Unnecessary interventions for the management of hip osteoarthritis: a population-based cohort study.

BACKGROUND: Patients aged 40-60 years who require total hip arthroplasty (THA) often first receive unindicated hip arthroscopy or magnetic resonance imaging (MRI). Our objective was to identify potentially inappropriate resource utilization before THA, specifically reporting on the proportion of patients aged 40-60 years who underwent hip arthroscopy or MRI in the year before THA. METHODS: We conducted a retrospective, population-based study at the provincial level. We retrieved data from the Canadian Institute for Health Information (CIHI). We included all Ontario residents who underwent an elective, primary THA for osteoarthritis between Apr. 1, 2004, and Mar. 31, 2016. We identified the rates and timing of patients who underwent an MRI or hip arthroscopy before their index THA. RESULTS: The percentage of patients who underwent an MRI before THA increased significantly over the study period, from 8.7% in 2004 to 23.8% in 2015. There was also a significant but variable trend in the percentage of patients who underwent a hip arthroscopy before THA. CONCLUSION: Our results demonstrate a high, gradually increasing proportion of patients who received a hip MRI and a low but increasing proportion of patients who received hip arthroscopy in close proximity to THA. Multidisciplinary collaboration may improve knowledge translation and help reduce the rate of clinically unnecessary diagnostic and therapeutic interventions in this population of patients who require THA.

Hip Circumferential Labral Reconstruction Provides Similar Distractive Stability to Labral Repair After Cam Over-Resection in a Biomechanical Model.

PURPOSE: To evaluate the change in hip distractive stability after a cam over-resection, labral tear, repair, labrectomy, or circumferential 6- or 10-mm labral reconstruction in a biomechanical model. METHODS: Ten fresh-frozen matched-pair human cadaveric hips were analyzed using a materials testing system to measure the force and distance required to disrupt the suction seal of the hip (1) with an intact capsule and labrum; (2) after a capsulectomy and labral repair; (3) after a capsulectomy, 5-mm cam over-resection and labral repair; (4) after a capsulectomy, 5-mm cam over-resection and labral tear; (5) after a capsulectomy, 5-mm cam over-resection and labrectomy; and (6) after a capsulectomy, 5-mm cam over-resection and a 6- or 10-mm circumferential labral reconstruction with iliotibial band (5 hips each). Each specimen was retested at 0° flexion, 45° flexion, and 45° flexion and at 15° internal rotation and analyzed using nonparametric statistical methods. RESULTS: The Friedman test of differences was significant among structural conditions and hip positions (P = .001). In all positions, the resistive force that opposed the disruption of the suction seal in an intact hip was significantly greater compared with all other conditions. The resistive force for the capsulectomy, 5-mm cam over-resection and labrectomy condition was significantly less compared with almost all other conditions and hip positions. A qualitative suction seal was achieved in 20% of hip specimens with a 6-mm labral reconstruction, whereas a seal was in achieved 60% of specimens with a 10-mm labral reconstruction. CONCLUSIONS: After a cam over-resection, a circumferential labral reconstruction improves the distractive stability of a labral deficient hip, comparable to a labral repair or tear in a biomechanical model. CLINICAL RELEVANCE: Circumferential labral reconstruction may be a viable treatment option for patients with ongoing symptoms after hip arthroscopy with evidence of a cam over-resection and a deficient labrum.

Survivorship of Modern Cementless Total Knee Arthroplasty: Analysis From the Canadian Joint Replacement Registry.

BACKGROUND: Cementless total knee arthroplasty (TKA) is rising in popularity. The literature supporting its use over cemented TKA remains sparse. Using the Canadian Joint Replacement Registry (CJRR), we sought to investigate cementless versus cemented fixation in modern primary TKA and (1) determine whether there is an overall difference in revision by fixation, (2) perform a subanalysis of the most-commonly used cementless TKA brand in Canada, and (3) identify the reasons for revision. METHODS: The CJRR data was used to analyze TKA designs with cemented and cementless versions. Revision risk is reported as all-cause cumulative percent revision (CPR). Reasons for revision were analyzed. Cox proportional hazards models were used to report adjusted hazard ratios (HR) controlling for age, sex, patella resurfacing, and bearing constraints. We included 202,880 primary TKAs performed between 2012 and 2021. Of those, 9,163 (4.5%) were cementless. RESULTS: The CPR at 8 years was 4.49% for cementless and 3.14% for cemented implants. After adjusting for confounders, we did not detect a difference in revision risk overall (HR 0.87 [95% CI (confidence interval) 0.73 to 1.04], P = 0.128). However, the most commonly used cementless TKA brand demonstrated a CPR of 1.95% compared to 2.19% for its cemented version at 4 years. Furthermore, we detected a significantly lower revision risk compared to its cemented version after adjusting for confounders (HR 0.66 [95% CI 0.51 to 0.85], P = 0.001). The 4 most common reasons for revision in both groups were the following: (1) infection, (2) instability, (3) aseptic loosening, and (4) pain of unknown origin. CONCLUSIONS: Using CJRR data adjusted for confounding factors, no difference in revision risk was detected between cemented and cementless implants overall. However, for the most common brand of cementless TKA used in Canada, there was a lower risk of revision than its corresponding cemented version. The reasons for revision were similar.

Association between synovial tissue damage and pain in late-stage knee osteoarthritis: A cross-sectional study.

OBJECTIVE: To identify the presence and distribution of histopathological features of synovial inflammation and tissue damage, and to test their associations with ultrasound (US) imaging measures of synovitis and patient-reported measures of pain in knee osteoarthritis (OA). DESIGN: In the cross-sectional study of 122 patients undergoing surgery for painful late-stage (Kellgren-Lawrence Grade 3 or 4) knee OA, we compared US measures of synovitis (n = 118) and pain (Knee Injury and Osteoarthritis Outcome Score) to histopathological measures of inflammation vs. synovial tissue damage in synovial tissue biopsies. Associations of histopathological features with US measures of inflammation or pain were assessed using linear or logistic regression while controlling for covariates. RESULTS: Histopathological features of inflammation were associated with higher odds of moderate/severe US synovitis (odds ratio [OR] = 1.34 [95%CI 1.04, 1.74), whereas features of synovial tissue damage were associated with lower odds of moderate/severe US synovitis (OR = 0.77 [95%CI 0.57, 1.03]). Worse histopathological scores for synovial tissue damage were associated with more pain (-1.47 [95%CI -2.88, -0.05]), even while adjusting for synovial inflammation (-1.61 [95%CI -3.12, -0.10]). CONCLUSIONS: Synovial tissue damage is associated with pain in late-stage knee OA, independent from inflammation and radiographic damage. These novel findings suggest that preventing synovial tissue damage may be an important goal of disease-modifying OA therapy.

Survivorship and Outcomes of 2-Stage Revision for Infected Total Hip Arthroplasty at a Mean of 7-Year Follow-Up.

BACKGROUND: Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following total hip arthroplasty (THA). The objectives of the study were to (1) determine the minimum 2-year infection-free survivorship of 2-stage revision THA, (2) determine the causative organisms for repeat 2-stage revision THA, and (3) characterize the results of failed 2-stage revisions and evaluate patient-reported outcome measures (PROMs). METHODS: A retrospective chart review was completed for patients who underwent 2-stage revision THA for PJI. Prospective data were collected on each patient, including demographics, causative organisms, complications, and type of reoperation. The PROMs, including Harris Hip Score, 12-item Short-Form Health Survey, and Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained prior to 2-stage revision THA surgery and annually as part of standard clinical and radiographic follow-up. RESULTS: A total of 328 patients who underwent a 2-stage revision THA for a PJI were included in the study (mean age 67 years [range, 28 to 90], mean body mass index of 30.6 [range, 15 to 57]). The overall infection-free survivorship for 2-stage revision THA was 73.8% at a minimum of 2 years (range, 2 to 20). Overall, 194 (59.1%) patients who had successful infection eradication underwent a 2-revision THA only. The most common single organisms infected were Staphylococcus aureus (12.5%) and Staphylococcus epidermidis (11%). Higher reoperation rates were found in cases with methicillin-resistant Staphylococcus aureus and polymicrobial infections. All PROMs showed statistical improvement from preoperatively to the latest follow-up appointment. CONCLUSIONS: Two-stage revision THA is associated with a good success rate in the treatment of PJIs at mid-term to long-term follow-up. Polymicrobial and methicillin-resistant Staphylococcus aureus infections are poor prognostic factors, making the eradication of infection more difficult. The management of PJIs continues to be one of the most important orthopaedic challenges to treat.

Evaluation of the Effectiveness of Canadian Cardiovascular Society Guidelines in Minimizing Cardiac Events After Total Hip Arthroplasty.

BACKGROUND: The aim of the study was to analyze the Canadian Cardiovascular Society (CCS) guidelines for routine postoperative troponin testing after elective total hip arthroplasty (THA) to reduce the mortality rate resulting from myocardial injury. The purpose of this study was to assess the prognostic relevance of implementing these guidelines to minimize cardiac events in patients undergoing elective THA. METHODS: Patients who underwent THA surgery in 2020 were included in the study. The inclusion criteria were elective THA patients aged ≥45 years, while emergency, revision, and simultaneous bilateral THA surgeries were excluded. The patients were categorized into 4 groups based on the CCS guidelines. RESULTS: The study included 669 patients who had an average age of 67 years. There were 43 patients (6.4%), who experienced a rise in troponin levels ≥30 ng/L and developed myocardial injury after noncardiac surgery. Among these patients, 8 developed cardiac complications, and one experienced a serious cardiac event that resulted in death. Notably, there was a significant increase in the length of hospital stay for patients who received the postoperative screening protocol. CONCLUSIONS: The implementation of the CCS guidelines for routine postoperative troponin testing in elective THA surgery did not significantly decrease the rate of cardiac events or mortality.

Short-Term (90 Days) Clinical Outcomes Following the Day of Surgery Conversion of Inpatient to Same-Day Hip and Knee Arthroplasty.

BACKGROUND: The incidence of total joint arthroplasty is increasing, with added emphasis on shifting care toward outpatient surgery. This has demonstrated improvements in costs and care; however, safety must be prioritized. Published assessment tools highlight candidates for outpatient surgery; however, they often do not define patients who have a worse prognosis. Limited healthcare resources occasionally force patients to convert to outpatient surgery or risk cancellation, creating a dilemma for both patients and surgeons. We evaluated the short-term (90-day) outcomes of patients converted from planned inpatient admission to same-day discharge on day of surgery outpatients and sought to identify any groups at risk, who may not be appropriate for this conversion. METHODS: We identified all patients undergoing planned inpatient total hip or knee arthroplasty at a tertiary academic medical center over a 2-year period. We included patients discharged the day of surgery for analysis, excluding revision procedures and those performed for fracture care. A manual chart review identified demographic factors and primary outcome measures; including reoperation, readmission, and emergency room visits within a 90-day postoperative period. RESULTS: We identified a total of 80 patients who converted from inpatient to outpatient surgery over a 2-year interval. Over the first 90 days postoperatively 4 (5%) patients were readmitted: 2 (2.5%) for medical complications and 2 (2.5%) for reoperation. There were 2 (2.5%) reoperations; one (1.25%) for manipulation under anesthesia, and one (1.25%) for periprosthetic joint infection. There were 5 (6.3%) wound complications; however, only one (1.25%) required surgical intervention. A total of 5 (6.3%) patients returned to an emergency department, leading to a single (1.25%) hospital readmission. CONCLUSIONS: Hospital and healthcare resources are occasionally limited to the extent that patients must convert to outpatient surgery or risk cancellation. At our institution, the same-day conversion of planned inpatient hip and knee arthroplasty patients to outpatient surgery was safe and did not increase short-term clinical outcomes or complications.

Central cone design demonstrates greater micromotion compared to keel design in cementless tibial baseplates: A biomechanical analysis.

PURPOSE: The purpose of this study was to compare micromotion of two new cementless tibial baseplates to a cementless design with well-published clinical success. METHODS: Three cementless tibial baseplate designs (fixed-bearing [FB] with keel and cruciform pegs, rotating-platform with porous central cone and pegs, FB with cruciform keel and scalloped pegs) were evaluated on sawbone models. Loading was applied to the baseplate at a rate of 1 Hz for 10,000 cycles, which represents 6-8 weeks of stair descent. This time frame also represents the approximate time length for the induction of biologic fixation of cementless implants. Compressive and shear micromotion at the sawbone-implant interface were measured. RESULTS: At the end of the loading protocol, the central cone rotating-platform design exhibited greater micromotion at the anterior (p < 0.001), posterior (p < 0.001) and medial locations (p = 0.049) compared to the other two implants. The central cone design also exhibited greater translational micromotion in the sagittal plane at the medial (p = 0.001) and lateral locations (p = 0.034) and in the coronal plane anteriorly (p = 0.007). CONCLUSION: The cementless central cone rotating-platform baseplate demonstrated greater vertical and translational micromotion compared to the two FB baseplates with a keel underloading. This may indicate lower initial mechanical stability in implants without a keel, which possibly affects osseointegration. The implication of this is yet unknown and requires further long-term clinical follow-up to correlate these laboratory findings. LEVEL OF EVIDENCE: V (biomechanical study).

Hip Labral and Capsular Repair Are Unable to Restore Distractive Stability in a Biomechanical Model.

PURPOSE: To evaluate the change in hip distractive stability after a capsulotomy, labral tear, and simultaneous repair of both the capsule and the labrum in a biomechanical model. METHODS: Ten fresh-frozen human cadaveric hips were analyzed using a materials testing system to measure the distractive force and distance required to disrupt the hip suction seal under the following conditions: (1) native intact capsule and labrum, (2) 2- or 4-cm interportal capsulotomy (IPC), (3) labral tear, (4) T extension, (5) labral repair, (6) T extension repair, and (7) IPC repair. Each specimen was retested at 0° of flexion, 45° of flexion, and 45° of flexion with 15° of internal rotation. RESULTS: A significantly higher distractive force was required to rupture the suction seal in the intact condition compared with IPC (P = .012; 95% confidence interval [CI], 4.9-42.4); IPC and labral tear (P = .002; 95% CI, 11.3-49.4); IPC, labral tear, and T extension (P = .001; 95% CI, 13.9-51.5); IPC, labral repair, and T extension (P < .001; 95% CI, 20.8-49.7); IPC, labral repair, and T extension repair (P = .002; 95% CI, 12.5-52.4); and IPC repair, labral repair, and T extension repair (P = .01; 95% CI, 5.8-46.1). The IPC condition required a higher distractive force in isolation than when combined with a labral tear (P = .14; 95% CI, 1.2-12.0), T extension (P = .005; 95% CI, 2.8-15.3), or labral repair (P = .002; 95% CI, 4.4-18.8). CONCLUSIONS: The distractive resistance of an intact hip capsule and labrum was not restored once the soft tissues were violated, despite labral repair with a loop technique and capsular repair with interrupted figure-of-8 sutures. CLINICAL RELEVANCE: Time-zero complete capsular repair with concomitant labral repair may not be adequate to restore distractive hip stability after hip arthroscopy, reinforcing the use of postoperative precautions in the early postoperative period.

The Microbial Revolution in the World of Joint Replacement Surgery.

Background: The prevalence of revision surgery due to aseptic loosening and periprosthetic joint infection (PJI) following total hip and knee arthroplasty is growing. Strategies to prevent the need for revision surgery and its associated health-care costs and patient morbidity are needed. Therapies that modulate the gut microbiota to influence bone health and systemic inflammation are a novel area of research. Methods: A literature review of preclinical and clinical peer-reviewed articles relating to the role of the gut microbiota in bone health and PJI was performed. Results: There is evidence that the gut microbiota plays a role in maintaining bone mineral density, which can contribute to osseointegration, osteolysis, aseptic loosening, and periprosthetic fractures. Similarly, the gut microbiota influences gut permeability and the potential for bacterial translocation to the bloodstream, increasing susceptibility to PJI. Conclusions: Emerging evidence supports the role of the gut microbiota in the development of complications such as aseptic loosening and PJI after total hip or knee arthroplasty. There is a potential for microbial therapies such as probiotics or fecal microbial transplantation to moderate the risk of developing these complications. However, further investigation is required. Clinical Relevance: Modulation of the gut microbiota may influence patient outcomes following total joint arthroplasty.

Cementless Total Knee Arthroplasty: Does Age Affect Survivorship and Outcomes?

BACKGROUND: Despite the growing popularity of cementless total knee arthroplasty (TKA) in younger patients, the outcomes are unclear in the elderly population. We aimed to compare the clinical outcomes and survivorship of cementless TKA between different age groups. METHODS: Utilizing our prospectively collected institutional database, we retrospectively reviewed all patients undergoing primary cementless TKAs at a tertiary care institute. We identified 347 TKA, which were divided into 3 groups based on age at the time of surgery. Group A was ≤ 60 years, Group B was 60 to ≤ 70 years, and Group C was > 70 years. We compared clinical outcomes (Knee Society Clinical Rating System [KSCRS], Western Ontario and McMaster University Osteoarthritis Index [WOMAC], and Veterans Rand 12 Item Health Survey [VR-12]) and survivorship between the groups. RESULTS: At final follow-up, range of motion, KSCRS, WOMAC, and VR-12 physical score were comparable (P > .05). The VR-12 Mental score was higher in Group B and Group C than in Group A (P = .003). Compared to preoperative scores, the change in KSCRS, WOMAC, and VR-12 physical and mental scores was comparable at the final follow-up (P > .05). No patient underwent revision for aseptic loosening. CONCLUSIONS: There were no cases of revision surgery for aseptic loosening in our cohort of 347 cementless TKAs. Patients > 70 years of age undergoing cementless TKA can achieve clinical scores equivalent to those of younger patients at short term (2-year) follow-up. Longer-term survivorship is still required, but based on early data, cementless TKA can be a safe option for older patients.

Gap patterns and radiographic follow-up of newer-generation cementless total knee arthroplasty designs.

BACKGROUND: Interest in cementless total knee arthroplasty (TKA) has increased with advancement of biomaterials and implant design and associated improved longevity. We sought to evaluate the gap patterns and radiolucent zones radiographically for 2 newer-generation cementless TKA designs. METHODS: We retrospectively reviewed our single-institution database between January 2017 and December 2019. We identified patients with a porous keeled tibia base-plate with 4-bullet cruciform spikes and peri-apatite coated femoral component (study group 1) and patients who received a cementless porous coated femoral component and rotating platform tibia baseplate with 4 peripheral porous coated pegs around a central cone (study group 2). We identified gap patterns at 6 weeks and at 1 year or more postoperatively on radiographs, noting indications for reoperation. RESULTS: We identified 228 patients in study group 1 and 41 patients in study group 2. At 1-year follow-up, we found evidence of resolved femoral gaps in 52 (72.2%) of 72 patients in study group 1 and 10 (58.8%) of 17 patients in study group 2 (p = 0.124). We identified 27 (84.3%) of 32 patients in study group 1 and 7 (70.0%) of 10 patients in study group 2 with resolved tibia gaps (p = 0.313). After 1 year, there were significantly more Zone 3a femoral zonal radiolucent gaps (p = 0.001) and Zone 8 tibia zonal radiolucent gaps (p = 0.002) in study group 2 than in study group 1. There were 4 reoperations for study group 1 and 0 reoperations for study group 2. CONCLUSION: The modern cementless TKA systems have varied gap patterns in postoperative radiographs, which may be attributed to the implant design. Most radiolucent gaps resolve radiographically on follow-up.

Minimum 2-Year Outcomes of a Modern Monoblock Titanium Fluted Tapered Revision Stem for Complex Primary and Revision Total Hip Arthroplasty.

BACKGROUND: Modular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. This study reports the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years of follow-up. METHODS: We identified 126 patients who received a single monoblock TFT stem: 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous periprosthetic joint infection, 42 for aseptic loosening, 9 for trunnionosis, and 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3-month follow-up were determined. We evaluated the number and indications for reoperations. RESULTS: The mean time from surgery was 3.9 years (range, 2.0 to 6.9). A paired t-test analysis showed significant improvement from preoperative versus postoperative clinical outcome scores (P < .001) for Harris Hip Score (38.76 ± 15.24 versus 83.42 ± 15.38), Western Ontario and McMaster Universities Arthritis Index (45.6 ± 19.0 versus 69.9 ± 21.3), Veterans RAND 12 Item Health Survey Physical component (31.7 ± 8.1 versus 37.8 ± 11.3), and Veterans RAND 12 Item Health Survey Mental component (48.2 ± 12.2 versus 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%), and Grade 4 (1.6%) cases. There were 18 reoperations (14.7%), with 13 for periprosthetic joint infection (7 treated with implant retention and 6 treated with a 2-stage revision), 4 for instability, and 1 for acetabular aseptic loosening. There were no aseptic failures of the stem. CONCLUSIONS: This novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.

Effect of Surgical Technique, Implant Design, and Time of Examination on Contact Kinematics: A Study of Bicruciate-Stabilized and Posterior-Stabilized Total Knee Arthroplasty.

BACKGROUND: Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) designs attempt to approximate natural knee mechanics. Multiple surgical techniques, including gap balancing (GB) and measured resection (MR), have been developed to provide optimal implant positioning and soft-tissue balance. The goal of this study was to determine the effect of surgical technique on BCS TKA contact kinematics. Secondary goals included investigating the change of kinematics over time and comparing BCS TKA kinematics to a posterior-stabilized (PS) design. METHODS: The study included the BCS-GB, BCS-MR, and PS-MR groups. The BCS-GB and BCS-MR groups underwent weight-bearing radiostereometric analysis for multiple knee flexion angles at 3 months and 1 year postoperatively, whereas the PS-MR group was imaged at 1 year postoperatively. The medial and lateral contact kinematics were determined from implant poses. RESULTS: There were no differences in BCS TKA kinematics between the GB and MR techniques. There were differences in the mid-flexion ranges when comparing the 3-month and 1-year kinematics of the BCS design; however, they were less than 1.5 mm. Differences existed between the kinematics of the BCS and PS designs at all flexion angles for the medial condyle (P < .0006) and at 0° of flexion on the lateral condyle (P < .0001). CONCLUSIONS: Contact kinematics for a BCS design were similar for both surgical techniques, suggesting both are appropriate for this design. Small, likely clinically insignificant differences were found between 3-month and 1-year kinematics. The BCS TKA kinematics differed from the PS design; however, it is unclear whether these differences improve clinical outcomes.

Phantom validation of a novel RSA-based impingement metric to assess component-on-component impingement risk.

Component-on-component impingement in total hip arthroplasty may lead to post-operative complications including dislocation. Despite numerous clinical studies focusing on reducing this risk, assessment methods remain limited to qualitative radiography, finite element analysis, and cadaver studies. There is a need for more precise measurements of impingement in the research setting. We aimed to validate a novel RSA-based impingement metric to measure component-on-component impingement in vivo. A phantom experiment of a standard metal-on-polyethylene total hip system was performed. RSA examinations were performed as typical for a traditional weight-bearing RSA exam for large joints. The phantom was placed in 10 possible impinged positions and one neutral position. Double exposure radiographs were taken to measure repeatability. The closest distance between the skirt of the head and the inner circumference of the acetabular cup liner was measured to assess impingement risk. Distances between the closest point of the hood to the edge of the cup in 10 impinged positions ranged from 0.05 to 1.03 mm, with the average being 0.67 mm. In the neutral position, the distance measured is 11.02 mm. Excellent repeatability was observed, with a standard deviation of 0.03 mm with an r value of 0.09. A validated RSA-based risk metric was established to evaluate in vivo hip impingement. A 1 mm threshold may be proposed to define impingement where distances approaching 1.00 mm are at a greater risk of impingement. This simplified metric holds promise for upcoming clinical studies on component-on-component impingement.

Assessing brain integrity in patients with long-term and well-functioning metal-based hip implants.

Production of metal debris from implant wear and corrosion processes is now a well understood occurrence following hip arthroplasty. Evidence has shown that metal ions can enter the bloodstream and travel to distant organs including the brain, and in extreme cases, can induce sensorial and neurological diseases. Our objective was tosimultaneously analyze brain anatomy and physiology in patients with long-term and well-functioning implants. Included were subjects who had received total hip or hip resurfacing arthroplastywith an implantation time of a minimum of 7 years (n = 28) and age- and sex-matched controls (n = 32). Blood samples were obtained to measure ion concentrations of cobalt and chromium, and the Montreal Cognitive Assessment was performed. 3T MRI brain scans were completed with an MPRAGE sequence for ROI segmentation and multiecho gradient echo sequences to generate QSM and R2* maps. Mean QSM and R2* values were recorded for five deep brain and four middle and cortical brain structures on both hemispheres: pallidum, putamen, caudate, amygdala, hippocampus, anterior cingulate, inferior temporal, and cerebellum. No differences in QSM or R2* or cognition scores were found between both groups (p > 0.6654). No correlation was found between susceptibility and blood ion levels for cobalt or chromium in any region of the brain. No correlation was found between blood ion levels and cognition scores. Clinical significance: Results suggest that metal ions released by long-term and well-functioning implants do not affect brain integrity.

Predictors of Undergoing Revision Within 5 Years of Total Knee Arthroplasty: A Population-Based Study.

BACKGROUND: The objective of this study was to identify the rate and risk factors for revision total knee arthroplasty (TKA) within the first 5 years postoperative. Our secondary objective was to identify the rate of additional surgical procedures and death. METHODS: We conducted a retrospective cohort study among patients in Ontario, Canada who underwent an elective, primary TKA between April 1, 2007, and March 31, 2014, for osteoarthritis. We excluded patients under 40 years and who had undergone a TKA within the previous 15 years. Our final study cohort included 94,193 patients. We reported the proportion of the study cohort who experienced revision surgery within 2 and 5 years of the primary TKA; secondary surgery within 5 years. We conducted Cochran-Armitage tests for trends to assess changes in the proportion of patients who experienced each of the study outcomes, and multivariable logistic regressions to evaluate predictors of a revision TKA. RESULTS: There were 3,112 (3.3%) patients who had a revision within 5 years, and 1,866 (2.0%) within 2 years of their primary TKA. 3,316 (3.5%) had a secondary surgery (0.6% patellar resurfacing; 1.6% manipulation; 1.3% synovectomy; 0.5% washout; 0.9% debridement). Lower age, men, lower income, higher comorbidity score, depression, previous arthroscopy, lower surgeon volume, and general anesthesia were all significant positive predictors of revision. CONCLUSIONS: In our study cohort, 2.0% of patients had a revision TKA within 2 years, and 3.3% within 5 years of their primary TKA. Preoperative identification of risk factors may reduce the future prevalence of revision TKAs.

Acetabular cup fixation with and without screws following primary total hip arthroplasty: migration evaluated by radiostereometric analysis.

BACKGROUND: Early cup migration after total hip arthroplasty (THA) is correlated to late revision due to aseptic loosening. However, the use of screws for increased cup stability remains unclear and debated. The purpose of this study is to assess acetabular migration between cups fixated with and without the use of screws. METHODS: Patients underwent primary THA using either a direct anterior (DA) or a direct lateral (DL) approach. The DA surgeon routinely supplemented cup fixation with 1 or 2 screws while the DL surgeon used no screws. At 7 follow-up visits up to 2 years post operation, patients underwent radiostereometric analysis (RSA) imaging for implant migration tracking. The primary outcome was defined as proximal cup migration measured with model-based RSA. RESULTS: 68 patients were assessed up to 2 years post operation, n = 43 received screws and n = 25 did not. The use of screws had a significant effect on cup migration (p = 0.018). From 2 weeks to 2 years post operation, the total mean migration was 0.403 ± 0.681 mm and 0.129 ± 0.272 mm (p = 0.319) for cups with and without screws, respectively. The number of screws used also had a significant impact, with cups fixated with 1 screw migrating more than cups fixated with 2 (p = 0.013, mean difference 0.712 mm). CONCLUSIONS: Acetabular cups fixated with only 1 screw resulted in greater migration than cups with no screws or 2 screws, though the mean magnitude was well under the 1.0 mm threshold for unacceptable migration. However, 3 of the 24 patients who received only 1 screw exceeded the 1.0 mm threshold for unacceptable migration. Ultimately, the results of this study show that the use of 2 screws to supplement cup fixation can provide good implant stability that is equivalent to a secure press-fit component with no screws.Clinical trial registration: ClinicalTrials.gov (NCT03558217).

A multimodal assessment of cementless tibial baseplate fixation using radiography, radiostereometric analysis, and magnetic resonance imaging.

Fixation in cementless total knee arthroplasty is provided by osseous integration. Radiography, radiostereometric analysis (RSA), and magnetic resonance imaging (MRI) were used simultaneously to investigate fixation. Relationships between RSA-measured implant micromotions and MRI-evaluated osseous integration at the component-bone interface were assessed in 10 patients up to 6 months postoperation. Supine MRI (using multispectral imaging sequences) and RSA exams were performed to evaluate osseous integration and measure longitudinal migration, respectively. Inducible displacement was measured from standing RSA exams. Radiolucent lines were detected on conventional radiographs. Of 10 patients, 6 had fibrous membranes detected on MRI. No fluid or osteolytic interfaces were found, and no components were scored loose. Of 10 patients, 6 had radiolucent lines detected. Average maximum total point motion (MTPM) for longitudinal migration at 6 months was 0.816 mm (range 0.344-1.462 mm). Average MTPM for inducible displacement at 6 months was 1.083 mm (range 0.553-1.780 mm). Fictive points located in fibrous-classified baseplate quadrants had greater longitudinal migration than fictive points located in baseplate quadrants with normal interfaces at 2 weeks (p = 0.031), 6 weeks (p = 0.046), and 3 months (p = 0.047), and greater inducible displacements at 3 months (p = 0.011) and 6 months (p = 0.045). Greater early micromotion may be associated with the presence of fibrous membranes at the component-bone interface. Clinical significance: This multimodal imaging study contributes knowledge of the fixation of modern cementless TKA, supporting the notion that osseous integration is important for optimal implant fixation.

Major complications after total hip arthroplasty with the direct anterior approach at a high-volume Ontario tertiary care centre.

BACKGROUND: The rate of major surgical complications for high-volume orthopedic surgeons using the direct anterior approach (DAA) in Ontario, Canada, is not known. The purpose of this study was to investigate the rate of major surgical complications after total hip arthroplasty (THA) using DAA performed by experienced orthopedic surgeons at a high-volume tertiary care centre in Ontario. METHODS: We conducted a retrospective cohort review of primary THA through DAA performed by 2 experienced fellowship-trained surgeons at an academic hospital in London, Ontario, between Jan. 1, 2012, and May 1, 2019. We excluded the first 100 cases to allow for surgeon learning curves. We recorded major surgical complications (intraoperative events, postoperative periprosthetic fractures, dislocation requiring closed or open reduction, implant failure [aseptic loosening or subsidence], early (< 6 wk) deep wound infection requiring irrigation and débridement, late (≥ 6 wk) deep wound infection requiring irrigation and débridement, and wound complications [wound dehiscence, stitch abscess, erythema, hematoma or seroma]) within 1 year of THA. RESULTS: A total of 875 primary DAA THA procedures were included. The rates of surgical complications were 0.9% for intraoperative events, 1.5% for postoperative periprosthetic fractures, 0.8% for implant failure, 0.7% for early deep wound infection, 0.1% for late deep wound infection and 3.2% for wound complications; there were no cases of dislocation. The rate of revision for implant failure within 1 year was 0.1%. Male sex was associated with a greater risk of implant failure (p = 0.01), and having a higher body mass index was associated with both increased rates of infection (p < 0.01) and having a wound complication (p < 0.01). CONCLUSION: Intraoperative events, postoperative periprosthetic fractures, implant failure, deep wound infection and wound complications accounted for the major surgical complications within 1 year of THA through DAA. The low revision rate suggests that DAA is a safe approach for THA.