Aspirin Thromboprophylaxis Following Primary Total Knee Arthroplasty Is Associated With a Lower Rate of Early Prosthetic Joint Infection Compared With Other Agents.

BACKGROUND: Patients undergoing total knee arthroplasty (TKA) are at increased risk of venous thromboembolism (VTE). Aspirin has been shown to be effective at reducing rates of VTE. In select patients, more potent thromboprophylaxis is indicated, which has been associated with increased rates of bleeding and wound complications. This study aimed to evaluate the effect of thromboprophylaxis choice on the rates of early prosthetic joint infection (PJI) following TKA. METHODS: A review of 11,547 primary TKA patients from 2013 to 2019 at a single academic orthopaedic hospital was conducted. The primary outcome measure was PJI within 90 days of surgery as measured by Musculoskeletal Infection Society criteria. There were 59 (0.5%) patients diagnosed with early PJI. Chi-square and Welch-2 sample t-tests were used to determine statistically significant relationships between thromboprophylaxis and demographic variables. Significance was set at P < .05. Multivariate logistic regression adjusted for age, body mass index, sex, and Charlson comorbidity index was performed to identify and control for independent risk factors for early PJI. RESULTS: There was a statistically significant difference in the rates of early PJI between the aspirin and non-aspirin group (0.3 versus 0.8%, P < .001). Multivariate logistic regressions revealed that patients given aspirin thromboprophylaxis had significantly lower odds of PJI (odds ratios = 0.51, 95% confidence interval = 0.29-0.89, P = .019) compared to non-aspirin patients. CONCLUSION: The use of aspirin thromboprophylaxis following primary TKA is independently associated with a lower rate of early PJIs. Arthroplasty surgeons should consider aspirin as the gold standard thromboprophylaxis in all patients in which it is deemed medically appropriate and should carefully weigh the morbidity of PJI in patients when non-aspirin thromboprophylaxis is considered. LEVEL OF EVIDENCE: Retrospective, Therapeutic Level III.

Comparison of silver-embedded occlusive dressings and negative pressure wound therapy following total joint arthroplasty in high BMI patients: a randomized controlled trial.

INTRODUCTION: High body mass index (BMI) and wound drainage following total joint arthroplasty (TJA) can lead to wound healing complications and periprosthetic joint infection. Silver-embedded occlusive dressings and negative pressure wound therapy (NPWT) have been shown to reduce these complications. The purpose of this prospective trial was to compare the effect of silver-embedded dressings and NPWT on wound complications in patients with BMI ≥ 35 m/kg2 undergoing TJA. METHODS: We conducted a randomized control trial of patients who had a BMI > 35 m/kg2 and were undergoing primary TJA between October 2017 and February 2020. Patients who underwent revision surgery, or those with an active infection, previous scar, history of wound healing complications, post-traumatic degenerative joint disease with hardware, or inflammatory arthritis were excluded. Patients were randomized to receive either a silver-embedded occlusive dressing (control) or NPWT. Frequency distributions, means, and standard deviations were used to describe patient demographics, postoperative complications, 90-day readmissions, and reoperations. T-test and chi-squared tests were used to test for significant differences between continuous and categorical variables, respectively. RESULTS: Two hundred-thirty patients with 3-month follow-up were included. One-hundred-fifteen patients received the control and 115 patients received NPWT. There were six patients (5.2%) in the control group with wound complications (drainage: n = 5, non-healing wound: n = 1) and two patients (1.7%) in the NPWT with complications (drainage: n = 2). There were no 90-day readmissions in the control group versus two (1.8%) 90-day readmissions in the NPWT group. Finally, three patients (2.6%) in the control group underwent reoperations (irrigation and debridement [I&D], I&D with modular implant exchange, and implant revision), while none in the NPWT group had undergone reoperation. The two groups showed insignificant differences in wound complications (p = 0.28), 90-day readmissions (p = 0.50), and reoperations (p = 0.25). CONCLUSION: Patients with BMI ≥ 35 m/kg2 undergoing TJA have no statistical difference in early wound complications, readmissions, or reoperations when treated with either silver-embedded dressings or NPWT.

Role of non-ASA VTE prophylaxis in risk for manipulation following primary total knee arthroplasty.

INTRODUCTION: Stiffness and decreased range of motion frequently lead to hindrance of activities of daily living and dissatisfaction follow total knee arthroplasty (TKA). This study aims to evaluate the effect of non-aspirin (ASA) chemoprophylaxis and determine patient-related risk factors for stiffness and need for manipulation under anesthesia (MUA) following primary TKA. MATERIALS AND METHODS: A review of all patients undergoing primary TKA from 2013 to 2019 at a single academic orthopedic hospital was conducted. The primary outcome measure was MUA performed post-operatively. Chi-square analysis and Mann-Whitney U test were used to determine statistically significant relationships between risk factors and outcomes. Significance was set at p < 0.05. Univariate logistic regression was performed to control for identified independent risk factors for MUA. RESULTS: A total of 11,550 patients undergoing primary TKA from January 2013 to September 2019 at an academic medical center were included in the study. Increasing age and Charlson Comorbidity Index were associated with statistically significant decreased odds of MUA (0.93, 95% CI: 0.92-0.94, p < 0.001, OR 0.71, 95% CI 0.63-0.79, p < 0.001). Active smokers had a 2.01 increased odds of MUA (OR 2.01, 95% CI 1.28, 3.02, p < 0.001). There was no significant difference in rates of MUA between ASA and non-ASA VTE prophylaxis (p 0.108). CONCLUSIONS: Younger age, lower CCI, and history of smoking are associated with a higher rate, while different chemical VTE prophylaxis does not influence rate of MUA after TKA. Arthroplasty surgeons should consider these risk factors when counseling patient preoperatively. Understanding each patients' risk for MUA allows surgeons to appropriately set preoperative expectations and reasonable outcome goals.

Learning curve for active robotic total knee arthroplasty.

PURPOSE: Total Knee Arthroplasty (TKA) procedures incorporate technology in an attempt to improve outcomes. The Active Robot (ARo) performs a TKA with automated resections of the tibia and femur in efforts to optimize bone cuts. Evaluating the Learning Curve (LC) is essential with a novel tool. The purpose of this study was to assess the associated LC of ARo for TKA. METHODS: A multi-center prospective FDA cohort study was conducted from 2017 to 2018 including 115 patients that underwent ARo. Surgical time of the ARo was defined as Operative time (OT), segmented as surgeon-dependent time (patient preparation and registration) and surgeon-independent time (autonomous bone resection by the ARo). An average LC for all surgeons was computed. Complication rates and patient-reported outcome (PRO) scores were recorded and examined to evaluate for any LC trends in these patient related factors. RESULTS: The OT for the cases 10-12 were significantly quicker than the OT time of cases 1-3 (p < 0.028), at 36.5 ± 7.4 down from 49.1 ± 17 min. CUSUM and confidence interval analysis of the surgeon-dependent time showed different LCs for each surgeon, ranging from 12 to 19 cases. There was no difference in device related complications or PRO scores over the study timeframe. CONCLUSION: Active Robotic total knee arthroplasty is associated with a short learning curve of 10-20 cases. The learning curve was associated with the surgical time dedicated to the robotic specific portion of the case. There was no learning curve-associated device-related complications, three-dimensional component position, or patient-reported outcome scores. LEVEL OF EVIDENCE: Level II.

Incarceration History and HIV Care Among Individuals Living with HIV in Florida, 2014-2018.

The present study examines the HIV continuum of care outcomes among people living with HIV (PLWH) who have either recent (< 12-months) or distal (> 12-months) incarceration history compared to those without an incarceration history. A self-administered survey (as part of the Florida Cohort Study (n = 932)) was used to collect data on demographic information, linkage to care, retention in care, HIV medication adherence, viral suppression, and incarceration history. Those with recent incarceration history were least likely to report HIV medication adherence greater than or equal to 95% of the time (χ2 = 8.79; p = 0.0124), always take their medications as directed (χ2 = 15.29; p = 0.0005), and to have durable viral suppression (χ2 = 16.65; p = 0.0002) compared to those distally or never incarcerated. In multivariable analyses, those never and distally incarcerated had greater odds of care linkage ([vs recently incarcerated] AOR = 2.58; CI: 1.31, 5.07; p = 0.0063, AOR = 2.09; CI: 1.11, 3.95; p = 0.0228, respectively). Those never incarcerated had greater odds of taking ART as directed ([vs recently incarcerated] AOR = 2.53; CI: 1.23 - 5.19; p = 0.0116). PLWH with an incarceration history may need more on-going monitoring and follow-up HIV care than those without previous incarceration regardless of when incarceration occurred.

RESUMEN: El presente estudio examina el cuidado continuo entre las personas que viven con VIH (PVVS) con antecedentes penales recientes (en los últimos 12 meses) o más (> 12 meses) en comparación con aquellos sin antecedentes penales. Se utilizaron datos del Estudio de Cohorte de la Florida (n = 932). Se utilizó una encuesta auto administrada para recopilar datos sobre variables demográficas, vínculo al cuidado, retención al cuidado, adherencia a medicamentos contra el VIH, supresión viral e historial de encarcelamiento. Aquellos con antecedentes penales recientes fueron menos probable de reportar adherencia a medicamentos contra el VIH, mayor o igual a, el 95% de las ocasiones (χ2 = 8.79; p = 0.0124), tomando siempre sus medicamentos según las instrucciones (χ2 = 15.29; p = 0.0005), y tener una supresión viral duradera (χ2 = 16.65; p = 0.0002) en comparación con los encarcelados en el pasado o nunca encarcelados. En los análisis multivariables, aquellos que nunca fueron encarcelados y aquellos que estuvieron encarcelados hace mucho tiempo atrás tuvieron mayor probabilidad de estar vinculados con el cuidado médico ([en contraste con aquellos recientemente encarcelados]AOR = 2.58; CI: 1.31, 5.07; p = 0.0063, AOR = 2.09; CI: 1.11, 3.95; p = 0.0228, respectivamente). Aquellos que nunca fueron encarcelados tuvieron mayor probabilidad de tomar la TAR según indicado ([en contraste con aquellos recientemente encarcelados] AOR = 2.53; CI: 1.23 ­ 5.19; p = 0.0116). PVVS con historial de encarcelamiento necesitan más monitoreo y cuidado de seguimiento continuo en comparación con aquellos sin encarcelaciones previas, independientemente de cuando ocurrió el encarcelamiento.

Lack of small tibial component size availability for females in a highly utilized total knee arthroplasty system.

PURPOSE: Surgeons must rely on manufacturers to provide an appropriate distribution of total knee arthroplasty (TKA) sizes. There is a lack of literature regarding current appropriateness of tibial sizing schemes according to sex. As such, a study was devised assessing the adequacy of off-the-shelf tibial component size availability according to sex. METHODS: A search was conducted to identify all primary TKAs between July 2012 and June 2019 performed using a single implant. Baseline patient characteristics were collected (age, weight, height, BMI, and race). Two cohorts were created according to patient sex. Tibial sizes for each cohort were collected. Tibial component bar graph and histogram were created according to component sizes. Skewness and kurtosis were calculated for each distribution. Overhang was noted and measured radiographically. RESULTS: A total of 864 patients were identified, 38.7% males and 61.3% females. Most patients were Caucasian, and BMI was similar between cohorts. Tibial size distribution for males was as follows: 0.3% C, 4.8% D, 16.5% E, 40.1% F, 31.4% G, 6.9% H. Tibial size distribution for females was as follows: 30.8% C, 42.8% D, 23.0% E, 2.6% F, 0.8% G, 0.0% H. Histograms and normal curves demonstrated a fairly symmetric distribution of sizes for males (skewness = - 0.31, kurtosis = - 0.03). The distribution for females was positively skewed (skewness = 0.57, kurtosis = 0.12). Overall, overhang was noted in 16.6% of all size C tibias. CONCLUSIONS: The results of this study highlight an implant-specific discrepancy in size availability affecting female patients which could result in inferior outcomes. The authors urge manufacturers to critically assess current implant size distribution availability to ensure both genders are adequately, and equally represented. LEVEL OF EVIDENCE: IV.

Differences in Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) Scores for a Single Surgeon Comparing Two Institutions: An Unfair Reimbursement Metric.

BACKGROUND: Emphasis on value-based purchasing links physician financial remuneration to patient-derived outcome scores. Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) surveys aim to provide a uniform comparison tool. Of the 22 different survey questions, only 3 (13.6%) focus on experience related to doctors. We sought to determine how HCAHPS scores differ for a single surgeon performing more than 500 total joint arthroplasties annually, divided almost equally between two centers. METHODS: HCAHPS data from 2015 to 2018 for a single, fellowship-trained arthroplasty surgeon were collected from two different hospitals. More than 200 cases were performed at each center with the same staff. One center is a large metropolitan academic-teaching hospital, and the other is a suburban private hospital. The purpose of the study was to determine if differences existed regarding HCHAPS scores between the two institutions. RESULTS: A significant difference was found between institutions regarding questions pertaining to "hospital environment," "admission process," and "hospital staff concern for pain," with more patients responding favorably in Institution Two than Institution One. CONCLUSION: Patient perceptions and ratings of overall experience differ significantly between hospitals even when surgery is performed by a single surgeon. These results lend credence to the fact that surgeons should not be unduly penalized for the hospital in which they operate, and financial remuneration involving HCAHPS scores must be approached with caution. This unfair system could potentially drive surgeons to perform the majority of their cases in the hospital system with higher scores in the nonphysician related domains as this would affect overall patient satisfaction, and thus, financial compensation.

Factors Affecting Range of Motion After Revision Total Knee Arthroplasty.

BACKGROUND: Range of motion (ROM) after revision total knee arthroplasty (RTKA) is an important clinical outcome, as decreased ROM can lead to patient dissatisfaction and diminished mobility. This study sought to determine the effect of type of revision, implant constraint level, and reason for revision has on RTKA ROM. METHODS: A retrospective review of 832 RTKA cases from 2011 to 2019 was conducted at a single, urban academic institution. Patients who underwent aseptic RTKA and had preoperative and 1-year postoperative ROM in their chart were included. The ΔROM was calculated by subtracting the preoperative ROM from the 1-year postoperative ROM. ROM was compared between tibial polyethylene liner-only revisions (liner) and all other revision types (component) and based on reason for revision. Subanalysis was performed within the liner and component revision cohorts to determine the effect of reason for revision and implant constraint level on ROM. RESULTS: In total, 290 patients qualified. Forty-two patients had liner revisions (14.5%) and 248 had component revisions (85.5%). The ΔROM for component revision cases was significantly higher than liner exchange only (10° ± 24° vs.1° ± 19°; P = .03). ΔROM was not significant when comparing the level of implant constraint nor was it when separating and comparing by type of revision. Component revisions due to instability were found to significantly decrease ΔROM. CONCLUSION: Component revision cases have significantly improved ΔROM when compared with liner-only revision. Constraint level is not significantly associated with changes in ROM in either liner or component revisions. Component revisions due to instability significantly reduce ΔROM.

Is Surgical Approach for Primary Total Hip Arthroplasty Associated With Timing, Incidence, and Characteristics of Periprosthetic Femur Fractures?

BACKGROUND: Periprosthetic femur fractures (PFF) involving primary total hip arthroplasty (THA) remain a significant concern. The purpose of this study was to evaluate the effect of surgical approach during primary THA on early PFF with respect to fracture timing, incidence, radiographic parameters, and surgery-related factors. METHODS: A retrospective review of all patients with PFF during or after primary THA from 2011 to 2019 was conducted at a single, urban academic institution. Of the study cohort of 11,915 patients, 79 patients with PFF were identified (0.66%). Direct anterior (DA), posterior anterior (PA), and laterally based (LA) cohorts were formed based on the surgical approach. PA and LA groups were combined to form a nonanterior (NA) cohort. Radiographic parameters, surgical factors, and fracture mechanism were analyzed. RESULTS: The incidence of fracture across approaches was 0.70% (33/4707; DA), 0.63% (35/5600; PA), and 0.68% (11/1608; LA) (P = .97). Time from THA to fracture was significantly shorter in the DA cohort (12.5 ± 14.1 days) than the NA cohort (48.2 ± 120.6 days) (P = .05). Postoperatively identified, atraumatic PFFs were more common in the DA cohort (78.3%, 18/23) than the NA cohort (51.6%, 16/31) (P = .045). There were no differences between groups in radiographic or other clinical parameters. CONCLUSION: Patients who underwent DA THA have significantly shorter time to PFF and were more often identified postoperatively with an atraumatic mechanism than patients who underwent NA approaches. The known difficulty in femoral exposure and stem placement with the DA approach may play a role in contributing to a higher rate of intraoperative or early postoperative PFF.

Does the Organism Profile of Periprosthetic Joint Infections Change With a Topical Vancomycin Powder and Dilute Povidone-Iodine Lavage Protocol?

BACKGROUND: While vancomycin powder and dilute povidone-iodine (VIP) is associated with fewer total joint arthroplasty (TJA) periprosthetic joint infections (PJI), its effect on PJI organism profiles is unclear. This study evaluates primary TJA PJI organism profiles before and after the implementation of a VIP protocol. METHODS: In total, 18,299 primary TJAs performed at a university-affiliated, not-for-profit orthopedic hospital from before (1/2012-12/2013) and after (1/2016-12/2019) a VIP protocol was initiated were reviewed to identify deep PJIs that occurred within 90 days of the index arthroplasty as defined by the Musculoskeletal Infection Society guidelines. Demographics, overall organism incidence (n/TJAs), and relative organism incidence (n/PJIs) from the two cohorts were compared. RESULTS: In total, 103 TJA PJIs were identified (pre-VIP: 32/3982; VIP: 71/14,317). Following the introduction of VIP, the overall and relative incidence of coagulase-negative staphylococcal TJA PJIs significantly decreased (overall: 0.20% to 0.04%, P = .004; relative: 25.00% to 8.45%, P = .031). In response, the relative incidence of MSSA TJA PJIs significantly increased (18.75% to 40.85%, P = .042). Broken down by arthroplasty type, VIP was associated with a significantly lower overall incidence of coagulase-negative staphylococcal total knee arthroplasty (TKA) PJIs (0.27% to 0.06%, P = .015), a significantly lower overall incidence of MRSA TKA PJIs (0.18% to 0.03%, P = .031), and a nonsignificant decrease in the overall incidence of gram-negative TKA PJIs (0.18% to 0.04%, P = .059). No organism profile changes were found in total hip arthroplasty PJIs. CONCLUSION: VIP is not associated with more difficult to treat primary TJA PJIs. While promising, these findings require a prospective randomized controlled trial for confirmation. LEVEL OF EVIDENCE: Level III, Retrospective cohort study.

Topical Vancomycin Powder and Dilute Povidone-Iodine Lavage Reduce the Rate of Early Periprosthetic Joint Infection After Primary Total Knee Arthroplasty.

BACKGROUND: Vancomycin powder and dilute povidone-iodine lavage (VIP) was introduced to reduce the incidence of periprosthetic joint infection (PJI) in high-risk total knee arthroplasty (TKA) patients. We hypothesize that VIP can reduce the incidence of early PJI in all primary TKA patients, regardless of preoperative risk. METHODS: An infection database of primary TKAs performed before a VIP protocol was implemented (January 2012-December 2013), during a time when only high-risk TKAs received VIP (January 2014-December 2015), and when all TKAs received VIP (January 2016-September 2019) at an urban, university-affiliated, not-for-profit orthopedic hospital was retrospectively reviewed to identify patients with PJI. Criteria used for diagnosis of PJI were the National Healthcare Safety Network and Musculoskeletal Infection Society guidelines. RESULTS: VIP reduced early primary TKA PJI incidence in both the high-risk and all-risk cohorts compared with the pre-VIP cohort by 44.6% and 56.4%, respectively (1.01% vs 0.56% vs 0.44%, P = .0088). In addition, after introducing VIP to all-risk TKA patients, compared with high-risk TKA patients, the relative risk of PJI dropped an additional 21.4%, but this finding did not reach statistical significance (0.56% vs 0.44%, P = .4212). There were no demographic differences between the 3 VIP PJI cohorts. CONCLUSION: VIP is associated with a reduced early PJI incidence after primary TKA, regardless of preoperative risk. With the literature supporting its safety and cost-effectiveness, VIP is a value-based intervention, but given the nature of this historical cohort study, a multicenter randomized controlled trial is underway to definitively confirm its efficacy.

Versatility and accuracy of a novel image-free robotic-assisted system for total knee arthroplasty.

INTRODUCTION: Technological advances alongside increased demand for knee replacement surgery have led to the development of a novel image-free bed rail-mounted robotic-assisted system for total knee arthroplasty (TKA). The device is capable of real-time tracking to accommodate for leg motion during bone resection allowing for precise control and positioning of the bone saw in the planned resection plane. The purpose of this study is to discuss the versatility and accuracy of this novel image-free robotic-assisted technology in TKA. METHODS AND MATERIALS: The novel robotic-assisted system underwent a stepwise assessment to verify its versatility and accuracy. First, functional accuracy was bench tested to evaluate predetermined surgical plans independent of user variability and anatomic variability compared to conventional instrumentation. This was followed by assessments utilizing cadaveric specimens for resection accuracy, implant positioning, and soft tissue involvement. RESULTS: Test bench accuracy revealed overall pooled linear positional accuracy of 0.326 ± 0.249 mm and pooled angular positional accuracy of 0.365 ± 0.611°. Resection errors for both robotic and conventional cohorts ranged between 0.6° and 1.9°. Concerning coronal alignment, 33/40 robotic specimen were within ± 1° and 38/40 within ± 3° of the femoral varus-valgus target, compared with 17/40 and 37/40 with conventional instrumentation, respectively. Twenty-four of the 40 robotic specimens were within ± 1° and 40/40 within ± 3° of the tibial varus-valgus target compared with 15/40 and 32/40 with conventional instrumentation, respectively. Soft tissue structures were uncompromised in all robotic-assisted cases. Conventional instruments revealed two cases of partial cleavage of the posterior cruciate ligament and two instances of a compromised posterior medial capsule. There were no significant differences between the two techniques concerning the samples that were uncompromised and fully functional (40/40 vs. 38/40, p = 0.49). CONCLUSION: The novel image-free robotic-assisted surgical system demonstrates excellent benchtop accuracy to aid bony resection in cadaveric specimens. It offers notable improvement in coronal implant alignment compared to conventional instrumentation.

Reduced Aseptic Loosening With Fully Cemented Short-Stemmed Tibial Components in Primary Cemented Total Knee Arthroplasty.

BACKGROUND: Recently, the use of short tibial stems in the obese population undergoing total knee arthroplasty (TKA) has been proposed. Thus, we designed a study to assess tibial component survivorship after primary TKA using a single implant both with and without a fully cemented stem extension performed by a single surgeon. METHODS: A search of our institutional research database was performed. A minimum 2-year follow-up was selected. Cohorts were created according to patient body mass index (BMI; >40 kg/m2 and <40 kg/m2) and the presence (stemmed tibia [ST]) or absence (non-stemmed tibia [NST]) of a short tibial stem extension. Kaplan-Meier survival analyses for aseptic loosening and log-rank tests were performed. RESULTS: A total of 236 patients were identified (ST = 162, NST = 74). Baseline patient characteristics were statistically similar between cohorts with the exception of BMI which was greater in the ST cohort (32.9 kg/m2, 30.6 kg/m2; P = .01). Kaplan-Meier survival analysis at 5 years was superior for the BMI < 40 kg/m2 cohort (98.9%, 93.1%; P = .045), the ST cohort (100%, 94.5%; P = .006), and the BMI > 40 kg/m2 with ST cohort at 4 years (71.4%, 100%; P = .008). CONCLUSION: Morbid obesity and a short native tibial stem design appear to be associated with aseptic loosening in primary TKA. This appears to be mitigated through the use of an ST. As such, the use of ST may be considered in at-risk patients. Alternatively, implants with longer native stem designs can be employed. Modern short-stemmed tibial components may need to be redesigned.

Cefazolin remains the linchpin for preventing acute periprosthetic joint infection following primary total knee arthroplasty.

AIMS: Despite recent literature questioning their use, vancomycin and clindamycin often substitute cefazolin as the preoperative antibiotic prophylaxis in primary total knee arthroplasty (TKA), especially in the setting of documented allergy to penicillin. Topical povidone-iodine lavage and vancomycin powder (VIP) are adjuncts that may further broaden antimicrobial coverage, and have shown some promise in recent investigations. The purpose of this study, therefore, is to compare the risk of acute periprosthetic joint infection (PJI) in primary TKA patients who received cefazolin and VIP to those who received a non-cephalosporin alternative and VIP. METHODS: This was a retrospective cohort study of 11,550 primary TKAs performed at an orthopaedic hospital between 2013 and 2019. The primary outcome was PJI occurring within 90 days of surgery. Patients were stratified into two groups (cefazolin vs non-cephalosporin) based on their preoperative antibiotic. All patients also received the VIP protocol at wound closure. Bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify the odds ratio of PJI. RESULTS: In all, 10,484 knees (90.8%) received cefazolin, while 1,066 knees (9.2%) received a non-cephalosporin agent (either vancomycin or clindamycin) as preoperative prophylaxis. The rate of PJI in the cefazolin group (0.5%; 48/10,484) was significantly lower than the rate of PJI in the non-cephalosporin group (1.0%; 11/1,066) (p = 0.012). After controlling for confounding variables, the odds ratio (OR) of developing a PJI was increased in the non-cephalosporin cohort compared to the cefazolin cohort (OR 2.389; 1.2 to 4.6); p = 0.01). CONCLUSION: Despite the use of topical irrigant solutions and addition of local antimicrobial agents, the use of a non-cephalosporin perioperative antibiotic continues to be associated with a greater risk of TKA PJI compared to cefazolin. Strategies that increase the proportion of patients receiving cefazolin rather than non-cephalosporin alternatives must be emphasized. Cite this article: Bone Jt Open 2022;3(1):35-41.

A Novel Machine Learning Predictive Tool Assessing Outpatient or Inpatient Designation for Medicare Patients Undergoing Total Knee Arthroplasty.

BACKGROUND: Removal of total joint arthroplasty from the inpatient-only list has created significant confusion regarding which patients qualify for an inpatient designation. The purpose of this study is to develop and validate a novel predictive tool for assessing who will be an outpatient vs inpatient after total knee arthroplasty (TKA). METHODS: A cohort of Medicare patients undergoing primary TKA between January 2018 and September 2019 were retrospectively reviewed. Baseline demographics and patient characteristics were obtained, and their distributions for outpatient (less than 2 midnights) and inpatient stay were assessed. Subsequently, a XGBoost machine learning model was trained using 80% of the TKA patients, and the remaining 20% of patients were involved in testing the model's performance in terms of accuracy and the average area under the receive operating characteristic curve. RESULTS: Eight hundred ninety-nine Medicare patients underwent TKA at our institution between January 2018 and September 2019. Of which, 625 patients had outpatients stays, and 274 qualified for inpatient designation. Significant associations were demonstrated between inpatient visits and the following factors: higher body mass index, increased age, better functional scores, multidimensional fatigue inventory, Charlson Comorbidity Index, American Society of Anesthesiologists score, female gender, cardiac history, and the Revised Cardiac Risk Index. The XGBoost model for predicting an inpatient or outpatient stay was 63.3% accurate, with area under the receive operating characteristic curve of 68.8%. CONCLUSIONS: Using readily available key baseline characteristics, functional scores, and comorbidities, this machine-learning model accurately predicts the probability of an "outpatient" vs "inpatient" stay after TKA in the Medicare population. body mass index, age, VR12 functional scores, and multidimensional fatigue inventory scores had the highest influence on this predictive model.

Increased Rate of Early Periprosthetic Joint Infection in Total Hip Arthroplasty With the Use of Alternatives to Cefazolin Despite Additional Gram-Negative Coverage.

Background: Periprosthetic joint infection (PJI) remains one of the most devastating complications following total joint arthroplasty. Appropriate prophylactic antimicrobial administration and antibiotic stewardship are major factors impacting the risk of PJI in total hip arthroplasty (THA). The purpose of our study was to evaluate whether cefazolin administration was superior to noncefazolin antibiotics in prevention of PJI after primary THA. Material and methods: A review of 9910 patients undergoing primary THA from 2013 to 2019 at a single institution was conducted. The primary outcome was PJI within 90 days of surgery. The Musculoskeletal Infection Society definition of PJI was used for this analysis. Groups were those receiving cefazolin + expanded gram-negative antimicrobial prophylaxis (EGNAP) and those receiving an alternative to cefazolin + EGNAP. Chi-square tests were conducted to determine statistical significance. Multivariate logistic regression was performed to eliminate confounders. Results: 9028 patients received cefazolin + EGNAP, and 882 patients received an alternative to cefazolin + EGNAP. PJI rate using the Musculoskeletal Infection Society criteria was 0.82% (81/9910). PJI rate in the cefazolin + EGNAP group was 0.75% (68/9028). In the group receiving an alternative to cefazolin + EGNAP, the PJI rate was 1.47% (13/882). This difference was statistically significant (P = .023). On multivariate analysis, the odds ratio for developing PJI when an alternative to cefazolin was used was 2.05 (P = .022). When comparing alternatives, there remained a statistically significant increased PJI rate when the alternative used was clindamycin (odds ratio 2.65, P = .007). Conclusion: Our data demonstrate that in the presence of EGNAP in THA, there was a higher PJI rate when clindamycin was given as an alternative to cefazolin. The number of THA patients receiving alternatives to cefazolin must be minimized. Level of Evidence: III, Retrospective Cohort Study.

Increased Rates of Tibial Aseptic Loosening in Primary Cemented Total Knee Arthroplasty With a Short Native Tibial Stem Design.

BACKGROUND: Emerging evidence has suggested that both obesity and a short, native tibial stem (TS) design may be associated with early aseptic loosening in total knee arthroplasty. The use of short, fully cemented stem extensions may mitigate this risk. As such, we devised a multicenter study to confirm or negate these claims. METHODS: A search of our institutional research databases was done. A minimum 2-year time from index procedure was selected. Cohorts were created according to patient body mass index and the presence (stemmed tibia [ST]) or absence (nonstemmed tibia [NST]) of a short TS extension. Kaplan-Meier survival analyses for aseptic loosening and log-rank tests were done. RESULTS: A total of 1,350 patients were identified (ST = 500, NST = 850). The mean time to the final follow-up in cases without aseptic loosening for the ST cohort was 3.5 years (2.8-6.3) and 5.0 years (2.9-6.3) for the NST cohort (P < 0.001). Kaplan-Meier survival analysis at 6 years was superior for the ST cohort (100%, 98.5%; P = 0.025), and a trend toward superior 5-year survival was observed for body mass index <40 kg/m2 (99.1%, 93.2%; P = 0.066). The mean time to aseptic loosening was 2.4 years (0.9-4.5), with approximately 40% occurring within the first 2 years. CONCLUSIONS: Short, native TS design is associated with early aseptic loosening in primary cemented total knee arthroplasty. This can be mitigated through the use of an ST. More cost-effective solutions include (1) use of implants with longer native stem designs or (2) redesign of short TS implants.

The Association Between Clopidogrel and Gastrointestinal Bleeding After Primary Total Joint Arthroplasty.

BACKGROUND: Anticoagulation after total joint arthroplasty has been demonstrated to reduce venous thromboembolism. However, anticoagulation can lead to adverse bleeding events. The purpose of this study was to assess if an association exists between specific anticoagulation modalities, such as clopidogrel, and postoperative gastrointestinal (GI) bleeding. METHODS: A prospective cohort of Medicare patients undergoing total joint arthroplasty from 2017 to 2019 (3535 patients) was retrospectively reviewed. The baseline characteristics and anticoagulation methods were compared between the "GI bleed" cohort and the "non-GI bleed cohort." Independent t-tests were conducted for continuous variables, while chi-squared analysis was conducted for dichotomous variables. RESULTS: Thirteen patients (0.42%) sustained a postoperative complication of a GI bleed. The mean age for patients sustaining a GI bleed was 69.23 years compared with 72.30 years for the non-GI bleed cohort (P = .11). Six patients who sustained a GI bleed (46%) were on an anticoagulation therapy other than aspirin, and this trended toward significance (P = .09). Five patients who sustained a GI bleed (38%) were on clopidogrel (P < .01). Seven percent of patients on clopidogrel sustained a postoperative GI bleed (P < .01). None of the patients who sustained a postoperative GI bleed had a history of peptic ulcer disease. CONCLUSION: Patients on clopidogrel in the acute perioperative period demonstrated a strong association with the complication of postoperative GI bleeding. Arthroplasty surgeons should be aware of this association to educate and monitor patients on clopidogrel therapy and to work as part of interdisciplinary teams to assess the risks vs benefits of perioperative clopidogrel.