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

Preoperative Oswestry Disability Index Should not be Utilized to Determine Surgical Eligibility for Patients Requiring Lumbar Fusion for Degenerative Lumbar Spine Disease

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate how preoperative Oswestry Disability Index (ODI) thresholds might affect minimal clinically important difference (MCID) achievement following lumbar fusion.

SUMMARY OF BACKGROUND DATA

As payers invest in alternative payment models, some are suggesting threshold cutoffs of patient-reported outcomes (PROMs) in reimbursement approvals for orthopedic procedures. The feasibility of this has not been investigated in spine surgery.

MATERIALS/METHODS

We included all adult patients undergoing one to three-level primary lumbar fusion at a single urban tertiary academic center from 2014 to 2020. ODI was collected preoperatively and one year postoperatively. We implemented theoretical threshold cutoffs at increments of 10. MCID was set at 14.3. The percent of patients meeting MCID were determined among patients "approved" or "denied" at each threshold. At each threshold, the positive predictive value (PPV) for MCID attainment was calculated.

RESULTS

A total 1368 patients were included and 62.4% (N=364) achieved MCID. As the ODI thresholds increased, a greater percent of patients in each group reached the MCID. At the lowest ODI threshold, 6.58% (N=90) of patients would be denied, rising to 20.2%, 39.5%, 58.4%, 79.9%, and 91.4% at ODI thresholds of 30, 40, 50, 60, and 70, respectively. The PPV increased from 0.072 among patients with ODI>20 to 0.919 at ODI>70. The number of patients denied a clinical improvement in the denied category per patient achieving the MCID increased at each threshold (ODI>20: 1.96; ODI>30: 2.40; ODI>40: 2.75; ODI>50: 3.03; ODI>60: 3.54; ODI>70: 3.75).

CONCLUSION

Patients with poorer preoperative ODI are significantly more likely to achieve MCID following lumbar spine fusion at all ODI thresholds. Setting a preoperative ODI threshold for surgical eligibility will restrict access to patients who may benefit from spine fusion despite ODI>20 demonstrating the lowest predictive value for MCID achievement.

LEVEL OF EVIDENCE

3.

Anatomical site of radiographic degeneration is an independent variable influencing outcome of total knee arthroplasty

OBJECTIVES

We aimed to determine whether the site of anatomical degenerative change could be identified as an independent risk factor influencing clinical outcome of total knee arthroplasty (TKA) 12 months postoperatively.

METHODS

We compared preoperative, postoperative and the change observed in Oxford Knee Score (OKS) amongst TKA patients categorised as primarily medial, lateral or patellofemoral osteoarthritis (PFJOA). Multivariable regression analysis was conducted on 434 consecutive knees in 333 patients, adjusting for sex, age and body mass index (BMI).

RESULTS

Adjusted estimates showed that preoperatively, patients with medial and lateral osteoarthritis (OA) had a lower mean OKS of 2.1 (p ​= ​0.049) and 2.3 (p ​= ​0.056) points respectively, while those with PFJOA had mean scores 2.7 points higher (p ​= ​0.062). There was no statistically significant difference between compartments in absolute postoperative OKS. The greatest improvement of 30.1 points (95% confidence interval (CI) 16.9-36.0, p ​= ​0.012) in OKS was observed for those with lateral OA, followed by 28.9 points (95% CI 16.7-35.3, p ​= ​0.049) for those with medial OA. The improvement observed postoperatively in patients with PFJOA was less than that observed for the average of the cohort at 24.5 (95% CI 11.5-29.7, p ​= ​0.088).

CONCLUSIONS

The site of compartmental involvement in knee OA is an independent factor influencing clinical outcome of TKA. With arthroplasty registry adoption of patient-reported outcome measures (PROMs), this study supports precise anatomical categorisation of knee OA in outcome studies.

LEVEL OF EVIDENCE

Level III, Retrospective consecutive clinical study.

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.

Patient Selection in Randomized Controlled Trials of Total Knee Arthroplasty: A Systematic Review Assessing Inclusion Criteria

BACKGROUND

Patients undergo total knee arthroplasty (TKA) at widely disparate stages of osteoarthritis, raising the possibility of high heterogeneity among patients enrolled in TKA research studies. Obscuration of treatment effectiveness and other problems that may stem from cohort heterogeneity can be controlled in clinical studies by rigorously defining target patients. The purpose of this review was to determine the extent to which randomized controlled trials (RCTs) on TKA use osteoarthritis severity, as defined by radiographic grade or patient-reported outcome measures (PROMs), in their inclusion criteria, and to investigate potential impact on outcome.

METHODS

A search of PubMed, Embase, Scopus, Web of Science, and Cochrane databases used a combination of terms involving TKA, PROMs, and radiographic scoring. A total of 1,227 studies were independently reviewed by 2 screeners for the above terms. RCTs with ≥100 patients (236) and with <100 patients (325) undergoing TKA were analyzed with regard to the specific inclusion criteria and recruitment process.

RESULTS

Among the identified RCTs with ≥100 patients, 18 (<8%, with a total of 2,952 randomized patients) used specific radiographic scoring or PROM thresholds in their inclusion criteria. Eleven of the 18 studies used specific radiographic scoring, such as the Kellgren-Lawrence or Ahlbäck classifications. Three studies used preoperative PROM thresholds: Knee Society Knee Score of <60, Knee Society Function Score of <60, Oxford Knee Score of <20, and Hospital for Special Surgery Score of <60. Among studies with <100 patients, 48 (<15%) used specific inclusion criteria.

CONCLUSIONS

The vast majority of RCTs (>85%) did not enroll patients based on disease severity, as measured by PROM score thresholds or radiographic classifications, in their inclusion criteria. The lack of consistent inclusion criteria likely results in heterogeneous cohorts, potentially undermining the validity of RCTs on TKA.

LEVEL OF EVIDENCE

Prognostic Level I . See Instructions for Authors for a complete description of levels of evidence.

United States Experience With a Femoral Neck Retaining Total Hip Arthroplasty Stem: A Retrospective Study With Control Comparison From the Literature

BACKGROUND

Femoral neck retaining prostheses have gained popularity in Europe, but the United States has not seen the same trends occurring. Previous reports demonstrate high survivorship for these implants, but to our knowledge, there are no reports examining US data.

METHODS

After institutional review board approval, 824 primary total hip arthroplasties utilizing a femoral neck-retaining prosthesis were examined for femoral component survivorship rates. European studies were systematically reviewed to determine survivorship rates. The data were used to formulate a Kaplan-Meier survivorship curve and compare US data to that of the European studies.

RESULTS

European studies demonstrated survivorship rates for all causes of 97.7 and 99.0% for aseptic loosening at an average of 6 years (range, 4.5 to 10). The current study demonstrated an all-cause 94% Kaplan-Meier survivorship estimate at 5 years and when aseptic loosening only was considered, survivorship increased to 99.4% at 5 years and 98.4% at 11 years.

CONCLUSION

This femoral neck-retaining prosthesis demonstrated excellent survivorship that is comparable to the rates seen in European studies as well as the rates of standard and mid-stem prostheses in the United States.

When Do We Perform Elective Total Knee Arthroplasty? General and Demographic-Specific Trends of Preoperative Pain and Function among 10,327 Patients

Total knee arthroplasty (TKA) is the sole disease-modifying intervention for end-stage osteoarthritis. However, the temporal trends and stratification of age and patient demographics of pain and function levels at which surgeons perform TKA have not been characterized. The present investigation aimed to analyze the temporal trends of preoperative pain and functional patient-reported outcomes measures (PROMs) over the past 5 years when stratifying patient demographics. A prospective cohort of all patients who underwent primary elective TKA between January 2016 and December 2020 at a North American integrated tertiary health care system was retrospectively reviewed. The primary outcome was quarterly baseline (preoperative) pain and function PROM values before primary elective TKA. Evaluated PROMs included Knee Osteoarthritis Outcome Score (KOOS)-pain and KOOS-physical function shortform (PS) for the 5-year study period and were stratified by patient demographics (age, sex, race, and body mass index [BMI]). A total of 10,327 patients were analyzed. Preoperative pain levels remained unchanged over the study period for patients in the 45- to 64-year category (P-trend = 0.922). Conversely, there was a significant improvement in preoperative pain levels in the 65+ years group. Sex-stratified trends between males and females did not demonstrate a significant change in pre-TKA baseline pain over the study period (P-trend = 0.347 and P-trend = 0.0744). Both white and black patients demonstrated consistent KOOS-pain levels throughout the study period (P-trend = 0.0855 and P-trend = 0.626). Only white patients demonstrated improving preoperative KOOS-PS (P-trend = 0.0001), while black and "other" patients demonstrated consistent lower preoperative functional levels throughout the study period (P-trend = 0.456 and P-trend = 0.871). All BMI categories demonstrated relatively consistent preoperative KOOS-pain and KOOS-PS except for overweight and obese patients who demonstrated progressive improvement in preoperative KOOS-PS over the study period. Patients and surgeons are electing to perform primary TKA at higher levels of preoperative function. Stratification by race showed black patients did not experience a similar trend of improving function and exhibited a consistently lower functional level versus white patients. This disparity is likely to be multifactorial but may indicate underlying barriers to TKA access.

Patient appropriateness for total knee arthroplasty and predicted probability of a good outcome

OBJECTIVES

One-fifth of total knee arthroplasty (TKA) recipients experience a suboptimal outcome. Incorporation of patients' preferences in TKA assessment may improve outcomes. We determined the discriminant ability of preoperative measures of TKA need, readiness/willingness and expectations for a good TKA outcome.

METHODS

In patients with knee osteoarthritis (OA) undergoing primary TKA, we preoperatively assessed TKA need (Western Ontario-McMaster Universities OA Index (WOMAC) Pain Score and Knee injury and Osteoarthritis Outcome Score (KOOS) function, arthritis coping), health status, readiness (Patient Acceptable Symptom State, depressive symptoms), willingness (definitely yes-yes/no) and expectations (outcomes deemed 'very important'). A good outcome was defined as symptom improvement (met Outcome Measures in Rheumatology and Osteoarthritis Research Society International (OMERACT-OARSI) responder criteria) and satisfaction with results 1 year post TKA. Using logistic regression, we assessed independent outcome predictors, model discrimination (area under the receiver operating characteristic curve, AUC) and the predicted probability of a good outcome for different need, readiness/willingness and expectations scenarios.

RESULTS

Of 1,053 TKA recipients (mean age 66.9 years (SD 8.8); 58.6% women), 78.1% achieved a good outcome. With TKA need alone (WOMAC pain subscale, KOOS physical function short-form), model discrimination was good (AUC 0.67, 95% CI 0.63 to 0.71). Inclusion of readiness/willingness, depressive symptoms and expectations regarding kneeling, stair climbing, well-being and performing recreational activities improved discrimination (p=0.01; optimism corrected AUC 0.70, 0.66-0.74). The predicted probability of a good outcome ranged from 44.4% (33.9-55.5) to 92.4% (88.4-95.1) depending on level of TKA need, readiness/willingness, depressive symptoms and surgical expectations.

CONCLUSIONS

Although external validation is required, our findings suggest that incorporation of patients' TKA readiness, willingness and expectations in TKA decision-making may improve the proportion of recipients that experience a good outcome.

Instruments to assess appropriateness of hip and knee arthroplasty: a systematic review

OBJECTIVE

To assess criteria and psychometric properties of instruments for assessing appropriateness of elective joint arthroplasty (JA) for adults with primary hip and knee osteoarthritis (OA).

METHODS

A systematic review guided by Cochrane methods and PRISMA guidelines. Studies were searched in five databases. Eligible articles include all study designs developing, testing, and/or using an instrument to assess JA appropriateness. Two independent reviewers screened and extracted data. Instruments were compared with Hawker et al. JA consensus criteria. Psychometric properties of instruments were described and appraised guided by Fitzpatrick's and COSMIN approaches.

RESULTS

Of 55 instruments included, none met all Hawker et al. JA consensus criteria. Criteria the most met were pain (n = 50), function (n = 49), quality of life (n = 33), and radiography (n = 24). Criteria the least met were clinical evidence of OA (n = 18), expectations (n = 15), readiness for surgery (n = 11), conservative treatments (n = 8), and patient/surgeon agree benefits outweigh risks (n = 0). Instrument by Arden et al. met the most criteria (6 of 9). The most tested psychometric properties were appropriateness (n = 55), face/content validity (n = 55), predictive validity (n = 29), construct validity and feasibility (n = 24). The least tested psychometric properties were intra-rater reliability (n = 3), internal consistency (n = 5), and inter-rater reliability (n = 13). Instruments by Gutacker et al. and Osborne et al. met the most psychometric properties (4 of 10).

CONCLUSION

Most instruments included traditional criteria for assessing JA appropriateness but did not include a trial of conservative treatments or shared decision-making elements. There was limited evidence on psychometric properties.

Should We Aim to Help Patients "Feel Better" or "Feel Good" After Total Hip Arthroplasty? Determining Factors Affecting the Achievement of the Minimal Clinically Important Difference and Patient Acceptable Symptom State

BACKGROUND

Recent attempts have been made to use preoperative patient-reported outcome measure (PROM) thresholds as prior authorization criteria based on the assumption that patients who have higher baseline scores are less likely to achieve the minimal clinically important difference (MCID). This study aimed to identify factors affecting the achievement of MCID and patient acceptable symptom state (PASS) after total hip arthroplasty (THA), and to determine the overlap between the two outcomes.

METHODS

We identified 3,581 primary, unilateral THAs performed at a single practice in 2015-2019. PROMs including Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) and 12-item Short Form Health Survey were collected preoperatively and 1-year postoperatively. The likelihood of attaining PASS according to attainment of MCID was assessed. Multivariable regression was used to identify independent predictors of MCID and PASS.

RESULTS

In total, 79.8% achieved MCID and 73.6% achieved PASS for HOOS-JR. Approximately 1 in 7 patients who achieved MCID did not eventually achieve PASS. Worse preoperative HOOS-JR (odd ratio 0.933) was associated with MCID attainment. Better preoperative HOOS-JR (odd ratio 1.015) was associated with PASS attainment. Men, lower body mass index, better American Society of Anesthesiologists score, and better preoperative 12-item Short Form Health Survey mental score were predictors of MCID and PASS. Age, race, ethnicity, Charlson Comorbidity Index, and smoking status were not significant predictors.

CONCLUSION

Preoperative PROMs were associated with achieving MCID and PASS after THA, albeit in opposite directions. Clinicians should strive to help patients "feel better" and "feel good" after surgery. Preoperative PROMs should not solely be used to prioritize access to care.

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 Paradox of Patient-Reported Outcome Measures: Should We Prioritize "Feeling Better" or "Feeling Good" After Total Knee Arthroplasty?

BACKGROUND

The use of preoperative patient-reported outcome measure (PROM) thresholds for patient selection in arthroplasty care has been questioned recently. This study aimed to identify factors affecting achievement of the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) after total knee arthroplasty (TKA) and determine the overlap between the two outcomes.

METHODS

We identified 1,239 primary, unilateral TKAs performed at a single institution in 2015-2019. PROMs including the Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and 12-item Short Form Health Survey (SF-12) were collected preoperatively and 1-year postoperatively. The likelihood of attaining PASS as per attainment of MCID was assessed. A multivariable regression was used to identify predictors of MCID and PASS.

RESULTS

In total, 71.3% achieved MCID and 75.5% achieved PASS for KOOS-JR. Only 7.7% achieved MCID but not PASS, whereas almost twice this number did not achieve MCID but did achieve PASS (11.9%). Poorer preoperative KOOS-JR (OR 0.925), better SF-12 physical (OR 1.025), and mental (OR 1.027) were associated with MCID attainment. In contrast, better preoperative KOOS-JR (OR 1.030) and SF-12 mental (OR 1.025) were associated with PASS attainment. Age, gender, race, ethnicity, body mass index, Charlson index, American Society of Anesthesiologists classification, and smoking status were not significant predictors.

CONCLUSION

Preoperative PROMs were associated with achieving MCID and PASS after TKA, albeit some positively and some negatively. In the era of value-based care, clinicians should not only strive to help patients "feel better" but also ensure that patients "feel good" after surgery. This study does not support the use of PROMs in prioritizing access to care.

Survivorship and Outcomes of Femoral Neck Preserving Stems in Primary Total Hip Arthroplasty

BACKGROUND

Short-stem femoral implants (SSFIs) promote the preservation of bone in the femoral neck, reduce soft tissue disruption, and facilitate minimally invasive surgical techniques. The purpose of this study was to report the revision rate, complication rate, patient satisfaction, patient-reported outcomes, and radiographic outcomes of patients who underwent total hip arthroplasty (THA) with the Alteon Neck Preserving Femoral Stem (ANPS).

METHODS

A prospectively maintained database was reviewed which analyzed 92 THAs between the years 2016 and 2018. Patient-reported outcomes, patient satisfaction, complication rates, and radiographic outcomes were assessed at 2-5 years postoperatively.

RESULTS

The final cohort consisted of 63 hips. Five patients (7.9%) underwent revision surgery and 2 (3.2%) had other complications not requiring revision. Survivorship when considering only the femoral component was 93.7% at an average of 41.4 months of follow-up. The average postoperative Oxford Hip Score (41.5 ± 8.3) and Harris Hip Score (77.9 ± 16.6) demonstrated significant improvement among our nonrevised patients, respectively (P < .001). Radiographs demonstrated spot welding in 56% of arthroplasties most commonly in Gruen Zones 2, 3, and 13 and that femur radiolucencies were visualized in 58% predominantly along the distal aspect of the stem. Radiographic femoral component subsidence was present in 9.7% of patients.

CONCLUSION

The ANPS may be less reliable than previously reported. Our cohort's revision rate was unacceptably high with 6.3% requiring revision surgery for femoral component loosening in less than 5 years. Surgeons should consider the challenges and prohibitive failure rate associated with SSFIs before routine usage in THA.

Machine learning algorithms do not outperform preoperative thresholds in predicting clinically meaningful improvements after total knee arthroplasty

PURPOSE

Patient-reported outcome measures (PROMs) are important measures of success after total knee arthroplasty (TKA) and being able to predict their improvements could enhance preoperative decision-making. Our study aims to compare the predictive performance of machine learning (ML) algorithms and preoperative PROM thresholds in predicting minimal clinically important difference (MCID) attainment at 2 years after TKA.

METHODS

Prospectively collected data of 2840 primary TKA performed between 2008 and 2018 was extracted from our joint replacement registry and split into a training set (80%) and test set (20%). Using the training set, ML algorithms were developed using patient demographics, comorbidities and preoperative PROMs, whereas the optimal preoperative threshold was determined using ROC analysis. Both methods were used to predict MCID attainment for the SF-36 PCS, MCS and WOMAC at 2 years postoperatively, with predictive performance evaluated on the independent test set.

RESULTS

ML algorithms and preoperative PROM models performed similarly in predicting MCID for the SF-36 PCS (AUC: 0.77 vs 0.74), MCS (AUC: 0.95 vs 0.95) and WOMAC (AUC: 0.89 vs 0.88). For each outcome, the most important predictor of MCID attainment was the patient's preoperative PROM score. ROC analysis also identified optimal preoperative threshold values of 33.6, 54.1 and 72.7 for the SF-36 PCS, MCS and WOMAC, respectively.

CONCLUSION

ML algorithms did not perform significantly better than preoperative PROM thresholds in predicting MCID attainment after TKA. Future research should routinely compare the predictive ability of ML algorithms with existing methods and determine the type of clinical problems which may benefit the most from it.

LEVEL OF EVIDENCE

II.

When is Surgery Performed? Trends, Demographic Associations, and Phenotypical Characterization of Baseline Patient-Reported Outcomes Before Total Hip Arthroplasty

BACKGROUND

Evaluating trends and drivers of baseline patient-reported outcome measures (PROMs) is critical to understanding when patients and providers elect to undergo surgery. We aimed to assess the following: (1) 5-year trends in baseline PROMs pre-THA (total hip arthroplasty) stratified by patient determinants; (2) patient factor associated with poor preoperative hip pain/function; (3) phenotypes of combined pain/function PROMs at baseline; and (4) intersurgeon variability in PROM thresholds at surgery.

METHODS

A prospective cohort of 6,902 primary THAs was enrolled (January 2016 to December 2020). Patient/surgeon details and PROMs were collected at point of care preoperatively. Outcomes included trends (5 years; 20 quarters) in Hip disability and Osteoarthritis Outcome Score (HOOS)-Pain and HOOS-PS (Physical Function Short-Form), stratified by patient demographics. Patients were further classified into phenotype categories of above or equal to median pain/function (P+PS+); below median pain/function (P-PS-); above or equal to median pain but below median function (P+PS-); and below median pain but above or equal to median function (P-PS+).

RESULTS

Baseline HOOS-Pain was consistent across the study period (P-trend = .166), while HOOS-PS demonstrated increasing function (P-trend = .015). Such trends were appreciable in males, females, and White (P-trend < .001, each) but not Black patients (P-trend = .67). Higher odds ratio (OR) of low baseline HOOS-Pain and HOOS-PS were detected among females (HOOS-Pain: OR 1.75, 95% confidence interval [CI] 1.55-1.98, P < .001; HOOS-PS: OR 1.56, 95% CI 1.38-1.77, P < .001), Black patients (HOOS-Pain: OR 1.64, 95% CI 1.35-2.82, P < .001; HOOS-PS: OR 1.59, 95% CI 1.34-1.89, P < .001), and smokers (HOOS-Pain: OR 1.56, 95% CI 1.29-1.89, P < .001; HOOS-PS: OR 1.52, 95% CI 1.25-1.85, P < .001). The P-PS- cohort (32.4%) had lowest age (65.2 ± 11.1 years), highest body mass index (31.6 ± 6.9 kg/m²), females (64.8%), Black (15.8%), and current smokers (12.2%). There was significant intersurgeon preoperative PROM variation in HOOS-Pain and HOOS-PS (P < .001, each).

CONCLUSION

In contrast to the general population, Black patients have consistently received THA at lower functional levels throughout the 5-year period. Females, smokers, and Black patients were more likely to have poorer pain and function at THA. PROMs assessment as combined pain-function phenotypes may provide a more comprehensive interpretation of patient status preoperatively.

Using Artificial Intelligence to Revolutionise the Patient Care Pathway in Hip and Knee Arthroplasty (ARCHERY): Protocol for the Development of a Clinical Prediction Model

BACKGROUND

Hip and knee osteoarthritis is substantially prevalent worldwide, with large numbers of older adults undergoing joint replacement (arthroplasty) every year. A backlog of elective surgery due to the COVID-19 pandemic, and an aging population, has led to substantial issues with access to timely arthroplasty surgery. A potential method to improve the efficiency of arthroplasty services is by increasing the percentage of patients who are listed for surgery from primary care referrals. The use of artificial intelligence (AI) techniques, specifically machine learning, provides a potential unexplored solution to correctly and rapidly select suitable patients for arthroplasty surgery.

OBJECTIVE

This study has 2 objectives: (1) develop a cohort of patients with referrals by general practitioners regarding assessment of suitability for hip or knee replacement from National Health Service (NHS) Grampian data via the Grampian Data Safe Haven and (2) determine the demographic, clinical, and imaging characteristics that influence the selection of patients to undergo hip or knee arthroplasty, and develop a tested and validated patient-specific predictive model to guide arthroplasty referral pathways.

METHODS

The AI to Revolutionise the Patient Care Pathway in Hip and Knee Arthroplasty (ARCHERY) project will be delivered through 2 linked work packages conducted within the Grampian Data Safe Haven and Safe Haven Artificial Intelligence Platform. The data set will include a cohort of individuals aged ≥16 years with referrals for the consideration of elective primary hip or knee replacement from January 2015 to January 2022. Linked pseudo-anonymized NHS Grampian health care data will be acquired including patient demographics, medication records, laboratory data, theatre records, text from clinical letters, and radiological images and reports. Following the creation of the data set, machine learning techniques will be used to develop pattern classification and probabilistic prediction models based on radiological images. Supplemental demographic and clinical data will be used to improve the predictive capabilities of the models. The sample size is predicted to be approximately 2000 patients-a sufficient size for satisfactory assessment of the primary outcome. Cross-validation will be used for development, testing, and internal validation. Evaluation will be performed through standard techniques, such as the C statistic (area under curve) metric, calibration characteristics (Brier score), and a confusion matrix.

RESULTS

The study was funded by the Chief Scientist Office Scotland as part of a Clinical Research Fellowship that runs from August 2021 to August 2024. Approval from the North Node Privacy Advisory Committee was confirmed on October 13, 2021. Data collection started in May 2022, with the results expected to be published in the first quarter of 2024. ISRCTN registration has been completed.

CONCLUSIONS

This project provides a first step toward delivering an automated solution for arthroplasty selection using routinely collected health care data. Following appropriate external validation and clinical testing, this project could substantially improve the proportion of referred patients that are selected to undergo surgery, with a subsequent reduction in waiting time for arthroplasty appointments.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN18398037; https://www.isrctn.com/ISRCTN18398037.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/37092.

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.

Loss to patient-reported outcome measure follow-up after hip arthroplasty and knee arthroplasty

Aims

The aim of this study was to determine satisfaction rates after hip and knee arthroplasty in patients who did not respond to postoperative patient-reported outcome measures (PROMs), characteristics of non-responders, and contact preferences to maximize response rates.

Methods

A prospective cohort study of patients planned to undergo hip arthroplasty (n = 713) and knee arthroplasty (n = 737) at a UK university teaching hospital who had completed preoperative PROMs questionnaires, including the EuroQol five-dimension health-related quality of life score, and Oxford Hip Score (OHS) and Oxford Knee Score (OKS). Follow-up questionnaires were sent by post at one year, including satisfaction scoring. Attempts were made to contact patients who did not initially respond. Univariate, logistic regression, and receiver operator curve analysis was performed.

Results

At one year, 667 hip patients (93.5%) and 685 knee patients (92.9%) had undergone surgery and were alive. No response was received from 151/667 hip patients (22.6%), 83 (55.0%) of whom were ultimately contacted); or from 108/685 knee patients (15.8%), 91 (84.3%) of whom were ultimately contacted. There was no difference in satisfaction after arthroplasty between initial non-responders and responders for hips (74/81 satisfied vs 476/516 satisfied; p = 0.847) or knees (81/93 satisfied vs 470/561 satisfied; p = 0.480). Initial non-response and persistent non-response was associated with younger age, higher BMIs, and worse preoperative PROMs for both hip and knee patients (p < 0.050). Being in employment was associated with persistent non-response for hip patients (p = 0.047). Multivariate analysis demonstrated that younger age (p < 0.038), higher BMI (p = 0.018), and poorer preoperative OHS (p = 0.031) were independently associated with persistent non-response to hip PROMs. No independent associations were identified for knees. Using a threshold of > 66.4 years predicted a preference for contact by post (area under the curve 0.723 (95% confidence interval (CI) 0.647 to 0.799; p < 0.001, though this CI crosses the 0.7 limit considered reliable).

Conclusion

The majority of initial non-responders were ultimately contactable with effort. Satisfaction rates were not inferior in patients who did not initially respond to PROMs.

Cite this article: Bone Jt Open 2022;3(4):275–283.

Is rationing of total hip arthroplasty justified? Working to optimize patient accessibility to surgery using long-term patient-reported outcome data

Aims

The aim of this study was to assess medium-term improvements following total hip arthroplasty (THA), and to evaluate what effect different preoperative Oxford Hip Score (OHS) thresholds for treatment may have on patients’ access to THA and outcomes.

Methods

Patients undergoing primary THA at our institution with an OHS both preoperatively and at least four years postoperatively were included. Rationing thresholds were explored to identify possible deprivation of OHS improvement.

Results

Overall, 2,341 patients were included. Mean OHS was 19.7 (SD 8.2) preoperatively and 39.7 (SD 9.8) at latest follow-up. An improvement of at least eight-points, the minimally important change (MIC), was seen in 2,072 patients (88.5%). The mean improvement was 20.0 points (SD 10.5). If a rationing threshold of OHS of 20 points had been enforced, 90.8% of those treated would have achieved the MIC, but only 54.3% of our cohort would have had access to surgery; increasing this threshold to 32 would have enabled 89.5% of those treated to achieve the MIC while only depriving 6.5% of our cohort. The ‘rationed’ group of OHS > 20 had significantly better OHS at latest follow-up (42.6 vs 37.3; p < 0.001), while extending the rationing threshold above 32 showed postoperative scores were more significantly affected by the ceiling effect of the OHS.

Conclusion

The OHS was not designed as a tool to ration healthcare, but if it had been used at our institution for this cohort, applying an OHS threshold of 20 to routine THA access would have excluded nearly half of patients from having a THA; a group in which over 85% had a significant improvement in OHS. Where its use for rationing is deemed necessary, use of a higher threshold may be more appropriate to ensure a better balance between patient access to treatment and chances of achieving good to excellent outcomes. Cite this article: Bone Jt Open 2022;3(3):196–204.

Radiographic severity, extent and pattern of cartilage loss are not associated with patient reported outcomes before or after total knee arthroplasty in end-stage knee osteoarthritis

BACKGROUND

The aim of this study was to determine if radiographic severity, extent or pattern of knee osteoarthritis was associated with pain and function before total knee arthroplasty (TKA) or improvement therein one year after TKA.

METHODS

A prospective study of 259 patients undergoing unilateral TKA for Kellgren-Lawrence (KL) grade ≥ 3 knee osteoarthritis was conducted: mean age 69.8 ± 9.7 (44-91); mean BMI 31.0 ± 5.8 (17-52); 152/259 (58.7%) female. Preoperative radiographs were assessed using the KL and Ahlback systems. Preoperatively and 1 year postoperatively patients completed Oxford Knee Scores, VAS-Pain and EQ-5D scores. Full thickness cartilage loss was recorded intraoperatively.

RESULTS

Median radiographic severity was Ahlback 2, KL 4: 51/259 (19.7%) hypertrophic; 23/259 (8.8%) atrophic. Neither Ahlback nor Kellgren-Lawrence OA grade was associated with OKS, VAS Pain or EQ-5D prior to TKA (p > 0.05). The extent and pattern of cartilage loss did not affect preoperative PROMs. Radiographic OA severity, compartment involvement, and pattern of cartilage loss were not significantly associated with PROMs or improvements therein following TKA (p > 0.05). Hypertrophic OA was associated with less pain before TKA (difference 6.8, 0.23-13.9 95%CI, p = 0.044), and worse improvement in OKS following TKA (difference -3.41, -6.8 to -0.05 95%CI, p = 0.047). Better preoperative OKS and hypertrophic OA were independently associated with poorer improvement in OKS 1 year following TKA (R² = 0.208).

CONCLUSION

Provided at least one compartment has KL grade ≥ 3 changes, further radiographic severity, pattern or extent of cartilage loss did not affect PROMs before or after TKA: multicompartmental was no worse than unicompartmental disease.

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.

Insights into patient preferences for elective surgery during the COVID-19 pandemic

AIMS

To investigate factors that contribute to patient decisions regarding attendance for arthroplasty during the COVID-19 pandemic.

METHODS

A postal questionnaire was distributed to patients on the waiting list for hip or knee arthroplasty in a single tertiary centre within the UK. Patient factors that may have influenced the decision to attend for arthroplasty, global quality of life (QoL) (EuroQol five-dimension three-level (EQ-5D-3L)), and joint-specific QoL (Oxford Hip or Knee Score) were assessed. Patients were asked at which 'COVID-alert' level they would be willing to attend an NHS and a "COVID-light" hospital for arthroplasty. Independent predictors were assessed using multivariate logistic regression.

RESULTS

Of 540 distributed questionnaires, 400 (74.1%; 236 awaiting hip arthroplasty, 164 awaiting knee arthroplasty) complete responses were received and included. Less than half (48.2%) were willing to attend for hip or knee arthroplasty while a UK COVID-19 epidemic was in circulation (COVID-alert levels 3 to 5). Patients with worse joint-specific QoL had a preference to proceed with surgery at COVID-alert levels 3 to 5 compared to levels 1 and 2 (hip arthroplasty odds ratio (OR) 1.54 (95% confidence interval (CI) 1.45 to 1.63); knee arthroplasty OR 1.16 (1.07 to 1.26)). The odds of patients with worse joint-specific QoL being willing to attend for surgery at COVID-alert levels 3 to 5 increased further if surgery in a private, "COVID-light" hospital was available (hip arthroplasty OR 3.50 (95% CI 3.26 to 3.71); knee arthroplasty OR 1.41 (95% CI 1.29 to 1.53).

CONCLUSION

Patient decisions surrounding elective surgery have been influenced by the global COVID-19 pandemic, highlighting the importance of patient involvement in ensuring optimized provision of elective surgery during these challenging times. Cite this article: Bone Jt Open 2021;2(4):261-270.

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 assess how the cost-effectiveness of total hip arthroplasty (THA) and total knee arthroplasty (TKA) varies with age, sex, and preoperative Oxford Hip or Knee Score (OHS/OKS); and to identify the patient groups for whom THA/TKA is cost-effective.

METHODS

We conducted a cost-effectiveness analysis using a Markov model from a United Kingdom NHS perspective, informed by published analyses of patient-level data. We assessed the cost-effectiveness of THA and TKA in adults with hip or knee osteoarthritis compared with having no arthroplasty surgery during the ten-year time horizon.

RESULTS

THA and TKA cost < £7,000 per quality-adjusted life-year (QALY) gained at all preoperative scores below the absolute referral thresholds calculated previously (40 for OHS and 41 for OKS). Furthermore, THA cost < £20,000/QALY for patients with OHS of ≤ 45, while TKA was cost-effective for patients with OKS of ≤ 43, since the small improvements in quality of life outweighed the cost of surgery and any subsequent revisions. Probabilistic and one-way sensitivity analyses demonstrated that there is little uncertainty around the conclusions.

CONCLUSION

If society is willing to pay £20,000 per QALY gained, THA and TKA are cost-effective for nearly all patients who currently undergo surgery, including all patients at and above our calculated absolute referral thresholds. Cite this article: Bone Joint J 2020;102-B(7):950-958.