Measures of the Appropriateness of Elective Orthopaedic Joint and Spine Procedures

Determining Appropriateness of Total Joint Arthroplasty for Hip and Knee Osteoarthritis: A Patient-Centred Conceptual Model

INTRODUCTION

Total joint arthroplasty (TJA) for osteoarthritis is one of several treatment options with benefits and harms that patients value differently. However, the process for determining TJA appropriateness does not sufficiently acknowledge patient perspectives. The aim of this paper is to propose an evidence-informed patient-centred conceptual model for elective TJA appropriateness for hip and knee osteoarthritis.

METHODS

Our interprofessional team developed a conceptual model for determining the appropriateness of adults considering elective TJA. The model was informed by a review of the evidence, a qualitative study we conducted with adults who underwent TJA for osteoarthritis to determine barriers and facilitators to the use of appropriateness criteria, and the research and clinical experience of team members.

RESULTS

Appropriateness is providing health services (e.g., TJA) with net benefits to the right patient at the right time. The proposed Patient-centred Elective TJA Appropriateness Conceptual Model involves three key steps. First, assess adults with osteoarthritis to determine eligibility for TJA. Second, acknowledge the patient's informed preferences including their expectations and goals. Third, explore and support their mental and physical readiness for TJA. Given that osteoarthritis is a chronic condition, these steps can be revisited over time with patients.

DISCUSSION AND CONCLUSION

Our proposed conceptual model reconceptualises the appropriateness of TJA to be more patient-centred. Hence, this approach has the potential to be a more inclusive approach and ensure patients undergoing TJA are eligible, ready to proceed, and achieve what matters most to them. Future research is needed to test and validate the model.

Evaluation of "appropriate use criteria" for surgical decision-making in lumbar degenerative spondylolisthesis. A controlled, multicentre, prospective observational study

INTRODUCTION

Selecting patients with lumbar degenerative spondylolisthesis (LDS) for surgery is difficult. Appropriate use criteria (AUC) have been developed to clarify the indications for LDS surgery but have not been evaluated in controlled studies.

METHODS

This prospective, controlled, multicentre study involved 908 patients (561 surgical and 347 non-surgical controls; 69.5 ± 9.7y; 69% female), treated as per normal clinical practice. Their appropriateness for surgery was afterwards determined using the AUC. They completed the Core Outcome Measures Index (COMI) at baseline and 12 months' follow-up. Multiple regression adjusting for confounders evaluated the influence of appropriateness designation and treatment received on the 12-month COMI and achievement of MCIC (≥ 2.2-point-reduction).

RESULTS

As per convention, appropriate (A) and uncertain (U) groups were combined for comparison with the inappropriate (I) group. For the adjusted 12-month COMI, the benefit of surgery relative to non-surgical care was not significantly greater for the A/U than the I group (p = 0.189). There was, however, a greater treatment effect of surgery for those with higher baseline COMI (p = 0.035). The groups' adjusted probabilities of achieving MCIC were: 83% (A/U, receiving surgery), 71% (I, receiving surgery), 50% (A/U, receiving non-surgical care), and 32% (I, receiving non-surgical care).

CONCLUSIONS

A/U patients receiving surgery had the highest chances of achieving MCIC, but the AUC were not able to identify which patients had a greater treatment effect of surgery relative to non-surgical care. The identification of other characteristics that predict a greater treatment effect of surgery, in addition to baseline COMI, is required to improve decision-making.

Six-month pain and function outcome expectations were established for total knee arthroplasty using the smallest worthwhile effect

INTRODUCTION

Interpretations of patient-reported outcome measures following knee arthroplasty lack context and typically do not account for costs, risks and benefits compared to an alternative treatment. The primary purpose of our paper is to estimate expectations patients have for pain and function destination outcome, six-months following surgery relative to the outcome expected if knee arthroplasty was not done. Secondary purposes were to determine if statistically significant changes in the smallest worthwhile six-month outcome occurred following an interactive discussion and to assess the construct validity of the expected six-month outcome obtained at baseline.

METHODS

This was a secondary analysis of a prospective longitudinal cohort study of 121 patients undergoing knee arthroplasty. Smallest worthwhile effect estimates were determined and expected six-month KOOS Pain and Function, daily activity measures were established during a pre-operative visit.

RESULTS

The average six-month expected (the destination of interest) KOOS Pain score was 75 (IQR = 64 to 86) and the average KOOS Function, daily activity score was 74 (IQR = 59 to 86). The smallest worthwhile effect discussion led to significant changes in expected destination scores. For example, KOOS Pain expected outcome changed from 87.7 (9.8) to 75.0 (13.6), a statistically significant reduction in expected outcome (t(119) = 16.942, p < 0.001.

CONCLUSION

Six-month expected KOOS outcomes following knee arthroplasty were established and approximate the average six-month outcomes reported in the literature. Validity of these estimates was established. These data can be used to aid shared decision-making discussions regarding patient expectations of knee arthroplasty outcomes during a patient encounter.

Establishing the Minimally Important Difference for the KOOS-Joint Replacement and PROMIS Global-10 in Patients After Total Knee Arthroplasty

Background

Despite the overall prevalence and success of total knee arthroplasty (TKA), a significant portion of patients are dissatisfied with their outcomes.

Purpose

To assess the responsiveness and determine the minimally important difference (MID) of 2 patient-reported outcome measures (PROMs)-the Knee injury and Osteoarthritis Outcome Score-Joint Replacement (KOOS-JR) and the Patient-Reported Outcomes Measurement Information System Global-10 (PROMIS 10)-in patients after TKA.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

Included were patients who underwent TKA from August 2015 through August 2019 and completed baseline and postoperative KOOS-JR and PROMIS 10 surveys. The PROMIS 10 consists of 2 domains: physical health and mental health. Estimates for the reliable change index (RCI) and MID, using anchor-based and distribution-based methods, were calculated for each PROM. Regression modeling was used to determine whether patient and clinical factors predicted MID thresholds or MID achievement.

Results

A total of 1315 patients were included. Distribution-based MIDs, calculated using various methods from baseline scores, ranged from 19.3 to 31 for the KOOS-JR, and the RCI was 4.38. Of these patients, 293 (22.3%) demonstrated small or moderate improvement, and this cohort was included in the calculation of anchor-based MIDs. The anchor-based MIDs were 16.9 and 24.3 at 3-month and 1-year follow-up, respectively, and 66% of patients achieved the MID at 12 months. Higher preoperative PROM score, male sex, non-White race, and current smoker status were predictive of failing to achieve the anchor-based MID for KOOS-JR at 1 year postoperatively (P < .05). Higher preoperative PROM score and any 90-day adverse event predicted lower thresholds of important change in anchor-based MIDs. Higher baseline PROM scores, younger age, male sex, non-White ethnicity, higher American Society of Anesthesiologists classification, preoperative narcotics use, not smoking, and longer hospital stay were all associated with lower odds of achieving the MID on the KOOS-JR or either of the PROMIS 10 subscales.

Conclusion

The study results demonstrated relevant values for interpretation of the KOOS-JR and PROMIS 10. While patient demographics did not accurately predict which patients would achieve the MID, some potential factors predicting successful patient-reported outcomes after TKA were identified.

Exploring appropriateness criteria for informing the total knee arthroplasty decision-making process: An interpretive descriptive study

RATIONAL

The Hawker appropriateness criteria for total knee arthroplasty (TKA) are: osteoarthritis symptoms impacting quality of life, evidence of osteoarthritis, trial of conservative treatments, patient's realistic expectations, patient/surgeon agree benefits outweigh risks, and readiness for surgery. Little is known about the barriers and facilitators of using the Hawker et al. appropriateness criteria for TKA in clinical practice.

AIMS AND OBJECTIVES

Explore the barriers and facilitators to using appropriateness criteria for TKA in making decisions for adults with knee osteoarthritis.

METHODS

Interpretive descriptive qualitative study at an academic hospital. Purposive sampling aimed to recruit: (1) healthcare team members at all levels influencing care delivery, and (2) adults with TKA assessed at the hospital clinic. Semi-structured interviews asked about the barriers/facilitators to using the Hawker appropriateness criteria. Data analysis consisted of inductive thematic analysis with themes mapped to the Consolidated Framework for Implementation Research domains.

RESULTS

Nine healthcare professionals and 14 adults with TKA participated and identified common barriers to using the Hawker appropriateness criteria: (a) intervention characteristics domain: difficulty to assess criteria, patients expecting healthcare professionals to decide, limited accessibility to conservative treatments; (b) individuals characteristics domain: no need to change current TKA process, clinical judgement limited to OA severity/age, implicit assessment of subjective criteria; (c) inner setting domain: TKA information received after decision made; and (d) outer setting domain: no timely access to TKA. A facilitator of use was evidence/buy-in fosters programme changes.

CONCLUSION

Barriers to using the criteria relevant to clinical practice and the healthcare system were identified while only one facilitator was revealed. Interventions tailored to these barriers are needed to support the use of the Hawker appropriateness criteria in TKA decision-making.

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.

Denosumab prevented periprosthetic bone resorption better than risedronate after total hip arthroplasty

INTRODUCTION

Periprosthetic fracture caused by periprosthetic bone loss is an important concern in total hip arthroplasty (THA). Denosumab has been approved for postmenopausal women with osteoporosis who are at high risk of fracture. In this randomized controlled trial, we compared the effects of denosumab and risedronate on periprosthetic bone mineral density (BMD) after THA.

MATERIALS AND METHODS

The current study analyzed 108 patients who were scheduled to have THA. For 2 years, the patients were randomly assigned to the following two treatment groups: denosumab (60 mg subcutaneously every 6 months) or risedronate (17.5 mg oral weekly). The BMD changes in all Gruen zones and bone turnover markers were measured at the 5th postoperative day (baseline) and 6, 12, 18, and 24 months postoperatively.

RESULTS

The mean BMD in zones 1, 2, 6, and 7 was significantly higher with denosumab all administration at all postoperative time points compared to the risedronate group. The mean percentage changes in the BMD in these zones from baseline to 24 months postoperatively were + 11.9, + 2.9, + 8.1, and + 5.9% with denosumab group and - 9.6% -3.6, - 2.3, and - 19.2% with risedronate, respectively. The osteoclastic marker, tartrate-resistant acid phosphatase-5b (TRACP-5b), was significantly lower in the denosumab group compared to the risedronate group by 2 months.

CONCLUSION

Denosumab is more effective in preventing periprosthetic bone resorption than risedronate in the proximal femur. It also increased BMD around the stem implant following THA.

Artificial intelligence in knee arthroplasty: current concept of the available clinical applications

Background

Artificial intelligence (AI) is defined as the study of algorithms that allow machines to reason and perform cognitive functions such as problem-solving, objects, images, word recognition, and decision-making. This study aimed to review the published articles and the comprehensive clinical relevance of AI-based tools used before, during, and after knee arthroplasty.

Methods

The search was conducted through PubMed, EMBASE, and MEDLINE databases from 2000 to 2021 using the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA).

Results

A total of 731 potential articles were reviewed, and 132 were included based on the inclusion criteria and exclusion criteria. Some steps of the knee arthroplasty procedure were assisted and improved by using AI-based tools. Before surgery, machine learning was used to aid surgeons in optimizing decision-making. During surgery, the robotic-assisted systems improved the accuracy of knee alignment, implant positioning, and ligamentous balance. After surgery, remote patient monitoring platforms helped to capture patients’ functional data.

Conclusion

In knee arthroplasty, the AI-based tools improve the decision-making process, surgical planning, accuracy, and repeatability of surgical procedures.

The Effect of Patient Age and Surgical Appropriateness and Their Influence on Surgeon Recommendations for Primary TKA: A Cross-Sectional Study of 2,037 Patients

BACKGROUND

Rising total knee arthroplasty (TKA) rates in younger patients raises concern about appropriateness. We asked: are younger individuals who seek consultation for TKA less likely to be appropriate for and, controlling for appropriateness, more likely to be recommended for surgery?

METHODS

This cross-sectional study was nested within a prospective cohort study of knee osteoarthritis (OA) patients referred for TKA from 2014 to 2016 to centralized arthroplasty centers in Alberta, Canada. Pre-consultation, questionnaires assessed patients' TKA appropriateness (need, based on knee symptoms and prior treatment; readiness/willingness to undergo TKA; health status; and expectations) and contextual factors (for example, employment). Post-consultation, surgeons confirmed study eligibility and reported their TKA recommendation. Using generalized estimating equations to control for clustering by surgeon, we assessed relationships between patient age (<50, 50 to 59, ≥60 years) and TKA appropriateness and receipt of a surgeon TKA recommendation.

RESULTS

Of 2,037 participants, 3.3% and 22.7% were <50 and 50 to 59 years of age, respectively, 58.7% were female, and 35.5% were employed. Compared with older participants, younger participants reported significantly worse knee symptoms, higher use of OA therapies, higher TKA readiness, and similar willingness, but had higher body mass index and were more likely to smoke and to consider the ability to participate in vigorous activities, for example, sports, as very important TKA outcomes. TKA was offered to 1,500 individuals (73.6% overall; 52.2%, 71.0%, and 75.4% of those <50, 50 to 59, and ≥60 years, respectively). In multivariate analyses, the odds of receiving a TKA recommendation were higher with greater TKA need and willingness, in nonsmokers, and in those who indicated that improved ability to go upstairs and to straighten the leg were very important TKA outcomes. Controlling for TKA appropriateness, patient age was not associated with surgeons' TKA recommendations.

CONCLUSIONS

Younger individuals with knee OA referred for TKA had similar or greater TKA need, readiness, and willingness than older individuals. Incorporation of TKA appropriateness criteria into TKA decision-making may facilitate consideration of TKA benefits and risks in a growing population of young, obese individuals with knee OA.

CLINICAL RELEVANCE

Younger people seeking TKA for knee OA had significant OA pain and disability despite recommended OA therapies, suggesting appropriateness for surgical consideration. However, they were significantly more likely to have morbid obesity, to smoke, and to consider return to vigorous activities, like sport, as important TKA outcomes. Whether the short- and longer-term risks of TKA are outweighed by the benefits is unclear and warrants additional research.

Effectiveness of patient decision aids for total hip and knee arthroplasty decision-making: a systematic review

OBJECTIVES

To determine the effectiveness of patient decision aids (PtDAs) compared to alternative interventions (including usual care) on decision quality and quality of the decision-making process for adults with hip and knee osteoarthritis considering primary elective total joint arthroplasty.

METHODS

A systematic review guided by Cochrane methods and PRISMA reporting guidelines. Studies were searched in five databases. Included studies were RCTs evaluating the effect of PtDAs on total joint arthroplasty decision-making. Study quality was appraised with Cochrane's risk of bias tool. Quality and strength of recommendations were appraised with GRADE.

RESULTS

Ten included studies were conducted in North American using the same PtDA. Compared to usual care, PtDA groups demonstrated increased decision quality (e.g., higher knowledge, more informed values-based choices) and quality of the decision making process (e.g., decreased decisional conflict) (6 trials). Secondary outcomes showed increased surgeon satisfaction within the consultation and no difference in patient satisfaction or uptake of the chosen option (surgery: RR 1.03, 95% CI = 0.84 to 1.25; I² = 66%; 4 trials). When PtDAs formtats were compared, there were similar effects but no difference between PtDAs (4 trials).

CONCLUSIONS

There was low to very low GRADE certainty of evidence for the effect of PtDAs on decision quality and quality of the decision-making process compared to usual care. No differences were found when different formats of PtDAs were compared (moderate to very low GRADE certainty of evidence).

Observing the use of knee arthroplasty appropriateness tools in clinical practice: do appropriateness criteria tools predict surgeon decision-making?

OBJECTIVE

The primary aim of this study was to evaluate the agreement between surgeons and two validated total knee arthroplasty (TKA) appropriateness tools, and secondarily to compare Australian appropriateness rates to those reported internationally.

METHODS

A consecutive sample of patients from one public hospital arthroplasty clinic and a convenience sample from private rooms of surgeons in New South Wales, Australia (n = 11), referred for surgical opinion regarding TKA were enrolled over 1 year. Surgeons applied appropriateness tools created by Escobar et al. and the American Academy of Orthopaedic Surgeons (AAOS). Correlation between the appropriateness tools and surgeon's decisions were evaluated.

RESULTS

There were 368 patients enrolled, and contrasting rates of being "appropriate" for surgery were identified between the Escobar (n = 109, 29.6%) and AAOS (n = 292, 79.3%) tools. Surgeon agreement with the Escobar tool was substantial (ĸ = 0.61, 95%CI: 0.53-0.69) compared to slight with the AAOS tool (ĸ = 0.11, 95%CI: 0.06-0.16). Of those advised against TKA (n = 179, 48.6%), the AAOS tool suggested many patients (n = 111, 62.0%) were "appropriate" compared to the Escobar tool (n = 12, 6.7%).

CONCLUSIONS

Surgeons rated patients seeking opinion for TKA as appropriate over half the time, however the AAOS tool had low correlation with surgeons as opposed to the Escobar tool. This was illustrated by both tools rating a majority of patients to be operated on as appropriate, but only the AAOS tool considering most patients not chosen for surgery to be appropriate. When comparing previously published appropriateness rates, appropriateness in Australia, USA, Spain and Qatar was found to be similar.

Development and Underlying Structure of a Second-Generation Appropriateness Classification System for Total Knee Arthroplasty

OBJECTIVE

Evidence supports the validity of total knee arthroplasty (TKA) appropriateness classification based on the RAND Corporation and University of California Los Angeles system.The system, however, is ~2 decades old, and the science and clinical application of TKA has changed dramatically. We undertook this study to describe the methods used to develop a second-generation system and to examine the structure of the system to determine the extent to which each of the indication criteria informed appropriateness.

METHODS

Multivariable multinomial regression analyses determined the extent to which each of the 8 individually analyzed indication criteria informed appropriateness judgments. Classification tree analysis illustrates how the indication criteria, in combination, led to judgments of appropriate, inappropriate, or uncertain.

RESULTS

An expert panel selected 8 indication criteria (i.e., age, knee pain, function, radiographic osteoarthritis severity, osteoarthritis location, psychological factors, pain catastrophizing, and comorbidities). A total of 1,008 clinical scenarios were written, based on the criteria. Regression analyses indicated that age, knee pain, function, and radiographic severity dominated prediction of appropriateness, while the other criteria played a smaller role. Classification tree analysis confirmed the regression findings.

CONCLUSION

Our second-generation classification system, which incorporates contemporary indicators of TKA prognosis and risk, demonstrated preliminary evidence for utility in clinical practice.

Online Decision Aids for Knee Arthroplasty: An Environmental Scan

BACKGROUND

Knee arthroplasty is a high-risk, resource-intensive procedure that should be reserved for patients in whom the benefit will outweigh the risks. The provision of high-quality, publicly available decision aids can help patients to balance the benefits against the harms of treatments and to assist informed decision-making. The aim of this study was to identify and evaluate the content and readability of freely available knee arthroplasty decision aids.

METHODS

A systematic search using an environmental scan methodology of publicly available online materials was performed in December 2018. Included materials were assessed for quality using the International Patient Decision Aid Standards instrument (IPDASi), understandability and actionability from a patient's perspective using the Patient Education Materials Assessment Tool (PEMAT), and readability grade level using the Flesch-Kincaid Grade Level and the Gunning Fog Index.

RESULTS

Of 761 online materials screened, 26 decision aids were identified. Only 18 (69%) may be considered to meet criteria to be defined as a decision aid and 4 (15%) met criteria suggesting that the material did not introduce potential harmful bias according to the IPDASi. The mean score (and standard deviation) for all decision aids was 74% ± 12% for understandability and 44% ± 19% for actionability using the PEMAT. Readability indices indicated a mean minimum reading level of Grade 10 (10.8 ± 2.5). No decision aid included a wait-and-see option.

CONCLUSIONS

Few high-quality decision aids exist for patients considering knee arthroplasty and none include a wait-and-see option. Many do not provide actionable options and are pitched at above-average reading levels. Developers need to address these issues to encourage high-quality decision-making, especially for those with low health literacy.

Treatment of type III supracondylar humerus fractures: adherence and limitations of American Academy of Orthopedic Surgeons Appropriate Use Criteria App

The American Academy of Orthopedic Surgeons (AAOS) published Appropriate Use Criteria (AUC) in 2014 to aid physicians in the management of pediatric supracondylar humerus fractures. AUC should be evaluated in real practice, and if necessary modified based on identified problems. This study compares AAOS AUC recommendations with actual treatment performed in a cohort of patients treated for type III supracondylar humerus fractures. Medical record review of patients treated for type III supracondylar humerus fractures at our hospital from 2009 to 2016. Criteria required by the AAOS AUC were collected and entered into the AAOS AUC web-based application to determine the 'appropriateness' and score of each treatment. These were compared with the actual treatment the patient received. Over the study period, 585 patients (mean age: 6.5 years, 51% male, 49% female) were treated for type III supracondylar humerus fractures. Of the 585 cases, 561 (95.9%) were classified as 'appropriate', 24 (4.1%) as 'maybe appropriate', and 0 (0%) as 'rarely appropriate'. Of the 'maybe appropriate' cases there was a significant decrease in the proportion that deviated from the AUC over time (P = 0.0076). The main reasons for deviation were that an open reduction was performed due to difficulty with closed reduction (75% of deviations) or the surgery was not performed emergently (25% of deviations). The vague definition of 'emergent' and not allowing for open reduction if needed are limitations of the AUC that should be clarified or improved by the AAOS.

Association between the appropriateness of surgery, according to appropriate use criteria, and patient-rated outcomes after surgery for lumbar degenerative spondylolisthesis

INTRODUCTION

Treatment failures in spine surgery are often attributable to poor patient selection and the application of inappropriate treatment. We used published appropriate use criteria (AUC) to evaluate the appropriateness of surgery in a large group of patients operated for lumbar degenerative spondylolisthesis (LDS) and to evaluate its association with outcome.

METHODS

This was a retrospective analysis of prospectively collected outcome data from patients operated in our Spine Centre, 2005-2012. Appropriateness of surgery was judged based on the AUC. Patients had completed the multidimensional Core Outcome Measures Index (COMI) before surgery and at 3 months' and 1, 2 and 5 years' follow-up (FU).

RESULTS

In total, 448 patients (69.8 ± 9.6 years; 323 (72%) women) were eligible for inclusion and the AUC could be applied in 393 (88%) of these. Surgery was considered appropriate (A) in 234 (59%) of the patients, uncertain/equivocal (U) in 90 (23%) and inappropriate (I) in 69 (18%). A/U patients had significantly (p < 0.05) greater improvements in COMI than I patients at each FU time point. The minimal clinically important change (MCIC) score for COMI was reached by 82% A, 76% U and 54% I patients at 1-year FU (p < 0.001, I vs A and U); the odds of achieving MCIC were 3-4 times greater in A/U patients than in I patients.

CONCLUSIONS

The results suggest a relationship between appropriateness of surgery for LDS and the improvements in COMI score after surgery. The findings require confirmation in prospective studies that also include a control group of non-operated patients.

Comparison of an Artificial Intelligence-Enabled Patient Decision Aid vs Educational Material on Decision Quality, Shared Decision-Making, Patient Experience, and Functional Outcomes in Adults With Knee Osteoarthritis: A Randomized Clinical Trial

IMPORTANCE

Decision aids can help inform appropriate selection of total knee replacement (TKR) for advanced knee osteoarthritis (OA). However, few decision aids combine patient education, preference assessment, and artificial intelligence (AI) using patient-reported outcome measurement data to generate personalized estimations of outcomes to augment shared decision-making (SDM).

OBJECTIVE

To assess the effect of an AI-enabled patient decision aid that includes education, preference assessment, and personalized outcome estimations (using patient-reported outcome measurements) on decision quality, patient experience, functional outcomes, and process-level outcomes among individuals with advanced knee OA considering TKR in comparison with education only.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial at a single US academic orthopedic practice included 129 new adult patients presenting for OA-related knee pain from March 2019 to January 2020. Data were analyzed from April to May 2020.

INTERVENTION

Patients were randomized into a group that received a decision aid including patient education, preference assessment, and personalized outcome estimations (intervention group) or a group receiving educational material only (control group) alongside usual care.

MAIN OUTCOMES AND MEASURES

The primary outcome was decision quality, measured using the Knee OA Decision Quality Instrument (K-DQI). Secondary outcomes were collaborative decision-making (assessed using the CollaboRATE survey), patient satisfaction with consultation (using a numerical rating scale), Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS JR) score, consultation time, TKR rate, and treatment concordance.

RESULTS

A total of 69 patients in the intervention group (46 [67%] women) and 60 patients in the control group (37 [62%] women) were included in the analysis. The intervention group showed better decisional quality (K-DQI mean difference, 20.0%; SE, 3.02; 95% CI, 14.2%-26.1%; P < .001), collaborative decision-making (CollaboRATE, 8 of 69 [12%] vs 28 of 60 [47%] patients below median; P < .001), satisfaction (numerical rating scale, 9 of 65 [14%] vs 19 of 58 [33%] patients below median; P = .01), and improved functional outcomes at 4 to 6 months (mean [SE] KOOS JR, 4.9 [2.24] points higher in intervention group; 95% CI, 0.8-9.0 points; P = .02). The intervention did not significantly affect consultation time (mean [SE] difference, 2.23 [2.18] minutes; P = .31), TKR rates (16 of 69 [23%] vs 7 of 60 [12%] patients; P = .11), or treatment concordance (58 of 69 [84%] vs 44 of 60 [73%] patients; P = .19).

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, an AI-enabled decision aid significantly improved decision quality, level of SDM, satisfaction, and physical limitations without significantly impacting consultation times, TKR rates, or treatment concordance in patients with knee OA considering TKR. Decision aids using a personalized, data-driven approach can enhance SDM in the management of knee OA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03956004.

Protocol for systematic review: patient decision aids for total hip and knee arthroplasty decision-making

BACKGROUND

Total hip and knee arthroplasty are a highly performed surgery; however, patient satisfaction with surgery results and patient involvement in the decision-making process remains low. Patient decision aids (PtDAs) are tools used in clinical practices to facilitate active patient involvement in healthcare decision-making. Nonetheless, PtDA effects have not been systematically evaluated for hip and knee total joint arthroplasty (TJA) decision-making. The aim of this systematic review is to determine the effect of patient decision aids compared to alternative of care on quality and process of decision-making when provided to adults with hip and knee osteoarthritis considering primary elective TJA.

METHODS

This systematic review will follow the Cochrane Handbook for Systematic Reviews. This protocol was reported based on the PRISMA-P checklist guidelines. Studies will be searched in CINAHL, MEDLINE, Embase, PsycINFO, and Web of Science. Eligible studies will be randomized control trial (RCT) evaluating the effect of PtDA on TJA decision-making. Descriptive and meta-analysis of outcomes will include decision quality (knowledge and values-based choice), decisional conflict, patient involvement, decision-making process satisfaction, actual decision made, health outcomes, and harm(s). Risk of bias will be evaluated with Cochrane's risk of bias tool for RCTs. Quality and strength of recommendations will be appraised with Grades of Recommendation, Assessment, Development and Evaluation (GRADE).

DISCUSSION

This review will provide a summary of RCT findings on PtDA effect on decision-making quality and process of adults with knee and hip osteoarthritis considering primary elective TJA. Further, it will provide evidence comparing different types of PtDA used for TJA decision-making. This review is expected to inform further research on joint replacement decision-making quality and processes and on ways PtDAs facilitate shared decision-making for orthopedic surgery.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020171334.

Does Productivity-Based Physician Compensation Affect Surgical Rates for Elective Arthroplasty Surgery?

BACKGROUND

Surgeon compensation models could potentially influence the utilization of elective procedures. We assessed whether transitioning from salaried to a relative value unit (RVU) productivity-based physician compensation model changed the surgical rate and patient selection in elective total hip and knee arthroplasty (THA and TKA) procedures.

METHODS

Our institution transitioned from salaried to RVU productivity-based reimbursement in July 2016. We performed a retrospective analysis on patients undergoing primary THA and TKA from July 2014 to July 2018 before and after the transition (salary period n = 820; RVU period n = 1188). Beta regression was used to determine the reimbursement structure as a predictor of surgery. The surgical rate was defined as the number of primary THA and TKA procedures per reimbursement period divided by all arthroplasty and osteoarthritis outpatient clinic encounters.

RESULTS

There was a surgical rate of 15.8% (95% confidence interval [CI] 13.8%-17.8%) THA and 16.7% (95% CI 15.1%-18.1%) TKA procedures during RVU reimbursement compared to 11.1% (95% CI 9.8%-12.8%) THA and 11.7% (95% CI 10.5%-12.8%) TKA procedures during the salaried period (P < .001). The adjusted odds of undergoing a THA or TKA procedure increased in the RVU compared to the salaried model (THA odds ratio 1.48, 95% CI 1.43-1.53; TKA odds ratio 1.50, 95% CI 1.46-1.55; P < .001). There were no significant differences in patient age, gender, race, body mass index, or Charlson Comorbidity Index in salaried vs RVU productivity periods (P > .05 for all covariates).

CONCLUSIONS

Productivity-based physician compensation may encourage higher rates of elective arthroplasty procedures without broadening patient selection.

Advanced decision-making using patient-reported outcome measures in total joint replacement

Up to one-third of total joint replacement (TJR) procedures may be performed inappropriately in a subset of patients who remain dissatisfied with their outcomes, stressing the importance of shared decision-making. Patient-reported outcome measures capture physical, emotional, and social aspects of health and wellbeing from the patient's perspective. Powerful computer systems capable of performing highly sophisticated analysis using different types of data, including patient-derived data, such as patient-reported outcomes, may eliminate guess work, generating impactful metrics to better inform the decision-making process. We have created a shared decision-making tool which generates personalized predictions of risks and benefits from TJR based on patient-reported outcomes as well as clinical and demographic data. We present the protocol for a randomized controlled trial designed to assess the impact of this tool on decision quality, level of shared decision-making, and patient and process outcomes. We also discuss current concepts in this field and highlight opportunities leveraging patient-reported data and artificial intelligence for decision support across the care continuum.

Predicting knee replacement in participants eligible for disease-modifying osteoarthritis drug treatment with structural endpoints

OBJECTIVE

Evaluate associations between 2-year change in radiographic or quantitative magnetic resonance imaging (qMRI) structural measures, and knee replacement (KR), within a subsequent 7-year follow-up period.

METHOD

Participants from the Osteoarthritis Initiative were selected based on potential eligibility criteria for a disease-modifying osteoarthritis (OA) drug trial: Kellgren-Lawrence grade 2 or 3; medial minimum joint space width (mJSW) ≥2.5 mm; knee pain at worst 4-9 in the past 30 days on an 11-point scale, or 0-3 if medication was taken for joint pain; and availability of structural measures over 2 years. Mean 2-year change in structural measures was estimated and compared with two-sample independent t-tests for KR and no KR. Area under the receiver operating characteristic curve (AUC) was estimated using 2-year change in structural measures for prediction of future KR outcomes.

RESULTS

Among 627 participants, 107 knees underwent KR during a median follow-up of 6.7 years after the 2-year imaging period. Knees that received KR during follow-up had a greater mean loss of cartilage thickness in the total femorotibial joint and medial femorotibial compartment on qMRI, as well as decline in medial fixed joint space width on radiographs, compared with knees that did not receive KR. These imaging measures had similar, although modest discrimination for future KR (AUC 0.62, 0.60, and 0.61, respectively).

CONCLUSIONS

2-year changes in qMRI femorotibial cartilage thickness and radiographic JSW measures had similar ability to discriminate future KR in participants with knee OA, suggesting that these measures are comparable biomarkers/surrogate endpoints of structural progression.

Denosumab Prevents Early Periprosthetic Bone Loss After Uncemented Total Hip Arthroplasty: Results from a Randomized Placebo-Controlled Clinical Trial

Implant loosening is the most common indication for revision surgery after total hip arthroplasty (THA). Although bone resorption around the implants plays a pivotal role in the pathophysiology of loosening, it is unknown whether potent early inhibition of osteoclasts could mitigate this process and thus reduce the need for revision surgery. We performed a randomized, double-blind, placebo-controlled phase 2 trial in 64 patients aged 35 to 65 years with unilateral osteoarthritis of the hip. They underwent surgery with an uncemented THA and were randomized to either two subcutaneous doses of denosumab (n = 32) or placebo (n = 32) given 1 to 3 days and 6 months after surgery. Patients were followed for 24 months. Primary outcome was periprosthetic bone mineral density (BMD) of the hip at 12 months as measured by dual-energy X-ray absorptiometry (DXA). In addition, [¹⁸ F] sodium fluoride positron emission tomography/CT (F-PET) was performed in half of the patients for analysis of periprosthetic standardized uptake value (SUV). Analyses were made according to intention-to-treat principles. The trial was registered at ClinicalTrials.gov 2011-001481-18, NCT01630941. Denosumab potently inhibited early periprosthetic bone loss. After 12 months, BMD in the denosumab group was 32% (95% confidence interval [CI] 22-44) higher in Gruen zone 7 and 11% (95% CI 8-15) higher in zones 1 to 7. After 24 months, the difference in BMD between groups had decreased to 15% (95% CI 4-27) in zone 7 and 4% (95% CI 0-8) in zones 1 to 7. In both groups, SUV increased after surgery, but the increase was less pronounced in the denosumab group. Biochemical markers of bone metabolism decreased in the denosumab group in the first 12 months, but a rebound effect with marker concentrations above baseline was observed after 24 months. Denosumab potently prevents early periprosthetic bone loss after uncemented THA; however, the effect diminishes after discontinuation of treatment. Further research is needed to determine whether this bone loss will prove to be of clinical importance and, if so, whether the positive effect observed in this study could be preserved by either prolonged treatment with denosumab or additional antiresorptive treatment. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.

Regional differences between the US, Scandinavia, and South Korea in patient demographics and patient-reported outcomes for primary total knee arthroplasty

INTRODUCTION

Differences in total knee arthroplasty (TKA) patient demographics and clinical outcomes may exist between international regions, yet research is limited. The aim of this study was, therefore, to compare TKA patient demographics and patient-reported outcome measure (PROM) scores between the US, Scandinavia, and South Korea.

MATERIALS AND METHODS

A total of 398 TKA patients from three regions were assessed: 169 in Scandinavia (3 centers), 129 in the US (3 centers), and 100 patients in South Korea (2 centers). Regional variation in patient demographics was assessed using Kruskal-Wallis H tests. Regional variation in PROM scores from preoperative, 1-, 3- and 5-year visits was assessed using piecewise linear mixed effect models. The PROMs analyzed were a numerical rating scale for satisfaction and the Knee Osteoarthritis Outcome Score.

RESULTS

South Korean patients were the oldest (p < 0.001) and had the highest Charnley class (p < 0.001); US patients had the highest BMI (p < 0.001); Scandinavian patients had the lowest preoperative KL grade (p < 0.001). Scandinavian patients were associated with better preoperative and worse postoperative PROM scores. Scandinavian patients were also associated with moderately lower levels of satisfaction. These differences were lessened but remained significant after controlling for relevant demographic and surgical factors.

CONCLUSIONS

Regional differences were found in TKA patient demographics and PROMs between the US, Scandinavia, and South Korea. The regional differences in patient demographics support the need for more research and clear guidelines related to TKA appropriateness criteria. The better preoperative and worse postoperative Scandinavian PROM scores may have been related to their less severe KL grade but might also reflect cultural differences in how patients reflect on their health state when answering PROMs. Clinicians should be aware of these international differences in PROM scores when interpreting studies conducted in different international regions. Future studies should investigate TKA variation between more international regions and assess intraregional variation.

LEVEL OF EVIDENCE

Level III.

Increased early mortality and morbidity after total hip arthroplasty in patients with socioeconomic disadvantage: a report from the Swedish Hip Arthroplasty Register

Background and purpose - Socioeconomic status is associated with the outcome of major surgery. We investigated the association of socioeconomic status with the risk of early mortality and readmissions after primary total hip arthroplasty (THA). Patients and methods - We obtained information on income, education, immigration, and cohabiting status as well as comorbidities of 166,076 patients who underwent primary THA due to primary osteoarthritis (OA) from the Swedish Hip Arthroplasty Register, the Swedish National Inpatient Register and Statistics Sweden. Multivariable Cox regression models were fitted to estimate the adjusted risk of mortality or readmissions within 90 days after index surgery. Results - Compared with patients on a low income, the adjusted risk of 30-day mortality was considerably lower in patients on a high income (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3-0.7) and in those on a medium income (HR 0.7, CI 0.6-0.9). Similar risk reductions were found for the endpoint 90-day mortality. Patients with a high income had a lower adjusted risk of readmission for cardiovascular reasons than those with a low income (HR 0.7, CI 0.6-0.9), as had those with a higher level of education (adjusted HR 0.7, CI 0.6-0.9). Patients with higher socioeconomic status had a lower degree of comorbidities than socioeconomically disadvantaged patients. However, adjusting for socioeconomic confounders in multivariable models only marginally influenced the predictive ability of the models, as expressed by their area under the curve. Interpretation - Income and level of education are strongly associated with early mortality and readmissions after primary THA, and both parameters are closely connected to health status. Since adjustment for socioeconomic confounders only marginally improved the predictive ability of multivariable regression models our findings indicate that comorbidities may under certain circumstances serve as an acceptable proxy measure of socioeconomic background.

Appropriateness and Total Hip Arthroplasty: Determining the Structure of the American Academy of Orthopaedic Surgeons System of Classification

OBJECTIVE

In late 2017, the American Academy of Orthopaedic Surgeons (AAOS) published an appropriateness classification system using the RAND/University of California, Los Angeles (UCLA) approach for patients with hip osteoarthritis (OA). We determined the contribution of predictor variables in the system to final classification, rated as "appropriate," "may be appropriate," or "rarely appropriate" for hip arthroplasty.

METHODS

An AAOS-appointed expert panel developed 270 clinical vignettes incorporating all permutations of 5 evidence-driven indication variables associated with hip arthroplasty outcome or need. Indication variables were age, function-limiting pain severity, radiographic hip OA severity, hip motion, and presence of modifiable prognostic risk factors. Multinomial regression determined the relative contribution of each variable and a classification tree method determined variable combinations contributing to final classification.

RESULTS

Patient age and hip OA severity were the dominant predictors of appropriateness classification in both statistical models. Function-limiting pain made a slight contribution relative to age and hip OA severity while hip motion and the presence of modifiable prognostic factors did not meaningfully contribute to final classification. The regression model explained about 99% of the variance and the classification tree had an accuracy of 87.8%.

CONCLUSION

Classification for hip arthroplasty appropriateness in the AAOS system is driven almost exclusively by age and OA severity. Function-limiting pain, a major reason patients seek surgery, contributes only slightly to the AAOS appropriateness criteria. The system relies heavily on traditional variables of patient age and radiographic hip OA severity. Future study of actual patient outcomes is needed to further test the validity of the AAOS system.

Short-term functional recovery after total joint arthroplasty is unaffected by bundled payment participation

Background

Bundled payment models for lower extremity total joint arthroplasty (TJA) aim to improve value by decreasing costs via efficient care pathways. It is unclear how such models affect patient-centered outcomes such as functional recovery. We aimed to determine whether participation in bundled payment for TJA negatively affects patients’ functional recovery.

Methods

All patients, regardless of payer, undergoing elective TJA between July 2014 and December 2016 were identified retrospectively and categorized into prebundle (n = 680) and postbundle (n = 1216) cohorts. Mixed-effects linear regression and Wald postests were used to test for differences in patients’ functional recovery during the hospital period and over 12 months after TJA between cohorts. We also used multivariate regression to test for differences in hospital length of stay (LOS) and postacute care (PAC) facility use between cohorts.

Results

Compared with the prebundle cohort, patients in the postbundle cohort demonstrated a small and nonmeaningful difference in the trajectory of functional recovery in the hospital [χ²(3) = 31.3, P < .01] and no difference in the 12 months after TJA [χ²(3) = 3.9, P = .28]. They had a 0.4-day shorter hospital LOS (95% confidence interval: −0.5, −0.3) and decreased odds for PAC facility use (adjusted odds ratio = 0.3; 95% confidence interval: 0.2, 0.4).

Conclusions

Participation in bundled payment for TJA was not associated with significant changes in patients’ functional recovery, an important patient-centered outcome. For the postbundle cohort, hospital LOS and PAC facility use were decreased, consistent with previous studies describing cost-saving strategies in bundled payment. These findings support the need for an ongoing study of the long-term sustainability of these value-based payment models.

Factors associated with the orthopaedic surgeon's decision to recommend total joint replacement in hip and knee osteoarthritis: an international cross-sectional study of 1905 patients

OBJECTIVE

To determine factors associated with orthopaedic surgeons' decision to recommend total joint replacement (TJR) in people with knee and hip osteoarthritis (OA).

DESIGN

Cross-sectional study in eleven countries. For consecutive outpatients with definite hip or knee OA consulting an orthopaedic surgeon, the surgeon's indication of TJR was collected, as well as patients' characteristics including comorbidities and social situation, OA symptom duration, pain, stiffness and function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), joint-specific quality of life, Osteoarthritis Research Society International (OARSI) joint space narrowing (JSN) radiographic grade (0-4), and surgeons' characteristics. Univariable and multivariable logistic regressions were performed to identify factors associated with the indication of TJR, adjusted by country.

RESULTS

In total, 1905 patients were included: mean age was 66.5 (standard deviation [SD], 10.8) years, 1082 (58.0%) were women, mean OA symptom duration was 5.0 (SD 7.0) years. TJR was recommended in 561/1127 (49.8%) knee OA and 542/778 (69.7%) hip OA patients. In multivariable analysis on 516 patients with complete data, the variables associated with TJR indication were radiographic grade (Odds Ratio, OR for one grade increase, for knee and hip OA, respectively: 2.90, 95% confidence interval [1.69-4.97] and 3.30 [2.17-5.03]) and WOMAC total score (OR for 10 points increase: 1.65 [1.32-2.06] and 1.38 [1.15-1.66], respectively). After excluding radiographic grade from the analyses, on 1265 patients, greater WOMAC total score was the main predictor for knee and hip OA; older age was also significant for knee OA.

CONCLUSION

Radiographic severity and patient-reported pain and function play a major role in surgeons' recommendation for TJR.

Gaps in appropriate use of treatment strategies in osteoarthritis

Optimal management of osteoarthritis (OA) requires a combination of therapies, with behavioral (e.g., exercise and weight management) and rehabilitative components at the core, accompanied by pharmacological treatments and, in later stages, consideration of joint replacement surgery. Although multiple sets of OA treatment guidelines have been developed, there are gaps in the implementation of these recommendations. Key areas of concern include the underuse of exercise, weight management, and other behavioral and rehabilitation strategies as well as the overuse of opioid analgesics. In this review, we describe the major categories of treatment strategies for OA, including self-management, physical activity, weight management, physical therapy and other rehabilitative therapies, pharmacotherapies, and joint replacement surgery. For each category, we discuss the current evidence base to report on appropriate use, data regarding adherence to treatment recommendations, and potential approaches to optimize use.

Neonatal screening and selective sonographic imaging in the diagnosis of developmental dysplasia of the hip

Aims

The aim of this prospective cohort study was to evaluate the effectiveness of the neonatal hip instability screening programme.

Patients and Methods

The study involved a four-year observational assessment of a neonatal hip screening programme. All newborns were examined using the Barlow or Ortolani manoeuvre within 72 hours of birth; those with positive findings were referred to a ‘one-stop’ screening clinic for clinical and sonographic assessment of the hip. The results were compared with previous published studies from this unit.

Results

A total of 124 newborns with a positive Barlow or Ortolani manoeuvre, clunk positive, or ‘unstable’ were referred. Five were found to have clinical instability of the hip. Sonographically, 92 newborns had Graf Type I hips, 12 had Graf Type II hips, and 20 had Graf Type IV hips. The positive predictive value (PPV) of clinical screening was 4.0% and the PPV of sonography was 16.1%. This has led to an increased rate of surgery for DDH.

Conclusion

Compared with previously published ten-year and 15-year studies, there has been a marked deterioration in the PPV in those referred with potential instability of the hip. There appears to be a paradox, with rising referrals and a decreasing PPV combined with an increasing rate of surgery in newborns with developmental dysplasia of the hip. Cite this article: Bone Joint J 2018;100-B:806–10.

Early Clinically Relevant Improvement in Quality of Life and Clinical Outcomes 1 Year Postsurgery in Patients with Knee and Hip Joint Arthroplasties

Objective To measure and identify the determinants of the outcomes after hip/knee arthroplasty (HA/KA) in patients with osteoarthritis during the first postsurgical year. Design In this prospective observational study, we evaluated the preoperative and postoperative (3, 6, and 12 months) outcomes of 626 patients who underwent HA (346 with median age 65 years, 59% female) or KA (280 with median age 66.5 years, 54% female) between 2008 and 2013. Generic and specific tools were used to measure health-related quality of life (HRQoL) and utility. Good outcome was defined as an improvement in WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) greater than or equal to the minimal important difference (MID). Regressions were performed to evaluate the relationship between preoperative and postoperative measures and evolution of WOMAC/good outcome. Results We observed an almost systematic improvement of all parameters for up to 12 months, but especially at the 3-month follow-up. The low number of comorbidities and the absence of postoperative complications were the common determinants of improvement of WOMAC total score after 12 months. Other parameters (background of the joint, preoperative function and length of hospital stay in KA group; place of discharge in HA group) affected the evolution of WOMAC scores. 87.09% of HA and 73.06% of KA patients experienced a good outcome. A small number of comorbidities, a worse preoperative function, a shortened hospital stay (KA only), and an absence of early postoperative complications (HA only) significantly predicted a good outcome. Conclusions Intermediate HRQoL following HA or KA improved quickly from preoperative levels for all instruments. More than 70% of patients achieved a good outcome defined as improved pain, stiffness and disability and the predictors are slightly close.

Appropriateness Criteria for Total Knee Arthroplasty: Additional Comments and Considerations

Appropriateness classification for total knee arthroplasty (TKA) has received substantial attention recently, and Katz and colleagues published an Orthopaedic Forum on the topic in The Journal of Bone & Joint Surgery in February 2017. Classifications of appropriateness are particularly important given the rapid rise in use of TKA and a variety of third-party payer approaches designed to control health-care costs. We respond to some of the concerns addressed by Katz and colleagues, and elaborate on what we believe are some important issues related to both older and newer appropriateness criteria for TKA.

Appropriateness and total knee arthroplasty: an examination of the American Academy of Orthopaedic Surgeons appropriateness rating system

OBJECTIVE

The American Academy of Orthopaedic Surgeons (AAOS) recently published appropriateness criteria for patients with knee osteoarthritis (OA) who are being considered for total knee arthroplasty (TKA). We evaluated the extent to which predictor variables used by the AAOS contribute to final classification, rated as "appropriate," "may be appropriate" or "rarely appropriate."

METHODS

The RAND/UCLA Appropriateness method was used by AAOS to develop 864 clinical vignettes, each incorporating eight evidence-based variables associated with TKA outcome or need. Variables included function-limiting pain severity, knee OA severity, knee motion and age among others. The contribution of each variable to the overall classification was determined using multinomial regression. A classification tree method was applied to determine the combinations of variables that contributed to final classification for each vignette.

RESULTS

Multinomial regression indicated that patient age, knee motion, OA severity and location were the four most powerful predictors of final classification. Function limiting pain, knee instability and lower limb alignment contributed little to the final classification. The classification tree had an accuracy of 86.7% and the most important contributors to classification were age, knee OA severity and pattern.

CONCLUSION

Function limiting pain, the most frequent reason endorsed by patients seeking TKA does not meaningfully contribute to the newly developed AAOS appropriateness criteria. The system is highly dependent on traditional variables that surgeons consider when evaluating patients for TKA: patient age, knee OA severity, knee OA pattern and knee motion.

In-situ Generated Tribomaterial in Metal/Metal Contacts: current understanding and future implications for implants

Artificial hip joints operate in aqueous biofluids that are highly reactive towards metallic surfaces. The reactivity at the metal interface is enhanced by mechanical interaction due to friction, which can change the near-surface structure of the metal and surface chemistry. There are now several reports in the literature about the in-situ generation of reaction films and tribo-metallurgical transformations on metal-on-metal hip joints. This paper summarizes current knowledge and provides a mechanistic interpretation of the surface chemical and metallurgical phenomena. Basic concepts of corrosion and wear are illustrated and used to interpret available literature on in-vitro and in-vivo studies of metal-on-metal hip joints. Based on this review, three forms of tribomaterial, characterized by different combinations of oxide films and organic layers, can be determined. It is shown that the generation of these tribofilms can be related to specific electrochemical and mechanical phenomena in the metal interface. It is suggested that the generation of this surface reaction layer constitutes a way to minimize (mechanical) wear of MoM hip implants.