OARSI/OMERACT initiative to define states of severity and indication for joint replacement in hip and knee osteoarthritis. An OMERACT 10 Special Interest Group

Using Two Predictive Models to Capture Two Types of Poor Outcomes in Knee Arthroplasty: A Multisite Longitudinal Cohort Study

OBJECTIVE

Poor outcome after knee arthroplasty (KA), a common major surgery worldwide, reportedly occurs in approximately 20% of patients. These patients demonstrate minimal improvement, at least moderate knee pain, and difficulty performing many routine daily activities. The purposes of our study were to comprehensively determine poor outcome risk after KA and to identify predictors of poor outcome.

METHODS

Data from 565 participants with KA in the Osteoarthritis Initiative and the Multicenter Osteoarthritis studies were used. Previously validated latent class analyses (LCAs) of good versus poor outcome trajectories of Western Ontario and McMaster Universities Arthritis Index (WOMAC) Pain and Disability were generated to describe minimal improvement and poor final outcome. The modified Escobar RAND appropriateness system was used to generate classifications of appropriate, inconclusive, and rarely appropriate. Multivariable prediction models included LCA-based good versus poor outcome, modified Escobar classifications, and evidence-driven preoperative prognostic variables.

RESULTS

Modified Escobar appropriateness classifications were nonsignificant predictors of WOMAC Pain good versus poor outcomes, indicating the methods provide independent outcome estimates. For WOMAC Pain and WOMAC Disability, approximately 34% and 45% of participants, respectively, had a high probability of either minimal improvement via "rarely appropriate" classifications or poor outcome via LCA. In multivariable prediction models, greater contralateral knee pain consistently predicted poor outcome (eg, odds ratio 1.21, 95% confidence interval 1.10-1.33).

CONCLUSION

Appropriateness criteria and LCA estimates provided combined poor outcome estimates that were approximately double the commonly reported poor outcome of 20%. Rates of poor outcome could be reduced if clinicians screened patients using appropriateness criteria and LCA predictors before surgery to optimize 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.

Retention of kinematic patterns during a 6-minute walk test in people with knee osteoarthritis

BACKGROUND

Knee osteoarthritis (OA) is a chronic condition affecting the entire joint and surrounding tissue, resulting in pain, stiffness and impaired movement. Recent studies have suggested the use of physical performance tests, such as the six-minute walk test (6MWT) to assess joint function for those with knee OA. This study assessed lower limb sagittal plane joint angles during a 6MWT for people with mild-moderate knee OA.

METHODS

Thirty-one participants (18 male, 13 female; 62.9 ± 8.4 years) with knee OA were recruited. Gait data were collected in a single session during which participants completed a 6MWT around a 20 m course. Sagittal plane joint angles for the hip, knee and ankle were calculated during the first and last minute of the 6MWT. Statistical parametric mapping (SPM) was used to investigate changes in kinematic traces over the gait cycle.

RESULTS

Mean joint angles for the hip and knee showed no significant differences between the first and last minute of the 6MWT. Ankle joint kinematic traces indicated there to be a decrease in plantarflexion approaching toe-off in the last minute of the test - a 1.5° reduction from the first minute. No significant differences were calculated for walking speed or joint range of motion.

DISCUSSION

The lack of significant change in joint kinematic parameters and walking speed suggests the relative fatigue and pain burden to the participant over the duration of the 6-minute period is insufficient to elicit any mechanical changes to walking gait.

Knee-extensor strength, symptoms, and need for surgery after two, four, or six exercise sessions/week using a home-based one-exercise program: a randomized dose-response trial of knee-extensor resistance exercise in patients eligible for knee replacement (the QUADX-1 trial)

OBJECTIVE

To investigate firstly the efficacy of three different dosages of one home-based, knee-extensor resistance exercise on knee-extensor strength in patients eligible for knee replacement, and secondly, the influence of exercise on symptoms, physical function and decision on surgery.

METHOD

One-hundred and forty patients eligible for knee replacement were randomized to three groups: 2, 4 or 6 home-based knee-extensor resistance exercise-sessions per week (group 2, 4 and 6 respectively) for 12 weeks.

PRIMARY OUTCOME

isometric knee-extensor strength.

SECONDARY OUTCOMES

Oxford Knee Score, Knee injury and Osteoarthritis Outcome Score, average knee pain last week (0-10 numeric rating scale), 6-min walk test, stair climbing test, exercise adherence and "need for surgery".

RESULTS

Primary analysis: Intention-to-treat analysis of 140 patients did not find statistically significant differences between the groups from baseline to after 12 weeks of exercise in isometric knee-extensor strength: Group 2 vs 4 (0.003 Nm/kg (0.2%) [95% CI -0.15 to 0.15], P = 0.965) and group 4 vs 6 (-0.04 Nm/kg (-2.7%) [95% CI -0.15 to 0.12], P = 0.628). Secondary analysis: Intention-to-treat analyses showed statistically significant differences between the two and six sessions/week groups in favor of the two sessions/week group for Oxford Knee Score: 4.8 OKS points (15.2%) [1.3 to 8.3], P = 0.008) and avg. knee pain last week (NRS 0-10): -1.3 NRS points (-19.5%) [-2.3 to -0.2], P = 0.018. After the 12-week exercise intervention, data were available for 117 patients (N = 39/group): 38 (32.5%) patients wanted surgery and 79 (67.5%) postponed surgery. This was independent of exercise dosage.

CONCLUSION

In patients eligible for knee-replacement we found no between-group differences in isometric knee extensor strength after 2, 4 and 6 knee-extensor resistance exercise sessions per week. We saw no indication of an exercise dose-response relationship for isometric knee-extensor strength and only clinically irrelevant within group changes. For some secondary outcome (e.g., KOOS subscales) we found clinically relevant within group changes, which could help explain why only one in three patients decided to have surgery after the simple home-based exercise intervention.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02931058. Preprint: https://doi.org/10.1101/2021.04.07.21254965.

Risk factors associated with the occurrence of total knee arthroplasty in patients with knee osteoarthritis: a nested case–control study

Objectives:

The aim of this study was to investigate changes over time in osteoarthritis risk factors most closely associated with the occurrence of total knee arthroplasty (TKA). We hypothesize that the robustness of a longitudinal case–control study will provide new information on the association between changes in various clinical and structural parameters in different time frames before TKA.

Methods:

Cases (195; TKA after cohort entry) and controls (468) matched for age, gender, income, WOMAC pain, Kellgren–Lawrence grade and follow-up duration were from the Osteoarthritis Initiative cohort. Associations between changes in sociodemographic, clinical, imaging and osteoarthritis therapies with the occurrence of TKA were performed using conditional logistic regression analyses.

Results:

Worsening of WOMAC scores (cOR 1.02–1.20, p ⩽ 0.012), KOOS (1.02–1.04, p ⩽ 0.014), knee injuries sustained in the previous 30–40 years (women 2.70, p = 0.034) and valgus alignment (1.10, p = 0.052) were associated with the occurrence of TKA. Also associated with TKA was cartilage volume loss in the lateral (overall 1.76, p = 0.025; women 1.93, p = 0.047) and medial compartments (⩾10%, overall 1.54, p = 0.027; men 2.34, p = 0.008), occurrence of medial meniscal extrusion (overall 1.77, p = 0.046; men 2.86, p = 0.028), and increase in bone marrow lesions (BMLs) for women (1.09, p = 0.048). The association of risk factors with TKA was reinforced when both an increase in WOMAC pain and cartilage volume loss (1.85, p = 0.001) were combined. Pain medication usage, mainly narcotics and intra-articular steroid injections (IASI), was also associated with TKA, with no impact on changes in cartilage loss or structure.

Conclusion:

This study provides new information about gender differences in risk factors associated with the occurrence of TKA. Worsening of valgus alignment, cartilage volume loss in the lateral compartment, BMLs and older injuries are important risk factors in women, while medial compartment cartilage loss and meniscal extrusion are in men. The use of pain medication and IASI although associated was found not causal with TKA.

Association Between Knee Joint Muscle Activation and Knee Joint Moment Patterns During Walking in Moderate Medial Compartment Knee Osteoarthritis: Implications for Secondary Prevention

OBJECTIVE

To determine associations between knee moment features linked to osteoarthritis (OA) progression, gait muscle activation patterns, and strength.

DESIGN

Cross-sectional secondary analysis.

SETTING

Gait laboratory.

PARTICIPANTS

Convenience sample of 54 patients with moderate, medial knee OA (N=54).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Knee moments and quadriceps and hamstrings activation were examined during walking. Knee extensor and flexor strength were measured. Waveform patterns were extracted using principal component analysis. Each measured waveform was scored against principal components (PCs) that captured overall magnitude (PC1) and early to midstance difference (PC2) features, with higher PC2 scores interpreted as greater moment differential and more prolonged muscle activity. Correlations were calculated between moment PC scores and muscle PC and strength scores. Regression analyses determined moment PC score variance explained by muscle PC scores and strength.

RESULTS

All correlations for knee adduction moment difference feature (KAMPC2) and prolonged muscle activity (PC2) were significant (r=-0.40 to -0.54). Knee flexion moment difference feature (KFMPC2) was significantly correlated with all quadriceps and medial hamstrings PC2 scores (r=-0.47 to -0.61) and medial hamstrings magnitude feature (PC1) (r=-0.52). KAMPC2 was significantly correlated with knee flexor strength (r=0.43), and KFMPC2 was significantly correlated with knee extensor (r=0.60) and flexor (r=0.55) strength. Regression models including muscle PC2 scores and knee flexor strength explained 46% of KAMPC2 variance, whereas muscle PC2 scores and knee extensor strength explained 59% of KFMPC2 variance.

CONCLUSIONS

Muscle activation patterns and strength explained significant variance in moment difference features, highest for the knee flexion moment. This supports that exercises such as neuromuscular training, focused on appropriate muscle activation patterns, and strengthening have the potential to alter dynamic loading gait patterns associated with knee OA clinical progression.

Osteoarthritis Research Society International (OARSI): Past, present and future

We provide a detailed account of the origin and establishment of the Osteoarthritis Research Society International (OARSI) and celebrate its history from inception to the current day. We discuss the mission, vision and strategic objectives of OARSI and how these have developed and evolved over the last 3 decades. We celebrate the achievements of the society as we approach its 30th birthday, honor the entire presidential line and respectfully pay tribute to the past presidents who are no longer with us. We reflect on the strong foundations of our society, OARSI's efforts to disseminate understanding of the health, disability and economic burdens of osteoarthritis (OA) to policymakers, and the exciting initiatives to make the society inclusive and international. We thank our corporate and industrial sponsors, who have supported us over many years, without whom our annual congresses would not have been possible. We celebrate our longstanding strategic partnership with our publisher, Elsevier, and the successful launch of our new journal Osteoarthritis and Cartilage Open, the most significant new development in our dissemination toolbox. For the first time in the history of the organization, our annual congress was cancelled in April 2020 and the 2021 meeting will be virtual. Despite the numerous challenges posed by the ongoing COVID-19 pandemic and the need to adapt quickly to a rapidly changing landscape, we must remain optimistic about the future. We will take advantage of new exciting opportunities to advance our mission and vision to enhance the quality of life of persons with OA.

[Decision for total hip arthroplasty-the surgeons' view]

BACKGROUND

The decision for total hip arthroplasty (THA) is based on pain, loss of function, radiological changes and failed conservative therapy. These criteria are rarely based on systematic research and have not been integrated in generally accepted treatment guidelines. Aim of our study was, therefore, to analyse which decision criteria German orthopaedic and trauma surgeons use in order to recommend THA for patients with hip osteoarthritis.

MATERIALS AND METHODS

From 10/2019 to 07/2020 we conducted a nation-wide survey among 218 orthopaedic and trauma surgeons about their criteria for and against THA surgery, as well as their treatment objectives.

RESULTS

147 fully completed questionnaires were analysed. Pain (99%), limitation of movement (99%), as well as impairment of walking distance (97%), and the subjective burden (97%) were the most frequent criteria. 97% and 96% of surgeons consider prescription of analgesics and physical therapy, as well as a lack of their effectiveness, as criteria for THA. 87% see radiological changes grade Kellgren & Lawrence III as threshold. A recommendation against surgery is triggered by obesity (BMI ≥ 40 kg/m²) in 48% and by the presence of an active infection in 96%.

CONCLUSIONS

Current surgeons' practice criteria of recommendations for THA in Germany seem to reflect widely nationally and internationally discussed recommendations. Particular attention is given to patient factors like pain, loss of function and subjective burden, as well as previous conservative treatment and contraindications, like poorly controlled diabetes or an active infection, whereas morbid obesity is not seen as contraindication by all surgeons.

Concept Endpoints Informing Design Considerations for Confirmatory Clinical Trials in Osteoarthritis

OBJECTIVE

There is an unmet need for therapies that target the underlying pathophysiology of osteoarthritis (OA). However, defining appropriate measures for clinical trials of such therapies is challenging. Our objective is to propose concept clinical endpoints that directly capture clinical benefit in this setting and evaluate the feasibility of their use.

METHODS

This analysis used the multi-center, longitudinal, observational Osteoarthritis Initiative (OAI) database. OAI participants primarily had knee OA, with follow-up of up to nine years and assessments of joints, surgical interventions, performance outcomes, and patient-reported outcomes (PROs). We examined this dataset to identify existing outcome measures of direct clinical benefit. We evaluated the feasibility of conducting trials using these candidate endpoints by estimating incidence rates and resulting required sample sizes and study durations in time-to-event analyses.

RESULTS

We identified candidate endpoints based on total knee replacement (TKR) and composite endpoints defined by TKR and conservative thresholds of PROs of pain and function. Using time to TKR as an endpoint, a study with an average follow-up time of three years requires approximately 3,000 to 18,000 subjects depending on effect size. Alternatively, a composite endpoint such as 'time to TKR or severe pain or severely impaired functioning', the required sample sizes ranged from approximately 2,000 to 11,000 for a three-year study.

CONCLUSION

The proposed concept endpoints can reliably and feasibly evaluate effectiveness of therapies for this unmet need. In particular, the composite endpoint approach can substantially reduce sample sizes (up to approximately 40%) compared to the use of TKR alone.

The Arthroplasty Candidacy Help Engine tool to select candidates for hip and knee replacement surgery: development and economic modelling

BACKGROUND

There is no good evidence to support the use of patient-reported outcome measures (PROMs) in setting preoperative thresholds for referral for hip and knee replacement surgery. Despite this, the practice is widespread in the NHS.

OBJECTIVES/RESEARCH QUESTIONS

Can clinical outcome tools be used to set thresholds for hip or knee replacement? What is the relationship between the choice of threshold and the cost-effectiveness of surgery?

METHODS

A systematic review identified PROMs used to assess patients undergoing hip/knee replacement. Their measurement properties were compared and supplemented by analysis of existing data sets. For each candidate score, we calculated the absolute threshold (a preoperative level above which there is no potential for improvement) and relative thresholds (preoperative levels above which individuals are less likely to improve than others). Owing to their measurement properties and the availability of data from their current widespread use in the NHS, the Oxford Knee Score (OKS) and Oxford Hip Score (OHS) were selected as the most appropriate scores to use in developing the Arthroplasty Candidacy Help Engine (ACHE) tool. The change in score and the probability of an improvement were then calculated and modelled using preoperative and postoperative OKS/OHSs and PROM scores, thereby creating the ACHE tool. Markov models were used to assess the cost-effectiveness of total hip/knee arthroplasty in the NHS for different preoperative values of OKS/OHSs over a 10-year period. The threshold values were used to model how the ACHE tool may change the number of referrals in a single UK musculoskeletal hub. A user group was established that included patients, members of the public and health-care representatives, to provide stakeholder feedback throughout the research process.

RESULTS

From a shortlist of four scores, the OHS and OKS were selected for the ACHE tool based on their measurement properties, calculated preoperative thresholds and cost-effectiveness data. The absolute threshold was 40 for the OHS and 41 for the OKS using the preferred improvement criterion. A range of relative thresholds were calculated based on the relationship between a patient's preoperative score and their probability of improving after surgery. For example, a preoperative OHS of 35 or an OKS of 30 translates to a 75% probability of achieving a good outcome from surgical intervention. The economic evaluation demonstrated that hip and knee arthroplasty cost of < £20,000 per quality-adjusted life-year for patients with any preoperative score below the absolute thresholds (40 for the OHS and 41 for the OKS). Arthroplasty was most cost-effective for patients with lower preoperative scores.

LIMITATIONS

The ACHE tool supports but does not replace the shared decision-making process required before an individual decides whether or not to undergo surgery.

CONCLUSION

The OHS and OKS can be used in the ACHE tool to assess an individual patient's suitability for hip/knee replacement surgery. The system enables evidence-based and informed threshold setting in accordance with local resources and policies. At a population level, both hip and knee arthroplasty are highly cost-effective right up to the absolute threshold for intervention. Our stakeholder user group felt that the ACHE tool was a useful evidence-based clinical tool to aid referrals and that it should be trialled in NHS clinical practice to establish its feasibility.

FUTURE WORK

Future work could include (1) a real-world study of the ACHE tool to determine its acceptability to patients and general practitioners and (2) a study of the role of the ACHE tool in supporting referral decisions.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Differences in Baseline Joint Moments and Muscle Activation Patterns Associated With Knee Osteoarthritis Progression When Defined Using a Clinical Versus a Structural Outcome

Both structural and clinical changes can signify knee osteoarthritis progression; however, these changes are not always concurrent. A better understanding of mechanical factors associated with progression and whether they differ for structural versus clinical outcomes could lead to improved conservative management. This study examined baseline gait differences between progression and no progression groups defined at an average of 7-year follow-up using 2 different outcomes indicative of knee osteoarthritis progression: radiographic medial joint space narrowing and total knee arthroplasty. Of 49 individuals with knee osteoarthritis who underwent baseline gait analysis, 32 progressed and 17 did not progress using the radiographic outcome, while 13 progressed and 36 did not progress using the arthroplasty outcome. Key knee moment and electromyography waveform features were extracted using principal component analysis, and confidence intervals were used to examine between-group differences in these metrics. Those who progressed using the arthroplasty outcome had prolonged rectus femoris and lateral hamstrings muscle activation compared with the no arthroplasty group. Those with radiographic progression had greater mid-stance internal knee rotation moments compared with the no radiographic progression group. These results provide preliminary evidence for the role of prolonged muscle activation in total knee arthroplasty, while radiographic changes may be related to loading magnitude.

[Prescription frequency of physical therapy and analgesics before total hip and knee arthroplasy : An epidemiological analysis of routine health care data from Germany]

BACKGROUND

Osteoarthritis of the hip or knee joint is a widespread disease with a strong influence on the quality of life. At present, the extent of conservative treatment with physical therapies and analgesics before the use of a total joint arthroplasty (TJA) of the hip or knee is largely unclear in Germany.

OBJECTIVES

The aim was to analyze the prescription frequency according to regional and socio-demographic factors.

MATERIALS AND METHODS

Based on routine health care data from BARMER insurance, patients who received a TJA of the hip or knee from 2011 to 2013 were analyzed. Included were consistently insured patients with the main discharge diagnosis of osteoarthritis who did not receive any further TJA for eight quarters before and after replacement. The prescription frequency of physical therapies and analgesics, stratified according to age groups, gender, number of comorbidities and federal state was analyzed.

RESULTS

40,242 persons with hip TJA and 35,652 persons with knee TJA were included. In the year prior to surgery, 49.4% of patients (hip TJA: 49.9%; knee TJA: 48.9%) received at least one physical therapy and 81.0% were prescribed analgesics. Regionally, the prescription frequency of physical therapies for hip TJA varied between 35.7% (Bremen) and 70.6% (Saxony) and for knee TJA between 37.6% (Saarland) and 66.9% (Saxony).

CONCLUSION

The prescription frequency of physical therapy does not fully correspond to current treatment recommendations. The prescription of physical therapies in the year before the TEP shows regional differences, with fundamentally lower prescription frequencies in the former states of West Germany.

A 12-item short form of the Hip disability and Osteoarthritis Outcome Score (HOOS-12): tests of reliability, validity and responsiveness

OBJECTIVE

To evaluate reliability, validity and responsiveness of HOOS-12, a 12-item short form of the 40-item Hip disability and Osteoarthritis Outcome Score (HOOS). HOOS-12 provides Pain, Function and Quality of Life (QOL) scale scores and a summary hip impact score.

DESIGN

Data from 1,273 FORCE-TJR hip osteoarthritis (OA) patients who completed HOOS before and six and 12 months after total hip replacement (THR) were analyzed. HOOS-12 includes a pain frequency item and three items measuring pain during increasingly difficult (sitting/lying, walking, stairs) activities; function items about standing, rising from sitting, getting in/out of a car, and walking on an uneven surface; and the 4-item HOOS QOL scale. Percent computable scale scores, floor and ceiling effects, internal consistency reliability, validity (scale correlations, tests of known groups validity using one-way analysis of variance (ANOVA)), and responsiveness (effect sizes (ES), standardized response means (SRM)) were compared for HOOS-12, full-length HOOS, HOOS-PS and HOOS, JR.

RESULTS

Internal consistency reliability was above 0.70 for all HOOS-12 scales and above 0.90 for the HOOS-12 Summary score. Validity and responsiveness of HOOS-12 Pain, Function and QOL scales were satisfactory and reached similar conclusions as comparable full-length HOOS scales. The HOOS-12 Summary score was highly responsive in discriminating between groups who differed in global ratings of post-THR change in physical capabilities and had high ES and SRM standardized response means.

CONCLUSIONS

HOOS-12 was a reliable and valid alternative to HOOS in THR patients with moderate to severe OA and provided three domain-specific and summary hip impact scores with substantially reduced respondent burden.

Prevalence and treatment of hip and knee osteoarthritis in people aged 60 years or older in Germany: an analysis based on health insurance claims data

Objective

Osteoarthritis (OA) is highly prevalent throughout the world, especially in the elderly population, and is strongly associated with patients’ frailty. However, little is known about the prevalence and treatment of OA in elderly patients in routine clinical care in Germany.

Materials and methods

As a part of Linking Patient-Reported Outcomes with CLAIms Data for Health Services Research in Rheumatology (PROCLAIR), a cross-sectional study using claims data from a large Germany statutory health insurance (BARMER) was conducted. We included people aged 60 years or older and assessed the prevalence of OA of the hip or knee, defined as having outpatient diagnoses (ICD: M16 or M17) in at least two quarters of 2014. The use of conservative treatment, including analgesics and physical therapy, and total joint replacement was studied. Analyses were stratified by age, sex, comorbidities, and level of care dependency defined by social law.

Results

A total of 595,754 patients (mean age: 74.9 years; 69.8% female) were diagnosed with OA (21.8%), with the highest prevalence in those between 80 and 89 years (31.0%) and in females compared to males (23.9% vs 18.3%). Prevalence decreased with increasing level of care dependency from 30.5% in patients with a low level (0/1) to 18.7% in the highest level of care dependency. A total of 63.4% of the patients with OA received analgesics, with higher use with increasing age. Physical therapy was prescribed to 43.1% of the patients, but use decreased with age. In all, 5.3% of the patients received total joint replacement in 2014.

Conclusion

The lower frequency of coded OA with increasing level of care dependency may reflect underdiagnosis, and patients with many other medical problems seem to be at risk for inadequate recognition and treatment of their OA.

The "tipping point" for 931 elective shoulder arthroplasties

BACKGROUND

A patient with arthritis usually experiences the progression of symptoms over time. At some stage, the patient may decide that the symptoms have reached a level of severity that leads him or her to elect to proceed with joint replacement; we refer to this degree of symptom severity as the "tipping point." Our goal was to study the factors that influenced the tipping point for patients undergoing elective shoulder arthroplasty.

METHODS

We analyzed the characteristics of 931 patients undergoing shoulder arthroplasty to determine the factors affecting the tipping point as characterized by the patients' comfort and function at the time they determined their symptoms had progressed to the point when this elective surgery was merited.

RESULTS

The preoperative Simple Shoulder Test (SST) score for all patients averaged 3.6 ± 2.7. The average tipping points were different for the ream-and-run procedure (mean SST score, 5.0 ± 2.5), hemiarthroplasty (mean SST score, 3.1 ± 3.3), total shoulder arthroplasty (mean SST score, 3.0 ± 2.4), cuff tear arthropathy arthroplasty (mean SST score, 2.8 ± 2.5), and reverse total shoulder arthroplasty (mean SST score, 1.5 ± 1.8). A number of other factors were significantly associated with a higher tipping point: younger age, better health, male sex, commercial insurance, married, nonuse of narcotics, use of alcohol, and shoulder problem not related to work.

CONCLUSIONS

Analysis of the tipping point-the patients' self-assessed comfort and function at the point they decide to undergo shoulder joint replacement-provides a means by which surgeons can understand the factors influencing the indications for these procedures.

Impact of oral osteoarthritis therapy usage among other risk factors on knee replacement: a nested case-control study using the Osteoarthritis Initiative cohort

BACKGROUND

The aim of this study was to measure the association between exposure to commonly used oral osteoarthritis (OA) therapies and relevant confounding risk factors on the occurrence of knee replacement (KR), using the Osteoarthritis Initiative (OAI) database.

METHODS

In this nested case-control design study, participants who had a KR after cohort entry were defined as "cases" and were matched with up to four controls for age, gender, income, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, Kellgren-Lawrence grade, and duration of follow up. Exposure to oral OA therapies (acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), cyclooxygenase-2 (COX-2) inhibitors, narcotics, and glucosamine/chondroitin sulfate) was determined within the 3 years prior to the date of the KR. Conditional regression analyses were performed to estimate the association between KR and exposure to oral OA therapies and other potential confounding risk factors.

RESULTS

A total of 218 participants who underwent a KR (cases) were matched to 540 controls. The median time to KR was 4.3 years among cases. The majority in both groups were Caucasian with mean age of 69 years and 61% were female. Numerically, cases were more exposed to acetaminophen, NSAIDs, and COX-2 inhibitors. Exposure to narcotics and glucosamine/chondroitin sulfate was relatively similar between cases and controls. No significant association was found between the occurrence of KR and exposure to any of the oral OA therapies within the 3 years prior to KR. A significantly higher occurrence of KR was found in Caucasian subjects (OR 1.84; 95% CI, 1.13-2.99; p = 0.015) and subjects with body mass index (BMI) ≥ 27 kg/m² (OR 1.65; 95% CI, 1.06-2.58; p = 0.027).

CONCLUSION

This study provides evidence that the main risk factors leading to KR are disease severity, symptoms and high BMI. Importantly, exposure to oral OA therapies was not associated with the occurrence of KR.

Patients and surgeons provide endorsement of core domains for total joint replacement clinical trials

Background

Our objective in this study was to examine whether stakeholders further endorse the core domain set proposed by the Outcome Measures in Rheumatology Trials (OMERACT) total joint replacement (TJR) working group.

Methods

We emailed a survey to 3810 hip/knee arthroplasty patients and 49 arthroplasty surgeons at a high-volume arthroplasty center to rate the importance of each core domain (i.e., pain, function, patient satisfaction, revision surgery, adverse events, and death) and two additional domains (i.e., cost and participation). Ratings were on a 1–9 scale, with 1–3 indicating limited or no importance for patients, 4–6 being important but not critical, and 7–9 being critical. We calculated median (IQR) values and compared ratings by sex, age, and participant type using the Wilcoxon rank-sum test.

Results

The questionnaire was completed by 1295 patients (34%) and 21 surgeons (43%). Patient nonresponders were similar to responders in age (≥55 years, 85.7% vs. 88.6%), sex (female, 57.5% vs. 57.3%), and joint procedure (total hip replacement, 56.9% vs. 63.2%). Overall, all core domains and one noncore domain (i.e., participation) were confirmed as “critical” by both stakeholder groups. Cost was rated as only “important” but not “critical” by surgeons. A completed consensus for all the core domains persisted even when we stratified by sex, age, arthritis type, and the affected joint (knee vs. hip). We received suggestions for additional critical domains from 217 patients and 5 surgeons, prompting the inclusion of 2 research agenda items.

Conclusions

Our study confirmed a consensus rating of the OMERACT TJR core domain set as critical for patients. This broad endorsement should encourage the identification of candidate outcome instruments to further develop a TJR core measurement set that can harmonize reporting in TJR clinical trials.

Hip Inflammation MRI Scoring System (HIMRISS) to predict response to hyaluronic acid injection in hip osteoarthritis

OBJECTIVE

To assess predictors of response, according to hip MRI inflammatory scoring system (HIMRISS), in a sample of patients with hip osteoarthritis (OA) treated by hyaluronic acid (HA) injection.

METHOD

Sixty patients with hip OA were included. Clinical outcomes were assessed at baseline and three months after HA injection by WOMAC. On hip MRI performed before HA injection, bone marrow lesion (BML) and synovitis were assessed by HIMRISS by four readers. The inter-reader reliability of HIMRISS was for HIMRISS total, acetabular BML, femoral BML and synovitis-effusion respectively 0.86, 0.64, 0.83 and 0.78. Associations between MRI features and clinical data were assessed. Logistic regression (univariate and multivariate) was used to explore associations between MRI features and response to HA injection, according to WOMAC50 response at three months.

RESULTS

In total, 45.5% of patients met WOMAC50 response. Five adverse events were reported. At baseline, WOMAC function correlated significantly to HIMRISS synovitis-effusion (r=0.27, P=0.03). In univariate analysis, BML femoral according to binary assessment (P=0.025), HIMRISS BML femoral (P=0.0038), HIMRISS BML acetabular (P=0.042), HIMRISS total (P=0.0092) were associated negatively with WOMAC50 response. In multivariate analysis, adjusted for age and BMI, HIMRISS femoral BML (P=0.02) and HIMRISS total (P=0.016) were negatively associated with response. At a HIMRISS threshold of<15, 82% of patients were responders, with specificity SP=0.97, sensitivity SN=0.39, and positive and negative predictive values of 0.91 and 0.64, respectively.

CONCLUSION

HIMRISS is reliable for total scores and sub-domains. It permits identification of responders to HA injection in hip OA patients.

Systolic and pulse pressure associate with incident knee osteoarthritis: data from the Osteoarthritis Initiative

We evaluated the relationship of systolic blood pressure, diastolic blood pressure, pulse pressure, and treatment with antihypertensives with knee osteoarthritis incidence in a US cohort. We performed a longitudinal study (2004-2010) nested within the Osteoarthritis Initiative Study including only individuals without knee osteoarthritis at baseline. Systolic blood pressure, diastolic blood pressure, and pulse pressure were assessed at baseline, 12-, 24-, and 36-month visits. Knee radiographs at baseline, 12-, 24-, 36- and 48-month visits defined radiographic osteoarthritis, Kellgren and Lawrence grade ≥2. We performed logistic regression, adjusting for age, sex, body mass index, NSAID use, number of antihypertensive medications, diabetic medications, and cholesterol medications. One thousand nine hundred and thirty people (6040 observations) were included. Annual incidence rates of radiographic osteoarthritis by systolic blood pressure quartiles (lowest to highest) were 2.1, 3.4, 3.7, and 3.7%. Fully adjusted odds ratios of incident radiographic osteoarthritis (OA) for the 2nd-4th quartiles were 1.6, 1.7, and 1.6 relative to the lowest quartile (p for trend = 0.03). Pulse pressure results were similar. There was no association with diastolic blood pressure. Compared to those not taking any antihypertensive medications, those taking ≥3 had decreased odds (0.4, 0.1-1.0) of developing incident OA. In a US cohort, higher systolic blood pressure and pulse pressure are associated with increased incidence of radiographic knee osteoarthritis while treatment with ≥3 antihypertensive medications was associated with reduced incidence. These findings suggest a new and promising avenue for research on disease modification in knee osteoarthritis.

Do outcomes reported in randomised controlled trials of joint replacement surgery fulfil the OMERACT 2.0 Filter? A review of the 2008 and 2013 literature

BACKGROUND

It is not known, whether outcome reporting in trials of total joint arthroplasty in the recent years is adequate or not. Our objective was to assess whether outcomes reported in total joint replacement (TJR) trials fulfil the Outcome Measures in Rheumatology (OMERACT) Filter 2.0.

METHODS

We systematically reviewed all TJR trials in adults, published in English in 2008 or 2013. Searches were conducted in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. Two authors independently applied the inclusion criteria for the studies, and any disagreement was resolved with a third review author. All outcome measures were abstracted using a pre-piloted standardised data extraction form and assessed for whether they mapped to one of the three OMERACT Filter 2.0 core areas: pathophysiological, life impact, and death.

RESULTS

From 1635 trials identified, we included 70 trials (30 in 2008 and 40 in 2013) meeting the eligibility criteria. Twenty-two (31%) trials reported the three essential OMERACT core areas. Among the 27 hip replacement surgery trials and 39 knee replacement surgery trials included, 11 hip (41%) and nine knee (23%) trials reported all three essential OMERACT core areas. The most common outcome domains/measures were pain (20/27, 74%) and function (23/27, 85%) in hip trials and pain (26/39, 67%) and function (27/39, 69%) in knee trials. Results were similar for shoulder and hand joint replacement trials.

CONCLUSIONS

We identified significant gaps in the measurement of OMERACT core outcome areas in TJR trials, despite the majority reporting outcome domains of pain and function. An international consensus of key stakeholders is needed to develop a core domain set for reporting of TJR trials.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014009216.

Outcome Measures Used in Arthroplasty Trials: Systematic Review of the 2008 and 2013 Literature

OBJECTIVE

Previously published literature assessing the reporting of outcome measures used in joint replacement randomized controlled trials (RCT) has revealed disappointing results. It remains unknown whether international initiatives have led to any improvement in the quality of reporting and/or a reduction in the heterogeneity of outcome measures used. Our objective was to systematically assess and compare primary outcome measures and the risk of bias in joint replacement RCT published in 2008 and 2013.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL for RCT investigating adult patients undergoing joint replacement surgery. Two authors independently identified eligible trials, extracted data, and assessed risk of bias using the Cochrane tool.

RESULTS

Seventy RCT (30 in 2008, 40 in 2013) met the eligibility criteria. There was no significant difference in the number of trials judged to be at low overall risk of bias (n = 6, 20%) in 2008 compared with 2013 [6 (15%); chi-square = 0.302, p = 0.75]. Significantly more trials published in 2008 did not specify a primary outcome measure (n = 25, 83%) compared with 18 trials (45%) in 2013 (chi-square = 10.6316, p = 0.001). When specified, there was significant heterogeneity in the measures used to assess primary outcomes.

CONCLUSION

While less than a quarter of trials published in both 2008 and 2013 were judged to be at low overall risk of bias, significantly more trials published in 2013 specified a primary outcome. Although this might represent a temporal trend toward improvement, the overall frequency of primary outcome reporting and the wide heterogeneity in primary outcomes reported remain suboptimal.

Differences in presentation, progression and rates of arthroplasty between hip and knee osteoarthritis: Observations from an osteoarthritis cohort study-a clear role for conservative management

Aim

To describe the natural progression and the rates of arthroplasty of a cohort of hip and knee osteoarthritis (OA) patients.

Methods

An observational study of 247 consecutive patients who attended an OA clinic between May 2008 and August 2009. Follow‐up survey was conducted from July 2014 to December 2014, with the primary end point being joint replacement surgery.

Results

One hundred and sixty‐seven patients had knee OA and 80 patients had hip OA. When adjusted for other variables (age, gender, body mass index, Kellgren‐Lawrence stage, symptom duration, presence of OA elsewhere and pain score), patients with hip OA demonstrated 86% increased hazard of surgery compared to knee OA patients (95% CI increase of 19% to 193%). At 6 years after initial consultation, 67% of patients with knee OA did not require a knee replacement surgery, while 40% (30, 51) of hip OA patients did not undergo surgery (95% CI: 59–74%). Overall at 6 years, 58% of patients (95% CI: 51–64%) did not undergo joint replacement surgery.

Conclusion

Knee and hip OA patients appear to behave differently, with hip OA patients more likely to undergo arthroplasty. There is a significant number of both hip OA and knee OA patients who did not require arthroplasty at the end of 6 years, suggesting a major role for conservative therapy.

Outcome Assessment in Total Knee Arthroplasty: A Systematic Review and Critical Appraisal

BACKGROUND

The Outcome Measures in Rheumatology (OMERACT) initiative developed a core outcome set (COS) of domains to assess effectiveness of interventions for knee osteoarthritis. These domains (pain, physical function, patient global assessment, imaging at 1 year) should be assessed in every trial to make research evidence meaningful and comparable. We systematically evaluated and critically appraised the use of measurement instruments and outcome domains in prospective studies evaluating patients with knee osteoarthritis undergoing total knee arthroplasty (TKA) and assessed their accordance with the OMERACT COS.

METHODS

Literature search was performed until August 26, 2014, in Medline and Embase. Clinical trials and prospective observational studies with ≥50 participants and a follow-up of ≥1 year were included. We collected general study characteristics, comprehensive information on measurement instruments, and corresponding domains used.

RESULTS

This systematic review identified low accordance of used outcome domains with the OMERACT COS of domains published in 1997. Only 4 of 100 included studies included all recommended core domains. Pain (85% of studies) and physical function (86%) were assessed frequently, whereas patient global assessment (21%) and joint imaging (≥1 year; 27%) were rarely assessed. There was substantial heterogeneity in the use of measurement instruments (n = 111) investigating TKA.

CONCLUSION

More efforts are required to implement the existing COS. In addition, a more consistent use of adequate measurement instruments is important to make research evidence on TKA more relevant, better comparable, and thus more useful for guideline developers and clinical decision makers.

Adverse events and survival after closing- and opening-wedge high tibial osteotomy: a comparative study of 412 patients

PURPOSE

Varus medial knee osteoarthritis (OA) can be treated with a closing-wedge (CW) or opening-wedge (OW) high tibial osteotomy (HTO). Little is known about the adverse event (AE) rate of these techniques. The purpose of this study was to examine the AE rate and survival rate of a consecutive series of 412 patients undergoing CW- or OW-HTO.

METHODS

Medical records were retrospectively screened, and all patients who underwent HTO from 1993 to 2012 at the Erasmus University Medical Centre were assessed with a self-administered questionnaire. Patients filled in the intermittent and constant osteoarthritis pain score, knee injury and osteoarthritis outcome score, and a general questionnaire focusing on AE.

RESULTS

Medical records of 412 patients (354 CW- and 112 OW-HTOs) were screened. Of the 358 eligible patients, 291 (81 %) returned their questionnaire. A total of 80 AE (17 %) were found in 466 osteotomies. In the CW-group, 47 (13 %) serious adverse events (SAE) and 2 (0.6 %) AE were found. In the OW-group, 17 (15 %) SAE and 14 (13 %) AE were found. The most common AE was in 14 (4 %) patients of the CW-group sensory palsy of the common peroneal nerve. The most common AE in the OW-group was persistent pain at the iliac crest [11 (9.8 %) patients]. Hardware was removed in 48 % of the CW-osteotomies and 71 % of the OW-osteotomies (p < 0.05). The probability of survival was 75 % after 10 years in the CW-group versus 90 % in the OW-group (p < 0.05). In both groups, an equal number of patients were "in need for prosthesis" according to OARSI criteria.

CONCLUSION

OW-HTO was associated with more AE than CW-HTO. OW-HTO resulted in better survival than CW-HTO. However, in both groups an equal number of patients were in need for prosthesis.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Cost utility modeling of early vs late total knee replacement in osteoarthritis patients

Given the dramatic increase in the number of total knee replacement (TKR) surgeries in developed countries, the issue of the best time for surgery needs to be addressed from an economic perspective.

OBJECTIVE

To assess, from the perspective of the healthcare payer, the cost-utility of two surgical strategies in which knee replacement is performed at the early or late stage of the disease in patients with knee osteoarthritis (OA).

DESIGN

Patient data and evidence from published literature on economic costs and outcomes in OA, including utilities, non-pharmacological, pharmacological and surgical options, combined with population life tables were entered in a Markov model of OA. The model represented the lifetime experience of a cohort of patients following their therapeutic management, discounting costs (euros) and utilities (quality-adjusted life-years) at 4% annually.

RESULTS

In the base-case scenario, early TKR cost €6,624 more than late TKR (€76,223 vs €69,599) with a 0.15 gain in QALYs (18.675 vs 18.524). This yielded an incremental cost-utility ratio (ICUR) of 43,631 €/QALY. Sensitivity analyses of the most influential uncertain parameters were performed and did not modify the direction of the conclusions: early TKR cost between €3,655 and €7,194 more than late TKR with a gain in QALYs between 0.15 and 0.39. The ICUR ranged from 17,131 €/QALY to 48,241 €/QALY.

CONCLUSION

Our data do not support the early TKR strategy over the late TKR strategy in knee OA patients from a medico-economic perspective.

Indication criteria for total hip or knee arthroplasty in osteoarthritis: a state-of-the-science overview

BACKGROUND

This systematic review gives an overview of guidelines and original publications as well as the evidence on which the currently proposed indication criteria are based. Until now such a state-of-the-science overview was lacking.

METHODS

Websites of orthopaedic and arthritis organizations (English/Dutch language) were independently searched by two authors for THA/TKA guidelines for OA. Furthermore, a systematic search strategy in several databases through August 2014 was performed. Quality of the guidelines was assessed with the AGREE II instrument, which consists of 6 domains (maximum summed score of 6 indicating high quality). Also, the level of evidence of all included studies was assessed.

RESULTS

We found 6 guidelines and 18 papers, out of 3065 references. The quality of the guidelines summed across 6 domains ranged from 0.46 to 4.78. In total, 12 THA, 10 TKA and 2 THA/TKA indication sets were found. Four studies stated that no evidence-based indication criteria are available. Indication criteria concerning THA/TKA consisted of the following domains: pain (in respectively 11 and 10 sets), function (12 and 7 sets), radiological changes (10 and 9 sets), failed conservative therapy (8 and 4 sets) and other indications (6 and 7 sets). Specific cut-off values or ranges were often not stated and the level of evidence was low.

CONCLUSION

The indication criteria for THA/TKA are based on limited evidence. Empirical research is needed, especially regarding domain specific cut-off values or ranges at which the best postoperative outcomes are achieved for patients, taking into account the limited lifespan of a prosthesis.

Can We Predict Those With Osteoarthritis Who Will Worsen Following a Chronic Disease Management Program?

OBJECTIVE

To identify predictors of worsening symptoms and overall health of the treated hip or knee joint following 26 weeks of a nonsurgical chronic disease management program for hip and knee osteoarthritis (OA) and to examine the consistency of these predictors across 3 definitions of worsening.

METHODS

This prospective cohort study followed 539 participants of the program for 26 weeks. The 3 definitions of worsening included symptomatic worsening based on change in the Western Ontario and McMaster Universities Osteoarthritis Index Global score (WOMAC-G) measuring pain, stiffness, and function; a transition scale that asked about overall health of the treated hip or knee joint; and a composite outcome including both. Multivariate logistic regression models were constructed for the 3 definitions of worsening.

RESULTS

Complete data were available for 386 participants: mean age was 66.3 years, 69% were female, 85% reported knee joint pain as primary symptom (signal joint), 46% were waitlisted for total joint arthroplasty (TJA). TJA waitlist status, signal joint, 6-Minute Walk Test (6MWT), depressive symptoms, pain, and age were independently associated with at least 1 definition of worsening. TJA waitlist status and 6MWT remained in the multivariate models for the transition and composite definitions of worsening.

CONCLUSION

Participants reporting worsening on the transition scale did not consistently meet the WOMAC-G definition of worsening symptoms. TJA waitlist status was predictive of the composite definition of worsening, a trend apparent for the transition definition. However, variables that predict worsening remain largely unknown. Further research is required to direct comprehensive and targeted management of patients with hip and knee OA.

The MRI-detected osteophyte score is a predictor for undergoing joint replacement in patients with end-stage knee osteoarthritis

OBJECTIVES

The aim of this prospective cohort study was to examine whether MRI-detected osteoarthritis (OA)-structural changes at baseline could predict knee OA patients who would undergo total knee arthroplasty (TKA).

METHODS

In total, 128 end-stage medial-type knee OA patients were enrolled and followed up for 6 months. MRI using the whole-organ MRI scoring (WORMS) method, radiographic findings, visual analog scale (VAS) for pain and a patient-oriented outcome measure, and the Japanese Knee Osteoarthritis Measure (JKOM) were recorded at baseline. The area under the curve (AUC) was estimated to determine the discriminative value of the prediction models.

RESULTS

While 74 patients (57.8%) did not undergo TKA, the remaining 54 patients (42.2%) underwent TKA during this period. The AUCs of the receiver operating characteristic (ROC) curve for the activities of daily living (ADL) score evaluated by the JKOM ADL score [0.70 (95% CI: 0.60-0.79)] and osteophyte score [0.72 (0.64-0.81)] were 0.70 or greater. The JKOM ADL score (17/40) and the osteophyte score (30/98) showed relative risks (RR) of 2.61 (1.32-5.15) and 3.01 (1.39-6.52) for undergoing TKA, respectively.

CONCLUSION

The osteophyte score detected by MRI, in addition to ADL score, was found to be an important factor in determining whether the patient should undergo TKA.

Preoperative timed single leg standing time is associated with the postoperative activity of daily living in aged disabled patients with end-stage knee osteoarthritis at six-months after undergoing total knee arthroplasty

OBJECTIVES

The aim of the present study was to investigate the effect size (ES) of total knee arthroplasty (TKA) for the symptoms and lower limb function and identify preoperative factor(s) associated with the post-operative activity of daily living (ADL) in aged patients with end-stage knee OA undergoing TKA.

METHODS

Fifty-nine aged patients with end-stage knee OA (mean age: 74.6 years) were enrolled in this study. The symptoms and lower limb function of the patients were evaluated using the Japanese Knee Osteoarthritis Measure (JKOM), the timed up and go (TUG) test and timed single-legged stance test with eyes open (TSLS) before and after six months from the operation.

RESULTS

While the ES of TKA for the improvement of pain was 2.83, the ES of TKA for the improvement of ADL, TUG and TSLS were 1.30, 0.59, and 0.49, respectively. While the post-operative ADL score was not associated with the preoperative ADL or pain scores, it was associated with the preoperative TUG and TSLS scores. A multiple regression analysis revealed that the one preoperative factor associated with the postoperative ADL was the TSLS.

CONCLUSION

The preoperative TSLS is associated with the postoperative ADL in aged disabled patients with end-stage knee OA.

Incidence and prevalence of total joint replacements due to osteoarthritis in the elderly: risk factors and factors associated with late life prevalence in the AGES-Reykjavik Study

Background

Total joint replacements (TJRs) should be considered as one of few definite endpoints in osteoarthritis research. We analyzed factors associated with late-life prevalence and risk factors for incidence of TJRs due to osteoarthritis in a population based cohort.

Methods

After exclusion of inflammatory arthritis and fractures as causes of TJR, 5170 participants in the AGES-Reykjavik Study (mean age (SD) 76.4(6), 58 % females) were included for osteoarthritis studies. Three thousand one hundred thirty-three of them had a follow-up visit 5 years later.

Results

The prevalence of having at least one joint replacement operation due to OA was 13.6 % and the yearly incidence was 1.4 %/year during the five-year follow-up. Factors positively associated with late life prevalence of TJR included BMI, hand OA severity, female gender, finger length ratio and spine BMD. Risk factors for TJRs in the incidence group were symptoms at initial visit, prior TJR in the contralateral joint and BMI. Much stronger associations were seen for TKR than for THR with discriminatory analysis showing an AUC 0.71 for late life prevalence and 0.84 for the incidence.

Conclusions

This study illustrates the importance of the different information expressed by late life prevalence vs. incidence on the factors associated with severe osteoarthritis of the knee and hip. The observation that prior TJR is a risk factor for subsequent TJR in the contralateral joint has not been described previously. The high power predictions for TKR suggest that a predictive model may be feasible, particularly if it can be extended by the addition of further predictive variables, perhaps through genetic, biomarker or imaging data.

Three-dimensional biomechanical gait characteristics at baseline are associated with progression to total knee arthroplasty

Objective

To determine if baseline 3-dimensional (3-D) biomechanical gait patterns differed between those patients with moderate knee osteoarthritis (OA) who progressed to total knee arthroplasty (TKA) and those that did not, and whether these differences had predictive value.

Methods

Fifty-four patients with knee OA had ground reaction forces and segment motions collected during gait. 3-D hip, knee, and ankle angles and moments were calculated over the gait cycle. Amplitude and temporal waveform characteristics were determined using principal component analysis. At followup 5–8 years later, 26 patients reported undergoing TKA. Unpaired t-tests were performed on baseline demographic and waveform characteristics between TKA and no-TKA groups. Receiver operating curve analysis, stepwise discriminate analysis, and logistic regression analysis determined the combination of features that best classified TKA and no-TKA groups and their predictive ability.

Results

Baseline demographic, symptomatic, and radiographic variables were similar, but 7 gait variables differed (P < 0.05) between groups. A multivariate model including overall knee adduction moment magnitude, knee flexion/extension moment difference, and stance–dorsiflexion moment had a 74% correct classification rate, with no overtraining based on cross-validation. A 1-unit increase in model score increased by 6-fold the odds of progression to TKA.

Conclusion

In addition to the link between higher overall knee adduction magnitude and future TKA, an outcome of clear clinical importance, novel findings include altered sagittal plane moment patterns indicative of reduced ability to unload the joint during midstance. This combination of dynamic biomechanical factors had a 6-fold increased odds of future TKA; adding baseline demographic and clinical factors did not improve the model.

Hip Arthroplasty or Medical Management: A Challenging Treatment Decision for Younger Patients

The two main treatment options for total hip arthroplasty (THA), medical management and surgical intervention, have advantages and disadvantages, creating a challenging decision. Treatment decisions are further complicated in a younger population (≤50) as the potential need for revision surgery is probable. We examined the relationship of selected variables to the decision-making process for younger patients with symptomatic OA. Thirty-five participants chose surgical intervention and 36 selected medical management for their current treatment. Pain, activity restrictions, and total WOMAC scores were statistically significant (P < .05) for patients selecting surgical intervention. No difference in quality of life was shown between groups. Pain was the only predictor variable identified, however, activity restrictions were also influential variables as these were highly correlated with pain.

Outcome Domains and Measures in Total Joint Replacement Clinical Trials: Can We Harmonize Them? An OMERACT Collaborative Initiative

Objective.

To develop a plan for harmonizing outcomes for people undergoing total joint replacement (TJR), to achieve consensus regarding TJR outcome research.

Methods.

The TJR working group met during the 2014 Outcome Measures in Rheumatology (OMERACT) 12 meeting in Budapest, Hungary. Multiple conference calls preceded the face-to-face meeting. Brief presentations were made during a 1.5-h meeting, which included an overview of published systematic reviews of TJR trials and the results of a recent systematic review of TJR clinical trial outcome domains and measures. This was followed by discussion of potential core set areas/domains for TJR clinical trials (as per OMERACT Filter 2.0) as well as the challenges associated with the measurement of these domains.

Results.

Working group participants discussed which TJR clinical trial outcome domains/areas map to the inner versus outer core for core domain set. Several challenges were identified with TJR outcomes including how to best measure function after TJR, elucidating the source of the pre- and post-TJR joint pain being measured, joint-specific versus generic quality of life instruments and the importance of patient satisfaction and revision surgery as outcomes. A preliminary core domain set for TJR clinical trials was proposed and included pain, function, patient satisfaction, revision, adverse events, and death. This core domain set will be further vetted with a broader audience.

Conclusion.

An international effort with active collaboration with the orthopedic community to standardize key outcome domains and measures is under way with the TJR working group. This effort will be further developed with new collaborations.

The assessment of outcome after total knee arthroplasty: are we there yet?

The routine use of patient reported outcome measures (PROMs) in evaluating the outcome after arthroplasty by healthcare organisations reflects a growing recognition of the importance of patients' perspectives in improving treatment. Although widely embraced in the NHS, there are concerns that PROMs are being used beyond their means due to a poor understanding of their limitations. This paper reviews some of the current challenges in using PROMs to evaluate total knee arthroplasty. It highlights alternative methods that have been used to improve the assessment of outcome.

Preoperative pain and function profiles reflect consistent TKA patient selection among US surgeons

BACKGROUND

As the number of primary total knee arthroplasties (TKAs) performed in the United States increases, policymakers have questioned whether the indications and timing of TKA have evolved so that surgery is offered earlier.

QUESTIONS/PURPOSES

We analyzed data from a US national TKA cohort to evaluate variation in surgeon selection criteria for elective unilateral TKA based on preoperative patient-reported pain and function scores.

METHODS

Preoperative SF-36 (Physical Component Summary [PCS]/physical function) scores and Knee Injury and Osteoarthritis Outcome Score (KOOS) (pain, activities of daily living/function) of 4900 patients undergoing elective unilateral TKA enrolled in this national database of prospectively followed patients from 22 states were evaluated. The 25th, 50th, and 75th percentile pain and function scores for patients cared for in 24 orthopaedic offices with 20 or more patients in the database were compared to assess whether consistent preoperative criteria are used in selecting patients undergoing TKA across settings.

RESULTS

The preoperative global function (PCS median, 32.6; national norm, 50; SD, 10) and knee-specific function (KOOS median, 51.5; maximum score, 100; SD, 17) percentile scores represented substantial patient disability, because both values approached 2 SDs below ideal. Consistency in patients across 24 surgeon offices, and more than 100 surgeons, was noted because site-specific medians varied from the national median by less than the minimum clinically important change.

CONCLUSIONS

These data suggest that despite the rapidly growing use of TKA, surgeons in the participating sites use consistent patient criteria in scheduling TKA. Today's patients report significant pain and disability, supporting the need for TKA.

Use of a validated algorithm to judge the appropriateness of total knee arthroplasty in the United States: a multicenter longitudinal cohort study

OBJECTIVE

In previous studies conducted outside the US, ∼20% of total knee arthroplasty (TKA) surgeries were judged to be inappropriate. The present study was undertaken to determine the prevalence rates of TKA surgeries classified as appropriate, inconclusive, and inappropriate in a knee osteoarthritis population in the US.

METHODS

We used a modification of a validated appropriateness classification system and applied it to patients in the Osteoarthritis Initiative data set who underwent TKA. A variety of preoperative data were used in the classification, including Western Ontario and McMaster Universities Osteoarthritis Index pain and physical function scores, radiographic features, knee motion and laxity measures, and age.

RESULTS

Data on 205 patients who underwent TKA were examined. The prevalence rates for classification of the procedure as appropriate, inconclusive, and inappropriate were 44.0% (95% confidence interval [95% CI] 37-51%), 21.7% (95% CI 16-28%), and 34.3% (95% CI 27-41%), respectively.

CONCLUSION

Approximately one-third of TKA surgeries were judged to be inappropriate. Variation in the characteristics of patients undergoing TKA was extensive. These data support the need for consensus development of criteria for patient selection among US practitioners treating patients who are potential candidates for TKA. Among the important issues, consensus development needs to address variation in patient characteristics and the relative importance of preoperative status and subsequent outcome.

Selecting those to refer for joint replacement: who will likely benefit and who will not?

Osteoarthritis (OA) is one of the 10 most disabling diseases in developed countries and worldwide estimates are that 10% of men and 18% of women aged over 60 years have symptomatic OA, including moderate and severe forms. Total joint replacement (TJR) is considered the most effective treatment for end-stage OA in those who have exhausted available conservative interventions. The demand for TJR is continually rising due to the ageing population; in the United States, more than 1 million TJRs were performed in 2010 and the number of procedures is projected to exceed 4 million in the US by 2030. It has been estimated that of all hip and knee replacements performed, approximately one quarter of the patients may be considered inappropriate candidates. Predicting who will benefit from TJR and who will not would seem critical in terms of containing the current and projected expenditure as well as improving satisfaction in TJR recipients. Few formal predictive tools are available to aid referring clinicians to determine those likely to be good or poor responders to surgery and current available tools tend to focus on disease severity alone with little consideration of risk factors that may predict a poor outcome or impede an effective response to surgery. This review examines the tools available to assist with assessing appropriateness for TJR; investigates the modifiable risk factors associated with poor outcome; and identifies areas for future research in selecting those appropriate for joint replacement.

A reference case for economic evaluations in osteoarthritis: an expert consensus article from the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO)

BACKGROUND

General recommendations for a reference case for economic studies in rheumatic diseases were published in 2002 in an initiative to improve the comparability of cost-effectiveness studies in the field. Since then, economic evaluations in osteoarthritis (OA) continue to show considerable heterogeneity in methodological approach.

OBJECTIVES

To develop a reference case specific for economic studies in OA, including the standard optimal care, with which to judge new pharmacologic and non-pharmacologic interventions.

METHODS

Four subgroups of an ESCEO expert working group on economic assessments (13 experts representing diverse aspects of clinical research and/or economic evaluations) were charged with producing lists of recommendations that would potentially improve the comparability of economic analyses in OA: outcome measures, comparators, costs and methodology. These proposals were discussed and refined during a face-to-face meeting in 2013. They are presented here in the format of the recommendations of the recently published Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement, so that an initiative on economic analysis methodology might be consolidated with an initiative on reporting standards.

RESULTS

Overall, three distinct reference cases are proposed, one for each hand, knee and hip OA; with diagnostic variations in the first two, giving rise to different treatment options: interphalangeal or thumb-based disease for hand OA and the presence or absence of joint malalignment for knee OA. A set of management strategies is proposed, which should be further evaluated to help establish a consensus on the "standard optimal care" in each proposed reference case. The recommendations on outcome measures, cost itemisation and methodological approaches are also provided.

CONCLUSIONS

The ESCEO group proposes a set of disease-specific recommendations on the conduct and reporting of economic evaluations in OA that could help the standardisation and comparability of studies that evaluate therapeutic strategies of OA in terms of costs and effectiveness.

Updating the OMERACT filter: implications for imaging and soluble biomarkers

OBJECTIVE

The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imaging and Soluble Biomarker Session at OMERACT 11 aimed to provide a guide for the iterative development of an imaging or biochemical measurement instrument so it can be used in therapeutic assessment.

METHODS

A hierarchical structure was proposed, reflecting 3 dimensions needed for validating an imaging or biochemical measurement instrument: outcome domain(s), study setting, and performance of the instrument. Movement along the axes in any dimension reflects increasing validation. For a given test instrument, the 3-axis structure assesses the extent to which the instrument is a validated measure for the chosen domain, whether it assesses a patient-centered or disease-centered variable, and whether its technical performance is adequate in the context of its application. Some currently used imaging and soluble biomarkers for rheumatoid arthritis, spondyloarthritis, and knee osteoarthritis were then evaluated using the original OMERACT Filter and the newly proposed structure. Breakout groups critically reviewed the extent to which the candidate biomarkers complied with the proposed stepwise approach, as a way of examining the utility of the proposed 3-dimensional structure.

RESULTS

Although there was a broad acceptance of the value of the proposed structure in general, some areas for improvement were suggested including clarification of criteria for achieving a certain level of validation and how to deal with extension of the structure to areas beyond clinical trials.

CONCLUSION

General support was obtained for a proposed tri-axis structure to assess validation of imaging and soluble biomarkers; nevertheless, additional work is required to better evaluate its place within the OMERACT Filter 2.0.

Disability for daily living is a predictor for joint replacement in patients with end-stage knee osteoarthritis

The objective indicators which reflect the past results of end-stage knee osteoarthritis (OA) patients who have already received total knee arthroplasty (TKA) could be helpful for physicians to discuss with patients who are considering TKA. The aim of this prospective cohort study was to examine whether we could predict the knee OA patients who would receive TKA in advance based on baseline data, and to set cut-off points for receiving TKA. The two-hundred and forty end-stage medial-type knee OA patients were enrolled and followed up for 6 months while performing therapeutic exercises. Radiographic findings, visual analog scale for pain and a patient-oriented outcome measure, the Japanese Knee Osteoarthritis Measure (JKOM), were recorded at baseline. Relative risks (RRs) using the area under the curve (AUC) for a receiver operating characteristic (ROC) curve were calculated to evaluate several scores for receiving TKA. While 119 patients (55.3 %) did not undergo TKA, the remaining 96 patients (44.7 %) underwent TKA during this period. The AUCs of the ROC curve for the JKOM total score [0.71 (95 % CI 0.64-0.79)] were higher than those for radiographic parameters. Among the JKOM subcategories, JKOM category III, which indicates the condition in daily life, showed the highest AUC of 0.72 (0.65-0.80). The JKOM total score (65/100) and JKOM category III score (17/40) showed RRs of 2.20 (1.33-3.63) and 1.95 (1.18-3.22) for receiving TKA, respectively. The presence of disability in daily living was found to be an important factor determining whether the patient should undergo TKA.

Changes in structure and symptoms in knee osteoarthritis and prediction of future knee replacement over 8 years

The objective of this study was to assess the association between changes in joint space width (JSW, i.e., structure) or Western Ontario and McMaster Universities (WOMAC) score (i.e., symptoms) over 3 years in patients with knee osteoarthritis and the occurrence of knee replacement over 8 years. We followed 133 subjects with primary knee osteoarthritis prospectively for a mean of 8 years. JSW (standard radiography) and symptoms (total WOMAC score) were assessed every year for 3 years. The rate of knee replacement was recorded for the following 5 years. Logistic regressions were performed according to the intention-to-treat principle. After 8 years' follow-up, ten patients (7.5 %) had undergone a knee replacement. The changes in JSW or WOMAC score over 3 years were significantly associated with the occurrence of knee replacement during the following 5 years (p = 0.02 and p = 0.03, respectively). Each 0.1-mm narrowing of JSW over 3 years was associated with a 14 % (95 % CI 3-25 %) increased risk for knee replacement. For every 10 % increase in WOMAC score, the risk for joint replacement was increased by 16 % (95 % CI 1-33 %). When JSW and WOMAC score were included in the same statistical model, they were still significantly associated with risk for knee replacement (p = 0.02 and p = 0.03, respectively), but JSW change was the only variable that remained significant after adjusting for all potential confounders. Our results suggest that changes in symptoms and, more particularly, in structure over 3 years in patients with osteoarthritis reflect a clinically relevant progression of the disease.

Exercise therapy may postpone total hip replacement surgery in patients with hip osteoarthritis: a long-term follow-up of a randomised trial

Background

Exercise treatment is recommended for all patients with hip osteoarthritis (OA), but its effect on the long-term need for total hip replacement (THR) is unknown.

Methods

We conducted a long-term follow-up of a randomised trial investigating the efficacy of exercise therapy and patient education versus patient education only on the 6-year cumulative survival of the native hip to THR in 109 patients with symptomatic and radiographic hip OA. Results regarding the primary outcome measure of the trial, self-reported pain at 16 months follow-up, have been reported previously.

Results

There were no group differences at baseline. The response rate at follow-up was 94%. 22 patients in the group receiving both exercise therapy and patient education and 31 patients in the group receiving patient education only underwent THR during the follow-up period, giving a 6-year cumulative survival of the native hip of 41% and 25%, respectively (p=0.034). The HR for survival of the native hip was 0.56 (CI 0.32 to 0.96) for the exercise therapy group compared with the control group. Median time to THR was 5.4 and 3.5 years, respectively. The exercise therapy group had better self-reported hip function prior to THR or end of study, but no significant differences were found for pain and stiffness.

Conclusions

Our findings in this explanatory study suggest that exercise therapy in addition to patient education can reduce the need for THR by 44% in patients with hip OA. ClinicalTrials.gov number NCT00319423 (original project protocol) and NCT01338532 (additional protocol for long-term follow-up).

Defining and mapping the person with osteoarthritis for population studies and public health

Objective. To determine population-based estimates for the prevalence of the person with OA, predicted to be the single greatest cause of disability in the general population by 2030, in order to inform the planning and commissioning of health, social care and prevention services.

Methods. A postal survey to all adults ≥50 years of age registered with eight general practices in the UK. Self-reported data on chronic joint pain in four body regions (hand, hip, knee, foot) and the disabling nature of the pain was collected to determine gender and age-group specific prevalence estimates of clinical OA in the joint region and in the person. Multiple imputation and weighted logistic regression was used to allow for missing data.

Results. A total of 26 705 mailed surveys resulted in 18 474 responses (adjusted response = 71.8%). Approximately half of the mailed population had OA in at least one of the four regions (53.23%, 95% CI 52.3, 54.1) and less than half of these had disabling OA (21.87%, 95% CI 21.2, 22.5). The more joint regions involved, the more likely that the OA was disabling. OA prevalence was higher in females and increased with age. Applied to the population of England, this yielded an estimated 3.5 million persons with disabling OA, including 1.45 million people between 50 and 65 years of age and 370 000 ≥85 years of age.

Conclusions. A simple approach to defining the person with OA can contribute to population comparisons, public health projections and health care needs assessments.

The diagnostic performance of radiography for detection of osteoarthritis-associated features compared with MRI in hip joints with chronic pain

OBJECTIVE

To evaluate the diagnostic performance of radiography for the detection of MRI-detected osteoarthritis-associated features in various articular subregions of the hip joint.

MATERIALS AND METHODS

Forty-four patients with chronic hip pain (mean age, 63.3 ± 9.5 years), who were part of the Hip Osteoarthritis MRI Scoring (HOAMS) cohort, underwent both weight-bearing anteroposterior pelvic radiography and 1.5 T MRI. The HOAMS study was a prospective observational study involving 52 subjects, conducted to develop a semiquantitative MRI scoring system for hip osteoarthritis features. In the present study, eight subjects were excluded because of a lack of radiographic assessment. On radiography, the presence of superior and medial joint space narrowing, superior and inferior acetabular/femoral osteophytes, acetabular subchondral cysts, and bone attrition of femoral head was noted. On MRI, cartilage, osteophytes, subchondral cysts, and bone attrition were evaluated in the corresponding locations. Diagnostic performance of radiography was compared with that of MRI, and the area under curve (AUC) was calculated for each pathological feature.

RESULTS

Compared with MRI, radiography provided high specificity (0.76-0.90) but variable sensitivity (0.44-0.78) for diffuse cartilage damage (using JSN as an indirect marker), femoral osteophytes, acetabular subchondral cysts and bone attrition of the femoral head, and a low specificity (0.42 and 0.58) for acetabular osteophytes. The AUC of radiography for detecting overall diffuse cartilage damage, marginal osteophytes, subchondral cysts and bone attrition was 0.76, 0.78, 0.67, and 0.82, respectively.

CONCLUSIONS

Diagnostic performance of radiography is good for bone attrition, fair for marginal osteophytes and cartilage damage, but poor for subchondral cysts.

How to define responders in osteoarthritis

BACKGROUND

Osteoarthritis is a clinical syndrome of failure of the joint accompanied by varying degrees of joint pain, functional limitation, and reduced quality of life due to deterioration of articular cartilage and involvement of other joint structures.

SCOPE

Regulatory agencies require relevant clinical benefit on symptoms and structure modification for registration of a new therapy as a disease-modifying osteoarthritis drug (DMOAD). An international Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) and International Osteoporosis Foundation was convened to explore the current burden of osteoarthritis, review current regulatory guidelines for the conduct of clinical trials, and examine the concept of responder analyses for improving drug evaluation in osteoarthritis.

FINDINGS

The ESCEO considers that the major challenges in DMOAD development are the absence of a precise definition of the disease, particularly in the early stages, and the lack of consensus on how to detect structural changes and link them to clinically meaningful endpoints. Responder criteria should help identify progression of disease and be clinically meaningful. The ideal criterion should be sensitive to change over time and should predict disease progression and outcomes such as joint replacement.

CONCLUSION

The ESCEO considers that, for knee osteoarthritis, clinical trial data indicate that radiographic joint space narrowing >0.5 mm over 2 or 3 years might be a reliable surrogate measure for total joint replacement. On-going research using techniques such as magnetic resonance imaging and biochemical markers may allow the identification of these patients earlier in the disease process.