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Cementless tibial components have shown improvements in clinical performance compared to predicate designs, though evidence supporting mid-term performance and fixation is scarce. The purpose of this study is to determine the mid-term survivorships, revision rates, and reasons why 3-dimensional printed cementless tibial baseplates (3DTKAs) failed compared to other cementless as well as cemented tibial baseplates reported from the American Joint Replacement Registry (AJRR) data.All primary total knee arthroplasty (TKA) cases performed in patients 65 years of age or older within the AJRR from January 2, 2012 through June 30, 2020 were queried. A total of 28,631 3DTKAs were identified from 428 institutions. These were compared to all other "aggregated cementless tibia" (n = 7,577) and "aggregated cemented tibia" (n = 550,133) cases. Centers for MedicareMedicaid Services data over the same time period were merged with AJRR data to determine survivorship and patient-timed incident revision rates per 1,000 years. Failure reasons were tracked during this study period.At 60 months, Kaplan-Meier implant survivorship was 98.9% (CI 98.7-99.0), 98.3% (CI 97.9-98.6), and 98.4% (CI 98.4-98.5) in the 3DTKA, aggregate cementless, and cemented knee cohorts, respectively (P .0001). Patient-timed incident revision rates were 3.11 (CI 2.75-3.53), 3.99 (CI 3.34-4.76), and 3.35 (CI 3.28-3.42) for those cohorts, which corresponds to a revision rate of 0.31%, 0.40%, and 0.34% per year.In this analysis, 3DTKA had favorable survivorship and lower revision rates compared to aggregate cementless and cemented TKAs implanted from the same national database during the same time period.

Aims Thresholds of acceptable early migration of the components in total knee arthroplasty (TKA) have traditionally ignored the effects of patient and implant factors that may influence migration. The aim of this study was to determine which of these factors are associated with overall longitudinal migration of well-fixed tibial components following TKA. Methods Radiostereometric analysis (RSA) data over a two-year period were available for 419 successful primary TKAs (267 cemented and 152 uncemented in 257 female and 162 male patients). Longitudinal analysis of data using marginal models was performed to examine the associations of patient factors (age, sex, BMI, smoking status) and implant factors (cemented or uncemented, the size of the implant) with maximum total point motion (MTPM) migration. Analyses were also performed on subgroups based on sex and fixation. Results In the overall group, only fixation was significantly associated with migration (p < 0.001). For uncemented tibial components in males, smoking was significantly associated with lower migration (p = 0.030) and BMI approached significance (p = 0.061). For females with uncemented components, smoking (p = 0.081) and age (p = 0.063) approached significance and were both associated with increased migration. The small number of self-reported smokers in this study warrants cautious interpretation and further investigation. For cemented components in females, larger sizes of tibial component were significantly associated with increased migration (p = 0.004). No factors were significant for cemented components in males. Conclusion The migration of uncemented tibial components was more sensitive to patient factors than cemented implants. These differences were not consistent by sex, suggesting that it may be of value to evaluate female and male patients separately following TKA. Cite this article: Bone Joint J 2022;104-B(4):444–451.

Rising total knee arthroplasty (TKA) rates in younger patients raises concern about appropriateness. We asked: are younger individuals who seek consultation for TKA less likely to be appropriate for and, controlling for appropriateness, more likely to be recommended for surgery?This cross-sectional study was nested within a prospective cohort study of knee osteoarthritis (OA) patients referred for TKA from 2014 to 2016 to centralized arthroplasty centers in Alberta, Canada. Pre-consultation, questionnaires assessed patients' TKA appropriateness (need, based on knee symptoms and prior treatment; readiness/willingness to undergo TKA; health status; and expectations) and contextual factors (for example, employment). Post-consultation, surgeons confirmed study eligibility and reported their TKA recommendation. Using generalized estimating equations to control for clustering by surgeon, we assessed relationships between patient age (50, 50 to 59, ≥60 years) and TKA appropriateness and receipt of a surgeon TKA recommendation.Of 2,037 participants, 3.3% and 22.7% were50 and 50 to 59 years of age, respectively, 58.7% were female, and 35.5% were employed. Compared with older participants, younger participants reported significantly worse knee symptoms, higher use of OA therapies, higher TKA readiness, and similar willingness, but had higher body mass index and were more likely to smoke and to consider the ability to participate in vigorous activities, for example, sports, as very important TKA outcomes. TKA was offered to 1,500 individuals (73.6% overall; 52.2%, 71.0%, and 75.4% of those50, 50 to 59, and ≥60 years, respectively). In multivariate analyses, the odds of receiving a TKA recommendation were higher with greater TKA need and willingness, in nonsmokers, and in those who indicated that improved ability to go upstairs and to straighten the leg were very important TKA outcomes. Controlling for TKA appropriateness, patient age was not associated with surgeons' TKA recommendations.Younger individuals with knee OA referred for TKA had similar or greater TKA need, readiness, and willingness than older individuals. Incorporation of TKA appropriateness criteria into TKA decision-making may facilitate consideration of TKA benefits and risks in a growing population of young, obese individuals with knee OA.Younger people seeking TKA for knee OA had significant OA pain and disability despite recommended OA therapies, suggesting appropriateness for surgical consideration. However, they were significantly more likely to have morbid obesity, to smoke, and to consider return to vigorous activities, like sport, as important TKA outcomes. Whether the short- and longer-term risks of TKA are outweighed by the benefits is unclear and warrants additional research.

River impoundments have transformed river ecosystems globally due to the modification of various abiotic and biotic factors. This study provides rare evidence quantifying how water supply reservoirs alter water temperature regimes and its effects on macroinvertebrate and diatom communities over a 4-year period. We obtained near-continuous water temperature measurements upstream and downstream of three reservoirs and analysed thermal variables in association with macroinvertebrate and diatom community indices (including taxonomic richness, proportion of Ephemeroptera, Plecoptera and Trichoptera taxa [%EPT] and diatom ecological guilds). Reservoirs typically decreased downstream thermal variability, with reduced summer temperatures and increased winter temperatures, and a delayed timing of annual temperature extremes. Marked differences in thermal regime modifications between reservoirs were observed, including evidence of inter-annual variation associated with inter-basin water transfers downstream of one reservoir. Biomonitoring indices showed associations with thermal indices that differed between site types (regulated versus non-regulated) and seasons (spring vs. autumn). Various macroinvertebrate and diatom indices capturing community diversity elements and sensitivities to different environmental pressures were associated with higher maximum summer temperatures and lower minimum winter temperatures, suggesting ecological effects of reduced thermal variation downstream of reservoirs. Different ecological responses to thermal indices were observed between seasons, likely due to organism life-cycle effects and intra-annual thermal variations. Contrasting macroinvertebrate and diatom communities were observed between regulated and non-regulated sites, which may be driven by differences in the thermal regime and other abiotic factors at regulated sites, including nutrient, sediment and flow regimes. Long-term continuous water temperature monitoring of both multiple regulated and non-regulated river systems is necessary to better understand the environmental and ecological effects of river impoundments. Given the extent to which river impoundment has modified stream temperatures globally, the inclusion of thermal regime data in environmental flow studies alongside hydrological information may guide the implementation of mitigation measures on impounded waterbodies. Natural Environment Research Council (NERC): NE/L002493/1

Aims In countries with social healthcare systems, such as Canada, patients may experience long wait times and a decline in their health status prior to their operation. The aim of this study is to explore the association between long preoperative wait times (WT) and acute hospital length of stay (LoS) for primary arthroplasty of the knee and hip. Methods The study population was obtained from the provincial Patient Access Registry Nova Scotia (PARNS) and the Canadian national hospital Discharge Access Database (DAD). We included primary total knee and hip arthroplasties (TKA, THA) between 2011 and 2017. Patients waiting longer than the recommended 180 days Canadian national standard were compared to patients waiting equal or less than the standard WT. The primary outcome measure was acute LoS postoperatively. Secondarily, patient demographics, comorbidities, and perioperative parameters were correlated with LoS with multivariate regression. Results A total of 11,833 TKAs and 6,627 THAs were included in the study. Mean WT for TKA was 348 days (1 to 3,605) with mean LoS of 3.6 days (1 to 98). Mean WT for THA was 267 days (1 to 2,015) with mean LoS of 4.0 days (1 to 143). There was a significant increase in mean LoS for TKA waiting longer than 180 days (2.5% (SE 1.1); p = 0.028). There was no significant association for THA. Age, sex, surgical year, admittance from home, rural residence, household income, hospital facility, the need for blood transfusion, and comorbidities were all found to influence LoS. Conclusion Surgical WT longer than 180 days resulted in increased acute LoS for primary TKA. Meeting a shorter WT target may be cost-saving in a social healthcare system by having shorter LoS. Cite this article: Bone Jt Open 2021;2(8):679–684.

Total knee arthroplasty (TKA) surgery improves knee joint kinematics and kinetics during gait for most patients, but a lack of evidence exists for the level and incidence of improvement that is achieved. The objective of this study was to quantify patient-specific improvements in knee biomechanics relative to osteoarthritis (OA) severity levels. Seventy-two patients underwent 3-dimensional (3D) gait analysis before and 1 year after TKA surgery, as well as 72 asymptomatic adults and 72 with moderate knee OA. A combination of principal component analysis and discriminant analyses were used to categorize knee joint biomechanics for patients before and after surgery relative to asymptomatic, moderate, and severe OA. Post-TKA, 63% were categorized with knee biomechanics consistent with moderate OA, 29% with severe OA, and 8% asymptomatic. The magnitude and pattern of the knee adduction moment and angle (frontal plane features) were the most significant contributors in discriminating between pre-TKA and post-TKA knee biomechanics. Standard of care TKA improves knee biomechanics during gait to levels most consistent with moderate knee OA and predominately targets frontal plane features. These results provide evidence for the level of improvement in knee biomechanics that can be expected following surgery and highlight the biomechanics most targeted by surgery.

Objective To assess the relationship between patients' expectations for total knee arthroplasty (TKA) and satisfaction with surgical outcome. Methods This prospective cohort study recruited patients with knee osteoarthritis (OA) ages ≥30 years who were referred for TKA at 2 hip/knee surgery centers in Alberta, Canada. Those who received primary, unilateral TKA completed questionnaires pre-TKA to assess TKA expectations (17-item Hospital for Special Surgery [HSS] TKA Expectations questionnaire) and contextual factors (age, sex, Western Ontario and McMaster Universities Osteoarthritis Index pain score, Knee Injury and Osteoarthritis Outcome Score physical function short form [KOOS-PS], 8-item Patient Health Questionnaire depression scale, body mass index [BMI], comorbidities, and prior joint replacement), and 1-year post-TKA to assess overall satisfaction with TKA results. Using multivariate logistic regression, we examined the relationship between TKA expectations (HSS TKA outcomes considered to be very important) and postoperative satisfaction (very satisfied versus somewhat satisfied versus dissatisfied). Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Results At 1 year, 1,266 patients with TKA (92.1%) reported their TKA satisfaction (mean ± SD age 67.2 ± 8.8 years, 60.9% women, and mean BMI 32.6 kg/m2 ); 74.7% of patients were very satisfied, 17.1% were somewhat satisfied, and 8.2% were dissatisfied. Controlling for other factors, an expectation of TKA to improve patients' ability to kneel was associated with lower odds of satisfaction (adjusted OR 0.725 [95% CI 0.54-0.98]). An expectation of TKA to improve psychological well-being was associated with lower odds of satisfaction for individuals in the lowest tertile of pre-TKA KOOS-PS scores (adjusted OR 0.49 [95% CI 0.28-0.84]), but higher odds for those in the highest tertile (adjusted OR 2.37 [95% CI 1.33-4.21]). Conclusion In patients with TKA, preoperative expectations regarding kneeling and psychological well-being were significantly associated with the level of TKA satisfaction at 1 year. Ensuring that patients' expectations are achievable may enhance appropriate provision of TKA.

Knee osteoarthritis patient phenotyping is relevant to developing targeted treatments and assessing the treatment efficacy of total knee arthroplasty (TKA). This study aimed to identify clusters among TKA candidates based on demographic and knee mechanic features during gait, and compare gait changes between clusters postoperatively. TKA patients underwent 3D gait analysis 1-week pre (n = 134) and 1-year post-TKA (n = 105). Principal component analysis was applied to frontal and sagittal knee angle and moment waveforms, extracting major patterns of variability. Age, sex, body mass index, gait speed, and frontal and sagittal pre-TKA angle and moment PC scores previously identified as relevant to TKA outcomes were standardized (mean = 0, SD = 1, [134 × 15]). Multidimensional scaling and machine learning-based hierarchical clustering were applied. Final clusters were validated by examining intercluster differences pre-TKA and gait feature changes (Post

Summary Background Although opioid analgesics are not generally recommended for treatment of knee osteoarthritis (OA), they are frequently used. We sought to determine the association between medical comorbidities and self-reported opioid analgesic use in these patients. Methods This cross-sectional study recruited patients referred to two provincial hip and knee clinics in Alberta, Canada for consideration of total knee arthroplasty. Standardized questionnaires assessed demographic (age, gender, income, education, social support, smoking status) and clinical (pain, function, total number of troublesome joints) characteristics, comorbid medical conditions, and non-surgical OA management participants had ever used or were currently using. Multivariable Poisson regression with robust estimate of the standard errors assessed the association between comorbid medical conditions and current opioid use, controlling for potential confounders. Results 2,127 patients were included: mean age 65.4 (SD 9.1) years and 59.2% female. Currently used treatments for knee OA were: 57.6% exercise and/or physiotherapy, 61.1% NSAIDs, and 29.8% opioid analgesics. In multivariable regression, controlling for potential confounders, comorbid hypertension (RR 1.18, 95% CI 1.02–1.37), gastrointestinal disease (RR 1.31, 95% CI 1.07–1.60), depressed mood (RR 1.25, 95% CI 1.05–1.48) and a higher number of troublesome joints (RR 1.04 per joint, 95% CI 1.00–1.09) were associated with opioid use, with no association found with having ever used recommended non-opioid pharmacological or non-pharmacological treatments. Conclusions In a large cohort of patients with knee OA, of 12 comorbidities assessed, comorbid hypertension, gastrointestinal disease, and depressed mood were associated with current use of opioid analgesics, in addition to total burden of troublesome joints. Improved guidance on the management of painful OA in the setting of common comorbidities is warranted.

The concept of environmental flows has been developed to manage human alteration of river flow regimes, as effective management requires an understanding of the ecological consequences of flow alteration. This study explores the concept of macroinvertebrate sensitivity to river flow alteration to establish robust quantitative relationships between biological indicators and hydrological pressures. Existing environmental flow classifications used by the environmental regulator for English rivers were tested using multilevel regression modelling. Results showed a weak relationship between the current abstraction sensitivity classification and macroinvertebrate response to flow pressure. An alternative approach, based on physically‐derived river types, was a better predictor of macroinvertebrate response. Intermediate sized lowland streams displayed the best model fit, while upland rivers exhibited poor model performance. A better understanding of the ecological response to flow variation in different river types could help water resource managers develop improved ecologically appropriate flow regimes, which support the integrity of river ecosystems.

To assess (1) patient expectations before total hip (THR) and knee (TKR) replacement; (2) which expectations are met and unmet 6 and 12 months post-surgery; (3) the role of unmet expectations in satisfaction. Questionnaires were mailed to consecutive patients following surgeon referral for primary THR or TKR. Patients listed their own expectations and also completed the Hospital for Special Surgery (HSS) Expectation Survey. We used content analysis to group expectations into themes. At 6 and 12 months post-surgery, patients were given a copy of their own list of individual expectations and reassessed each one as met or unmet. We also assessed fulfilled HSS expectations and satisfaction with surgery. The sample of 556 patients (49% THR, 57% female) had a mean age of 64 years (SD10). The five most frequent expectation themes were pain relief, mobility, walking, physical activities, and daily activities. Of these, physical activities had the lowest percentage met 12 months post-surgery. 95% (THR) and 87% (TKR) were satisfied/very satisfied with their surgery 12 months post-surgery. Very satisfied patients had a significantly greater percentage of met expectations (96% THR; 92% TKR) than dissatisfied patients (42% THR; 12% TKR). Although most expectations listed by patients were included in the HSS surveys, some were not, particularly for TKR. From 6 to 12 months, there was a significant increase in patient satisfaction for self-care, daily activities, and met expectations for THR and pain relief, self-care, daily activities, and recreational activities for TKR. Expectations should be explicitly addressed before surgery, including a discussion of realistic expectations, particularly for physical activities.

Aims A retrospective study was conducted to measure short-term in vivo linear and volumetric wear of polyethylene (PE) inserts in 101 total knee arthroplasty (TKA) patients using model-based radiostereometric analysis (MBRSA). Patients and Methods Nonweightbearing supine RSA exams were performed postoperatively and at six, 12, and 24 months. Weightbearing standing RSA exams were performed on select patients at 12 and 24 months. Wear was measured both linearly (joint space) and volumetrically (digital model overlap) at each available follow-up. Precision of both methods was assessed by comparing double RSA exams. Patient age, sex, body mass index, and Oxford Knee Scores were analyzed for any association with PE wear. Results Linear wear occurred at 0.015 mm/year (supine) and 0.220 mm/year (standing). Volumetric wear occurred at 10.3 mm3/year (supine) and 39.3 mm3/year (standing). Wear occurred primarily on the medial side of the joint. Weightbearing imaging greatly improved the reliability of measurement. Clinical precision of volumetric wear was 34 mm3. No significant associations were found between patient demographics or function scores and measured wear. Conclusion In vivo volumetric wear of TKAs can be assessed at short-term follow-up using MBRSA. Cite this article: Bone Joint J 2019;101-B:1348–1355.

Aims Patient-specific instrumentation of total knee arthroplasty (TKA) is a technique permitting the targeting of individual kinematic alignment, but deviation from a neutral mechanical axis may have implications on implant fixation and therefore survivorship. The primary objective of this randomized controlled study was to compare the fixation of tibial components implanted with patient-specific instrumentation targeting kinematic alignment (KA+PSI) versus components placed using computer-assisted surgery targeting neutral mechanical alignment (MA+CAS). Tibial component migration measured by radiostereometric analysis was the primary outcome measure (compared longitudinally between groups and to published acceptable thresholds). Secondary outcome measures were inducible displacement after one year and patient-reported outcome measures (PROMS) over two years. The secondary objective was to assess the relationship between alignment and both tibial component migration and inducible displacement. Patients and Methods A total of 47 patients due to undergo TKA were randomized to KA+PSI (n = 24) or MA+CAS (n = 23). In the KA+PSI group, there were 16 female and eight male patients with a mean age of 64 years (sd 8). In the MA+CAS group, there were 17 female and six male patients with a mean age of 63 years (sd 7). Surgery was performed using cemented, cruciate-retaining Triathlon total knees with patellar resurfacing, and patients were followed up for two years. The effect of alignment on tibial component migration and inducible displacement was analyzed irrespective of study group. Results There was no difference over two years in longitudinal migration of the tibial component between the KA+PSI and MA+CAS groups (reaching median maximum total point motion migration at two years of 0.40 mm for the KA+PSI group and 0.37 mm for the MA+CAS group, p = 0.82; p = 0.68 adjusted for age, sex, and body mass index (BMI) for all follow-ups). Both groups had mean migrations below acceptable thresholds. There was no difference in inducible displacement (p = 0.34) or PROMS (p = 0.61 for the Oxford Knee Score) between groups. There was no correlation between alignment and tibial component migration or alignment and inducible displacement. These findings support non-neutral alignment as a viable option with this component, with no evidence that it compromises fixation. Conclusion Kinematic alignment using patient-specific instrumentation in TKA was associated with acceptable tibial component migration, indicating stable fixation. These results are supportive of future investigations of kinematic alignment. Cite this article: Bone Joint J 2019;101-B:929–940.

Aims Early implant migration measured with radiostereometric analysis (RSA) has been proposed as a useful predictor of long-term fixation of tibial components in total knee arthroplasty. Evaluation of actual long-term fixation is of interest for cemented components, as well as for cementless fixation, which may offer long-term advantages once osseointegration has occurred. The objective of this study was to compare the long-term migration with one- and two-year migration to evaluate the predictive ability of short-term migration data and to compare migration and inducible displacement between cemented and cementless (porous metal monoblock) components at least ten years postoperatively. Patients and Methods Patients who had participated in RSA migration studies with two-year follow-up were recruited to return for a long-term follow-up, at least ten years from surgery. Two cemented tibial designs from two manufacturers and one porous metal monoblock cementless tibial design were studied. At the long-term follow-up, patients had supine RSA examinations to determine migration and loaded examinations (single leg stance) to determine inducible displacement. In total, 79 patients (54 female) returned, with mean time since surgery of 12 years (10 to 14). There were 58 cemented and 21 cementless tibial components. Results Migration at one year and two years was significantly correlated with long-term migration (p < 0.001). Median migration at the long-term follow-up was 0.6 mm (maximum total point motion; interquartile range (IQR) 0.4 to 0.9) for the cemented group and 0.6 mm (IQR 0.3 to 1.1) for the cementless group with no difference between groups (p = 0.99). Inducible displacement was significantly lower for the cementless components (p < 0.001). Conclusion Long-term migration was strongly correlated with two-year migration. Although long-term migration was not different for cemented or cementless tibial components, inducible displacement at the long-term visit was significantly lower for these cementless components, suggesting superior fixation. These findings support the predictive value of short-term migration in determining long-term fixation. Cite this article: Bone Joint J 2019;101-B(7 Supple C):55–60

Background and purpose — Thresholds of implant migration for predicting long-term successful fixation of tibial components in total knee arthroplasty have not separated cemented and uncemented fixation. We compared implant migration of cemented and uncemented components at 1 year and as the change in migration from 1 to 2 years. Patients and methods — Implant migration of 360 tibial components measured using radiostereometric analysis was compared at 1 year and as the change in migration from 1 to 2 years in 222 cemented components (3 implant designs) and 138 uncemented components (5 implant designs). Results — 1-year maximum total point motion was lower for the cemented tibial components compared with the uncemented components (median = 0.31 mm [0.03–2.98] versus 0.63 mm [0.11–5.19] respectively, p < 0.001, mixed model). The change in migration from 1 to 2 years, however, was equivalent for cemented and uncemented components (mean [SD] 0.06 mm [0.19] and 0.07 mm [0.27] mm respectively, p = 0.6, mixed model). Interpretation — These findings suggest that current thresholds of acceptable migration at 1 year may be better optimized by considering cemented and uncemented tibial components separately as higher early migration of uncemented components was not associated with decreased stability from 1 to 2 years.

Aims The introduction of a novel design of total knee arthroplasty (TKA) must achieve outcomes at least as good as existing designs. A novel design of TKA with a reducing radius of the femoral component and a modified cam-post articulation has been released and requires assessment of the fixation to bone. Radiostereometric analysis (RSA) of the components within the first two postoperative years has been shown to be predictive of medium- to long-term fixation. The aim of this study was to assess the stability of the tibial component of this system during this period of time using RSA. Patients and Methods A cohort of 30 patients underwent primary, cemented TKA using the novel posterior stabilized fixed-bearing (ATTUNE) design. There was an even distribution of men and women (15:15). The mean age of the patients was 64 years (sd 8) at the time of surgery; their mean body mass index (BMI) was 35.4 kg/m 2 (sd 7.9). RSA was used to assess the stability of the tibial component at 6, 12, and 24 months compared with a six-week baseline examination. Patient-reported outcome measures were also assessed. Results The mean maximum total point motion (MTPM) of the tibial component between 12 and 24 months postoperatively was 0.08 mm (sd 0.08), which is well below the published threshold of 0.2 mm (p < 0.001). Patient-reported outcome measures consistently improved. Conclusion The tibial component of this novel design of TKA showed stability between assessment 12 and 24 months postoperatively, suggesting an acceptably low risk of medium- to long-term failure due to aseptic loosening.

Obesity is an important comorbidity affecting outcomes after total joint arthroplasty. Consequently, surgeons may delay care of obese patients to first address obesity through different care pathways. The effect of obesity on patient wait times for total joint arthroplasty has not been explored. The purpose of this study was to evaluate the effect of obesity on access to total hip (THA) and knee (TKA) arthroplasty.The study data set was constructed from the Nova Scotia Health Authority's Horizon Patient Folder system and the Patient Access Registry Nova Scotia. Wait time was measured as days between the decision to treat and date of surgery. Body mass index (BMI) was calculated from a preoperative assessment, and patients were grouped into BMI categories. Multivariate log-linear regression was used to test for statistical differences, controlling for confounding factors.We observed longer wait times for TKA with increasing BMI weight class. Patients with BMIs greater than 50 had 34% longer waits than reference weight patients. However, THA recipients showed no statistical difference in wait times across weight categories. Furthermore, there was variability among surgeons in the wait times experienced by patients.The finding of longer wait times for TKAs, but not THAs, among patients who were obese was unexpected. This shows the variable wait times for THA and TKA that patients who are obese can experience with different surgeons. It is important to understand the variability in wait times so that efforts to standardize the patient experience can be accomplished.L’obésité est une comorbidité importante qui a des répercussions sur les résultats d’une arthroplastie totale. Ainsi, les chirurgiens pourraient reporter les soins aux patients obèses afin de d’abord traiter l’obésité par différents parcours de soins. Les effets de l’obésité sur le temps d’attente pour une arthroplastie totale n’ont pas été étudiés. La présente étude visait donc à évaluer les effets de l’obésité sur l’accès à une arthroplastie totale de la hanche (ATH) ou du genou (ATG).L’ensemble de données à l’étude provient du système Horizon Patient Folder de la Régie de la santé de la Nouvelle-Écosse et du registre d’accès des patients de la Nouvelle-Écosse. Le temps d’attente a été défini comme étant le nombre de jours séparant la décision de traitement et la date de l’intervention. L’indice de masse corporelle (IMC) a été calculé selon les données recueillies lors d’une évaluation préopératoire, et les patients ont été classés par catégorie d’IMC. Une régression loglinéaire multiple a été utilisée pour mesurer les différences statistiques et tenir compte des facteurs de confusion.Nous avons constaté que le temps d’attente pour une ATG augmente avec la catégorie d’IMC. En effet, les patients ayant un IMC de plus de 50 ont attendu 34 % plus longtemps que les patients du groupe de référence. Pourtant, il n’y avait aucune différence statistiquement significative entre les catégories d’IMC pour ce qui est du temps d’attente avant une ATH. De plus, le temps d’attente variait d’un chirurgien à l’autre.La conclusion selon laquelle les patients obèses attendent plus longtemps pour une ATG, mais pas pour une ATH, était inattendue. Cela met en évidence le temps d’attente variable que peuvent connaître les patients obèses selon les différents chirurgiens. Il est important de comprendre la variabilité du temps d’attente afin de normaliser l’expérience patient.

There are numerous reports of poor satisfaction after total knee arthroplasty (TKA), yet there is little known about when to use evidence-based models of care to improve patient outcomes.This study aimed to characterize longitudinal changes in patient-reported satisfaction after TKA and to identify factors for early identification of poor satisfaction.For a cohort of primary TKA surgeries (n = 86), patient-reported outcomes were captured one week before TKA and 6 weeks, 12 weeks, 6 months, and 1 and 2 years after TKA. "Satisfied" versus "not fully satisfied" patients were defined using a binary response (≥90 vs90) from a 100-point scale. Wilcoxon signed-rank tests identified changes in satisfaction between follow-up times, and longitudinal analyses examined demographic and questionnaire factors associated with satisfaction.Improvements in satisfaction occurred within the first 6 months after TKA (P ≤ 0.01). Preoperative patient-reported outcome measures alone were not predictive of satisfaction. Key factors that improved longitudinal satisfaction included higher Oxford Knee Scores (odds ratio (OR) = 2.1, P.001), general health (EQ-VAS, OR = 1.3, P = .03), and less visual analog scale pain (VAS; OR = 1.7, P.001). Differences in these factors between satisfied and not fully satisfied patients were identified as early as 6 weeks after surgery.Visibly different satisfaction profiles were captured among satisfied and not fully satisfied patient responses, with differences in patient-perceived joint function, general health, and pain severity occurring as early as 6 weeks after surgery. This study provides metrics to support early identification of patients at risk of poor TKA satisfaction, enabling clinicians to apply timely targeted treatment and support interventions, with the aim of improving patient outcomes.

To determine the relationship between patients' preoperative readiness for total knee arthroplasty (TKA) and surgical outcome at 1 year post-TKA.This prospective cohort study recruited patients with knee osteoarthritis (OA) who were ≥30 years and were referred for TKA at 2 hip/knee surgery centers in Alberta, Canada. Those who underwent primary unilateral TKA completed questionnaires prior to TKA to assess pain using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), physical disability using the Knee Injury and Osteoarthritis Outcome Score physical function short form, perceived arthritis coping efficacy, general self-efficacy, depressed mood using the Patient Health Questionnaire 8, body mass index, comorbidities, and TKA readiness (patient acceptable symptom state; willingness to undergo TKA); these same individuals also completed the above questionnaires 1 year post-TKA to assess surgical outcomes. A good TKA outcome was defined as an individual having improved knee symptoms, measured using the Osteoarthritis Research Society International-Outcome Measures in Rheumatology responder criteria, and overall satisfaction with results of the TKA. Poisson regression with robust error estimation was used to estimate the relative risk (RR) of a good outcome for exposures, before and after controlling for covariates.Of 1,272 TKA recipients assessed at 1 year post-TKA, 1,053 with data for the outcome assessed in the study were included (mean ± SD age 66.9 ± 8.8 years; 58.6% female). Most patients (87.8%) were definitely willing to undergo TKA and had "unacceptable" knee symptoms (79.7%). Among patients who underwent TKA, 78.1% achieved a good outcome. Controlling for pre-TKA OA-related disability, arthritis coping efficacy, comorbid hip symptoms, and depressed mood, definite willingness to undergo TKA and unacceptable knee symptoms were associated with a greater likelihood of a good TKA outcome, with adjusted RRs of 1.18 (95% confidence interval [95% CI] 1.04-1.35) and 1.14 (95% CI 1.02-1.27), respectively.Among patients who underwent TKA for knee OA, patients' psychological readiness for TKA and willingness to undergo TKA were associated with a greater likelihood of a good outcome. Incorporation of these factors in TKA decision-making may enhance patient outcomes and appropriate the use of TKA.

Background High-viscosity (HV) bone cements have been formulated to offer potentially advantageous handling characteristics. However, alteration in the handling characteristics could influence implant fixation and survival. The primary objective of this study was to use radiostereometric analysis after total knee arthroplasty to assess the migration of the Triathlon tibial component fixed with HV cement (Simplex HV). Methods Twenty-three patients were followed for two years with radiostereometric analysis examinations at 6 visits. Migration was compared with published thresholds and with a control group from a previously published study from the same center using the same implants fixed with a medium viscosity cement. Inducible displacement was assessed, and Oxford 12 Knee Scores and satisfaction were recorded. Results Mean maximum total point motion migration reaching 0.40 mm (SD 0.16) at one year, and 0.41mm (SD 0.17) at two years, demonstrating a pattern of stable fixation, below published thresholds of acceptable migration, and not significantly different from the control group. One implant had continuous migration between 1 and 2 years but was clinically asymptomatic. Mean maximum total point motion inducible displacement measured at least one year postoperatively was 0.3 mm (SD 0.12). Mean Oxford 12 Knee Scores improved from 19 (SD 7) preoperatively to 42 (SD 8) 2 years postoperatively. Conclusions The use of HV cement demonstrated an acceptable pattern of migration at 2 years, indicating low risk for aseptic loosening.

A large amount of data including joint kinematics, joint kinetics, clinical and functional measurements constitutes the clinical gait analysis basis which is a process whereby quantitative gait information are collected to aid in clinical decision-making. Therefore, better understanding the relationship between the biomechanical and clinical data for the knee osteoarthritis (OA) patient is for a relevant importance. It’s the purpose of this paper, which aims to analyze and visualize the correlation structure between biomechanical characteristics and clinical symptoms, and thus to provide an additional knowledge from the coupling of these parameters that will be useful for the pathology assessment of knee-joint disease in the end-staged knee OA patients. We perform two multivariate statistical approaches, first, a Canonical Correlation Analysis (CCA) to assess the multivariate association and, second, a graphical- based representation of the multivariate correlation to better understand the association between these multivariate data. Results show the usefulness of using such multivariate approaches to highlight association and specific correlation structure between the features and to extract meaningful information.

Background:. Over 20% of patients do not report clinically relevant pain relief or functional improvements after total knee arthroplasty (TKA). The aim of this study was to investigate the effect of demographics, pre-TKA knee-joint biomechanics, and postoperative changes in knee biomechanics on meaningful improvements in self-reported pain and function after TKA. Methods:. Forty-six patients underwent 3-dimensional gait analysis and completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire before and 1 year after TKA. Response to treatment in terms of pain relief and functional improvement (“pain and function responders”) was defined as improvements in WOMAC scores that met minimal clinically important difference thresholds in the pain and function domains. Differences between responder and non-responder demographics, severity of the osteoarthritis as seen radiographically, and knee kinematics and kinetics before TKA were explored using the t test and Mann-Whitney U test. Correlations and regression models were used to examine demographics, baseline knee kinematics and kinetics, and post-TKA kinematic and kinetic improvements associated with being a pain responder and a function responder separately. Analyses were conducted using a hypothesis-driving approach. Results:. Of the 46 patients, 34 were pain responders and 36 were function responders. Preoperatively, both responder groups had a higher radiographic severity (Kellgren-Lawrence) grade (p = 0.03) and pain responders were more symptomatic according to their WOMAC score (p < 0.04). Less preoperative stance-phase flexion-extension angle range (p ≤ 0.03), lower preoperative stance-phase adduction (varus) angle magnitude (p = 0.01), and less postoperative reduction in the adduction angle magnitude (p ≤ 0.009) were independently associated with more self-reported improvement in pain and function. Conclusions:. Patients with a higher radiographic severity grade, with specific frontal and sagittal knee kinematic patterns during gait before TKA, and who demonstrated less reduction in frontal plane angles during gait after TKA had greater self-reported pain and function score improvements after standard TKA. Gait analysis may aid preoperative identification of kinematic subgroups associated with self-reported improvements after TKA, and provide evidence that may inform triaging, surgical planning, and expectation management strategies. Level of Evidence:. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Objective:The disease burden of surgical site infection (SSI) following total knee (TKA) replacement is considerable and is expected to grow with increased demand for the procedure. Diagnosing and treating SSI utilizes both inpatient and outpatient services, and the timing of diagnosis can affect health service requirements. The purpose of this study was to estimate the health system costs of infection and to compare them across time-to-diagnosis categories.Methods:Administrative data from 2005–2016 were used to identify cases diagnosed with SSI up to 1 year following primary TKA. Uninfected controls were selected matched on age, sex and comorbidities. Costs and utilization were measured over the 2-year period following surgery using hospital and out-of-hospital data. Costs and utilization were compared for those diagnosed within 30, 90, 180, and 365 days. A subsample of cases and controls without comorbidities were also compared.Results:We identified 238 SSI cases over the study period. On average, SSI cases cost 8 times more than noninfected controls over the 2-year follow-up period (CaD$41,938 [US$29,965] vs CaD$5,158 [US$3,685]) for a net difference of CaD$36,780 (US$26,279). The case-to-control ratio for costs was lowest for those diagnosed within 30 days compared to those diagnosed later. When only patients without comorbidities were included, costs were >7 times higher.Conclusion:Our results suggest that considerable costs result from SSI following TKA and that those costs vary depending on the time of diagnosis. A 2-year follow-up period provided a more complete estimate of cost and utilization.

Background The use of cemented fixation for hip arthroplasty for femoral neck fractures has been advocated to limit the postoperative and intraoperative risk of periprosthetic fractures. However, there are concerns with the potential effects of cementing on patient mortality, particularly at the time of cementation. Methods This study examined the mortality rates of cemented compared to cementless hip arthroplasty fixation in a group of 5883 femoral neck fracture patients from 2001 to 2017. The data were derived from large administrative databases and census data. Confounders were identified and controlled with a multivariate analysis. The data were also stratified into 2 time frames, 2001-2008 and 2009-2017, to determine if there was an effect of more recent improvements in patient care or implant technology. Results Cemented fixation had a statistically significant reduction in mortality rates at 30, 90, and 365 days after surgery. There was no difference in mortality in 0, 1, or ≤7 days after discharge or during the admission. The mortality rate decreased but was still significantly increased with cementless fixation when the subjects were grouped from 2001 to 2008 and 2009 to 2017. Conclusion Based on this evidence, the cemented fixation of hip arthroplasty should be considered for patients with femoral neck fractures.

This paper aims to analyze the correlation structure between the kinematic and clinical parameters of an end-staged knee osteoarthritis population. The kinematic data are a set of characteristics derived from 3D knee kinematic patterns. The clinical parameters include the answers of a clinical questionnaire and the patient&rsquo, s demographic characteristics. The proposed method performs, first, a regularized canonical correlation analysis (RCCA) to evaluate the multivariate relationship between the clinical and kinematic datasets, and second, a combined visualization method to better understand the relationships between these multivariate data. Results show the efficiency of using different and complementary visual representation tools to highlight hidden relationships and find insights in data.

Copyright © 2018 by the American Society of Plastic Surgeons. Background: Soft-tissue complications often dictate the success of limb salvage and the overall outcome of open fractures. Based on prior work at the R Adams Cowley Shock Trauma Center, the authors hypothesize that wounds larger than 200 cm2 are associated with a greater likelihood of both flap-related reoperation and wound complications among patients requiring soft-tissue reconstruction with a rotational flap or free tissue transfer. Methods: This study was a secondary analysis of Fluid Lavage in Open Wounds trial data that included all patients who received a rotational or free tissue flap transfer for an open fracture. The primary outcome was flap-related reoperation within 12 months of injury. The secondary outcome was wound complication, which included events treated operatively or nonoperatively. Multivariable logistic regression was used to assess the association between wound size and outcomes, adjusting for confounders. Results: Seventeen percent of the 112 patients required a flap-related reoperation. A wound size greater than 200 cm2 was not associated with reoperation in an unadjusted model (p = 0.64) or adjusting for Gustilo type (p = 0.70). The sample had an overall wound complication rate of 47.3 percent. Patients with a wound size of greater than 200 cm2 were three times more likely to experience wound complications (OR, 3.05; 95 percent CI, 1.08 to 8.62; p = 0.04) when adjusting for moderate to severe wound contamination and wound closure in the operating room. Conclusion: The findings of this study demonstrate that wound surface area is an integral determinant for wound complication following soft-tissue flap treatment, but found no association between wound surface area and flap-related reoperation rates.

Background Total knee arthroplasty (TKA) is a highly effective procedure that yields reductions in pain and disability associated with end stage osteoarthritis (OA) of the knee. Quality of life instruments are frequently used to gauge the outcomes of total knee arthroplasty (TKA). However, research suggests that post-TKA reductions in symptom severity may not be the sole predictors of quality of life post-TKA. The primary objective of the present study was to examine the prognostic value of catastrophic thinking in health-related quality of life (HRQoL) judgments in patients with severe OA after TKA. Methods In this study we used a prospective cohort design to examine the value of pain catastrophizing in predicting HRQoL 1 year after TKA. Participants with advanced OA of the knee who were scheduled for TKA were recruited at one of three hospitals in Canada. The study sample consisted of 116 individuals (71 women, 45 men) who completed study questionnaires at their pre-surgical evaluation and 1 year after surgery. Hierarchical regression analysis was used to assess the unique contribution of pre-surgical pain catastrophizing to the prediction of post-surgical HRQoL judgments. Results The results of the hierarchical regression equation revealed that the overall model was significant, F (9,106) = 8.3, p

Introduction: Perceptions of injustice have been associated with problematic recovery outcomes in individuals with a wide range of debilitating pain conditions. It has been suggested that, in patients with chronic pain, perceptions of injustice might arise in response to experiences characterized by illness-related pain severity, depressive symptoms, and disability. If symptoms severity and disability are important contributors to perceived injustice (PI), it follows that interventions that yield reductions in symptom severity and disability should also contribute to reductions in perceptions of injustice. The present study examined the relative contributions of postsurgical reductions in pain severity, depressive symptoms, and disability to the prediction of reductions in perceptions of injustice. Methods: The study sample consisted of 110 individuals (69 women and 41 men) with osteoarthritis of the knee scheduled for total knee arthroplasty (TKA). Patients completed measures of perceived injustice, depressive symptoms, pain, and disability at their presurgical evaluation, and at 1-year follow-up. Results: The results revealed that reductions in depressive symptoms and disability, but not pain severity, were correlated with reductions in perceived injustice. Regression analyses revealed that reductions in disability and reductions in depressive symptoms contributed modest but significant unique variance to the prediction of postsurgical reductions in perceived injustice. Discussion: The present findings are consistent with current conceptualizations of injustice appraisals that propose a central role for symptom severity and disability as determinants of perceptions of injustice in patients with persistent pain. The results suggest that the inclusion of psychosocial interventions that target depressive symptoms and perceived injustice might augment the impact of rehabilitation programs made available for individuals recovering from TKA.

Introduction: Hemiarthroplasty is the preferred treatment for displaced femoral neck fractures in elderly patients. Recently, short tapered-wedge cementless stems have increasingly been used in this population. However, historic data has consistently shown higher rates of periprosthetic fracture with uncemented stems in hip fracture patients. This study aims to evaluate the rate of periprosthetic fracture requiring re-operation and all-cause mortality between cemented and uncemented femoral stem designs including more recent short tapered-wedge cementless stems in hip fracture patients. Methods: A retrospective chart and radiographic review of patients received bipolar hemiarthroplasty for femoral neck fractures from 2010–2016. Patients biologically (age ≥ 65 years) or physiologically (American Society of Anesthesiologists (ASA) class ≥ 3) elderly were eligible. The uncemented group was subdivided into tapered-wedge stems (a broach only system) and reamed uncemented stems. The primary outcome was periprosthetic fracture requiring re-operation. Results: We included 657 patients in total, with 296 and 361 patients in the uncemented and cemented stem groups respectively. In the uncemented group there were 197 tapered-wedge and 99 reamed uncemented stems. There was a significantly higher rate of periprosthetic fracture requiring re-operation in the uncemented group (3.0% vs. 0.6%) ( p ≤ 0.05). There were no significant differences in rates of all-cause mortality, infection or all-cause re-operation. Conclusions: Compared to modern uncemented femoral stem designs, cemented stems yield lower rates of periprosthetic fracture requiring re-operation, without increasing risk of all-cause mortality. Tapered-wedge stems had similar rates of re-operation due to periprosthetic fracture as reamed uncemented stems.

ObjectiveTo assess the relationship between comorbidities and amount of improvement in pain and physical function in recipients of total knee arthroplasty (TKA) for knee osteoarthritis (OA).DesignProspective cohort study.SettingTwo provincial central intake hip and knee centres in Alberta, Canada.Participants1051 participants (278 in 6-minute walk test (6MWT) subset), ≥30 years of age with primary knee OA referred for consultation regarding elective primary TKA; assessed 1 month prior and 12 months after TKA.Primary and secondary outcome measuresPre-post TKA change in knee OA pain (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), physical function (Knee injury and Osteoarthritis Outcome Score (KOOS) Physical Function Short-Form) and 6MWT walking distance; and the reporting of an acceptable symptom state (Patient Acceptable Symptom State (PASS)) at 12 months after TKA.ResultsMean participant age was 67 years (SD 8.8), 59% were female and 85% reported at least one comorbidity. Individuals with a higher number of comorbidities had worse pre-TKA and post-TKA scores for pain, physical function and 6MWT distance. At 12-month follow-up, mean changes in pain, function and 6MWT distance, and proportion reporting a PASS, were similar for those with and without comorbidities. In multivariable regression analysis, adjusted for potential confounders and clustering by surgeon, no specific comorbidities nor total number of comorbidities were associated with less improvement in pain, physical function or 6MWT distance at 12 months after TKA. Patients with diabetes (OR 0.64, 95% CI 0.44 to 0.94) and a higher number of lower extremity troublesome joints (OR 0.85, 95% CI 0.76 to 0.96) had lower odds of reporting a PASS.ConclusionFor individuals with knee OA, comorbid conditions do not limit improvement in pain, physical function or walking ability after TKA, and most conditions do not impact achieving an acceptable symptom state.

In rivers, the ecological effects of drought typically result in gradual adjustments of invertebrate community structure and functioning, punctuated by sudden changes as key habitats, such as wetted channel margins, become dewatered and dry. This paper outlines the development and application of a new index (Drought Effect of Habitat Loss on Invertebrates – DEHLI) to quantify the effects of drought on instream macroinvertebrate communities by assigning weights to taxa on the basis of their likely association with key stages of channel drying. Two case studies are presented, in which the DEHLI index illustrates the ecological development of drought conditions and subsequent recovery. These examples demonstrate persistent drought effects months or several years after river flows recovered. Results derived using DEHLI are compared with an established macroinvertebrate flow velocity-reactive index (Lotic-invertebrate Index for Flow Evaluation – LIFE score) and demonstrates its greater sensitivity to drought conditions. Data from a number of rivers in south east England were used to calibrate a statistical model, which was then used to examine the response of DEHLI and LIFE to a hypothetical multi-year drought. This demonstrated a difference in response between sampling seasons, with the spring model indicating a lagged response due to delayed recolonisation and the autumn model differentiating habitat loss and flow velocity-driven responses. The application of DEHLI and the principles which underlie it allow the effects of drought on instream habitats and invertebrates associated with short or long term weather patterns to be monitored, whilst also allowing the identification of specific locations where intervention via river restoration, or revision of existing abstraction licensing, may be required to increase resilience to the effect of anthropogenic activities exacerbated by climate change.

Despite the success of total knee arthroplasty, there continues to be a significant proportion of patients who are dissatisfied. One explanation may be a shape mismatch between pre- and postoperative distal femurs. The purpose of this study was to investigate methods suitable for matching a statistical shape model (SSM) to intraoperatively acquired point cloud data from a surgical navigation system and to validate these against the preoperative magnetic resonance imaging (MRI) data from the same patients. A total of 10 patients who underwent navigated total knee arthroplasty also had an MRI scan