Faculty Bibliography

BACKGROUND/UNASSIGNED:Periprosthetic joint infections (PJIs) following primary and revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA) have been studied, but a contemporary large-scale analysis of incidence has not been performed. This study assessed PJI incidence and trends for TKA, THA, rTKA, and rTHA using a contemporary database. METHODS/UNASSIGNED:Epic Cosmos database was retrospectively queried (2015-2023). Current procedureal terminology codes identified patients: 27447 (TKA), 27130 (THA), 27486 (rTKA one component), 27487 (rTKA both components), 27134 (rTHA both components), 27137 (rTHA acetabular component), and 27138 (rTHA femoral component). PJI rates were identified using International Classification of Diseases 9/10 codes and analyzed using linear regression. RESULTS/UNASSIGNED:= .08). CONCLUSIONS/UNASSIGNED:Significant PJI reduction after primary TKA and THA was observed over the last decade, but infection rates remained stable in revision cohorts. Further investigations are required to assess underlying reasons for observed PJI rate reductions following primary arthroplasty.

BACKGROUND:The impact of body mass index (BMI) on outcomes after total knee arthroplasty (TKA) is a highly debated topic. Our study aims to investigate the implications of BMI changes from the day of surgical booking to the surgery date on perioperative and postoperative outcomes. METHODS:We retrospectively reviewed patients who underwent elective, primary, unilateral TKA at an urban academic institution from 2015-2024 with a minimum 90-day follow-up. The cohort was classified into three groups by percent BMI change from surgical booking date to TKA date: Group 1, decrease in BMI; Group 2, 0-5% increase in BMI; and Group 3, > 5% increase in BMI. Propensity-score matching (1:1:1) based on age, gender, BMI at surgical booking, and smoking status was performed; perioperative and postoperative outcomes were compared. Multivariate regression analysis evaluated risk factors for interval change in BMI. RESULTS:Before matching, 12,990 patients were included, with 39.6% in Group 1, 41.2% in Group 2, and the remaining 19.2% in Group 3. Notably, Group 3 had the longest length of stay (50.3 h vs. 48.6 [1] & 47.1 [2]; P = 0.002) and the lowest discharge-to-home rates (88.7% vs. 89.8% [1] & 91.7% [2]; P = 0.014). No significant difference was seen in 90-day ED visits, 90-day readmissions, or revision rates. Logistic regression of the pre-match cohort found that prolonged surgical booking delays were associated with decreased all-cause revisions (OR = 0.98; P = 0.038), while percent BMI change in this period did not impact revision incidence. Duration of surgical booking delay had no impact on BMI changes in obese patients. CONCLUSION/CONCLUSIONS:Our study evaluated preoperative BMI change between surgical booking and TKA, finding that most patients (60.4%) gain weight during this time. While patients with significant BMI increases (> 5%) had longer hospital stays and lower discharge-to-home rates, Percent BMI change during this period did not impact all-cause or septic revision incidence.

The use of technology in adult reconstruction (AR) reflects a balance of perceived utility, workflow considerations, and training exposure. This study evaluated whether exposure to technology during residency and fellowship training influences early-career AR surgeons’ utilization of and attitudes towards technology in total joint arthroplasty (TJA). An online survey was distributed to a nationwide cohort of 51 AR surgeons who completed fellowship between 2011 and 2022 at 13 U.S. programs. Survey items assessed exposure to technology during training, utilization, and perceived impact of technology on clinical practice. 36 surgeons (71%) reported using technology in fewer than half their training cases (< 50% group), while 15 (29%) reported use in the majority of cases (> 50% group). Most surgeons (88%) reported access to technology in their current practice, with no statistically significant difference between training exposure groups (p = 0.999). Similarly, among those with access, most surgeons (78%) reported using technology in their current practice, with no statistically significant difference between training groups (p = 0.238). However, surgeons with greater exposure rated the importance of technology in TJA and its impact on patient outcomes significantly higher (p = 0.003 for both). Greater exposure to technology during training was thus associated with higher perceived value, though no significant differences in access or utilization in early practice were observed.

BACKGROUND:Weight management strategies before total hip arthroplasty (THA) include bariatric surgery and Glucagon-like peptide-1 receptor agonists, including semaglutide. Previous studies have reported higher THA implant failure in patients who had prior bariatric surgery. This study aimed to evaluate semaglutide as a weight management alternative for patients undergoing THA and any effects on perioperative outcomes. METHODS:A retrospective review of primary, elective THAs performed between 2012 and 2024 was conducted at a single, urban, academic center. The study identified 224 patients who had a history of bariatric surgery, 202 patients who had perioperative semaglutide use, and a control group of 2,991 patients who had a body mass index (BMI) > 35. Demographic variables and clinical outcomes were compared between cohorts. RESULTS:The bariatric patients were younger (57 versus 61, P = 0.012) and more often women (65.6 versus 57.4 versus 55.4%, P < 0.001) than semaglutide and control patients. Preoperative hemoglobin A1c was lowest in semaglutide patients (6.2 versus 5.7 versus 5.8%, P < 0.001). The changes in BMI varied across groups one year before and after THA (P < 0.001). The bariatric and semaglutide groups decreased their BMI by 1.4 and 0.8, respectively, and control patients increased by 0.4. Implant survivorship was 95.5% at 10 years. There was no correlation found between any cohort and 90-day emergency department visits, readmissions, and all-time revision. Higher American Society of Anesthesiologists class and Charlson Comorbidity Index ≥ 5 conferred increased complications. CONCLUSIONS:Semaglutide appears to be a safe alternative to bariatric surgery for weight management before THA, with similar implant survival and postoperative complication rates. Further studies are warranted to understand outcomes for THA patients who use semaglutide.

BACKGROUND:The impact of postoperative antithrombotic therapy (ATT) on complications such as periprosthetic joint infection (PJI) after total knee and hip arthroplasty (TKA and THA, respectively) remains understudied. We aimed to evaluate temporal trends in ATT use and the association between ATT type and PJI following primary TKA and THA. METHODS:We retrospectively reviewed 20,376 TKA and 16,076 THA patients receiving postoperative ATT between 2013 and 2025. Trends in ATT use were analyzed for all patients, but PJI incidence (2018 International Consensus Meeting definition) was assessed only in patients who had a minimum 90-day follow-up (14,663 TKA; 11,445 THA). Of these, 0.8% and 1.3% developed a PJI, respectively. Multivariate logistic regressions adjusted for age, sex, body mass index, smoking, and the Charlson Comorbidity Index were applied to assess the association between ATT and PJI. RESULTS:From 2013 to 2025, aspirin monotherapy increased to account for the majority of prophylaxis (TKA: 2.0 to 59.4%; THA: 3.1 to 82.2%). In contrast, the use of low-molecular-weight heparin (LMWH) declined (TKA: 87.6 to 0.8%; THA: 86.7 to 2.3%), as did warfarin (TKA: 4.1 to 0.3%; THA: 3.4 to 0.9%) and rivaroxaban (TKA: 6.8 to 4.2%; THA: 8.9 to 2.8%). During the same period, apixaban use increased (TKA: 0 to 10.0%; THA: 0 to 12.7%). Aspirin monotherapy was associated with lower odds of PJI compared to non-aspirin regimens (adjusted odds ratio [OR] 0.60, 95% confidence interval [CI] 0.45 to 0.81, P = 0.001). Conversely, warfarin (OR 8.01, 95% CI 3.41 to 18.88, P < 0.001) and LMWH (OR 1.89, 95% CI 1.35 to 2.64, P < 0.001) were independently associated with increased PJI risk in THA. CONCLUSION/CONCLUSIONS:Aspirin has become the dominant postoperative ATT agent. In THA, aspirin is associated with a significantly decreased risk of PJI compared to potent anticoagulants like warfarin and LMWH, while no such association was found in the TKA cohort. Surgeons should prioritize aspirin to minimize postoperative infection risk.

BACKGROUND:Postoperative improvement in patient-reported outcomes is a key measure of total hip arthroplasty success. The Minimum Clinically Important Difference (MCID) represents the smallest improvement perceived as beneficial. Distribution-based MCIDs have been criticized for producing thresholds smaller than anchor-based values, questioning their clinical relevance. We hypothesized they may capture early biological recovery signals associated with subsequent patient-reported outcomes and aimed to determine whether failure to achieve an early distribution-based MCID (seven to 31 days) was associated with failure to achieve a late anchor-based MCID (90 to 365 days). METHODS:This retrospective cohort study included patients undergoing primary unilateral total hip arthroplasty for osteoarthritis from January 1, 2021, to January 1, 2025, comprising 844 patients. Patients were included if they completed 'Hip disability and Osteoarthritis Outcome Score, Joint Replacement' questionnaires preoperatively, at seven to 31 days, and at 90 to 365 days. Distribution-based MCID was defined as a ≥ 7.8-point improvement, and anchor-based MCID as ≥ 23 points. Multivariable regression assessed associations between early distribution-based and late anchor-based MCID failure, adjusting for demographics and clinical factors. RESULTS:In the early period (seven to 31 days), 565 patients (67.0%) achieved the distribution-based MCID, whereas 573 (67.9%) achieved the late anchor-based MCID (90 to 365 days). Among patients who failed to attain an early distribution-based MCID, 54.1% (151 of 279) also failed the late anchor-based MCID, compared with 21.2% (120 of 565) among early achievers (P < 0.001). Early distribution-based MCID failure was a strong independent predictor of late anchor-based MCID failure (odds ratio: 2.61; 95% confidence interval: 1.85 to 3.68; P < 0.001). Higher baseline Hip disability and Osteoarthritis Outcome Score, Joint Replacement scores and facility-based discharge were also independently associated with late failure (P < 0.05). CONCLUSIONS:Failure to achieve an early distribution-based MCID is strongly associated with poor patient-reported outcomes up to one year. Early distribution-based MCID attainment may represent an important prognostic marker, enabling timely clinical intervention.

INTRODUCTION/BACKGROUND:While the learning curve for direct anterior approach (DAA) total hip arthroplasty (THA) is steep, no classification exists to predict technically challenging cases. We propose and validate a new Davidovitch direct anterior (DDA) classification system for predicting DAA THA case complexity. METHODS:We retrospectively reviewed primary DAA THAs by two fellowship-trained surgeons (October 2019 to June 2025). Exclusions included fracture, contralateral hardware, incomplete pelvis radiographs, or less than one year of follow-up. Cases were grouped into learning curve, proficient, and expert phases. Classification was based on preoperative antero-posterior (AP) pelvis radiographs. Operative time served as a proxy for case difficulty. Univariate and multivariate regressions assessed the effects of classification, surgeon experience, fixation method, and body mass index (BMI). RESULTS:Multivariate analyses of 283 cases, including DDA classification, surgeon experience, fixation method, and BMI, demonstrated that operative times were significantly longer for DDA 4 versus DDA 1 cases (P = 0.011). Operative time decreased across learning curve, proficient, and expert phases (P < 0.001). Higher BMI (P < 0.001) and cemented fixation (P = 0.004) independently increased operative time. There were 13 overall complications and two revision THAs within 90 days. CONCLUSION/CONCLUSIONS:This novel radiographic classification system predicted case difficulty in DAA THA, as DDA 4 cases took longer than DDA 1 cases, particularly during the learning curve. Beyond the learning curve, the impact of DDA classification on operative time diminished. This classification system has the potential to serve as a valuable preoperative tool for operative planning and workday efficiency, particularly for early-career surgeons on their learning curve.

BACKGROUND:Prolonged retention of antibiotic-loaded articulating spacers after the first stage of a two-stage revision for periprosthetic joint infection (PJI) can occur because of patient preference, surgeon preference, or medical reasons that prevent the planned second stage. Little is known about the frequency of persistent infections, mechanical complications, and functional results in patients with retained spacers. QUESTIONS/PURPOSES/OBJECTIVE:At a minimum follow-up of 2 years after spacer placement, among patients who do not undergo the second stage revision (replacement of the spacer with a definitive prosthesis of the hip or knee): (1) What was the survival of the spacer free from unplanned reoperation or removal, the cumulative incidence of symptomatic infection, and the overall (Kaplan-Meier) survivorship of the patients? (2) What is the cumulative incidence of mechanical complications (spacer fracture or dislocation)? (3) What is the ambulatory status of patients who have retained their spacers? METHODS:Between March 2011 and July 2023, a total of 111 and 152 patients underwent first-stage revision with an articulating spacer placement as part of a planned two-stage procedure for chronic PJI after THA and TKA at our institution, respectively. Of these, 21% (23 of 111) in the THA group and 24% (37 of 152) in the TKA group did not undergo the anticipated second-stage reimplantation at our institution at least 1 year after spacer placement. Among the original cohorts, 2% (2 of 111) of patients who underwent THA and 3% (4 of 152) of patients who underwent TKA subsequently underwent second-stage reimplantation at outside institutions when reviewed, leaving 19% (21 of 111) in the THA group and 22% (33 of 152) in the TKA group with retained spacers. Of the original cohorts, 7% (8 of 111) in the THA group and 5% (8 of 152) in the TKA group did not have a 2-year follow-up, leaving 12% (13 of 111) of patients with THA and 16% (25 of 152) of patients with TKA available for analysis with a minimum of 2 years of follow-up or death in this retrospective study. The median (range) follow-up from spacer placement to the latest follow-up was 5 years (2 to 11) for patients with THA and 4 years (2 to 8) for patients with TKA. In the THA cohort, the median (range) age was 72 years (59 to 86), and eight patients were female; the median BMI was 32 kg/m2, and the median Charlson comorbidity index (CCI) was 3.5. In the TKA cohort, the median (range) age was 69 years (45 to 83), 13 patients were female, the median BMI was 31 kg/m2, and the median CCI was 4. Complication data following spacer placement were obtained from the electronic medical record and by telephone follow-up when needed. Clinical symptoms (swelling, erythema, warmth, fever, drainage, sinus tract, and pain), inflammatory markers (C-reactive protein and erythrocyte sedimentation rate), available radiographic findings, and laboratory test results (including synovial fluid analysis when obtained) were reviewed for evidence of infection or spacer-related mechanical failure. Infection after the spacer placement was defined as failure when the treating surgeon determined that an unplanned return to the operating room or spacer removal was warranted, acknowledging that postoperative evaluation thresholds varied among surgeons. Spacer-related mechanical failure was defined as spacer fracture or dislocation leading to reoperation or spacer removal. Patients were classified based on whether they underwent an unplanned reoperation or spacer removal. Patients who did not undergo unplanned reoperation or spacer removal were further categorized based on use of chronic suppressive antibiotics (decisions regarding chronic antibiotic therapy were made by the treating surgeon and/or infectious disease team). Patients who underwent reoperation were those who returned to the operating room because of concerning clinical, imaging, and/or laboratory findings of infection or mechanical complications, and the treating surgeon decided to proceed with revision surgery. All reoperation decisions were made by fellowship-trained arthroplasty surgeons with high-volume experience in two-stage revision. We used a competing-risks model to estimate survival of the spacer free from unplanned reoperation or removal attributable to infection or mechanical complications (calculated as 1 minus the corresponding cumulative incidence), with death treated as a competing event. Kaplan-Meier analysis was used to estimate patient survivorship, with death as the endpoint. Mortality data were obtained from medical records and hospital databases and were confirmed by telephone follow-up with family members and public records when needed. Ambulatory status before and after spacer placement was summarized descriptively and reported only for patients with both prespacer and postspacer data available (10 THAs and 25 TKAs); no formal hypothesis testing was performed for ambulatory or functional measures. RESULTS:At 2 years of follow-up, the survival of the spacer free from unplanned reoperation or removal was 89% (95% confidence interval [CI] 80% to 99%) for patients with THA and TKA combined, the cumulative incidence of infection was 5% (95% CI 0% to 12%), and the Kaplan-Meier survivorship of the patients was 92% (95% CI 84% to 100%). The cumulative incidence of mechanical complications (spacer fracture or dislocation) was 5% (95% CI 0% to 13%). In the THA cohort (10 patients), ambulatory status before the first stage included two patients using a wheelchair, two using a walker, one using crutches, two using a cane, and three walking without assistive devices. At latest follow-up, four patients used a wheelchair, two used a walker, two used a cane, and two walked without assistive devices. In the knee cohort (25 patients), ambulatory status before the first stage included two patients using a wheelchair, five using a walker, 13 using a cane, and five walking without assistive devices. At latest follow-up, two patients used a wheelchair, five used a walker, 13 used a cane, and five walked without assistive devices. CONCLUSION/CONCLUSIONS:Retained articulating spacers can provide infection control in selected patients who do not proceed to reimplantation after first-stage spacer placement for PJI. Although infection-free spacer survival is achievable, these patients remain at risk for mechanical complications, including dislocation and fracture, as well as progressive functional decline. These risks should be clearly discussed during preoperative counseling to align expectations and support informed decision-making. Further studies are needed to refine patient selection, improve spacer durability, and standardize definitions of treatment success in PJI. LEVEL OF EVIDENCE/METHODS:Level III, case series.

The multiply revised total knee arthroplasty (TKA) poses unique surgical challenges. Patients who present to the office with a failed TKA or revision TKA expect durable, long-term fixation and improved function, yet bone loss and extensor mechanism insufficiency can easily complicate the reconstruction. The aim of this American Association of Hip and Knee Surgeons symposium is to provide up-to-date guidance for re-revision TKA with a specific focus on 1) safe exposure; 2) improved fixation with impaction grafting; 3) improved fixation using porous metal structural augmentation; and 4) managing the patella. After reviewing this paper, the reader should feel comfortable with standard and extensile exposures of a revision knee arthroplasty, understand the technique and outcomes for impaction bone grafting and the use of porous metal augmentation, and develop an algorithm for treating and optimizing patellofemoral kinematics through augmentation and reconstruction techniques.