Inadequate Classification of Poor Response After Total Knee Arthroplasty: A Comparative Analysis of 15 Definitions Using Data From the Dutch Arthroplasty Register and the Osteoarthritis Initiative Database.

BACKGROUND: Variations in defining poor response to total knee arthroplasty (TKA) impede comparisons of response after TKA over time and across hospitals. This study aimed to compare the prevalence, overlap, and discriminative accuracy of 15 definitions of poor response after TKA using 2 databases. METHODS: Data of patients one year after primary TKA from the Dutch Arthroplasty Register (n = 12,275) and the Osteoarthritis Initiative database (n = 204) were used to examine the prevalence, overlap (estimated by Cohen's kappa), and discriminative accuracy (sensitivity, specificity, positive predictive value, negative predictive value, and Youden index) of 15 different definitions of poor response after TKA. In the absence of a gold standard for measuring poor response to TKA, the numeric rating scale satisfaction (≤ 6 'poor responder') and the global assessment of knee impact (dichotomized: ≥ 4 'poor responder') were used as anchors for assessing discriminative accuracy for the Dutch Arthroplasty Register and Osteoarthritis Initiative dataset, respectively. These anchors were chosen based on a prior qualitative study that identified (dis)satisfaction as a central theme of poor responses to TKA by patients and knee specialists. RESULTS: The median (25th to 75th percentile) prevalence of poor responders in the examined definitions was 18.5% (14.0 to 25.5%), and the median Cohen's kappa for the overlap between pairs of definitions was 0.41 (0.32 to 0.59). Median (25th to 75th percentile) sensitivity was 0.45 (0.39 to 0.54), specificity was 0.86 (0.82 to 0.94), positive predictive value was 0.45 (0.34 to 0.62), negative predictive value was 0.89 (0.87 to 0.89), and the Youden index was 0.36 (0.20 to 0.43). CONCLUSIONS: This study found a lack of overlap between different definitions of poor response to TKA. None of the examined definitions adequately classified poor responders to TKA. In contrast, the absence of a poor response could be classified with confidence.

Physical activity amongst culturally and linguistically diverse communities in Australia: a scoping review.

BACKGROUND: Australia's overseas-born population continues to grow. This population is disproportionately affected by chronic, non-communicable diseases. Physical activity is the cornerstone of all chronic disease management. Engaging people from culturally and linguistically diverse (CALD) backgrounds in physical activity is an important public health objective. The purpose of this scoping review was to examine the factors that shape physical activity participation among people from CALD backgrounds in Australia. METHODS: This scoping review followed Arksey and O'Malley's framework. Medline, Embase and CINAHL were searched with key words relating to 'physical activity', 'CALD' and 'Australia' in July 2021 and again in February 2022 for qualitative studies published in English since 2000. Exclusion criteria were: participants < 18 years old, studies specifically focusing on populations with health issues, pregnant or postpartum states. Methodological quality of included studies was evaluated using the Critical Appraisal Skills Programme with the purpose of informing future research. Data extracted from each study were analysed thematically and results were interpreted using Acculturation theory. RESULTS: Of the 1130 studies, 17 met the inclusion criteria. Findings from each study were captured in three themes: Perceptions of physical activity; Acceptability and Appropriateness; and Access. Following migration, a decrease in physical activity, especially leisure-time activity, was reported. Common factors influencing physical activity engagement included perceptions of physical activity and wellbeing; language, financial and environmental barriers; as well as social, cultural, and religious considerations. CONCLUSION: This review identified several factors which may interact and contribute to the decline in self-reported physical activity upon migration. Findings from this review may be used to inform future health promotion initiatives targeting people from CALD backgrounds. Future research may benefit from devising a shared definition of physical activity and studying different CALD communities over time.

Patients' Views on AI for Risk Prediction in Shared Decision-Making for Knee Replacement Surgery: Qualitative Interview Study.

BACKGROUND: The use of artificial intelligence (AI) in decision-making around knee replacement surgery is increasing, and this technology holds promise to improve the prediction of patient outcomes. Ambiguity surrounds the definition of AI, and there are mixed views on its application in clinical settings. OBJECTIVE: In this study, we aimed to explore the understanding and attitudes of patients who underwent knee replacement surgery regarding AI in the context of risk prediction for shared clinical decision-making. METHODS: This qualitative study involved patients who underwent knee replacement surgery at a tertiary referral center for joint replacement surgery. The participants were selected based on their age and sex. Semistructured interviews explored the participants' understanding of AI and their opinions on its use in shared clinical decision-making. Data collection and reflexive thematic analyses were conducted concurrently. Recruitment continued until thematic saturation was achieved. RESULTS: Thematic saturation was achieved with 19 interviews and confirmed with 1 additional interview, resulting in 20 participants being interviewed (female participants: n=11, 55%; male participants: n=9, 45%; median age: 66 years). A total of 11 (55%) participants had a substantial postoperative complication. Three themes captured the participants' understanding of AI and their perceptions of its use in shared clinical decision-making. The theme Expectations captured the participants' views of themselves as individuals with the right to self-determination as they sought therapeutic solutions tailored to their circumstances, needs, and desires, including whether to use AI at all. The theme Empowerment highlighted the potential of AI to enable patients to develop realistic expectations and equip them with personalized risk information to discuss in shared decision-making conversations with the surgeon. The theme Partnership captured the importance of symbiosis between AI and clinicians because AI has varied levels of interpretability and understanding of human emotions and empathy. CONCLUSIONS: Patients who underwent knee replacement surgery in this study had varied levels of familiarity with AI and diverse conceptualizations of its definitions and capabilities. Educating patients about AI through nontechnical explanations and illustrative scenarios could help inform their decision to use it for risk prediction in the shared decision-making process with their surgeon. These findings could be used in the process of developing a questionnaire to ascertain the views of patients undergoing knee replacement surgery on the acceptability of AI in shared clinical decision-making. Future work could investigate the accuracy of this patient group's understanding of AI, beyond their familiarity with it, and how this influences their acceptance of its use. Surgeons may play a key role in finding a place for AI in the clinical setting as the uptake of this technology in health care continues to grow.

Reduction in Offset Is Associated With Worse Functional Outcomes Following Total Hip Arthroplasty.

BACKGROUND: Conflicting reports exist about the effect of offset variation on functional outcomes following total hip arthroplasty. Reproducing native hip offset is thought to optimize function by restoring biomechanics and appropriately tensioning the hip abductor muscles. The aim of this study is to assess the effect of failing to restore global hip offset in comparison to the native contralateral hip. METHODS: A retrospective analysis of a prospective patient cohort was performed on patients undergoing an elective primary total hip arthroplasty. A total of 414 patients who had a minimum of 12 months of follow-up were included. Postoperative plain radiographs were analyzed for offset and compared to the contralateral native hip. Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Veterans RAND 12 (VR-12) scores were assessed preoperatively and at 12 months postoperatively. RESULTS: Regression analyses indicated that a reduction in offset of >20 mm resulted in worse WOMAC pain (P = .005) and motion (P = .015) scores compared to those with maintained offset. WOMAC function (P = .063), global (P = .025), and VR-12 scores were not affected (physical P = .656; mental P = .815). Reduction in offset up to 20 mm and increased offset were not significantly associated with patient-reported outcome measures (P-values ranged from .102 to .995). CONCLUSION: This study demonstrated an association between reduction in offset by >20 mm and worse WOMAC pain and motion scores following total hip arthroplasty. Surgeons should avoid decreases in offset >20 mm in order to optimize functional outcomes.

Low grade of radiographic osteoarthritis predicts unsatisfactory response of the contralateral knee replacement in two-stage bilateral total knee arthroplasty.

PURPOSE: It is difficult to counsel patients with bilateral osteoarthritis who are unsatisfied with their first knee replacement as to whether they are likely to have a better outcome after the contralateral knee is replaced. The purpose of this study was to determine whether predictive factors can be found to prognosticate outcome of the second-side knee replacement when a patient has an unsatisfactory response to the first, with the hypothesis that predictors, such as prosthetic factors and radiographic level of osteoarthritis, may be able to predict a satisfactory response to the contralateral knee replacement. MATERIALS AND METHODS: An analysis of staged bilateral knee replacements performed at a tertiary arthroplasty centre from 2012 to 2018 was undertaken. A total of 550 knee replacements in 275 patients were included in this study. The primary variable measured was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Satisfactory response to surgery was defined as a WOMAC score improved by 17 points or more, and 56 or greater. Patients who did not achieve a satisfactory response with their first knee replacement were further analysed for predictive factors (age, sex, pre-operative score, mental score, socioeconomic status, type of prosthesis, use of navigation, patella resurfacing and radiographic osteoarthritis) of an unsatisfactory response for their contralateral knee replacement. RESULTS: Overall, 44 (16%) patients failed to achieve a satisfactory response from both their first and contralateral knee replacements. The factor most predictive of an unsatisfactory response to their first knee replacement was pre-operative mental health score. However, in patients who did not achieve a satisfactory response with their first knee replacement, radiographic osteoarthritis, as measured by the Kellgren-Lawrence (KL) score was the main predictor of satisfactory response for their contralateral knee replacement. Only patients with KL grade 4 osteoarthritis were likely to have a satisfactory response with their contralateral knee replacements (KL4 versus KL3, Odds ratio 3.57 (CI 1.26-10.03) p = 0.016*). Patients with KL grade 3 osteoarthritis were unlikely to have a satisfactory response, and in this series, no patient with KL grade 2 osteoarthritis had a satisfactory response. CONCLUSION: In a patient who has an unsatisfactory response to their first knee replacement, the best predictor of achieving a satisfactory response to his/her contralateral knee replacement is the level of radiographic osteoarthritis in that knee. LEVEL OF EVIDENCE: IV: Retrospective Cohort study.

No Difference in Quality-Of-Life Outcomes in the First 7 Years Following Primary Total Knee Arthroplasty Performed Using Computer Navigation Versus Conventional Referencing: A Propensity Score-Matched Analysis.

BACKGROUND: Computer navigation techniques can potentially improve both the accuracy and precision of prosthesis implantation in total knee arthroplasty (TKA) but its impact on quality-of-life outcomes following surgery remains unestablished. METHODS: An institutional arthroplasty registry was queried to identify patients with TKA performed between January 1, 2007 and December 31, 2019. Propensity score matching based on demographical, medical, and surgical variables was used to match computer-navigated to conventionally referenced cases. The primary outcomes were Veterans RAND 12 Item Health Survey scores (VR-12 PCS and MCS), Short Form 6 Dimension utility values (SF-6D), and quality-adjusted life years (QALYs) in the first 7 years following surgery. RESULTS: A total of 629 computer-navigated TKAs were successfully matched to 1,351 conventional TKAs. The VR-12 PCS improved by a mean of 12.75 and 11.94 points in computer-navigated and conventional cases at 12-month follow-up (P = .25) and the VR-12 MCS by 6.91 and 5.93 points (P = .25), respectively. The mean VR-12 PCS improvement at 7-year follow-up (34.4% of the original matched cohort) for navigated and conventional cases was 13.00 and 12.92 points (P = .96) and for the VR-12 MCS was 4.83 and 6.30 points (P = .47), respectively. The mean improvement in the SF-6D utility score was 0.164 and 0.149 points at 12 months (P = .11) and at 7 years was 0.115 and 0.123 points (P = .69), respectively. Computer-navigated cases accumulated 0.809 QALYs in the first 7 years, compared to 0.875 QALYs in conventionally referenced cases (P = .65). There were no differences in these outcomes among a subgroup analysis of obese patients (body mass index ≥ 30 kg/m2). CONCLUSION: The use of computer navigation did not provide an incremental benefit to quality-of-life outcomes at a mean of 2.9 years following primary TKA performed for osteoarthritis when compared to conventional referencing techniques.

Patterns and Predictors of Outpatient Antibiotic Dispensation Following Total Hip and Knee Arthroplasty.

BACKGROUND: This study aimed to evaluate the month-to-month prevalence of antibiotic dispensation in the 12 months before and after total knee arthroplasty (TKA) and total hip arthroplasty (THA) and to identify factors associated with antibiotic dispensation in the month immediately following the surgical procedure. METHODS: In total, 4,115 THAs and TKAs performed between April 2013 and June 2019 from a state-wide arthroplasty referral center were analyzed. A cross-sectional study used data from an institutional arthroplasty registry, which was linked probabilistically to administrative dispensing data from the Australian Pharmaceutical Benefits Scheme. Multivariable logistic regression was carried out to identify patient and surgical risk factors for oral antibiotic dispensation. RESULTS: Oral antibiotics were dispensed in 18.3% of patients following primary TKA and 12.0% of patients following THA in the 30 days following discharge. During the year after discharge, 66.7% of TKA patients and 58.2% of THA patients were dispensed an antibiotic at some point. Patients with poor preoperative health status were more likely to have antibiotics dispensed in the month following THA or TKA. Older age, undergoing TKA rather than THA, obesity, inflammatory arthritis, and experiencing an in-hospital wound-related or other infectious complications were associated with increased antibiotic dispensation in the 30 days following discharge. CONCLUSION: A high rate of antibiotic dispensation in the 30 days following THA and TKA has been observed. Although resource constraints may limit routine wound review for all patients by a surgeon, a select cohort may benefit from timely specialist review postoperatively. Several risk factors identified in this study may aid in identifying appropriate candidates for such changes to follow-up care.

Placebo Surgery Controlled Trials: Do They Achieve What They Set Out To Do? A Systematic Review.

OBJECTIVE: To explore whether placebo surgery controlled trials achieve what they set out to do by investigating discrepancy between projected and actual design aspects of trials identified through systematic review methods. SUMMARY BACKGROUND: Interest in placebo surgery controlled trials is growing in response to concerns regarding unnecessary surgery and the societal cost of low-value healthcare. As questions about the justifiability of using placebo controls in surgery have been addressed, attention is now being paid to more practical concerns. METHODS: Six databases were searched from inception - May 2020 (MEDLINE, Embase, Emcare, APA PsycInfo, CINAHL, Cochrane Library). Placebo surgery controlled trials with a published protocol were included. Three authors extracted "projected" design aspects from protocols and "actual" design aspects from main findings papers. Absolute and relative difference between projected and actual design aspects were presented for each trial. Trials were grouped according to whether they met their target sample size ("completed") and were concluded in a timely fashion. Pairs of authors assessed risk of bias. RESULTS: Of 24 trials with data available to analyse; 3 were completed and concluded within target timeframe; 10 were completed and concluded outside the target timeline; 4 were completed without clear target timeframes; 2 were incomplete and concluded within the target framework; 5 were incomplete and concluded outside the target timeline. Trials which reached the recruitment target underestimated trial duration by 88% and number of recruitment sites by 87%. CONCLUSIONS: Trialists need to factor additional time and sites into future placebo surgery controlled trials. A robust reporting framework of projected and actual trial design is imperative for trialists to learn from their predecessors. REVIEW REGISTRATION: PROSPERO (CRD42019133296).

Assessing the suitability of general practice electronic health records for clinical prediction model development: a data quality assessment.

BACKGROUND: The use of general practice electronic health records (EHRs) for research purposes is in its infancy in Australia. Given these data were collected for clinical purposes, questions remain around data quality and whether these data are suitable for use in prediction model development. In this study we assess the quality of data recorded in 201,462 patient EHRs from 483 Australian general practices to determine its usefulness in the development of a clinical prediction model for total knee replacement (TKR) surgery in patients with osteoarthritis (OA). METHODS: Variables to be used in model development were assessed for completeness and plausibility. Accuracy for the outcome and competing risk were assessed through record level linkage with two gold standard national registries, Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and National Death Index (NDI). The validity of the EHR data was tested using participant characteristics from the 2014-15 Australian National Health Survey (NHS). RESULTS: There were substantial missing data for body mass index and weight gain between early adulthood and middle age. TKR and death were recorded with good accuracy, however, year of TKR, year of death and side of TKR were poorly recorded. Patient characteristics recorded in the EHR were comparable to participant characteristics from the NHS, except for OA medication and metastatic solid tumour. CONCLUSIONS: In this study, data relating to the outcome, competing risk and two predictors were unfit for prediction model development. This study highlights the need for more accurate and complete recording of patient data within EHRs if these data are to be used to develop clinical prediction models. Data linkage with other gold standard data sets/registries may in the meantime help overcome some of the current data quality challenges in general practice EHRs when developing prediction models.

Opioid Use and Total Joint Replacement.

PURPOSE OF REVIEW: We provide an overview of recent research into the relationship between preoperative opioid use and total joint replacement outcomes. RECENT FINDINGS: Recent findings indicate that total joint replacement patients with a history of preoperative opioid use experience higher rates of infection, revision, short-term complications, and prolonged postoperative opioid use, along with fewer improvements in pain and function following surgery. These risks are particularly pronounced among chronic opioid users. While the baseline risk profiles of these patients may contribute to higher rates of adverse outcomes, it is also plausible that certain outcomes are directly impacted by opioid use through mechanisms such as opioid-induced hyperalgesia and immunosuppression. There is little available data on the efficacy of interventions that aim to mitigate these risks. Well-designed clinical trials are needed to evaluate the efficacy of targeted perioperative interventions that aim to improve outcomes for this high-risk surgical population. Where such trials are not feasible, additional high-quality observational studies are necessary to further our understanding of the mechanisms underlying the relationships between opioid use and specific adverse outcomes.

What Influences Patient Satisfaction after TKA? A Qualitative Investigation.

BACKGROUND: Patient satisfaction is a common measure of the success of an orthopaedic intervention. However, there is poor understanding of what satisfaction means to patients or what influences it. QUESTIONS/PURPOSES: Using qualitative study methodology in patients undergoing TKA, we asked: (1) What does it mean to be satisfied after TKA? (2) What factors influence satisfaction levels after TKA? METHODS: People in a hospital registry who had completed 12-month follow-up questionnaires and were not more than 18 months post-TKA at the time of sampling were eligible (n = 121). To recruit a sample that provided insight into a range of TKA experiences, we divided eligible candidates on the registry into quadrants based on their responder status and satisfaction level. A responder was an individual who experienced a clinically meaningful change in pain and/or function on the WOMAC according to the Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) responder criteria. Individuals were considered satisfied unless they indicated somewhat dissatisfied or very dissatisfied for one or more of the four items on the Self-Administered Patient Satisfaction Scale. From the resulting quadrants: responder satisfied, nonresponder satisfied, nonresponder dissatisfied, responder dissatisfied, we identified men and women with a range of ages and invited them to participate (n = 85). The final sample (n = 40), consisted of 10 responder satisfied, nine nonresponder satisfied, eight nonresponder dissatisfied, and 13 responder dissatisfied; 71% were women, with a mean age of 71 ± 7 years and a mean time since TKA surgery of 17 ± 2 months (range 13 to 25 months). Interview transcripts were analyzed by looking for factors in the participants' narrative that appeared to underscore their level of satisfaction and attaching inductive (data-derived, rather than a priori derived) codes to relevant sections of text. Coded data from participants who reported high and low levels of satisfaction were compared/contrasted and emerging patterns were mapped into a conceptual model. Recruitment continued until no new information was uncovered in data analysis of subsequent interviews, signalling to the researchers that further interviews would not change the key themes identified and data collection could cease. RESULTS: In those with high satisfaction levels, satisfaction was conceptualized as an improvement in pain and function. In those with low satisfaction levels, rather than an improvement, satisfaction was conceptualized as completely resolving all symptoms and functional limitations. In addition, we identified three pathways through which participants reached different levels of low and high satisfaction: (1) The full-glass pathway, characterized by no or minimal ongoing symptoms and functional deficits, which consistently led to high levels of satisfaction; (2) the glass-half-full pathway, characterized by ongoing symptoms and functional limitations, which led to high satisfaction; and (3) the glass-half-empty pathway, also characterized by ongoing symptoms and functional limitations, which led to low satisfaction levels. The latter two pathways were mediated by three core mechanisms (recalibration, reframing valued activities, and reconceptualization) influenced either positively or negatively by (1) a persons' thoughts and feelings such as optimism, self-efficacy, pain catastrophizing, external locus of control; and (2) social and contextual factors such as fulfilment of social roles, therapeutic alliance, lack of family/social support. CONCLUSIONS: This qualitative study suggests that for preoperative patients in whom unrealistically high hopes for complete symptom resolution and restoration of functional capacity persists, it may be appropriate to direct them away from TKA due to the risk of low satisfaction. For postoperative patients troubled by ongoing symptoms or functional limitations, clinicians may improve levels of satisfaction by targeting the three core mechanisms (recalibration, reframing valued activities, and reconceptualization) through addressing modifiable negative thoughts and feelings in interventions such as psychology or psychotherapy; and negative social and contextual factors by promoting a strong therapeutic alliance and engagement in community activities. Given that these factors may be identifiable preoperatively, future research is needed to explore if and how addressing them preoperatively may improve satisfaction post-TKA. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Better Knee, Better Me™: effectiveness of two scalable health care interventions supporting self-management for knee osteoarthritis - protocol for a randomized controlled trial.

BACKGROUND: Although education, exercise, and weight loss are recommended for management of knee osteoarthritis, the additional benefits of incorporating weight loss strategies into exercise interventions have not been well investigated. The aim of this study is to compare, in a private health insurance setting, the clinical- and cost-effectiveness of a remotely-delivered, evidence- and theory-informed, behaviour change intervention targeting exercise and self-management (Exercise intervention), with the same intervention plus active weight management (Exercise plus weight management intervention), and with an information-only control group for people with knee osteoarthritis who are overweight or obese. METHODS: Three-arm, pragmatic parallel-design randomised controlled trial involving 415 people aged ≥45 and ≤ 80 years, with body mass index ≥28 kg/m2 and < 41 kg/m2 and painful knee osteoarthritis. Recruitment is Australia-wide amongst Medibank private health insurance members. All three groups receive access to a bespoke website containing information about osteoarthritis and self-management. Participants in the Exercise group also receive six consultations with a physiotherapist via videoconferencing over 6 months, including prescription of a strengthening exercise and physical activity program, advice about management, and additional educational resources. The Exercise plus weight management group receive six consultations with a dietitian via videoconferencing over 6 months, which include a very low calorie ketogenic diet with meal replacements and resources to support behaviour change, in addition to the interventions of the Exercise group. Outcomes are measured at baseline, 6 and 12 months. Primary outcomes are self-reported knee pain and physical function at 6 months. Secondary outcomes include weight, physical activity levels, quality of life, global rating of change, satisfaction with care, knee surgery and/or appointments with an orthopaedic surgeon, and willingness to undergo surgery. Additional measures include adherence, adverse events, self-efficacy, and perceived usefulness of intervention components. Cost-effectiveness of each intervention will also be assessed. DISCUSSION: This pragmatic study will determine whether a scalable remotely-delivered service combining weight management with exercise is more effective than a service with exercise alone, and with both compared to an information-only control group. Findings will inform development and implementation of future remotely-delivered services for people with knee osteoarthritis. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12618000930280 (01/06/2018).

Risk Factors for Chronic Opioid Use Following Hip and Knee Arthroplasty: Evidence from New Zealand Population Data.

BACKGROUND: Patients awaiting total joint arthroplasty (TJA) have high rates of opioid use, and many continue to use opioid medications long term after surgery. The objective of this study is to estimate the risk factors associated with chronic opioid use after TJA in a comprehensive population-based cohort. METHODS: All patients undergoing TJA in the New Zealand public healthcare system were identified from Ministry of Health records. Dispensing of opioid medications up to 3 years postsurgery and potential risk factors, including demographic, socioeconomic, and surgery-related characteristics, pre-existing medical comorbidities, and use of other analgesic medications prior to surgery, were identified from linked population databases. Logistic regression analysis was used to identify factors associated with chronic postoperative opioid use. RESULTS: The strongest risk factor for chronic postoperative opioid use was preoperative opioid use. Other significant risk factors included perioperative opioid use, history of alcohol or drug abuse, younger age, female gender, knee arthroplasty, several comorbid health conditions, and preoperative use of some analgesic medications. Protective factors included higher education levels and preoperative use of nonsteroidal anti-inflammatory drugs. Most risk factors had similar effects on chronic postoperative opioid use irrespective of the length of follow-up considered (1, 2, or 3 years). CONCLUSION: This study of a comprehensive nationwide population-based cohort of TJA patients with 3 years of follow-up identified several modifiable risk factors and other easily measured patient characteristics associated with higher risk of long-term postoperative opioid use.

A Randomized Controlled Trial Comparing a Medial Stabilized Total Knee Prosthesis to a Cruciate Retaining and Posterior Stabilized Design: A Report of the Clinical and Functional Outcomes Following Total Knee Replacement.

BACKGROUND: The purpose of this randomized controlled trial was to compare the performance of 3 total knee joint replacement (TKJR) designs 6 months after the surgery. METHODS: Patients were recruited between March 2015 and March 2018. Patients with osteoarthritis consented for TKJR were randomly allocated to a medial stabilized (MS), cruciate retaining (CR), or posterior stabilized (PS) design. Primary outcome measures were self-reported improvement in pain and function 6 months after TKJR, using the Oxford Knee Score. Secondary outcome measures were the Western Ontario and McMaster Universities Osteoarthritis Index, Veterans RAND 12-item Health Survey, Knee Society Score 2011, Timed Up and Go test, and Six-Minute Walk Test. Twelve-month outcomes were also measured. RESULTS: Ninety participants enrolled, 83 were randomized: PS (n = 26), CR (n = 28), and MS (n = 29) designs. One case withdrew before surgery: planned use of non-study implant; 7 did not complete all outcome measures. No 6-month between-group difference was observed for the primary outcome. A 6-month difference was observed in Knee Society Score 2011 Satisfaction: MS favored over CR and PS. Clinically meaningful 12-month differences in Western Ontario and McMaster Universities Osteoarthritis Index Pain, Function, and Global Subscales were observed: MS favored over CR. Twelve-month differences occurred in Veterans RAND 12-item Health Survey mental well-being, favoring MS and PS over CR. CONCLUSION: MS prosthesis can be expected to yield similar clinical and functional outcomes to PS and CR designs 6 months after TKJR, and patients were more satisfied with their outcome. Compared with CR, patients with MS prosthesis also reported superior pain, function, and quality-of-life outcomes at 12 months.

Knee Arthroplasty Component Malrotation Does Not Affect Function or Quality of Life in the Short to Medium Term.

BACKGROUND: Component rotation in total knee arthroplasty is thought to affect patella tracking, flexion gap, and balancing and hence is hypothesized to affect function, pain, and longevity. Few studies have directly correlated post-operative component rotation to function and quality of life in the short to medium term post-operatively, with findings in the current literature conflicting. METHODS: A retrospective study of prospectively collected data was used to determine the effect of femoral, tibial, and combined component rotation in primary total knee arthroplasty with primary outcomes being function as measured by the Knee Society Score, pain and quality of life as measured by the Short-Form 12 score, and secondary outcome being prosthesis failure. Malrotation was defined using the current literature as being internally rotated from neutral, or externally rotated greater than 5° for the femoral component, internally rotated greater than 6° for the tibial component, or internally rotated from neutral for the 2 components combined. RESULTS: No clinically relevant correlation between function or quality of life and component rotation could be found at 5 years. However, it was noted that those patients with combined component malrotation (femoral rotation added to tibial rotation resulting in overall component internal rotation) improved less in overall pain scores than those that were not malrotated. CONCLUSION: In the mid-term, component malrotation may result in a decreased level of improvement from pain compared to pre-operative results. However, component malrotation does not make a significant difference to function or quality of life. LEVEL OF EVIDENCE: Level III: Therapeutic Study.

Body Mass Index Is Associated With All-cause Mortality After THA and TKA.

BACKGROUND: Both obesity and underweight are associated with a higher risk of mortality in adulthood, but the association between mortality after arthroplasty and extreme ranges of body mass index (BMI) have not been evaluated beyond the first year. QUESTIONS/PURPOSES: The purpose of this study was to investigate the association between BMI and all-cause mortality after TKA and THA. METHODS: Data from two arthroplasty registries, the St Vincent's Melbourne Arthroplasty (SMART) Registry from Australia and the Kaiser Permanente Total Joint Replacement Registry (KPTJRR) from the United States, were used to identify patients aged ≥ 18 years undergoing elective TKAs and THAs between January 1, 2002, and December 31, 2013. Same-day bilateral THA and hemiarthroplasties were excluded. All-cause mortality was recorded from the day of surgery to the end of the study (December 31, 2013). Data capture was complete for the SMART Registry. No patients were lost to followup in the KPTJRR cohort and 2959 (5%) THAs and 5251 (5%) TKAs had missing data. Cox proportional hazard regression was used to estimate the all-cause mortality associated with six BMI categories: underweight (< 18.5 kg/m), normal weight (18.5-24.9 kg/m), overweight (25.0-29.9 kg/m), obese class I (30.0-34.9 kg/m), obese class II (35.0-39.9 kg/m), and obese class III (> 40 kg/m). For TKA, the SMART cohort had a median followup of 5 years (range, 0-12 years) and the KPTJRR cohort had a median followup of 4 years (range, 0-12 years). For THA, the SMART cohort had a median followup of 5 years (range, 0-12 years) and the KPTJRR cohort had a median followup of 4 years (range, 0-12 years). RESULTS: In both the Australian and US cohorts, being underweight (Australia: hazard ratio [HR], 3.72; 95% confidence interval [CI], 1.94-7.08; p < 0.001 and United States: HR, 1.88; 95% CI, 1.33-2.64; p < 0.001) was associated with higher all-cause mortality after TKA, whereas obese class I (Australia: HR, 0.66; 95% CI, 0.47-0.92; p = 0.015; United States: HR, 0.71; 95% CI, 0.66-0.78; p < 0.001) or obese class II (Australia: HR, 0.54; 95% CI, 0.35-0.82; p = 0.004; United States: HR, 0.73; 95% CI, 0.66-0.81; p < 0.001) was associated with lower mortality when compared with normal-weight patients. In the US cohort, being overweight was also associated with a lower risk of mortality (HR, 0.76; 95% CI, 0.71-0.82; p < 0.001). In the US cohort, being underweight had a higher risk of mortality after THA (HR, 2.09; 95% CI, 1.65-2.64; p < 0.001), whereas those overweight (HR, 0.73; 95% CI, 0.67-0.80; p < 0.001), obese class I (HR, 0.68; 95% CI, 0.62-0.75; p < 0.001), or obese class II (HR, 0.71; 95% CI, 0.62-0.81; p < 0.001) were at a lower risk of mortality after THA when compared with normal-weight patients. In patients undergoing THA in the Australian cohort, we observed no association between BMI and risk of death. CONCLUSIONS: We found that even severe obesity is not associated with a higher risk of death after arthroplasty. Patients should be informed of this when considering surgery. Clinicians should be cautious when considering total joint arthroplasty in underweight patients without first considering their nutritional status. LEVEL OF EVIDENCE: Level III, therapeutic study.

What Is the Impact of Advancing Age on the Outcomes of Total Hip Arthroplasty?

BACKGROUND: The global demand for total hip arthroplasty (THA) is increasing, underscoring its moniker as the "operation of the century." However, debate still exists as to whether the elderly who undergo the operation achieve the same outcomes as those younger. In this study, we sought to investigate the association between older age and the risks and benefits of THA. METHODS: In this study, we aimed to compare the risks and benefits of THA of those aged ≥80 years vs those <80 years. We analyzed the physical status component of the Short-Form 12 Health Survey, complications within 12 months, all-cause mortality, length of hospital stay (LOS), and discharge to rehabilitation in 2457 cases of primary THA using multivariate modeling. RESULTS: There was no difference in improvement of those older vs the younger group in physical functioning. However, the older group had 2.87 times greater odds of experiencing a post-operative medical complication and 3.49 times the rate of all-cause mortality (P < .001). Additionally, the older group encountered an additional median 0.21-day increase in LOS and had 3.93 times greater odds of being discharged to rehabilitation rather than home (P < .001). We were unable to demonstrate any difference between groups in terms of post-operative surgical or wound-related complications. CONCLUSION: The elderly stand to gain equivalent benefits from THA as those younger in terms of physical functioning. However, this benefit needs to be balanced against the increased risk of post-operative medical complications, increased LOS, increased requirement for rehabilitation, and ultimately the increased risk of mortality.

Gap Balancing Sacrifices Joint-Line Maintenance to Improve Gap Symmetry: 5-Year Follow-Up of a Randomized Controlled Trial.

BACKGROUND: Gap balancing (GB) has been noted to sacrifice joint-line maintenance to improve gap symmetry. This study aims to determine whether this change affects function or quality of life in the midterm. METHODS: A prospective blinded randomized controlled trial was completed with 103 patients randomized to measured resection (n = 52) or GB (n = 51). Primary outcome measured was femoral component rotation. Secondary outcomes measured were joint-line change, gap symmetry, and function and quality-of-life outcomes. RESULTS: At 5 years, 83 of 103 patients (85%) were assessed. There was no significant difference between groups in terms of functional or quality of life outcomes. A subgroup analysis revealed that there was no significant association between those with asymmetrical flexion and/or extension or medial and/or lateral gaps during knee replacement and subsequent functional outcomes. No significant difference was detected with those with an elevated joint line and postoperative function. CONCLUSION: In the midterm, the resultant change in joint-line and maintained gap symmetry noted with GB does not result in significant change to function or quality of life.

The Impact of Regression to the Mean on Economic Evaluation in Quasi-Experimental Pre-Post Studies: The Example of Total Knee Replacement Using Data from the Osteoarthritis Initiative.

Many treatments are evaluated using quasi-experimental pre-post studies susceptible to regression to the mean (RTM). Ignoring RTM could bias the economic evaluation. We investigated this issue using the contemporary example of total knee replacement (TKR), a common treatment for end-stage osteoarthritis of the knee. Data (n = 4796) were obtained from the Osteoarthritis Initiative database, a longitudinal observational study of osteoarthritis. TKR patients (n = 184) were matched to non-TKR patients, using propensity score matching on the predicted hazard of TKR and exact matching on osteoarthritis severity and health-related quality of life (HrQoL). The economic evaluation using the matched control group was compared to the standard method of using the pre-surgery score as the control. Matched controls were identified for 56% of the primary TKRs. The matched control HrQoL trajectory showed evidence of RTM accounting for a third of the estimated QALY gains from surgery using the pre-surgery HrQoL as the control. Incorporating RTM into the economic evaluation significantly reduced the estimated cost effectiveness of TKR and increased the uncertainty. A generalized ICER bias correction factor was derived to account for RTM in cost-effectiveness analysis. RTM should be considered in economic evaluations based on quasi-experimental pre-post studies. Copyright © 2017 John Wiley & Sons, Ltd.