Faculty Bibliography

INTRODUCTION/BACKGROUND:Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is challenging to diagnose. We aimed to evaluate the impact of dry taps requiring saline lavage during preoperative intraarticular hip aspiration on the accuracy of diagnosing PJI before revision surgery. METHODS:A retrospective review was conducted for THA patients with suspected PJI who received an image-guided hip aspiration from May 2016 to February 2020. Musculoskeletal Infection Society (MSIS) diagnostic criteria for PJI were compared between patients who had dry tap (DT) versus successful tap (ST). Sensitivity and specificity of synovial markers were compared between the DT and ST groups. Concordance between preoperative and intraoperative cultures was determined for the two groups. RESULTS:In total, 335 THA patients met inclusion criteria. A greater proportion of patients in the ST group met MSIS criteria preoperatively (30.2%vs.8.3%, p<0.001). Patients in the ST group had higher rates of revision for PJI (28.4%vs.17.5%, p=0.026) and for any indication (48.4%vs.36.7%, p=0.039). MSIS synovial WBC count thresholds were more sensitive in the ST group (90.0%vs.66.7%). There was no difference in culture concordance (67.9%vs.65.9%,p=0.709), though the DT group had a higher rate of negative preoperative cultures followed by positive intraoperative cultures (85.7%vs.41.1%, p=0.047). CONCLUSION/CONCLUSIONS:Our results indicate that approximately one-third of patients have dry hip aspiration, and in these patients cultures are less predictive of intraoperative findings. This suggests that surgeons considering potential PJI after THA should apply extra scrutiny when interpreting negative results in patients who require saline lavage for hip joint aspiration.

INTRODUCTION:Obstructive sleep apnea (OSA) is a known risk factor for venous thromboembolism (VTE), defined as pulmonary embolism (PE) or deep vein thrombosis (DVT); however, little is known about its effect on VTE rates after total joint arthroplasty (TJA). This study sought to determine whether patients with OSA who undergo TJA are at greater risk for developing VTE versus those without OSA. METHODS:A retrospective analysis was conducted on 12,963 consecutive primary TJA patients at a single institution from 2016 to 2019. Patient demographic data were collected through query of the electronic medical record, and patients with a previous history of OSA and VTE within a 90-day postoperative period were captured using the International Classification of Disease, 10th revision diagnosis and procedure codes. RESULTS:Nine hundred thirty-five patients with OSA were identified. PE (0.6% versus 0.24%, P = 0.023) and DVT (0.1% versus 0.04%, P = 0.37) rates were greater for patients with OSA. A multivariate logistic regression revealed that patients with OSA had a higher odds of PE (odds ratio [OR] 3.821, P = 0.023), but not DVT (OR 1.971, P = 0.563) when accounting for significant demographic differences. Female sex and total knee arthroplasty were also associated with a higher odds of PE (OR 3.453 for sex, P = 0.05; OR 3.243 for surgery type, P = 0.041), but not DVT (OR 2.042 for sex, P = 0.534; OR 1.941 for surgery type, P = 0.565). CONCLUSION:Female patients with OSA may be at greater risk for VTE, specifically PE, after total knee arthroplasty. More attention toward screening procedures, perioperative monitoring protocols, and VTE prophylaxis may be warranted in populations at risk.

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.

Background/UNASSIGNED: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/UNASSIGNED: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/UNASSIGNED: = .007). Conclusion/UNASSIGNED: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/UNASSIGNED:III, Retrospective Cohort Study.

Current trajectories are set to create a large gap between total joint arthroplasty (TJA) supply and demand. Economics dictates that when the demand of consumers (TJA patients) exceeds supply (surgeons performing TJA), a new equilibrium should ideally be established at a higher price point. However, in TJA, the price is set by the government and, therefore, not subject to traditional economic models. Thus, reimbursements for TJA have decreased steadily over time. Fee for service is no longer the dominant reimbursement model for most orthopedic care. Surgeons play a critical role in the evolution and success of Value-Based Care (VBC) models, but this work is not reflected in recent payment changes for TJA. The regulatory environment is notoriously complex and affects our patients, surgeons, and institutions. It is imperative for orthopedic surgeons to continue to advocate for themselves by engaging with leadership, responding to surveys, and balancing outside influences to preserve patient access to TJA. Future payment models for musculoskeletal care must risk-stratify patients, appropriately reimburse for the work of revision TJA, and consider non-modifiable socioeconomic factors. Perioperative orthopedic surgical home (POSH) tools can ensure early appropriate care and proper care coordination for discharge. All of these factors, despite being framed within payment policy, ultimately affect access to orthopedic care for our patients.

Dual mobility designs in total arthroplasty allow for increased range of motion prior to impingement and dislocation. While valuable for reducing dislocation, dual mobility has its own unique complication profile that includes intraprosthetic dislocation, corrosion, and femoral notching. Despite these relatively rare complications, dual mobility articulations are valuable options for patients at higher risk of dislocation-both early and contemporary reports on dual mobility in total hip arthroplasty suggest that it can reduce the risk of dislocation without leading to unacceptable rates of complication or early revision. Cost analyses and longer follow-up studies on newer dual mobility designs will help determine the future of dual mobility in total hip arthroplasty.

BACKGROUND:Patients undergoing total joint arthroplasty (TJA) are at risk for developing periprosthetic joint infection (PJI). To treat PJI, orthopaedic surgeons can perform 1-stage or 2-stage revision arthroplasty. Although 2-stage revision yields superior long-term outcomes, the optimal antibiotic therapy duration and route of administration between stages remain uncertain. In this systematic review, we aimed to identify if variations in antibiotic therapy, duration, and administration during 2-stage hip or knee revision arthroplasty affect PJI eradication rates and surgical outcome measures. METHODS:A literature search was performed using the PubMed and Google Scholar databases to identify all original reports from January 2000 to June 2021 involving 2-stage revision arthroplasty to treat PJI. Studies were included if they specified antibiotic duration, an intravenous (IV) route of antibiotic administration, type of antibiotic, and 2-stage revision PJI eradication rate and had a mean or median follow-up of at least 2 years after the second-stage operation. Included studies were classified into 3 groups based on the length of IV antibiotic therapy after prosthesis explantation: prolonged IV antibiotic therapy of 4 to 6 weeks, shortened IV antibiotic therapy of ≤2 weeks, and shortened course of IV antibiotic therapy followed by 6 to 12 weeks of oral antibiotics. RESULTS:Nine studies were included. Three studies utilizing a prolonged IV antibiotic therapy had PJI eradication rates of 79% to 96%. Four studies using a shortened IV antibiotic therapy showed PJI eradication rates of 88% to 100%. Finally, 2 studies utilizing a shortened course of IV antibiotic therapy with oral antibiotics had PJI eradication rates of 95% and 97%. There was no significant difference in eradication rates across IV antibiotic duration strategies, despite a diverse array of cultured microorganisms across the studies. CONCLUSIONS:Although the numbers are small, this systematic review suggests that prolonged IV antibiotic duration, shortened IV antibiotic duration, and shortened IV antibiotic duration supplemented with oral antibiotics confer similar PJI eradication rates after hip or knee arthroplasty. LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:The purpose of this study is to determine if the number and types of patient-reported drug allergies are associated with prosthetic joint infection (PJI) and functional outcomes following total joint arthroplasty (TJA). METHODS:This is a retrospective review of all patients who underwent a primary, elective total hip (THA) or knee arthroplasty (TKA) over a 10-year period at a single academic institution. Demographic, clinical information, and number and type of patient-reported drug allergy was collected. Univariate and multivariate logistic regressions were performed to identify risk factors for PJI and risk of PJI based on number of allergies. Univariate analysis was also performed to identify if the number of patient-reported allergies affected functional outcome scores. RESULTS:Of 31,109 patients analyzed, there were 941 (3%) revisions for infection (491 knees and 450 hips). At least one allergy was reported by 16,435 (52.8%) patients, with a mean of 1.2 ± 1.9. Those who underwent revision for infection had a significantly higher number of reported allergies (1.68 ± 1.9 vs 1.23 ± 1.9, P < .0005, 95% confidence interval -0.58 to 0.33). On univariate regression the number of allergies independently predicted revision TJA for infection (P < .0001) as did age, gender, body mass index, and smoking status. On multivariate regression for each additional patient-reported allergy, risk of PJI increased by 1.11 times (95% confidence interval 1.07-1.14, P < .0001). Number of patient-reported allergies did not predict 3-month or 1-year functional outcome scores. CONCLUSION/CONCLUSIONS:Patients with a higher number of reported allergies may be at increased risk of PJI following TJA. LEVEL OF EVIDENCE/METHODS:Prognostic Level II.

AIMS/OBJECTIVE: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/CONCLUSIONS: 2022;3(1):35-41.

PURPOSE/OBJECTIVE: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/METHODS:IV.