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.

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.

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.

Multi-center experience with outpatient total hip arthroplasty via a standard posterolateral approach.

BACKGROUND: This study sought to evaluate the safety, efficacy, and resource utilization of a pilot outpatient surgery program for total hip arthroplasty compared to traditional inpatient total hip arthroplasty performed via the posterolateral approach. METHODS: A cohort of 68 patients from two sites were enrolled in a regional pilot project for outpatient total hip arthroplasty (THA) and matched 1:1 against a cohort of patients undergoing routine inpatient THA. Data was extracted retrospectively from patient and hospital charts including adverse events (AE), readmission within 90 days, emergency room (ER) visits, patient calls, patient-reported outcome measures, length of stay, and multiple surgical variables. RESULTS: The outpatient group had a mean hospital stay of 13 hours, whereas the inpatient group had a mean of 58 hours (p<0.001). Three outpatients and four inpatients experienced post-op complications. Three inpatients and one outpatient visited the ER within 8 weeks of surgery. No difference in pre-operative hemoglobin (p = 0.210), or surgical blood loss (p = 0.550) was found between study groups. There was no difference found between groups regarding Oxford-12 Hip Score improvement, nor satisfaction at six months, one and two years (p>0.125). CONCLUSION: This study demonstrates that outpatient THA using the posterolateral approach is as safe and effective as inpatient THA for overall healthy and carefully screened patients, based on the low rate of AEs observed and similar patient outcomes reported. Significantly reduced time in hospital demonstrates the reduced healthcare resources associated with outpatient THA.

Abrasive wear and metallosis associated with cross-linked polyethylene in total hip arthroplasty.

A 34-year-old female patient received a cobalt-chromium (CoCr) alloy femoral head on cross-linked polyethylene total hip replacement for the revision of her fractured ceramic-on-ceramic total hip replacement. The CoCr alloy femoral head became severely worn due to third-body abrasive wear by ceramic particles that could not be removed by synovectomy or irrigation at revision surgery. Ceramic particles were found embedded in the cross-linked polyethylene liner. The CoCr alloy femoral head exhibited a total mass loss of 14.2 g and the generated wear particles triggered metallosis in the patient. The present case study suggests not revising a fractured ceramic-on-ceramic total hip replacement with a CoCr alloy femoral head and a cross-linked polyethylene liner to avoid metallosis due to third-body abrasive wear.

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.

Early clinical results of a high-flexion, posterior-stabilized, mobile-bearing total knee arthroplasty: a US investigational device exemption trial.

Between May 2001 and June 2004, 388 total knee arthroplasty cases were enrolled in a prospective, randomized, multicenter investigational device exemption trial. Patients received either the investigational high-flexion mobile-bearing knee or a fixed-bearing control. At 2 to 4 years of follow-up, results in 293 patients with degenerative joint disease were compared using Knee Society Assessment and Function scores, radiographic results, complications analysis, and survival estimates. The mobile-bearing and fixed-bearing groups demonstrated similar, significant improvement over preoperative assessments in Knee Scores, maximum flexion, and range of motion. One mobile-bearing arthroplasty required revision. Radiographic results were unremarkable, and implant-related complications were rare in both groups. At this early follow-up, the investigational high-flexion mobile-bearing knee and its fixed-bearing counterpart demonstrated comparable, effective performance.

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.

Clinical failure analysis of contemporary ceramic-on-ceramic total hip replacements.

The present study investigates the performance of ceramic-on-ceramic total hip replacements by combining a retrieval analysis with a survivorship analysis to elucidate mechanisms that led to clinical failure. Semiquantitative surface damage assessment, contact profilometry, contour measurements, and scanning electron microscopy were performed to characterize the types and quantify the extent of surface damage on the retrieved ceramic components. The implantation period was positively correlated with both damage scores of the femoral heads (R = 0.573, p < 0.001) and the acetabular cups (R = 0.592, p < 0.001). Increased maximal out-of-roundness values of the femoral heads correlated with both increased metal transfer damage score (R = 0.384, p = 0.023) and increased stripe damage score (R = 0.729, p ≤ 0.001) of the acetabular liners. The damage rate (damage score/year) for both the retrieved heads and acetabular liners was at least 2.2-fold greater at inclination angles of >45° than the damage rate at inclination angles of ≤45°. For the retrieved femoral heads only, the linear wear rate of 25.5 ± 21.3 µm/year at inclination angles of >45° was 6-fold greater than the linear wear rate of 4.2 ± 2.3 µm/year at inclination angles of ≤45°. Metal transfer on the ceramic bearing surface could possibly contribute to fluid-film starvation and, in combination with an increased inclination angle, may facilitate an adhesive wear mechanism associated with stripe surface damage. At our institution, the clinical survivorship of ceramic-on-ceramic total hip replacements was 98.9% (a total of 9 out of 815 patients were revised within 10 years after total hip arthroplasty) with revision as the end point, suggesting their safe use in younger patients.

Presence of medical comorbidities in patients with infected primary hip or knee arthroplasties.

Many older patients undergoing primary hip or knee joint arthroplasty surgery have multiple medical problems. In this retrospective case-control study, the authors examined the individual and cumulative effects of various types of medical comorbidities on the risk of developing prosthetic joint infection after surgery. Case and control patients were matched by age, sex, and procedure. Analysis was undertaken using crude odds ratios (ORs) and multiple logistic regression analysis. Fifty-one patients with 52 joint infections were identified. Both diabetes mellitus (OR, 3.91; P = .04) and total number of medical conditions (OR, 1.35; P = .005) were associated with higher risk of infection. This information allows the orthopedic surgeon to inform patients more fully regarding the risks of surgery, and promotes the reduction and optimization of medical comorbidities before surgery.