Modes of failure of hip hemiarthroplasty for femoral neck fracture.

BACKGROUND: Hemiarthroplasty is a common treatment for displaced femoral neck fractures, but limited Canadian data are available about hemiarthroplasty failure. We evaluated the frequency and predictors of hemiarthroplasty failure in Manitoba. METHODS: In this retrospective multicentre province-wide study, billing and joint registry databases showed 4693 patients who had hemiarthroplasty for treatment of femoral neck fracture in Manitoba over an 11-year period (2005-2015), including 155 hips with subsequent reoperations (open or closed) for treatment of hemiarthroplasty failure. Hospital records were reviewed to identify modes of hemiarthroplasty failure, comorbidities and reoperations. Data were analyzed using χ2 test and Poisson and γ regression models. RESULTS: During our study period, 155 hips (154 patients [3%]) underwent 230 reoperations. Of these, 131 hips (85%) initially had an uncemented unipolar modular implant. Indications for first-time reoperation included periprosthetic femur fracture (49 hips [32%]), dislocation (45 hips [29%]), acetabular wear (28 hips [18%]) and infection (26 hips [17%]). There were 46 hips (30%) that had 2 or more reoperations. Reoperation for dislocation was associated with presence of dementia; acetabular wear was associated with absence of dementia. Time from hemiarthroplasty to reoperation was associated inversely with age at hemiarthroplasty, dislocation and dementia and was directly associated with acetabular wear. The risk of having 2 or more reoperations was associated independently with dislocation, infection, and alcohol abuse. CONCLUSION: Hemiarthroplasty for femoral neck fracture in Manitoba had a low frequency of failure. Risk factors for multiple reoperations included dislocation, infection and alcohol abuse.

Collection and Reporting of Patient-reported Outcome Measures in Arthroplasty Registries: Multinational Survey and Recommendations.

BACKGROUND: Patient-reported outcome measures (PROMs) are validated questionnaires that are completed by patients. Arthroplasty registries vary in PROM collection and use. Current information about registry collection and use of PROMs is important to help improve methods of PROM data analysis, reporting, comparison, and use toward improving clinical practice. QUESTIONS/PURPOSES: To characterize PROM collection and use by registries, we asked: (1) What is the current practice of PROM collection by arthroplasty registries that are current or former members of the International Society of Arthroplasty Registries, and are there sufficient similarities in PROM collection between registries to enable useful international comparisons that could inform the improvement of arthroplasty care? (2) How do registries differ in PROM administration and demographic, clinical, and comorbidity index variables collected for case-mix adjustment in data analysis and reporting? (3) What quality assurance methods are used for PROMs, and how are PROM results reported and used by registries? (4) What recommendations to arthroplasty registries may improve PROM reporting and facilitate international comparisons? METHODS: An electronic survey was developed with questions about registry structure and collection, analysis, reporting, and use of PROM data and distributed to directors or senior administrators of 39 arthroplasty registries that were current or former members of the International Society of Arthroplasty Registries. In all, 64% (25 of 39) of registries responded and completed the survey. Missing responses from incomplete surveys were captured by contacting the registries, and up to three reminder emails were sent to nonresponding registries. Recommendations about PROM collection were drafted, revised, and approved by the International Society of Arthroplasty Registries PROMs Working Group members. RESULTS: Of the 25 registries that completed the survey, 15 collected generic PROMs, most frequently the EuroQol-5 Dimension survey; 16 collected joint-specific PROMs, most frequently the Knee Injury and Osteoarthritis Outcome Score and Hip Disability and Osteoarthritis Outcome Score; and 11 registries collected a satisfaction item. Most registries administered PROM questionnaires within 3 months before and 1 year after surgery. All 16 registries that collected PROM data collected patient age, sex or gender, BMI, indication for the primary arthroplasty, reason for revision arthroplasty, and a comorbidity index, most often the American Society of Anesthesiologists classification. All 16 registries performed regular auditing and reporting of data quality, and most registries reported PROM results to hospitals and linked PROM data to other data sets such as hospital, medication, billing, and emergency care databases. Recommendations for transparent reporting of PROMs were grouped into four categories: demographic and clinical, survey administration, data analysis, and results. CONCLUSION: Although registries differed in PROM collection and use, there were sufficient similarities that may enable useful data comparisons. The International Society of Arthroplasty Registries PROMs Working Group recommendations identify issues that may be important to most registries such as the need to make decisions about survey times and collection methods, as well as how to select generic and joint-specific surveys, handle missing data and attrition, report data, and ensure representativeness of the sample. CLINICAL RELEVANCE: By collecting PROMs, registries can provide patient-centered data to surgeons, hospitals, and national entities to improve arthroplasty care.

A double-blind randomized controlled trial of total knee replacement using patient-specific cutting block instrumentation versus standard instrumentation

Background: Patient-specific cutting blocks in total knee arthroplasty have been promoted to improve mechanical alignment, reduce alignment outliers and improve patient outcomes. The aim of this study was to compare the efficacy of patient-specific instrumentation (PSI) and conventional instrumentation (CI) in achieving neutral alignment and accurate component positioning in total knee arthroplasty. Methods: We conducted a double-blinded randomized controlled trial in which patients were randomly assigned to treatment with either PSI or CI. Results: Fifty-four patients were included in the study. No relevant improvement in coronal alignment was found between the PSI and CI groups with post-hoc power of 0.91. Tibial slope was found to be more accurately reproduced to the preoperative target of 3° with PSI than with CI (3.8°± 3.1° v. 7.7°± 3.6°, respectively, p < 0.001). There were no differences found in patient-reported outcome measures, surgical time or length of hospital stay. Conclusion: Given the added cost of the PSI technique, its use is difficult to justify given the small improvement in only a single alignment parameter. Clinical trial registration: Clinicaltrials.gov, no. NCT03416946

Contexte: L'utilisation de guides de coupe sur mesure dans l'arthroplastie totale du genou a été recommandée pour améliorer l'alignement mécanique, réduire les alignements extrêmes et améliorer les résultats des patients. Cette étude cherchait à comparer la capacité des instruments sur mesure et des instruments classiques à engendrer un alignement neutre et un bon positionnement des composants dans le cadre d'une arthroplastie totale du genou. Méthodes: Nous avons mené un essai clinique randomisé à double insu. Les patients étaient répartis aléatoirement entre le groupe de traitement avec instruments sur mesure et le groupe de traitement avec instruments classiques. Résultats: Cinquante-quatre patients ont participé à l'étude. Aucune différence notable de l'alignement coronal entre les groupes n'a été relevée, pour une puissance observée de 0,91. La pente tibiale correspondait plus exactement à la cible préopératoire de 3° avec les instruments sur mesure qu'avec les instruments classiques (3,8° ± 3,1° contre 7,7° ± 3,6°, respectivement; p < 0,001). Il n'y avait aucune différence dans les mesures déclarées par les patients, la durée de l'intervention et la durée d'hospitalisation. Conclusion: Étant donné l'amélioration minime d'un seul paramètre d'alignement et le coût supérieur de la technique sur mesure, son utilisation est difficile à justifier. Enregistrement de l'essai: Clinicaltrials.gov, no NCT03416946.

Does oxidized zirconium make a difference? Midterm cohort survivorship of symmetric posterior condyle posterior-stabilized total knee arthroplasty

Background: A novel symmetric posterior condylar design and option of a femoral component with an outer zirconium oxide layer were introduced to a successful asymmetric condylar total knee arthroplasty system in 2005. Given the paucity of information on this modified design, we performed a study to determine its early to midterm survivorship and performance. Methods: Patients who received the Genesis II Symmetric Posterior Condyle or Legion Primary total knee (cobalt­chromium [CoCr] or oxidized zirconium­niobium [OxZr]) (Smith & Nephew) implanted at the study centre between March 2007 and December 2013 were enrolled into a prospective database. We retrospectively reviewed the database and performed survival analysis using Kaplan­Meier techniques. Results: There were 2178 patients (1359 women [62.4%]; mean age 64.6 yr; mean body mass index 35.0) with 2815 knee replacements available for analysis. Survival rates were 98.2% (95% confidence interval [CI] 97.6%­98.7%) for failure for any reason at 2 years and 96.8% (95% CI 96.0%­97.7%) at 5 years. Age (hazard ratio [HR] 0.97, 95% CI 0.94­0.997) and female sex (HR 0.45, 95% CI 0.27­0.75) were protective, whereas body mass index (HR 1.02, 95% CI 0.99­1.05) and OxZr implant (HR 1.11, 95% CI 0.57­2.18) did not influence survivorship. Oxford Knee Score values improved from a mean of 40.2 to 21.8 by 2 years (p < 0.001), with no difference between the CoCr and OxZr groups. Conclusion: The symmetric posterior condylar posterior-stabilized knee offers excellent midterm survivorship. Implant bearing surface did not have an influence on survivorship to 5 years, and, thus, use of OxZr implants may not be justified.

Contexte: Un nouveau modèle à condyles postérieurs symétriques et l'option d'un élément fémoral pourvu d'une couche d'oxyde de zirconium ont été introduits avec succès dans un système de prothèse totale du genou à condyles asymétriques en 2005. Compte tenu du manque de renseignements concernant ce modèle modifié, nous avons procédé à une étude pour en déterminer la survie et le rendement à court et à moyen terme. Méthodes: Les patients ayant reçu la prothèse à condyles postérieurs symétriques Genesis II ou une prothèse totale primaire Legion (au cobalt­chrome [CoCr] ou au zirconium­niobium oxydé [OxZr]) (Smith & Nephew) au centre de recherche entre mars 2007 et décembre 2013 ont été inscrits dans une base de données prospective. Nous avons procédé à une revue rétrospective de la base de données et effectué une analyse de survie à l'aide de techniques de Kaplan­Meier. Résultats: On a dénombré 2178 patients (dont 1359 femmes [62,4 %]; âge moyen 64,6 ans; indice de masse corporelle moyen 35,0) totalisant 2815 arthroplasties du genou pour analyse. Les taux de survie ont été de 98,2 % (intervalle de confiance [IC] à 95 % 97,6 %­98,7 %) pour le paramètre défaillance de toutes causes à 2 ans et de 96,8 % (IC à 95 % 96,0 %­97,7 %) à 5 ans. L'âge (risque relatif [RR] 0,97, IC à 95 % 0,94­0,997) et le fait d'être de sexe féminin (RR 0,45, IC à 95 % 0,27­0,75) ont conféré un effet protecteur, tandis que l'indice de masse corporelle (RR 1,02, IC à 95 % 0,99­1,05) et l'implant OxZr (RR 1,11, IC à 95 % 0,57­2,18) n'ont eu aucune influence sur la survie. Les scores Oxford d'évaluation du genou se sont améliorés, passant d'une moyenne de 40,2 à 21,8 en l'espace de 2 ans (p < 0,001), sans différence entre les groupes CoCr et OxZr. Conclusion: La prothèse du genou à condyles postérieurs symétriques postéro-stabilisée possède une excellente survie à moyen terme. La surface portant l'implant n'a pas eu d'influence sur la survie à 5 ans et, donc, l'utilisation d'implants OxZr ne sera peutêtre pas justifiée.

Radiostereometric analysis of keeled versus pegged glenoid components in total shoulder arthroplasty: a randomized feasibility study.

BACKGROUND: This study aimed to assess differences in the fixation and functional outcomes between pegged and keeled all-polyethylene glenoid components for standard total shoulder arthroplasty. METHODS: Patients were randomized to receive a keeled or pegged all-polyethylene glenoid component. We used model-based radiostereometric analysis (RSA) to assess glenoid fixation and subjective outcome measures to assess patient function. Follow-up examinations were completed at 6 weeks and 6, 12 and 24 months after surgery. Modifications to the RSA surgical, imaging and analytical techniques were required throughout the study to improve the viability of the data. RESULTS: Stymied enrolment resulted in only 16 patients being included in our analyses. The RSA data indicated statistically greater coronal plane migration in the keeled glenoid group than in the pegged group at 12 and 24 months. Functional outcome scores did not differ significantly between the groups at any follow-up. One patient with a keeled glenoid showed high component migration after 24 months and subsequently required revision surgery 7 years postoperatively. CONCLUSION: Despite a small sample size, we found significant differences in migration between glenoid device designs. Although clinically these findings are not robust, we have shown the feasibility of RSA in total shoulder arthroplasty as well as the value of a high-precision metric to achieve objective results in a small group of patients.

CONTEXTE: Cette étude avait pour objet d'évaluer les différences sur le plan de la fixation et des résultats fonctionnels entre les composants glénoïdiens à plots et à quille, tous deux en polyéthylène, dans une arthroplastie totale traditionnelle de l'épaule. MÉTHODES: La répartition des composants glénoïdiens en polyéthylène à plots et à quille a été faite de façon aléatoire. Nous nous sommes servis de modèles d'analyses radiostéréométriques (ARS) pour évaluer la fixation glénoïdienne et les indicateurs de résultats subjectifs, ce qui nous a ainsi permis d'évaluer les résultats fonctionnels des patients. Quatre examens de suivi ont été réalisés après la chirurgie : à 6 semaines, puis à 6 mois, à 12 mois et à 24 mois. Tout au long de l'étude, des ajustements ont été apportés aux modèles d'ARS de la chirurgie, de l'imagerie et des analyses afin d'améliorer la viabilité des données. RÉSULTATS: Des problèmes liés au recrutement ont fait en sorte que nous n'avons retenu que 16 patients dans le cadre de nos analyses. Les données d'ARS ont montré une migration statistiquement plus grande du plan frontal dans le groupe quille que dans le groupe plots à 12 et à 24 mois. Les résultats fonctionnels étaient sensiblement les mêmes d'un groupe à l'autre, peu importe le moment du suivi. Un patient du groupe quille a présenté une migration très importante du composant après 24 mois; il a dû subir une chirurgie de révision 7 ans après la chirurgie initiale. CONCLUSION: Malgré la petite taille de l'échantillon, nous avons observé des différences significatives dans la migration des composants, selon le type utilisé. Même si ces observations ne permettent pas d'arriver à des conclusions robustes d'un point de vue clinique, nous avons montré qu'il est possible d'avoir recours aux ARS en contexte d'arthroplastie totale de l'épaule et démontré la valeur associée à l'utilisation de mesures de haute précision pour l'obtention de résultats objectifs chez un petit groupe de patients.

In Vivo Wear Performance of Cobalt-Chromium Versus Oxidized Zirconium Femoral Total Knee Replacements.

This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design.

Trends in revision hip and knee arthroplasty observations after implementation of a regional joint replacement registry.

BACKGROUND: National joint replacement registries outside North America have been effective in reducing revision risk. However, there is little information on the role of smaller regional registries similar to those found in Canada or the United States. We sought to understand trends in total hip (THA) and knee (TKA) arthroplasty revision patterns after implementation of a regional registry. METHODS: We reviewed our regional joint replacement registry containing all 30 252 cases of primary and revision THA and TKA performed between Jan. 1, 2005, and Dec. 31, 2013. Each revision case was stratified into early (< 2 yr), mid (2-10 yr) or late (> 10 yr), and we determined the primary reason for revision. RESULTS: The early revision rate for TKA dropped from 3.0% in 2005 to 1.3% in 2011 (R(2) = 0.84, p = 0.003). Similarly, the early revision rate for THA dropped from 4.2% to 2.1% (R(2) = 0.78, p = 0.008). Despite primary TKA and THA volumes increasing by 35.5% and 39.5%, respectively, there was no concomitant rise in revision volumes. The leading reasons for TKA revision were infection, instability, aseptic loosening and stiffness. The leading reasons for THA revision were infection, instability, aseptic loosening and periprosthetic fracture. There were no discernible trends over time in reasons for early, mid-term or late revision for either TKA or THA. CONCLUSION: After implementation of a regional joint replacement registry we observed a significant reduction in early revision rates. Further work investigating the mechanism by which registry reporting reduces early revision risk is warranted.

CONTEXTE: Ailleurs qu'en Amérique du Nord, les registres nationaux des remplacements articulaires ont été efficaces pour réduire le risque de révision. Cependant, il y a peu d'information sur le rôle des plus petits registres régionaux comme ceux qu'on trouve au Canada et aux États-Unis. Nous avons donc cherché à comprendre les tendances en matière de révision des arthroplasties totales de la hanche (ATH) et du genou (ATG) après la création d'un registre régional. MÉTHODES: Nous avons passé en revue notre registre régional des remplacements articulaires, qui contient les 30 252 ATH et ATG primaires et de révision effectuées entre le 1er janvier 2005 et le 31 décembre 2013. Chaque cas de révision a été classé précoce (< 2 ans), moyen (de 2 à 10 ans) ou tardif (> 10 ans), et nous avons déterminé la raison principale de la révision. RÉSULTATS: Le taux de révision précoce pour l'ATG a diminué de 3,0 % en 2005 à 1,3 % en 2011 (R2 = 0,84, p = 0,003). De même, le taux de révision précoce pour l'ATH a diminué de 4,2 % à 2,1 % (R2 = 0,78, p = 0,008). Malgré une augmentation des nombres d'ATG et d'ATH primaires de 35,5 % et de 39,5 %, respectivement, il n'y a pas eu de hausse concomitante du nombre de révisions. Les principaux motifs de révision de l'ATG étaient l'infection, l'instabilité, le descellement aseptique et la raideur. Les principaux motifs de révision de l'ATH étaient l'infection, l'instabilité, le descellement aseptique et les fractures périprothétiques. Aucune tendance n'a été décelée au fil du temps dans les motifs de révision précoce, moyenne et tardive pour l'une ou l'autre des interventions. CONCLUSION: Nous avons observé une baisse significative des taux de révision précoce après la mise en œuvre d'un registre régional des remplacements articulaires. Il serait pertinent d'étudier plus en profondeur le mécanisme par lequel le signalement dans un registre réduit le risque de révision précoce.

Outcomes of unilateral and bilateral total knee arthroplasty in 238,373 patients.

Background and purpose - There is no consensus about the outcome of simultaneous vs. staged bilateral total knee arthroplasty (TKA). We examined this issue by analyzing 238,373 patients. Patients and methods - Demographic, clinical, and outcome data were evaluated for TKA patients (unilateral: 206,771; simultaneous bilateral: 6,349; staged bilateral: 25,253) from the Canadian Hospital Morbidity Database for fiscal years 2006-2007 to 2012-2013. Outcomes were adjusted for age, sex, comorbidities, and hospital TKA volume. Results - Simultaneous bilateral TKA patients were younger than staged bilateral TKA patients (median 64 years vs. 66 years), were more likely to be male (41% vs. 39%), and had a lower frequency of having ≥1 comorbid condition (2.9% vs. 4.2%). They also had a higher frequency of blood transfusions (41% vs. 19%), a shorter median length of stay (6 days vs. 8 days), a higher frequency of transfer to a rehabilitation facility (46% vs. 9%), and a lower frequency of knee infection (0.5% vs. 0.9%) than staged bilateral TKA patients, but they had higher rate of cardiac complications within 90 days (2.0% vs. 1.7%). Simultaneous patients had higher in-hospital mortality compared to the second TKA in staged patients (0.16% vs. 0.06%), but they had similar rates of in-hospital mortality compared to unilateral patients (0.16% vs. 0.14%). The cumulative 3-year revision rate was highest in the unilateral group (2.3%), but it was similar in the staged and simultaneous bilateral groups (1.4%). Interpretation - We found important differences between the outcomes of simultaneous and staged bilateral TKA. Further clarification of outcomes would be best determined in an adequately powered randomized trial, which would remove the selection bias inherent in this retrospective study design.

Aspirin versus low-molecular-weight heparin for extended venous thromboembolism prophylaxis after total hip arthroplasty: a randomized trial.

BACKGROUND: The role of aspirin in thromboprophylaxis after total hip arthroplasty (THA) is controversial. OBJECTIVE: To compare extended prophylaxis with aspirin and dalteparin for prevention of symptomatic venous thromboembolism (VTE) after THA. DESIGN: Multicenter randomized, controlled trial with a noninferiority design based on a minimal clinically important difference of 2.0%. Randomization was electronically generated; patients were assigned to a treatment group through a Web-based program. Patients, physicians, study coordinators, health care team members, outcome adjudicators, and data analysts were blinded to interventions. (Current Controlled Trials: ISRCTN11902170). SETTING: 12 tertiary care orthopedic referral centers in Canada. PATIENTS: 778 patients who had elective unilateral THA between 2007 and 2010. INTERVENTION: After an initial 10 days of dalteparin prophylaxis after elective THA, patients were randomly assigned to 28 days of dalteparin (n = 400) or aspirin (n = 386). MEASUREMENTS: Symptomatic VTE confirmed by objective testing (primary efficacy outcome) and bleeding. RESULTS: Five of 398 patients (1.3%) randomly assigned to dalteparin and 1 of 380 (0.3%) randomly assigned to aspirin had VTE (absolute difference, 1.0 percentage point [95% CI, -0.5 to 2.5 percentage points]). Aspirin was noninferior (P < 0.001) but not superior (P = 0.22) to dalteparin. Clinically significant bleeding occurred in 5 patients (1.3%) receiving dalteparin and 2 (0.5%) receiving aspirin. The absolute between-group difference in a composite of all VTE and clinically significant bleeding events was 1.7 percentage points (CI, -0.3 to 3.8 percentage points; P = 0.091) in favor of aspirin. LIMITATION: The study was halted prematurely because of difficulty with patient recruitment. CONCLUSION: Extended prophylaxis for 28 days with aspirin was noninferior to and as safe as dalteparin for the prevention of VTE after THA in patients who initially received dalteparin for 10 days. Given its low cost and greater convenience, aspirin may be considered a reasonable alternative for extended thromboprophylaxis after THA. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research.

Wear of a sequentially annealed polyethylene acetabular liner.

BACKGROUND AND PURPOSE: We previously reported on a randomized controlled trial (RCT) that examined the effect of adding tobramycin to bone cement after femoral stem migration. The present study examined femoral head penetration into both conventional and highly crosslinked polyethylene acetabular liners in the same group of RCT patients, with a minimum of 5 years of postoperative follow-up. PATIENTS AND METHODS: Linear penetration of the femoral head into an X3 (Stryker) crosslinked polyethylene (XLPE) liner was measured in 18 patients (19 hips) using radiostereometric analysis (RSA). Femoral head penetration was also measured in 6 patients (6 hips) with a conventional polyethylene liner (CPE), which served as a control group. RESULTS: The median proximal femoral head penetration in the XLPE group after 5.5 years was 0.025 mm with a steady-state penetration rate of 0.001 mm/year between year 1 and year 5. The CPE liner showed a median proximal head penetration of 0.274 mm after 7.2 years, at a rate of 0.037 mm/year. INTERPRETATION: The Trident X3 sequentially annealed XLPE liner shows excellent in vivo wear resistance compared to non-crosslinked CPE liners at medium-term implantation. The rate of linear head penetration in the XLPE liners after > 5 years of follow-up was 0.001 mm/year, which is in close agreement with the results of previous studies.

Trends in Cemented Fixation in Hemiarthroplasty for Hip Fractures in Canada.

Bacground: The use of cemented fixation is widely recommended in hip arthroplasty for hip fractures, although it is not used universally. Methods: We describe the trends in cementing prevalence in hemiarthroplasty for hip fractures in Canada for patients ≥55 years old between April 2017 and March 2022. Results: The national prevalence of cemented fixation increased from 43% in 2017/18 to 58% in 2021/22, but there was a large variety of both the baseline prevalence and the trends across the country and between individual hospitals. The proportion of surgeons only performing cementless fixation fell from 30% to 21% between 2018/19 and 2021/22. Conclusions: As cemented fixation is now universally recommended, more coordination is needed to track these trends and to help drive implementation of this evidence-based practice across Canada.

Consistent Factors Influence Body Mass Index Thresholds for Total Joint Arthroplasty Across Health-Care Systems: A Qualitative Study.

BACKGROUND: Body mass index (BMI) thresholds are used as eligibility criteria to reduce complication risk in total joint arthroplasty (TJA). This approach oversimplifies preoperative risk assessment and inadvertently restricts access to effective surgical treatment for osteoarthritis. A prior survey of orthopaedic surgeons in the United States identified complex underlying factors that influence BMI considerations. To understand whether similar factors exist and influence surgeons in a different health-care system setting, we investigated Canadian surgeons' views and use of BMI criterion thresholds for TJA access. METHODS: A cross-sectional online qualitative survey was conducted with orthopaedic surgeons performing TJA in the Canadian health-care system. Responses were anonymous and questions were open-ended to allow for candid perspectives. Survey data were coded and a systematic process was followed to identify major themes. Findings were compared with U.S. surgeon perspectives. RESULTS: Sixty-nine respondents had a mean age of 49.0 ± 11.4 years (range, 33 to 79 years), with a mean surgical experience duration of 15.7 ± 11.4 years (range, 2 to 50 years). Surgeons reported variable use of BMI thresholds in practice. Twelve interconnected factors that influence BMI considerations were identified: (1) variable evidence interpretation, (2) surgical challenge, (3) surgeon beliefs and biases, (4) hospital differences, (5) access to resources, (6) health system bias, (7) patient health status, (8) patient body fat distribution, (9) patient decisional burden (to lose weight or accept risk), (10) evidence gaps and uncertainties, (11) need for innovation, and (12) societal views. Nine themes matched with findings from U.S. surgeons. CONCLUSIONS: Parallel to the United States, complex, interconnected factors influence Canadian orthopaedic surgeons' variable use of BMI restrictions for TJA eligibility. Despite different health-care systems and reimbursement models, similar technical and personal factors were identified. With TJA practice guidelines advising against hard BMI criteria, attention regarding access to resources, surgical training, and innovations to address TJA complexity in patients with large bodies are critically needed. Future advancements in this sphere must balance barrier removal with risk reduction to ensure safe and equitable surgical care. CLINICAL RELEVANCE: This study may influence surgeon behaviors with regard to hard BMI cutoffs for TJA and encourage critical thought about factors that influence decisions about surgical eligibility for patients with high BMI.

Radiostereometric analysis and clinical outcomes of a novel reverse total hip system at two years.

Aims: Instability is a common cause of failure after total hip arthroplasty. A novel reverse total hip has been developed, with a femoral cup and acetabular ball, creating enhanced mechanical stability. The purpose of this study was to assess the implant fixation using radiostereometric analysis (RSA), and the clinical safety and efficacy of this novel design. Methods: Patients with end-stage osteoarthritis were enrolled in a prospective cohort at a single centre. The cohort consisted of 11 females and 11 males with mean age of 70.6 years (SD 3.5) and BMI of 31.0 kg/m2 (SD 5.7). Implant fixation was evaluated using RSA as well as Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score, Oxford Hip Score, Hip disability and Osteoarthritis Outcome Score, 38-item Short Form survey, and EuroQol five-dimension health questionnaire scores at two-year follow-up. At least one acetabular screw was used in all cases. RSA markers were inserted into the innominate bone and proximal femur with imaging at six weeks (baseline) and six, 12, and 24 months. Independent-samples t-tests were used to compare to published thresholds. Results: Mean acetabular subsidence from baseline to 24 months was 0.087 mm (SD 0.152), below the critical threshold of 0.2 mm (p = 0.005). Mean femoral subsidence from baseline to 24 months was -0.002 mm (SD 0.194), below the published reference of 0.5 mm (p < 0.001). There was significant improvement in patient-reported outcome measures at 24 months with good to excellent results. Conclusion: RSA analysis demonstrates excellent fixation with a predicted low risk of revision at ten years of this novel reverse total hip system. Clinical outcomes were consistent with safe and effective hip replacement prostheses.

Comparison of two hydroxyapatite-coated femoral components: a randomized clinical trial using radiostereometric analysis.

Aims: The primary aim of this trial was to compare the subsidence of two similar hydroxyapatite-coated titanium femoral components from different manufacturers. Secondary aims were to compare rotational migration (anteversion/retroversion and varus/valgus tilt) and patient-reported outcome measures between both femoral components. Methods: Patients were randomized to receive one of the two femoral components (Avenir or Corail) during their primary total hip arthroplasty between August 2018 and September 2020. Radiostereometric analysis examinations at six, 12, and 24 months were used to assess the migration of each implanted femoral component compared to a baseline assessment. Patient-reported outcome measures were also recorded for these same timepoints. Overall, 50 patients were enrolled (62% male (n = 31), with a mean age of 65.7 years (SD 7.3), and mean BMI of 30.2 kg/m2 (SD 5.2)). Results: The two-year subsidence was similar for Avenir (-0.018 mm (95% confidence interval (CI) -0.053 to 0.018) and Corail (0.000 mm (95% CI -0.027 to 0.026; p = 0.428). Both anteversion/retroversion (Avenir 0.139° (95% CI -0.204 to 0.481°); Corail -0.196° (95% CI -0.445 to 0.053°; p = 0.110) and varus/valgus tilt (Avenir -0.024° (95% CI -0.077 to 0.028); Corail -0.049° (95% CI -0.098 to 0.000°; p = 0.473) were not statistically significantly different. After two years, patients reported similar improvements in EuroQol five-dimension five-level health questionnaire (Avenir 0.22 (SD 0.2); Corail 0.22 (SD 0.18); p = 0.965) and other outcomes scores. Patient satisfaction on a five-point Likert scale was also similar between both groups after two years (Avenir 1.38 (SD 0.88); Corail 1.33 (SD 0.57); p = 0.846). Conclusion: The performance of both femoral components was similar in terms of stability and patient outcomes.

The Frank Stinchfield Award: Dislocation in revision THA: do large heads (36 and 40 mm) result in reduced dislocation rates in a randomized clinical trial?

BACKGROUND: Dislocation after revision THA is a common complication. Large heads have the potential to decrease dislocation rate, but it is unclear whether they do so in revision THA. QUESTIONS/PURPOSES: We therefore determined whether a large femoral head (36 and 40 mm) resulted in a decreased dislocation rate compared to a standard head (32 mm). METHODS: We randomized 184 patients undergoing revision THA to receive either a 32-mm head (92 patients) or 36- and 40-mm head (92 patients) and stratified patients by surgeon. The two groups had similar baseline demographics. The primary end point was dislocation. Quality-of-life (QOL) measures were WOMAC and SF-36. The mean followup for dislocation was 5 years (range, 2-7 years); the mean followup for QOL was 2.2 years (range, 1.6-4 years). RESULTS: In the 36- and 40-mm head group, the dislocation rate was 1.1% (one of 92) versus 8.7% (eight of 92) for the 32-mm head. There was no difference in QOL outcomes between the two groups. CONCLUSIONS: Our observations confirm a large femoral head (36 or 40 mm) reduces dislocation rates in patients undergoing revision THA at short-term followup. We now routinely use large heads with a highly crosslinked polyethylene acetabular liner in all revision THAs. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Rehospitalizations, early revisions, infections, and hospital resource use in the first year after hip and knee arthroplasties.

We examined 3 negative outcomes for 58 351 hip and knee arthroplasty patients: rehospitalization, revision and infection, and their impact on resource use in the year after surgery. In the year before surgery, 12.9% of elective hip and 10.2% of knee patients were hospitalized. In the year after, 14.8% of elective hip and 15.5% of knee patients were hospitalized, representing a 15% and 52% increase, respectively. Twenty-eight percent of emergent hip patients were hospitalized at least once preoperatively; this did not change after surgery. Revision occurred in 2.0% of emergent hip, 1.7% of elective hip, and 0.9% of knee patients. Joint infection was diagnosed in 1.3% of patients. The increased hospitalization after the elective hip and knee procedures represents an incremental cost of 10% over the index hospital stay.

Measurements of surface and subsurface damage in retrieved polyethylene tibial inserts of a contemporary design.

In the present study, surface and subsurface damage due to wear and creep in retrieved tibial inserts from the Genesis II total knee replacement (Smith & Nephew, Memphis, TN) are quantified. The utility of a number of recently validated micro-computed tomography (micro-CT) techniques for use in retrieval studies are also demonstrated. Sixteen inserts retrieved from patients after an implantation time from 0.5 to 86 months were examined. The inserts were scanned using micro-CT, and the three-dimensional surface deviations (corresponding to wear and creep) between the retrieved inserts and a reference geometry were determined. The subsurface of the inserts was also examined. Deviations within damage features were measured, and a surface deviation rate (mm/ year) was calculated from the length of implantation. No subsurface fatigue damage was found. The mean deviation within the most damaged regions of the articular surface was 0.115 ± 0.064 mm medially and 0.099 ± 0.061 mm laterally (p = 0.20). The mean articular deviation rate for inserts in vivo for more than 1 year was 0.049 mm/year and was reduced to 0.026 mm/year in inserts implanted for more than 4 years. Wear and creep of the Genesis II PE insert was comparable to reported values in other total knee replacements.

Paraneoplastic Clostridium septicum infection of a total knee arthroplasty.

We describe a case of a well-functioning total knee arthroplasty acutely infected with Clostridium septicum. This is the first reported infection of a prosthetic joint with this organism. A search for the source of this infection uncovered a colonic malignancy. This organism is highly associated with gastrointestinal malignancy, and appropriate investigation should be carried out when it is discovered. The importance of full anaerobic bacterial identification by the microbiology laboratory is underscored by this case.

Randomized trial of computer-assisted knee arthroplasty: impact on clinical and radiographic outcomes.

Computer-assisted surgery in knee arthroplasty is gaining popularity; however, the resulting outcome improvement is controversial. A double-blinded trial was performed with subjects randomized to undergo surgery with either computer-assisted or nonassisted instruments. Postoperatively, limb and implant alignment and rotation were assessed using both full-length radiographs and computed tomography in addition to clinical scores. One hundred twenty patients (141 knees) were randomized. No differences in Western Ontario MacMaster Osteoarthritis Score, Short Form-36, or flexion were seen. More varus limb alignment was seen in the computer-assisted group (1.9°) vs the nonassisted group (0.9°, P = .04) with no improvement in alignment precision. Rotational alignment of the components did not differ between groups. Computer-assisted surgery appeared to have minimal effect on knee implant arthroplasty with no improvement in limb alignment or early functional outcome.

Proximally versus fully porous-coated femoral stems: a multicenter randomized trial.

UNLABELLED: There are two broad-based categories of cementless femoral component designs: proximally porous-coated and fully porous-coated. While both have been widely used, there remains debate regarding differences in clinical outcome scores, relative incidence of thigh pain, and development of stress shielding. We investigated these variables in a multicenter prospective randomized blinded clinical trial of 388 patients from three centers: 198 patients had a proximally porous-coated tapered cementless femoral component and 190 patients had a fully porous-coated cementless femoral component. A minimum followup of 2 years (mean, 6.7 years; range, 2.0-8.65 years) was available in 367 of the 388 patients (95%). We observed no differences in age at surgery, body mass index, or preoperative clinical outcome scores (WOMAC, SF-12, Harris hip score, UCLA activity, thigh pain) with the two groups. We determined serial bone density changes in a subcohort of 72 patients from two of the three centers. The postoperative clinical outcome scores were similar at all followup intervals, and we observed no differences in the incidence of thigh pain at any time. Bone density reduction in Gruen Zone 7 was greater with the fully coated stem than the proximally coated stem (24% versus 15% reduction, respectively). Both fully and proximally coated stems performed well, with no clinical differences at 2 years' followup, except in bone mineral density evaluations. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.