTHA achieved MCID significantly faster than rTHA, irrespective of interval-censoring. These findings underscore the importance of setting realistic postoperative recovery expectations during perioperative patient counseling. Future studies should investigate the factors influencing time to achieve MCID and explore how to enhance rTHA techniques and perioperative management for improved patient outcomes.

LEVEL OF EVIDENCE

III.

Revision Total Knee Arthroplasty Achieves Minimal Clinically Important Difference Faster Than Primary Total Knee Arthroplasty

BACKGROUND

Revision total knee arthroplasty (rTKA) remains underexplored regarding patient-reported outcome measures (PROMs), particularly in terms of time to reach minimal clinically important difference (MCID). This study addresses this gap by comparing the time to achieve MCID between primary TKA (pTKA) and rTKA patients, providing valuable insights into their recovery trajectories.

METHODS

A total of 8,266 TKAs (7,618 pTKA and 648 rTKA) were retrospectively studied in a multi-institutional arthroplasty registry. Patients who completed the patient-reported outcomes measurement information system (PROMIS) global physical, PROMIS physical function short form 10a (PF-10a), and knee injury and osteoarthritis outcome score physical function short form (KOOS-PS) questionnaires were identified by Current Procedural Terminology codes. Survival curves with and without interval censoring were utilized to evaluate the time to achieve MCID.

RESULTS

Comparing the time to achieve MCID, rTKAs were significantly faster than pTKA for PROMIS global physical (3.5 versus 3.7 months, P = 0.004) and KOOS-PS (3.3 versus 4.2 months, P < 0.001), but similar for PROMIS PF-10a (4.4 versus 4.8 months, P = 0.057). Interval censoring also showed similar trends with earlier times to achieve MCID for rTKAs for PROMIS global physical (0.6 to 0.61 versus 0.97 to 0.97 months, P = 0.009) and KOOS-PS (0.97 to 0.97 versus 1.47 to 1.47 months, P < 0.001), but not for PROMIS PF-10a (2.43 to 2.54 versus 1.90 to 1.91 months, P = 0.92).

CONCLUSIONS

The present study revealed that the time to achieve MCID was faster in patients undergoing rTKA compared to those undergoing pTKA. These findings allow surgeons to reassure preoperative rTKA patients that their recovery to a MCID postoperatively may be quicker than expected, especially when compared to their initial recovery after primary TKA.

LEVEL OF EVIDENCE

Level III.

A multi-phase approach for developing a conceptual model and preliminary content for patient-reported outcome measurement in TKA patients: from a Chinese perspective

PURPOSE

Patient-reported outcome measures (PROMs) are being used more frequently in total knee arthroplasty (TKA). By utilizing high-quality scales, surgeons can achieve a more comprehensive and accurate evaluation of the effectiveness of TKA surgery. Currently, there is no widely accepted conceptual model for TKA PROMs. The objective of this study is to fill this gap by developing a conceptual model and preliminary content for a PROM that is specifically designed for TKA patients in mainland China.

METHODS

The study design consisted of three stages: (1) a targeted literature review followed by the formation of a conceptual model pool; (2) qualitative data collection involving experts and patients, leading to the development of the preliminary Chinese TKA PROM (CTP); and (3) review of the CTP by experts using the Delphi method, along with cognitive debriefing interviews with patients.

RESULTS

64 patients and 28 experts took part in this study. The conceptual model focused on six key concepts: pain, symptom, function, quality of life, expectation, and satisfaction. To match the model, the authors developed a total of 35 items.

CONCLUSION

A conceptual model and preliminary content for CTP was developed with substantial participation from patients and a multidisciplinary group of experts. The integration of patient and clinical perspectives ensured a comprehensive representation of all relevant disease experiences and the focus of clinical practice. With further refinement through psychometric testing, the CTP is positioned to provide a standardized, comprehensive measure for research specific to Chinese TKA patients.

Comparison of Time and Rate of Achieving Minimal Clinically Important Difference: Robotic Versus Manual Unicompartmental Knee Arthroplasty

BACKGROUND

Robotics in unicompartmental knee arthroplasty (UKA) continues to increase with the ever-growing demand to use technology in the surgical setting. However, no studies have used minimal clinically important difference (MCID) to compare patient-reported outcome measures (PROMs) between robotic UKA (rUKA) and manual UKA (mUKA). This study aimed to compare the rate of achieving MCID for improvement (MCID-I) and worsening (MCID-W) and the time to achieving MCID.

METHODS

We conducted a retrospective analysis of robotic and manual UKAs performed between 2016 and 2022. Preoperative and postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical, PROMIS Physical Function Short-Form 10a (PF-10a), and Knee Injury and Osteoarthritis Outcome Score-Physical Function Short-Form (KOOS-PS) scores were collected. Patients were stratified on reaching MCID-I, MCID-W, or "no notable change" (score between MCID-W and MCID-I). Survival curves with and without interval censoring were used to assess the time to achieving the MCID. Log-rank and weighted log-rank tests were used to compare groups.

RESULTS

A total of 256 UKAs (64 robotic and 192 manual) were analyzed. No differences were observed in the proportion of patients achieving MCID-I or MCID-W across all three PROMs. Similarly, median time to achieving MCID showed no significant differences between rUKA and mUKA for PROMIS Global Physical (3.3 versus 4.9 months, P = 0.44), PROMIS PF-10a (7.7 versus 8.3 months, P = 0.93), and KOOS-PS (3.0 versus 6.0 months, P = 0.055) scores, both with and without interval censoring.

DISCUSSION

This study indicates that rUKA and mUKA exhibit comparable rates of achieving MCID-I and MCID-W, along with similar median time to reach MCID. These findings offer valuable patient-centric insights into the effectiveness of rUKA. Additional studies evaluating the long-term outcomes of rUKA are needed to determine its long-term advantages.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Comparing Rates of Minimal Clinically Important Difference Between Manual and Robotic-Assisted Total Knee Arthroplasty

BACKGROUND

Differences in patient-reported outcome measures (PROMs) between manual total knee arthroplasty (mTKA) and robotic-assisted TKA (rTKA) have not been adequately assessed. We compared the minimal clinically important difference (MCID) for improvement (MCID-I) and worsening (MCID-W) between mTKA and rTKA patients.

METHODS

Patients who underwent primary TKA (874 mTKA and 439 rTKA) with complete preoperative and 1-year postoperative PROMs were retrospectively identified using a multihospital joint arthroplasty registry. Patient-Reported Outcomes Measurement Information System Physical Function Short Form 10a (PROMIS PF-10a), PROMIS Global - Physical, or Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form were collected. The MCID-I, MCID-W, and "no significant change" rates were calculated using distribution-based methods. Propensity score matching was performed to control for confounding.

RESULTS

Similar 90-day pulmonary embolism (P = 0.26), deep venous thrombosis (P = 0.67), and emergency department visit (P = 0.35) rates were found. The 90-day readmission rate for mTKA was 1.7 and 3.4% for rTKA (P = 0.08), and the overall revision rates were 2.2% for mTKA and 0.7% for rTKA (P = 0.07). Revision-free survival was 99% at one and 2 years for both groups (P = 0.65 and P = 0.43, respectively). There were no differences in the proportion of patients achieving MCID-I or MCID-W for PROMIS PF-10a, PROMIS Global - Physical, or Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form. The MCID-I for PROMIS PF-10a was achieved in 65.5 and 62.2% of patients who had mTKA and rTKA, respectively (P = 0.32).

CONCLUSIONS

Our study demonstrated similar complication rates and MCID-I and MCID-W attainment rates between mTKA and rTKA patients. Future studies should assess MCID attainment rates in the long term and in larger cohorts comparing mTKA and rTKA.

Time to Achieve Minimal Clinically Important Difference (MCID) in Robotic Versus Manual Total Knee Arthroplasty: A Comparative Analysis

BACKGROUND

Robotics in arthroplasty remains controversial due to the uncertainty of clinical outcomes in robotic total knee arthroplasty (rTKA). This study aimed to compare the time to achieve the minimal clinically important difference (MCID) between rTKA and manual TKA (mTKA).

METHODS

A total of 726 TKAs (416 robotic and 310 manual) were analyzed. We conducted a retrospective analysis of 726 TKAs performed between 2019 and 2022. Patient-reported outcomes were assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) global physical, PROMIS physical function-10a (PF-10a), and Knee Injury and Osteoarthritis Outcome Score-physical function short-form (KOOS-PS) scores, both preoperatively and postoperatively. Survival curves, accounting for interval censoring, were utilized to evaluate the time to achieve MCID. Statistical comparisons between groups were made using log-rank and weighted log-rank tests.

RESULTS

Comparing time to achieve MCID without interval censoring, the median time for rTKA was significantly lower than mTKA for PROMIS global physical (3.5 versus 3.7 months, P = 0.032) and KOOS-PS (3.7 versus 5.3 months, P = 0.002) but similar for PROMIS PF-10a (6.0 versus 6.7 months, P = 0.16). Notably, interval censoring showed similar times to achieve MCID for rTKA and mTKA in PROMIS global physical (0.53 to 0.54 versus 1.23 to 1.24 months, P = 0.31), PROMIS PF-10a (3.03 to 3.03 versus 2.17 to 2.17 months, P = 0.89), and KOOS-PS (1.47 to 1.47 versus 2.17 to 2.17 months, P = 0.27).

CONCUSIONS

Using time to MCID methodology, the median time to achieve MCID did not differ by surgical technique. The present study offers valuable patient-centric insights into preoperative expectations management and patient education. Further prospective studies with more granular patient-reported outcomes measurement collection are needed to evaluate the true effectiveness of robotics in arthroplasty.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Using QALYs as an Outcome for Assessing Global Prediction Accuracy in Diabetes Simulation Models

OBJECTIVES

(1) To demonstrate the use of quality-adjusted life-years (QALYs) as an outcome measure for comparing performance between simulation models and identifying the most accurate model for economic evaluation and health technology assessment. QALYs relate directly to decision making and combine mortality and diverse clinical events into a single measure using evidence-based weights that reflect population preferences. (2) To explore the usefulness of Q2, the proportional reduction in error, as a model performance metric and compare it with other metrics: mean squared error (MSE), mean absolute error, bias (mean residual), and R2.

METHODS

We simulated all EXSCEL trial participants (N = 14,729) using the UK Prospective Diabetes Study Outcomes Model software versions 1 (UKPDS-OM1) and 2 (UKPDS-OM2). The EXSCEL trial compared once-weekly exenatide with placebo (median 3.2-y follow-up). Default UKPDS-OM2 utilities were used to estimate undiscounted QALYs over the trial period based on the observed events and survival. These were compared with the QALYs predicted by UKPDS-OM1/2 for the same period.

RESULTS

UKPDS-OM2 predicted patients' QALYs more accurately than UKPDS-OM1 did (MSE: 0.210 v. 0.253; Q2: 0.822 v. 0.786). UKPDS-OM2 underestimated QALYs by an average of 0.127 versus 0.150 for UKPDS-OM1. UKPDS-OM2 predictions were more accurate for mortality, myocardial infarction, and stroke, whereas UKPDS-OM1 better predicted blindness and heart disease. Q2 facilitated comparisons between subgroups and (unlike R2) was lower for biased predictors.

CONCLUSIONS

Q2 for QALYs was useful for comparing global prediction accuracy (across all clinical events) of diabetes models. It could be used for model registries, choosing between simulation models for economic evaluation and evaluating the impact of recalibration. Similar methods could be used in other disease areas.

HIGHLIGHTS

Diabetes simulation models are currently validated by examining their ability to predict the incidence of individual events (e.g., myocardial infarction, stroke, amputation) or composite events (e.g., first major adverse cardiovascular event).We introduce Q2, the proportional reduction in error, as a measure that may be useful for evaluating and comparing the prediction accuracy of econometric or simulation models.We propose using the Q2 or mean squared error for QALYs as global measures of model prediction accuracy when comparing diabetes models' performance for health technology assessment; these can be used to select the most accurate simulation model for economic evaluation and to evaluate the impact of model recalibration in diabetes or other conditions.

Health-related quality of life after rehabilitation from knee surgery in rural and urban settings: a quasi-experimental study

BACKGROUND

Injury to the knee joint is associated with physical disability, stiffness, pain, restriction of movement and impairment of the person's quality of life, with a few treatment options, including surgery and rehabilitation. This study aims to evaluate the impact of a rehabilitation program on the quality of life reported by patients living in rural and urban areas after knee surgery, using patient-reported outcome measures (PROMs).

METHODS

This quasi-experimental study with two groups of participants undergoing primary knee surgery was carried out in two rehabilitation centers, one in an urban area and another in a rural one. The same intervention was structured, with assessments at the start of the study (t0) and after a 4-week program (t1), and a comparison was made between the gains in rural and urban areas. We used descriptive and inferential analysis to analyze the effect of the intervention on health-related quality of life (HRQoL) using a linear regression model.

RESULTS

Participants (n = 62 aged between 19 and 84 years (40% of the sample aged over 65years) and 61.9% female, showed improvements in their EQ-5D-5L and HADS scores after the rehabilitation program. Considering the dimensions of HRQoL in both groups, there was a significant improvement in all the components in the rural context (p < 0.005), and improvements in the Mobility (t = 3.48; p = 0.002) and EQ_VAS (t = - 3.77; p = 0.001) components in the urban context. The effect of the program on health gains considering the Mobility was significantly greater in the rural group (- 0.97) compared to the urban group (- 0.13), as well as in the Pain/Disability (- 0.73) vs. (- 0.13) respectively. After analyzing the confounding factors, the rehabilitation center variable indicated gains of the EQ-5D-5L dimensions in a rural context (β= -0.390; t = - 3.041; p = 0.004), with an average reduction in health problems.

CONCLUSION

There is evidence that the application of PROMs in rehabilitation programs after knee surgery is fundamental, considering the improvements in HRQoL and the optimization of anxiety/depression states in different contexts. PROMs should be applied systematically in clinical practice throughout the rehabilitation process, objectively measuring the results perceived by patients, and according to each context achieving health gains.

TRIAL REGISTRATION

registry-ClinicTrials; trial registration number-NCT06206018; data of registration-16/01/2024.

Patient Demographic Factors Impact KOOS JR Response Rates for Total Knee Arthroplasty Patients

The Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) is a validated patient-reported measure for assessing pain and function following total knee arthroplasty (TKA). This study investigates how patient demographic factors (i.e., age, sex, and race) correlate with KOOS JR response rates. This was a retrospective cohort study of adult, English-speaking patients who underwent primary TKA between 2017 and 2023 at an academic institution. KOOS JR completion status-complete or incomplete-was recorded within 90 days postoperatively. Standard statistical analyses were performed to assess KOOS JR completion against demographic factors. Among 2,883 total patients, 70.2% had complete and 29.8% had incomplete KOOS JR questionnaires. Complete status (all p < 0.01) was associated with patients aged 60 to 79 (71.8%), white race (77.6%), Medicare (81.7%), marriage (76.8%), and the highest income quartile (75.7%). Incomplete status (all p < 0.001) was associated with patients aged 18 to 59 (64.4%), Medicaid (82.4%), and lower income quartiles (41.6% first quartile, 36.8% third quartile). Multiple patient demographic factors may affect KOOS JR completion rates; patients who are older, white, and of higher socioeconomic status are more likely to participate. Addressing underrepresented groups is important to improve the utility and generalizability of the KOOS JR.

The ROSA robotic-arm system reliably restores joint line height, patella height and posterior condylar offset in total knee arthroplasty

INTRODUCTION

There is growing interest in the use of robotic TKA to improve accuracy of component positioning in Total Knee Arthroplasty (TKA). The aim of this study was to investigate the accuracy of implant component position using the ROSA® knee system with specific reference to Joint Line Height, Patella Height and Posterior Condylar Offset (PCO).

METHODS

This was a retrospective review of a prospectively-maintained database of the initial 100 consecutive TKAs performed by a high volume surgeon using the ROSA® knee system. Both the image-based and imageless workflow were used and two prosthesis types were implanted. To determine the accuracy of component positioning, the immediate post-operative radiograph was reviewed and compared with the immediate pre-operative radiograph with regards to Joint Line Height, Patella Height and Posterior Condylar Offset.

RESULTS

100 consecutive patients undergoing TKA using the ROSA system were included; mean age 70 years (range 49-95 years). Mean change in joint line height was 0.2 mm, patella height (Insall-Salvati ratio) 0.01 and posterior condylar offset 0.02 mm; there was no statistically significant difference between the pre and post-operative values. No difference was demonstrated between image-based or imageless workflows, or between implant design (Persona versus Vanguard) regarding joint line height, patella height and PCO.

CONCLUSION

This study validates the use of the ROSA® knee system in accurately restoring Joint Line Height, Patella Height and Posterior Condylar Offset in TKA surgery. No significant differences were found between imageless and image-based groups, or between implant designs (Persona versus Vanguard).

Can Robotic Arm-assisted Total Knee Arthroplasty Remain Cost-effective in Volume-based Procurement System in China? A Markov Model-based Study

OBJECTIVE

The volume based procurement (VBP) program in China was initiated in 2022. The cost-effectiveness of robotic arm assisted total knee arthroplasty is yet uncertain after the initiation of the program. The objective of the study was to investigate the cost-effectiveness of robotic arm-assisted total knee arthroplasty and the influence of the VBP program to its cost-effectiveness in China.

METHODS

The study was a Markov model-based cost-effectiveness study. Cases of primary total knee arthroplasty from January 2019 to December 2021 were included retrospectively. A Markov model was developed to simulate patients with advanced knee osteoarthritis. Manual and robotic arm-assisted total knee arthroplasties were compared for cost-effectiveness before and after the engagement of the VBP program in China. Probability and sensitivity analysis were conducted.

RESULTS

Robotic arm-assisted total knee arthroplasty showed better recovery and lower revision rates before and after initiation of the VBP program. Robotic arm-based TKA was superior to manual total knee arthroplasty, with an increased effectiveness of 0.26 (16.87 vs 16.61) before and 0.52 (16.96 vs 16.43) after the application of Volume-based procurement, respectively. The procedure is more cost-effective in the new procurement system (17.13 vs 16.89). Costs of manual or robotic arm-assisted TKA were the most sensitive parameters in our model.

CONCLUSION

Based on previous and current medical charging systems in China, robotic arm-assisted total knee arthroplasty is a more cost-effective procedure compared to traditional manual total knee arthroplasty. As the volume-based procurement VBP program shows, the procedure can be more cost-effective.

Rationing in an Era of Multiple Tight Constraints: Is Cost-Utility Analysis Still Fit for Purpose?

Cost-utility analysis may not be sufficient to support reimbursement decisions when the assessed health intervention requires a large proportion of the healthcare budget or when the monetary healthcare budget is not the only resource constraint. Such cases include joint replacement, coronavirus disease 2019 (COVID-19) interventions and settings where all resources are constrained (e.g. post-COVID-19 or in low/middle-income countries). Using literature on health technology assessment, rationing and reimbursement in healthcare, we identified seven alternative frameworks for simultaneous decisions about (dis)investment and proposed modifications to deal with multiple resource constraints. These frameworks comprised constrained optimisation; cost-effectiveness league table; 'step-in-the-right-direction' approach; heuristics based on effective gradients; weighted cost-effectiveness ratios; multicriteria decision analysis (MCDA); and programme budgeting and marginal analysis (PBMA). We used numerical examples to demonstrate how five of these alternative frameworks would operate. The modified frameworks we propose could be used in local commissioning and/or health technology assessment to supplement standard cost-utility analysis for interventions that have large budget impact and/or are subject to additional constraints.

Cost-effectiveness of patient specific vs conventional instrumentation for total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Over the past years, patient specific instrumentation (PSI) for total knee arthroplasty (TKA) has been implemented and routinely used. No clear answer has been given on its associated cost and cost-effectiveness when compared to conventional instrumentation (CI) for TKA.

AIM

To compare the cost and cost-effectiveness of PSI TKA compared to CI TKA.

METHODS

A literature search was performed in healthcare, economical healthcare, and medical databases (MEDLINE, EMBASE, CINAHL, Web of Science, Cochrane Library, EconLit). It was conducted in April 2021 and again in January 2022. Relevant literature included randomised controlled trials, retrospective studies, prospective studies, observational studies, and case control studies. All studies were assessed on methodological quality. Relevant outcomes included incremental cost-effectiveness ratio, quality-adjusted life years, total costs, imaging costs, production costs, sterilization associated costs, surgery duration costs and readmission rate costs. All eligible studies were assessed for risk of bias. Meta-analysis was performed for outcomes with sufficient data.

RESULTS

Thirty-two studies were included into the systematic review. Two were included in the meta-analysis. 3994 PSI TKAs and 13267 CI TKAs were included in the sample size. The methodological quality of the included studies, based on Consensus on Health Economic Criteria-scores and risk of bias, ranged from average to good. PSI TKA costs less than CI TKA when considering mean operating room time and its associated costs and tray sterilization per patient case. PSI TKA costs more compared to CI TKA when considering imaging and production costs. Considering total costs per patient case, PSI TKA is more expensive in comparison to CI TKA. Meta-analysis comparing total costs for PSI TKA, and CI TKA showed a significant higher cost for PSI TKA.

CONCLUSION

Cost for PSI and CI TKA can differ when considering distinct aspects of their implementation. Total costs per patient case are increased for PSI TKA when compared to CI TKA.

Factors associated with a clinically significant improvement in health-related quality of life after total knee arthroplasty

BACKGROUND

The aim was to identify independent preoperative factors associated with changes in health-related quality of life (HRQoL) following total knee arthroplasty (TKA), and whether these could be used as indicators for surgery.

METHODS

A retrospective study of 3127 TKA patients was undertaken that included 1194 (38.2%) male and 1933 (61.8%) female patients, with a mean age of 70.5 years (standard deviation 9.0). Patient demographics, body mass index and ASA grade, Oxford Knee Score (OKS) and EuroQol 5-dimension (EQ-5D) 3-level, which was used to assess HRQoL, were collected preoperatively and 2 years postoperatively.

RESULTS

When adjusting for confounding factors, obesity grade II (p = 0.002), ASA grade 3 (p = 0.002), and a better preoperative OKS (p < 0.001) or EQ-5D score (p < 0.001) were associated with a decreased improvement in the HRQoL at 2-years. A preoperative EQ-5D of < 0.8 (95.7% specific, AUC ≥ 67.0%) or an OKS of < 36 (97.1% specific, AUC ≥ 58.1%) was associated with a clinically significant improvement HRQoL. Patella resurfacing (n = 1454, 46.5%) was not independently associated with a clinical or statistically significant improvement in HRQoL. According to preoperative factors, no subgroup of patients benefited more from patella resurfacing according to improvement in their HRQoL.

CONCLUSION

ASA grade 3, grade II obesity, a better preoperative EQ-5D or OKS were independently associated with a lesser improvement in HRQoL. The thresholds identified in the EQ-5D or OKS for a clinically significant improvement in HRQoL may be used as potential indicators for referral for TKA. Patella resurfacing was not independently associated with a clinically important improvement in HRQoL.

LEVEL OF EVIDENCE

Retrospective diagnostic study, Level III.

The Oxford Knee Score is a reliable predictor of patients in a health state worse than death and awaiting total knee arthroplasty

BACKGROUND

The health-related quality of life of patients awaiting a total knee arthroplasty (TKA) deteriorates with increasing time to surgery and identification of those with the worst quality of life may help to prioritize patients. The aims were to identify and validate independent variable(s) associated with a health state worse than death (WTD) in patients awaiting a TKA and whether these variables influenced patients-reported outcome measures.

METHODS

A retrospective cohort of 5857 patients undergoing a primary TKA was identified from an established arthroplasty database. Patient demographics, body mass index (BMI), index of multiple deprivation, Oxford Knee Score (OKS), EuroQoL five dimension (EQ-5D) 3 level, and visual analogue scale (EQ-VAS) were collected preoperatively and one year postoperatively. An EQ-5D utility of less than zero was defined as WTD. A randomly selected subset of patients (n = 3076) was used to validate the variable that was most predictive of a state WTD and to assess the influence on patient-reported outcomes.

RESULTS

There were 771 (13.2%) patients with a health state WTD. Increasing social deprivation (P = 0.050), worse preoperative OKS (P < 0.001), or EQ-VAS (P < 0.001) were independently associated with a health state WTD. The OKS was the most reliable predictor (area under curve 88.9%, 95% CI 87.8 to 90.1, P < 0.001) of a health state WTD. A threshold value of 16 or less, 80% sensitive and specific, was validated and confirmed to have a negative predictive value of 97.5%. Patients with an OKS of 16 or less had a significantly greater improvement in their OKS (difference 6.9, P < 0.001) and EQ-5D score (difference 0.257, P < 0.001). When adjusting for confounding factors, a health status WTD was not associated with worse postoperative OKS (difference -0.6, 95% CI -1.4 to 0.3, P = 0.177), EQ-5D (difference -0.016, 95% CI -0.036 to 0.003, P = 0.097) or patient satisfaction (difference -1.8, 95% CI -4.3 to 0.7, P = 0.162).

CONCLUSION

A threshold score 16 or less in OKS was a reliable predictor of a health status WTD and was associated with a greater improvement in knee-specific and health-related quality of life following TKA.

The metabolic equivalent of task score : a useful metric for comparing high-functioning hip arthroplasty patients

AIMS

This study investigates the use of the metabolic equivalent of task (MET) score in a young hip arthroplasty population, and its ability to capture additional benefit beyond the ceiling effect of conventional patient-reported outcome measures.

METHODS

From our electronic database of 751 hip arthroplasty procedures, 221 patients were included. Patients were excluded if they had revision surgery, an alternative hip procedure, or incomplete data either preoperatively or at one-year follow-up. Included patients had a mean age of 59.4 years (SD 11.3) and 54.3% were male, incorporating 117 primary total hip and 104 hip resurfacing arthroplasty operations. Oxford Hip Score (OHS), EuroQol five-dimension questionnaire (EQ-5D), and the MET were recorded preoperatively and at one-year follow-up. The distribution was examined reporting the presence of ceiling and floor effects. Validity was assessed correlating the MET with the other scores using Spearman's rank correlation coefficient and determining responsiveness. A subgroup of 93 patients scoring 48/48 on the OHS were analyzed by age, sex, BMI, and preoperative MET using the other metrics to determine if differences could be established despite scoring identically on the OHS.

RESULTS

Postoperatively the OHS and EQ-5D demonstrate considerable negatively skewed distributions with ceiling effects of 41.6% and 53.8%, respectively. The MET was normally distributed postoperatively with no relevant ceiling effect. Weak-to-moderate significant correlations were found between the MET and the other two metrics. In the 48/48 subgroup, no differences were found comparing groups with the EQ-5D, however significantly higher mean MET scores were demonstrated for patients aged < 60 years (12.7 (SD 4.7) vs 10.6 (SD 2.4), p = 0.008), male patients (12.5 (SD 4.5) vs 10.8 (SD 2.8), p = 0.024), and those with preoperative MET scores > 6 (12.6 (SD 4.2) vs 11.0 (SD 3.3), p = 0.040).

CONCLUSION

The MET is normally distributed in patients following hip arthroplasty, recording levels of activity which are undetectable using the OHS. Cite this article: Bone Joint Res 2022;11(5):317-326.

UK poSt Arthroplasty Follow-up rEcommendations (UK SAFE): what does analysis of linked, routinely collected national data sets tell us about mid-late term revision risk after hip replacement? Retrospective cohort study

OBJECTIVE

To identify patients at risk of mid-late term revision of hip replacement to inform targeted follow-up.

DESIGN

Analysis of linked national data sets from primary and secondary care (Clinical Practice Research Datalink (CPRD-GOLD); National Joint Registry (NJR); English Hospital Episode Statistics (HES); Patient-Reported Outcome Measures (PROMs)).

PARTICIPANTS

Primary elective total hip replacement (THR) aged≥18.

EVENT OF INTEREST

Revision surgery≥5 years (mid-late term) after primary THR.

STATISTICAL METHODS

Cox regression modelling to ascertain risk factors of mid-late term revision. HR and 95% CI assessed association of sociodemographic factors, comorbidities, medication, surgical variables and PROMs with mid-late term revision.

RESULTS

NJR-HES-PROMs data were available from 2008 to 2011 on 142 275 THR; mean age 70.0 years and 61.9% female. CPRD GOLD-HES data covered 1995-2011 on 17 047 THR; mean age 68.4 years, 61.8% female. Patients had minimum 5 years postprimary surgery to end 2016. In NJR-HES-PROMS data, there were 3582 (2.5%) revisions, median time-to-revision after primary surgery 1.9 years (range 0.01-8.7), with 598 (0.4%) mid-late term revisions; in CPRD GOLD, 982 (5.8%) revisions, median time-to-revision 5.3 years (range 0-20), with 520 (3.1%) mid-late term revisions.Reduced risk of mid-late term revision was associated with older age at primary surgery (HR: 0.96; 95% CI: 0.95 to 0.96); better 6-month postoperative pain/function scores (HR: 0.35; 95% CI: 0.27 to 0.46); use of ceramic-on-ceramic (HR: 0.73; 95% CI: 0.56 to 0.95) or ceramic-on-polyethylene (HR: 0.76; 95% CI: 0.58 to 1.00) bearing surfaces.Increased risk of mid-late term revision was associated with the use of antidepressants (HR: 1.32; 95% CI: 1.09 to 1.59), glucocorticoid injections (HR: 1.33; 95% CI: 1.06 to 1.67) and femoral head size≥44 mm (HR: 2.56; 95% CI: 1.09 to 6.02)No association of gender, obesity or Index of Multiple Deprivation was observed.

CONCLUSION

The risk of mid-late term THR is associated with age at primary surgery, 6-month postoperative pain and function and implant factors. Further work is needed to explore the associations with prescription medications observed in our data.

Microfragmented Adipose Tissue Injection (MFAT) May Be a Solution to the Rationing of Total Knee Replacement: A Prospective, Gender-Bias Mitigated, Reproducible Analysis at Two Years

Background

Knee osteoarthritis (KOA) is a significant cause of disability in a globally ageing population. Knee replacement surgery has been shown to improve function and quality of life. Access to this intervention can be limited for a number of reasons including rationing of care, lack of healthcare provision in austere environments, and more recently, due to the cessation of elective orthopaedic care as a result of the COVID pandemic. Referral for knee replacement surgery is often guided by the patient's Oxford Knee Score (OKS). Recent therapies including treatment with microfragmented adipose tissue (MFAT) have emerged as alternatives to relieve pain and improve function in such patients.

Method

We identified all patients with KOA Kellgren-Lawrence grade 3 and 4 in our dataset of patients treated with a single injection of MFAT and applied published OKS thresholds for referral for TKR to separate them into 3 cohorts according to their functional impairment. 220 patients (95 females, 125 males) with KOA were given one MFAT injection. The function (OKS) and quality of life (EuroQol-5) prior to and 24 months after therapy were compared.

Results

MFAT injection provided a statistically significant improvement in the quality of life (EQ-5D) at 24 months in patients with a baseline OKS of 39 or less (p value: <0.001) as well as those with OKS of 27 or less who are deemed suitable for a knee replacement (p value: <0.001).

Conclusion

MFAT injection improves quality of life in patients with KOA who are deemed suitable for the knee replacement. MFAT is a low-morbidity alternative biological treatment and can delay the need for total knee replacement in suitable patients.

Patient-reported outcome measures used in patients undergoing total knee arthroplasty

Patient-reported outcome measures (PROMs) are being used increasingly in total knee arthroplasty (TKA). We conducted a systematic review aimed at identifying psychometrically sound PROMs by appraising their measurement properties. Studies concerning the development and/or evaluation of the measurement properties of PROMs used in a TKA population were systematically retrieved via PubMed, Web of Science, Embase, and Scopus. Ratings for methodological quality and measurement properties were conducted according to updated COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology. Of the 155 articles on 34 instruments included, nine PROMs met the minimum requirements for psychometric validation and can be recommended to use as measures of TKA outcome: Oxford Knee Score (OKS); OKS-Activity and Participation Questionnaire (OKS-APQ); 12-item short form Knee Injury and Osteoarthritis Outcome (KOOS-12); KOOS Physical function Short form (KOOS-PS); Western Ontario and McMaster Universities Arthritis Index-Total Knee Replacement function short form (WOMAC-TKR); Lower Extremity Functional Scale (LEFS); Forgotten Joint Score (FJS); Patient's Knee Implant Performance (PKIP); and University of California Los Angeles (UCLA) activity score. The pain and function subscales in WOMAC, as well as the pain, function, and quality of life subscales in KOOS, were validated psychometrically as standalone subscales instead of as whole instruments. However, none of the included PROMs have been validated for all measurement properties. Thus, further studies are still warranted to evaluate those PROMs. Use of the other 25 scales and subscales should be tempered until further studies validate their measurement properties. Cite this article: Bone Joint Res 2021;10(3):203-217.

The use of patient-reported outcome measures to guide referral for hip and knee arthroplasty

AIMS

To calculate how the likelihood of obtaining measurable benefit from hip or knee arthroplasty varies with preoperative patient-reported scores.

METHODS

Existing UK data from 222,933 knee and 209,760 hip arthroplasty patients were used to model an individual's probability of gaining meaningful improvement after surgery based on their preoperative Oxford Knee or Hip Score (OKS/OHS). A clinically meaningful improvement after arthroplasty was defined as ≥ 8 point improvement in OHS, and ≥ 7 in OKS.

RESULTS

The upper preoperative score threshold, above which patients are unlikely to achieve any meaningful improvement from surgery, is 41 for knees and 40 for hips. At lower scores, the probability of improvement increased towards a maximum of 88% (knee) and 95% for (hips).

CONCLUSION

By our definition of meaningful improvement, patients with preoperative scores above 41 (OKS) and 40 (OHS) should not be routinely referred to secondary care for possible arthroplasty. Using lower thresholds would incrementally increase the probability of meaningful benefit for those referred but will exclude some patients with potential to benefit. The findings are useful to support the complex shared decision-making process in primary care for referral to secondary care; and in secondary care for experienced clinicians counselling patients considering knee or hip arthroplasty, but should not be used in isolation. Cite this article: Bone Joint J 2020;102-B(7):941-949.

Who gets referred for knee or hip replacement? A theoretical model of the potential impact of evidence-based referral thresholds using data from a retrospective review of clinic records from an English musculoskeletal referral hub

OBJECTIVES

To estimate the relationship between patient characteristics and referral decisions made by musculoskeletal hubs, and to assess the possible impact of an evidence-based referral tool.

DESIGN

Retrospective analysis of medical records and decision tree model evaluating policy changes using local and national data.

SETTING

One musculoskeletal interface clinic (hub) in England.

PARTICIPANTS

922 adults aged ≥50 years referred by general practitioners with symptoms of knee or hip osteoarthritis.

INTERVENTIONS

We assessed the current frequency and determinants of referrals from one hub and the change in referrals that would occur at this centre and nationally if evidence-based thresholds for referral (Oxford Knee and Hip Scores, OKS/OHS) were introduced.

MAIN OUTCOME MEASURE

OKS/OHS, referrals for surgical assessment, referrals for arthroplasty, costs and quality-adjusted life years.

RESULTS

Of 110 patients with knee symptoms attending face-to-face hub consultations, 49 (45%) were referred for surgical assessment; the mean OKS for these 49 patients was 18 (range: 1-41). Of 101 hip patients, 36 (36%) were referred for surgical assessment (mean OHS: 21, range: 5-44). No patients referred for surgical assessment were above previously reported economic thresholds for OKS (43) or OHS (45). Setting thresholds of OKS ≤31 and OHS ≤35 might have resulted in an additional 22 knee referrals and 26 hip referrals in our cohort. Extrapolating hub results across England suggests a possible increase in referrals nationally, of around 13 000 additional knee replacements and 4500 additional hip replacements each year.

CONCLUSIONS

Musculoskeletal hubs currently consider OKS/OHS and other factors when making decisions about referral to secondary care for joint replacement. Those referred typically have low OHS/OKS, and introducing evidence-based OKS/OHS thresholds would prevent few inappropriate (high-functioning, low-pain) referrals. However, our findings suggest that some patients not currently referred could benefit from arthroplasty based on OKS/OHS. More research is required to explore other important patient characteristics currently influencing hub decisions.