Bispherical metal augment improved biomechanical stability in severe acetabular deficiency reconstruction: a comparative finite element analysis.

BACKGROUND: This study used finite element analysis (FEA) to compare the biomechanical stability of bispherical metal augment (BA) and wedge-shaped trabecular-metal augment (TA) in different acetabular defect reconstruction models, thereby explaining the application value of this novel bispherical augment in complex hip revision. METHODS: Three different acetabular defect pelvis models originating from three representative patients with different types of severe acetabular defects (Paprosky IIC, IIIA, and IIIB) were constructed and reconstruction with BA and TA technique was simulated. Based on the FEA models, the displacement of reconstruction implants, relative displacement of bone implants, and hemi-pelvic von Mises stress were investigated under static loads. RESULTS: BA acquired smaller reconstruction system displacement, less relative displacement of bone implants, and lower pelvic von Mises stress than TA in all Paprosky IIC, IIIA, and IIIB defect reconstructions. CONCLUSION: The FEA results show that BA could acquire favourable biomechanical stability in severe acetabular defect reconstruction. This technique is a reliable method in complex hip revision.

Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Total Hip Arthroplasty.

BACKGROUND: Frailty has been associated with poor outcomes and higher costs after primary total hip arthroplasty. However, frailty has not been studied in relation to outcomes after revision total hip arthroplasty (rTHA). This study examined the relationship between the Hospital Frailty Risk Score (HFRS), postoperative outcomes, and cost profiles following rTHA. METHODS: In this retrospective cohort study, we identified patients who underwent rTHA from January 2017 to November 2019 in the Nationwide Readmission Database. The 3 most frequently reported diagnosis codes for rTHA were then selected: dislocation; mechanical loosening; and infection. We calculated the HFRS for each patient to determine frailty status. We compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients, using multivariate logistic and negative binomial regressions to adjust for covariates. We identified 36,243 total patients who underwent rTHA. Overall, 15,448 patients had a revision for dislocation, 11,062 for mechanical loosening, and 9,733 for infection. RESULTS: Compared to nonfrail patients, frail patients had higher rates of 30-day readmission, longer length of stay, and higher hospitalization cost. Frail patients had significantly higher rates of 30-day complication and 30-day reoperation. CONCLUSIONS: Frailty, measured using HFRS, is associated with increased postoperative complications and costs after rTHA. The HFRS has the ability to efficiently identify frail patients at-risk for perioperative complications enabling care teams to better focus optimization interventions on this patient cohort.

Acetabular Augments Used in Revision Hip Arthroplasty: Minimum 10-year Follow-up of Implant Survivorships, Functional Scores, and Radiographic Outcomes.

BACKGROUND: Acetabular bone loss is a major challenge in the setting of revision total hip arthroplasty (THA). Porous tantalum augments have emerged as a viable solution to acetabular bone loss in revision THA. The purpose of this study was to evaluate the survivorship, clinical, and radiological outcomes of these implants. METHODS: We identified 104 augment implants from our retrospective chart review of revision total hip arthroplasty from June 2003 to July 2013. Of these patients, 75 (72.1%) were women, mean age at surgery was 66.2 years (range, 27 to 87); and a mean follow-up was 13.2 years (range, 0.25 to 18.2). Kaplan-Meier survival analysis was performed, with failure defined as revision for aseptic loosening of the acetabular reconstruction. RESULTS: There was significant improvement in the Harris Hip Score from 40.0 to 77.3 (P < 0.001) and the Oxford Hip Score from 14.9 to 36.3 (P < 0.001). Survivorship for failure due to aseptic loosening was 98.8% (95% CI [confidence interval] 96.4 to 100) at 24 months with 60 hips at risk, and 90.4% (95% CI 83.0 to 97.8) at 60 and 120 months with 38 and 18 hips at risk, respectively. The overall rate of all complications was 34 (32.7%). Of these complications, 21 (20.2%) required repeat revision surgery. The revision rate due to aseptic loosening of the augment, infection, dislocation, aseptic loosening of the femoral component, reconstruction failure, and heterotopic ossification was 7 (6.7%), 5 (4.8%), 4 (3.8%), 2 (1.9%), 2 (1.9%), and 1 (0.96%), respectively. CONCLUSION: Treatment of acetabular defects during revision THA using porous tantalum augments provides acceptable implant survivorship and favorable clinical outcomes at mid-term (5-10 year) and long-term (>10 year) follow-up.

Sex-Specific Implant Fixation Can Reduce Revision Rates in Total Hip Arthroplasty: Evidence From the Swiss National Joint Registry.

BACKGROUND: Patient's sex is considered a risk factor for revision following primary total hip arthroplasty (THA), but sex-specific treatment guidelines are lacking. The purpose was to assess sex-specificity of risk factors for periprosthetic femoral fractures (PFFs) and aseptic stem loosening (ASL) in a nationwide register study. METHODS: All uncemented and hybrid THAs for hip osteoarthritis registered in the Swiss National Joint Registry were considered. 86,423 THAs were analyzed. Comparable THA subsets for both sexes were obtained through propensity score matching (1:1). A sex-specific analysis of risk factors for early PFF or ASL was performed using recursive partitioning analyses. RESULTS: In women, PFFs were most significantly associated with uncemented THA fixation (P < .0001) and age (P < .01, threshold: 70.5 years). The ASLs were solely associated with patient age of <65 years (P = .023). In men, PFFs were associated exclusively with an American Society of Anesthesiologists (ASA) score >2 (P = .026). The ASLs were not correlated to any of the potential risk factors analyzed. A mathematical simulation indicated that avoiding uncemented THA fixation in women ≥70.5 years of age decreased the number of revisions within the observational period by 21% in this subset and by 4.9% in the entire patient population. CONCLUSION: Uncemented THA should be avoided in women >70.5 years due to the increased risk of early PFF, while the mode of stem fixation did not influence revision risk in men. A sex-specific regimen for THA fixation has the potential to markedly reduce early THA revision rates.

Indications, Clinical Outcomes, and Re-Revisions Following Revision Total Hip Arthroplasty - Does Age Matter?

BACKGROUND: Younger age is associated with increased revision incidence following primary total hip arthroplasty, though the association between age and repeat revision following revision total hip arthroplasty (rTHA) has not been described. This study aimed to describe the incidences and indications for subsequent revision (re-revision) following rTHA based on age. METHODS: Patients undergoing aseptic rTHA from 2011 to 2021 with minimum 1-year follow-up were retrospectively reviewed. Patients were stratified into 3 groups based on age at the time of index rTHA (ie, <55 years, 55 to 74 years, and >74 years). Perioperative characteristics, complications, and re-revisions were compared between groups. RESULTS: Of 694 included rTHAs, those in the >74 age group were more likely to undergo rTHA for periprosthetic fracture (P < .001) while those in the <55 age group were more likely to undergo rTHA for metallosis/taper corrosion (P = .028). Readmissions (P = .759) and emergency department visits (P = .498) within 90 days were comparable across ages. Rates of re-revision were comparable at 90 days (P = .495), 1 year (P = .443), and 2 years (P = .204). Kaplan-Meier analysis of all-cause re-revision at latest follow-up showed a nonstatistically significant trend toward increasing re-revisions in the <55 and 55 to 74 age groups. Using logistic regressions, smoking and index rTHA for instability were independently associated with re-revision, while age at index surgery was not. CONCLUSIONS: While indications for rTHA differ across age groups, rates of 2-year re-revision are statistically comparable between groups. Further studies are warranted to understand the association between age, activity, and re-revision rates after 5 years postoperatively.

Revision Dual Mobility Constructs With Unmatched Acetabular and Femoral Components Do Not Increase Failure Rate.

BACKGROUND: Dual mobility (DM) constructs for revision total hip arthroplasty (THA) have continued to grow in popularity to mitigate instability. This benefit comes at the cost of potential unique modes of failure, and there are theoretical concerns that combining femoral and acetabular components from different manufacturers could lead to increased failure rates. We aimed to investigate rates of reoperation between matched and unmatched DM implants used in revision THA. METHODS: We retrospectively reviewed 217 revision THAs performed with DM constructs between July 2012 and September 2021 at a single institution. Dual mobility (DM) constructs were classified as "matched" if the acetabular and femoral components were manufactured by the same company. They were classified as "unmatched" if the acetabular and femoral components were manufactured by different companies. The primary outcome was reoperation for any reason. RESULTS: There were 136 matched DM constructs and 81 unmatched constructs. Average follow-up was 4.6 years (range, 2.0 to 9.6 years). There was no difference in reoperation rate between matched and unmatched groups (11.0 versus 13.6%, P = .576). The most common reasons for reoperation in both groups were instability and periprosthetic joint infection. There was 1 revision for intraprosthetic dislocation in the matched group. CONCLUSIONS: The use of unmatched DM components in revision THA was common and did not increase the risk of reoperation at an average of 4.6-year follow-up. This information can be helpful in operative planning, but further research on long-term survival will be necessary.

Novel Technique for the Identification of Hip Implants Using Artificial Intelligence.

BACKGROUND: The anticipated growth of total hip arthroplasty will result in an increased need for revision total hip arthroplasty. Preoperative planning, including identifying current implants, is critical for successful revision surgery. Artificial intelligence (AI) is promising for aiding clinical decision-making, including hip implant identification. However, previous studies have limitations such as small datasets, dissimilar stem designs, limited scalability, and the need for AI expertise. To address these limitations, we developed a novel technique to generate large datasets, tested radiographically similar stems, and demonstrated scalability utilizing a no-code machine learning solution. METHODS: We trained, validated, and tested an automated machine learning-implemented convolutional neural network to classify 9 radiographically similar femoral implants with a metaphyseal-fitting wedge taper design. Our novel technique uses computed tomography-derived projections of a 3-dimensional scanned implant model superimposed within a computed tomography pelvis volume. We employed computer-aided design modeling and MATLAB to process and manipulate the images. This generated 27,020 images for training (22,957) and validation (4,063) sets. We obtained 786 test images from various sources. The performance of the model was evaluated by calculating sensitivity, specificity, and accuracy. RESULTS: Our machine learning model discriminated the 9 implant models with a mean accuracy of 97.4%, sensitivity of 88.4%, and specificity of 98.5%. CONCLUSIONS: Our novel hip implant detection technique accurately identified 9 radiographically similar implants. The method generates large datasets, is scalable, and can include historic or obscure implants. The no-code machine learning model demonstrates the feasibility of obtaining meaningful results without AI expertise, encouraging further research in this area.

Porous Metal Augments Have Comparable Outcomes to Other Constructs for Severe Acetabular Bone Loss at Mid-Term Follow-up.

BACKGROUND: Acetabular reconstruction options in the setting of severe bone loss remain limited, with few comparative studies published to date. The purpose of this study was to compare the outcomes of revision total hip arthroplasty (THA) for severe bone loss using porous metal augments to cup cage and triflange prostheses. METHODS: We reviewed a consecutive series of 180 patients who had Paprosky 3A or 3B acetabular defects and underwent revision THA. Patients treated with porous augments (n = 141) were compared with those who received cup cages or triflange constructs (n = 39). Failure of the acetabular construct was defined as undergoing acetabular revision surgery or radiographic evidence of loosening. RESULTS: There was no difference in acetabular component survivorship in patients undergoing revision THA with porous augments or a cage or triflange prosthesis (92.2 versus 87.2%, P = .470) at a mean follow-up of 6.6 ± 3.4 years. Overall, survivorship free from any revision surgery was comparable between the 2 groups (78.7 versus 79.5%, P = .720). There was also no difference in dislocation (5.7 versus 10.3%, P = .309) or periprosthetic joint infection rates (7.8 versus 10.3%, P = .623). In a subgroup analysis of patients who had pelvic discontinuity (n = 47), survivorship free from any revision surgery was comparable between the 2 groups (79.5 versus 72.2%, P = .543). CONCLUSIONS: Porous metal augments in the setting of severe acetabular bone loss demonstrated excellent survivorship at intermediate-term (mean 6.6 years follow-up, even in cases of pelvic discontinuity, with comparable outcomes to cup cages and triflanges. Instability and infection remain major causes of failure in this patient population, and long-term follow-up is needed.

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.

Chronic Anticoagulation is Associated With Increased Risk for Postoperative Complications Following Aseptic Revision Total Hip Arthroplasty.

BACKGROUND: With an aging global population, the incidence of revision total hip arthroplasty (rTHA) is expected to increase markedly. While patients undergoing primary total hip arthroplasty who require chronic anticoagulation (AC) have been associated with increased postoperative complications, less is known about the impact of chronic AC status on postoperative complications in the rTHA setting. This study sought to compare complication rates following aseptic rTHA between patients who were on chronic AC and those who were not. METHODS: A large national database was utilized to retrospectively identify 9,421 patients who underwent aseptic rTHA between 2014 and 2019. Patients were divided into 2 cohorts: 1,790 patients (19.0%) were in the chronic AC cohort (ie, having an AC prescription filled within 6 months prior to and following rTHA), and 7,631 patients (81.0%) were not on chronic AC. Postoperative complications at 90-days and 2-years were compared between cohorts utilizing univariate and multivariate analyses, controlling for sex, age, and comorbidities. RESULTS: At 90-days, chronic AC patients had increased odds of prosthetic joint infections (PJIs) (odds ratio [OR] 3.2, P < .001), surgical site infections (OR 3.6, P < .001), and mechanical prosthetic complications (OR 3.5, P < .001), which included any aseptic loosening, implant dislocation, or broken prosthetic. At 2-years, chronic AC patients had increased odds of PJI (OR 3.3, P < .001) as well as mechanical prosthetic complications (OR 3.2, P < .001). Chronic AC patients were also at increased risk for reoperation within 2 years after initial aseptic rTHA (OR 1.9, P < .001). CONCLUSIONS: Patients on chronic AC have significantly higher odds of 90-day and 2-year complications after aseptic rTHA. This includes increased odds of PJI, surgical site infection, and mechanical prosthetic complications. Patients receiving chronic AC who undergo rTHA should be counseled on the risk-benefit ratio of their chronic AC status in a multidisciplinary setting to optimize their postoperative outcomes.

Neighborhood Socioeconomic Disadvantage is Associated with Increased Healthcare Utilization After Septic and Aseptic Revision Total Hip Arthroplasty.

BACKGROUND: A greater Area Deprivation Index (ADI), a tool that gauges socioeconomic disadvantage at the neighborhood level, is associated with worse healthcare outcomes following primary total hip arthroplasty (THA). However, its association with revision THA (rTHA) is unknown. This study aimed to determine the association between ADI and rates of postoperative healthcare resource utilization following rTHA. METHODS: A total of 996 patients who underwent rTHA between 2016 and 2022 were enrolled in a prospective study. The primary outcomes assessed were non-home discharge disposition (DD), length of stay (LOS) ≥ 3 days, 90-day emergency department (ED) visits, and 90-day hospital readmissions. The ADI was calculated using the patient's home address at the time of surgery, with greater ADI indicating greater socioeconomic disadvantage. We evaluated the mediation effect of patient race on ADI and postoperative healthcare utilization using a multivariable logistic regression model. RESULTS: A higher median ADI was revealed for patients who experienced non -home discharge (P = 0.001), extended LOS (P < 0.001), and ED readmission within 90-days of surgery (P = 0.045). When comparing septic versus aseptic rTHA patients, there were significant differences in healthcare resource utilization but no difference in ADI between the two groups. For aseptic rTHA, ADI significantly mediated the effect of race on both non-home DD and LOS ≥ 3 (41% and 46% mediation, respectively). In septic rTHA, ADI mediated 31.1% of the effect of race on non-home DD, but showed minimal mediation effect on LOS. The mediation effect of ADI on ED admission and hospital readmission was minimal for both groups CONCLUSION: Higher ADI scores are associated with increased healthcare utilization after rTHA, including longer hospital stays and more non-home discharges. The ADI significantly mediates the effect of race on these outcomes, particularly in aseptic rTHA cases, suggesting that neighborhood socioeconomic factors play a crucial role in previously observed racial disparities.

Cup-Cage Construct for Treatment of Severe Acetabular Bone Loss in Revision Total Hip Arthroplasty: Clinical and Radiographic Outcomes at a Mean Follow-Up of 7.7 Years.

BACKGROUND: Acetabular reconstruction in the context of massive acetabular bone loss is challenging. Achieving implant stability in these situations requires special considerations. The cup-cage construct is a treatment option that addresses this issue. This study evaluates survivorship, complications, and functional outcomes using the cup-cage construct. METHODS: A total of 131 cup-cage implants (129 patients) were identified from our retrospective review of revision total hip arthroplasties from January 2003 to January 2022. Among these cases, 100 (76.3%) were women, the mean age at the time of surgery was 68 years (range, 29 to 92; SD [SD], 12.4), and the mean follow-up was 7.7 years (range, 0.02 to 20.3; SD, 5.1). Kaplan-Meier survivorship analysis was conducted with failure defined as revision surgery and/or failure of the cup-cage reconstruction. RESULTS: At a mean follow-up of 7.7 years, the cup-cage construct survivorship due to all-cause failure was 83.9% (95% CI [confidence interval]: 77.6 to 90.2) at 5 years with 88 hips at risk, 74.8% (95% CI: 66.2 to 83.4) at 10 years with 38 hips at risk, and 69.8% (95% CI: 59.4 to 80.2) at 15 years with 11 hips at risk. The survivorship due to failure from aseptic loosening was 96.7% (95% CI: 93.6 to 99.8) at 5 years with 88 hips at risk and 95.5% (95% CI: 91.6 to 99.4) at 10 and 15 years with 38 and 11 hips at risk, respectively. The revision rate for aseptic loosening of the cup and/or cage, infection, dislocation, and aseptic loosening of the femoral stem was 5 of 131 (3.8%), 12 of 131 (9.1%), 10 of 131 (7.6%), and 2 of 131 (1.5%). CONCLUSIONS: The cup-cage construct is a reliable treatment option for the treatment of various acetabular defects. There are favorable survivorship, clinical, and radiographic outcomes, with a satisfactory complication rate.

Inpatient Hospital Costs, Emergency Department Visits, and Readmissions for Revision Hip and Knee Arthroplasty.

BACKGROUND: Revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) tremendously burden hospital resources. This study evaluated factors influencing perioperative costs, including emergency department (ED) visits, readmissions, and total costs-of-care within 90 days following revision surgery. METHODS: A retrospective analysis of 772 revision TKAs and THAs performed on 630 subjects at a single center between January 2007 and December 2019 was conducted. Cost data were available from January 2015 to December 2019 for 277 patients. Factors examined included comorbidities, demographic information, preoperative Anesthesia Society of Anesthesiologists score, implant selection, and operative indication using mixed-effects linear regression models. RESULTS: Among 772 revisions (425 THAs and 347 TKAs), 213 patients required an ED visit, and 90 required hospital readmission within 90 days. There were 22.6% of patients who underwent a second procedure after their initial revision. Liver disease was a significant predictor of ED readmission for THA patients (multivariable odds ratio [OR]: 3.473, P = .001), while aseptic loosening, osteolysis, or instability significantly reduced the odds of readmission for TKA patients (OR: 0.368, P = .014). In terms of ED visits, liver disease increased the odds for THA patients (OR: 1.845, P = .100), and aseptic loosening, osteolysis, or instability decreased the odds for TKA patients (OR: 0.223, P < .001). Increased age was associated with increased costs in both THA and TKA patients, with significant cost factors including congestive heart failure for TKA patients (OR: $7,308.17, P = .004) and kidney disease for THA patients. Revision surgeries took longer than primary ones, with TKA averaging 3.0 hours (1.6 times longer) and THA 2.8 hours (1.5 times longer). CONCLUSIONS: Liver disease increases ED readmission risk in revision THA, while aseptic loosening, osteolysis, or instability decreases it in revision TKA. Increased age and congestive heart failure are associated with increased costs. These findings inform postoperative care and resource allocation in revision arthroplasty. LEVEL OF EVIDENCE: Economic and Decision Analysis, Level IV.

What's New in Periprosthetic Femur Fractures?

BACKGROUND: Periprosthetic femur fracture (PFF) is one of the most common indications for reoperation following total hip arthroplasty. METHODS/RESULTS: This article provides a review of a symposium on PFF that was presented at the American Association of Hip and Knee Surgeons 2023 annual meeting, including an overview of the Vancouver classification and its implications on treatment and subsequent complications, an updated approach to the management of intraoperative fractures, and finally, contemporary strategies for both osteosynthesis as well as revision arthroplasty for PFFs. CONCLUSION: As the incidence of PPF continues to increase, arthroplasty and trauma surgeons must be prepared to address this challenging complication with a contemporary understanding of the treatment options and their outcomes.

Outcomes of a Double-Cup Construct to Treat Paprosky 3A and 3B Acetabular Defects at a Mean of 39 Months.

BACKGROUND: Modular reconstruction systems based on porous tantalum (PT) prosthetic components have been increasingly used for the treatment of complex acetabular bone defects in revision total hip arthroplasty. We report a novel technique that applies a revision cup as a "super-augment" to form a "double-cup" construct for Paprosky type III defects. METHODS: A retrospective review was conducted on revision total hip arthroplasty cases, comparing those treated with double-cup constructs (DC group, n = 48) to those treated with PT shells and augments (PT group, n = 48). All procedures were performed at the same institute between 2017 and 2022. Clinical outcome evaluation utilized the Harris Hip Score, Oxford Hip Score, and the 36-Item Short Form Survey. Preoperative and postoperative radiographic assessments measured hip center of rotation (COR) position and leg length discrepancy. Additionally, postoperative complications and implant survivorship were monitored during the follow-up period. RESULTS: The clinical outcomes improved substantially in both groups, which showed no significant difference in the Harris Hip Score (P = .786), the Oxford Hip Score (P = .570), and the 36-Item Short Form Survey (P = .691). Compared to the PT group, the reconstruction COR was significantly closer to the anatomic COR (vertical distance: 2.630 versus 7.355 mm, P = .0034; horizontal distance: 1.881 versus -6.413 mm, P < .0001) in Paprosky 3B type defects. Additionally, postoperative leg length discrepancy was less in the DC group (-8.252 versus -1.821 mm, P = .0008). Dislocation was the main complication in the DC group, and only 1 patient received re-revision due to repeated dislocation. The cumulative survival rate of the DC group (100%; 95% confidence interval 100) was better than the PT group (83.4%; 95% confidence interval 70.5 to 98.6) when re-revisions for aseptic loosening were the endpoint (P = .046). CONCLUSIONS: The DC is a reliable revision technique for the reconstruction of Paprosky type III bone defects. Although dislocation remains challenging, the biomechanically superior restoration achieved by this technique lowers the risk of aseptic loosening.

Development and Validation of a Risk Calculator for Intensive Care Unit Admission After Total Hip Arthroplasty.

BACKGROUND: The purpose of this study was to develop and validate a risk stratification calculator to determine the risk of a patient requiring intensive care unit (ICU) admission following primary and revision total hip arthroplasty (THA). METHODS: Using a database of 12,342 THA procedures, with 132 ICU admissions, from 2005 to 2017, we developed models of ICU admission risk based on previously identified preoperative factors including age, heart disease, neurologic disease, renal disease, unilateral versus bilateral surgery, preoperative hemoglobin, blood glucose, and smoking status. Prior to developing the calculator, a set of logistic regressions were analyzed to determine weight and scoring for each variable. Once developed, we validated the risk calculator using a second independent institution. RESULTS: A separate risk calculator was developed for primary and revision THA. The area under the curve (AUC) for primary THA was 0.808 (95% confidence interval 0.740 to 0.876) and revision THA was AUC 0.795 (confidence interval 0.740 to 0.850). As an example, the primary THA risk calculator had a Total Points scale of 220, with 50 points associated with a 0.1% chance of ICU admission and 205 points associated with a 95% chance of ICU admission. Validation with an external cohort demonstrated satisfactory AUCs, sensitivities, and specificities for both primary THA (AUC 0.794, sensitivity 0.750, and specificity 0.722) and revision THA (AUC 0.703, sensitivity 0.704, and specificity 0.671) CONCLUSION: The externally validated risk calculators developed in this study can accurately predict ICU admission following primary and revision THA based on a number of readily available preoperative factors.

Age-Adjusted Modified Frailty Index Predicts 30-Day Complications and Mortality in Aseptic Revision Total Hip and Knee Arthroplasty.

BACKGROUND: The age-adjusted modified frailty index (aamFI) has been demonstrated to effectively predict postoperative complications and healthcare resource utilization in patients undergoing primary total joint arthroplasty. The purpose of this study was to evaluate the applicability of aamFI in patients undergoing aseptic revision total hip (rTHA) and knee arthroplasty (rTKA). METHODS: A national database was queried for patients undergoing aseptic rTHA and rTKA from 2015 to 2020. A total of 13,307 rTHA and 18,762 rTKA cases were identified. The aamFI was calculated by adding 1 additional point for age ≥73 years to the previously described 5-item modified frailty index (mFI-5). The area under the curve was calculated and compared to compare predictive accuracy between mFI-5 and aamFI. Logistic regression was used to investigate the relationship between aamFI and 30-day complications. RESULTS: The incidence of incurring any (≥1) complication increased from 15% for aamFI 0 to 45% for aamFI ≥5 after rTHA and from 5 to 55% after rTKA. Patients who had an aamFI ≥3 (reference aamFI = 0) had increased odds (rTHA: odds ratio (OR) 3.5, 95% confidence interval (CI) 2.9 to 4.1, P < .001; rTKA: OR 4.2, 95% CI 4.4 to 5.1, P < .001) of incurring at least 1 complication. The aamFI, compared to mFI-5, was a more accurate predictor of any complication (rTHA P < .001; rTKA P < .001) and 30-day mortality (rTHA P < .001; rTKA P < .003). CONCLUSION: The aamFI is an excellent predictor of complications in patients undergoing rTHA and rTKA. The addition of chronological age to the previously described mFI-5 improves the predictive value of this simple metric.

Unplanned Emergency Department Visits Following Revision Total Joint Arthroplasty: Incidences, Risk Factors, and Mortalities.

BACKGROUND: The incidence of unplanned emergency department (ED) visits following revision total joint arthroplasty is an indicator of the quality of postoperative care. The aim of this study was to investigate the incidences, timings, and characteristics of ED visits within 90 days after revision total joint arthroplasty. METHODS: A retrospective review of 457 consecutive cases, including 254 revision total hip arthroplasty (rTHA) and 203 revision total knee arthroplasty (rTKA) cases, was conducted. Data regarding patient demographics, timings of the ED encounter, chief complaints, readmissions, and diagnoses indicating reoperation were analyzed. RESULTS: The results showed that 41 patients who had rTHA (16.1%) and 14 patients who had rTKA (6.9%) returned to the ED within 90 days postoperatively. The incidence of ED visits was significantly higher in the rTHA group than in the rTKA group (P = .003). The most common surgery-related complications were dislocation among rTHA patients and wound conditions among rTKA patients. Apart from elevated calculated comorbidity scores, peptic ulcer in rTHA patients and cerebral vascular events and chronic obstructive pulmonary disease in rTKA patients might increase chances of unplanned ED visits. Patients who had ED visits showed significantly higher mortality rates than the others in both rTHA and rTKA cohorts (P = .050 and P = .008, respectively). CONCLUSIONS: The ED visits within 90 days are more common after rTHA than after rTKA. Patients in both ED visit groups after rTHA and rTKA demonstrated worse survival. Efforts should be made to improve quality of care to prevent ED visits.

Early Discharge for Revision Total Knee and Hip Arthroplasty: Predictors of Success.

BACKGROUND: The rate of revision total joint arthroplasties is expected to increase drastically in the near future. Given the recent pandemic, there has been a general push toward early discharge. This study aimed to assess for predictors of early postoperative discharge after revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA). METHODS: There were 77 rTKA and 129 rTHA collected between January 1, 2019 and December 31, 2021. Demographic data, comorbidities, a comorbidity index, the modified frailty index (mFI-5), and surgical history were collected. The Common Procedural Terminology codes for each case were assessed. Patients were grouped into 2 cohorts, early discharge (length of stay [LOS] <24 hours) and late discharge (LOS >24 hours). RESULTS: In the rTHA cohort, age >65 years, a history of cardiac or liver disease, an mFI-5 of >1, a comorbidity index of >2.7, a surgical time >122 minutes, and the need for a transfusion were predictors of prolonged LOS. Only the presence of a surgical time of >63 minutes or an mFI-5 >1 increased patient LOS in the rTKA cohort. In both rTHA and rTKA patients, periprosthetic joint infection resulted in a late discharge for all patients, mean 4.8 and 7.1 days, respectively. Dual component revision was performed in 70.5% of rTHA. Only 27.6% of rTKA were 2-component revisions or placements of an antibiotic spacer. CONCLUSIONS: Several patient and surgical factors preclude early discharge candidacy. For rTHA, an mFI-5 of >2/5, comorbidity index of >4, or a surgical time of >122 minutes is predictive of prolonged LOS. For rTKA, an mFI-5 of >2/5, Charlson Comorbidity Index of >5, or a surgical time of >63 minutes predicts prolonged LOS.

Incidence and Predictors of Subsidence Using Modular, Tapered, Fluted Titanium Femoral Stems in Aseptic Revision Total Hip Arthroplasty.

BACKGROUND: Tapered, fluted titanium (TFT) femoral stems have become the gold standard in revision total hip arthroplasty (rTHA). However, there is a paucity of data on TFT stem subsidence rates following aseptic rTHA. Subsidence can lead to instability, mechanical failure, leg-length discrepancy, and may require revision surgery. This study evaluated the incidences and predictors of TFT subsidence in aseptic rTHA. METHODS: A total of 102 TFT femoral stems of 4 designs were retrospectively reviewed. Stem subsidence was measured on digital radiographs taken immediately after surgery and at standard clinical follow-up. Patient characteristics, risk factors for subsidence, revision etiologies, and implant characteristics were recorded. Patient-reported outcome measures were also evaluated for a subset of cases. RESULTS: Overall, 12% of stems subsided >1 cm, and subsidence was minimal (<3 mm) in ≥64% of cases. From immediate postoperative to 1-month radiographic follow-up, 79% of stems subsided a mean of 2.9 mm (range, 0.1 to 12 mm). Beyond 1 month, subsidence was minimal for ≥77% of cases. In multivariate analyses, women and less femoral implant canal fill were associated with greater subsidence (P ≤ .034). The TFT stem design was not associated with early subsidence (P = .816). There were no modular junction fractures. There were 2 fractures and 2 subsidence-related revisions for aseptic loosening that occurred postoperatively. CONCLUSIONS: The amount of subsidence in TFT stems was low and was detectable in the early (less than 1 year) postoperative period. Maximizing TFT stem fill within the femoral canal appears to reduce the risk of subsidence without increasing femoral fracture rates and should be the goal with implantation of these devices. LEVEL OF EVIDENCE: IV-Case Series, No Control Group.