Faculty Bibliography

BACKGROUND:Robotic assistance (RA) is increasingly used in total knee arthroplasty (TKA) for more accurate bony resection and balancing. However, the impact of robotic TKA (RATKA) on clinical outcomes and patient-reported measures (PROMs) remains unclear. This study aims to compare RATKA and conventional TKA (CTKA) using a novel robotic system. METHODS:A retrospective review was conducted on 10,031 patients who underwent TKA from February 2021 to October 2024. 289 RATKAs were performed with a hand-held robotic system. These RATKA cases were 1:1 propensity-score matched to CTKA for patient demographics, surgeon, implant system, and articulation design. Postoperative and clinical outcomes including surgical time, length of stay (LOS), discharge disposition, 90-day emergency department (ED) visits, manipulation under anesthesia (MUA), debridement, reoperations and revisions were collected and analyzed. Patient-reported outcomes measures (PROMs) included Knee Injury and Osteoarthritis Outcome Scores (KOOS, JR) and Patient Reported Outcome Measurement Information System (PROMIS) scores. RESULTS:RATKA demonstrated significantly shorter LOS (30.04 vs. 51.91 hours, p < 0.001, respectively) compared to CTKA. There was no difference in surgical time (107.18 vs. 106.22 minutes, p = 0.349). Although there was no statistical difference in 90-day ED visits, the majority of the CTKA revisits were due to surgery-related causes when compared to the RATKAs (1.38% vs. 0.34%, p = 0.239). While RATKAs had higher incidence of MUAs (2.07% vs. 0.34%, p = 0.201), CTKAs had more reoperations (1 vs. 0, p = 0.369) and more revisions than the RATKAs (6 vs. 0, p = 0.117). In terms of PROMs, both RATKAs and CTKAs showed similar improvements in KOOS, JR and PROMIS pain scores following TKA, with no significant differences in the magnitude of improvement at early postoperative timepoints. However, at the one-year follow-up, RATKA demonstrated significantly greater reduction in PROMIS pain intensity (Δ-9.12, p = 0.032) compared to CTKAs. CONCLUSIONS:This retrospective analysis showed that the novel RATKA resulted in reduced length of stay, fewer reoperations, and greater reduction in one-year PROMIS pain intensity compared to CTKAs, despite having a higher incidence of MUA rates. Further research is needed to clarify these differences clinically and enhance patient outcomes.

INTRODUCTION/BACKGROUND:Robotic-assisted technologies provide the ability to avoid soft tissue release by utilizing more accurate bony cuts during total knee arthroplasty (TKA). However, the ideal limb alignment is not yet established. The aim of this study was to predict postoperative Coronal Plane Alignment of the Knee (CPAK) using corresponding native bony measurements. METHODS:This study analyzed a retrospective cohort of 530 primary robotic-assisted TKAs. Machine learning was utilized to predict appropriate target lateral distal femoral angles (LDFA) and medial proximal tibial angles (MPTA). Normalization of LDFA and MPTA alignments was performed using the min-max scaler operation on the training set with feature range [-1, 1] and repeated separately for the input and target distributions. A neural network of hidden dimensions (16, 8, 4) was trained via supervised learning to predict planned LDFA and MPTA values from preoperative LDFA and MPTA measurements. RESULTS:The model converged after 104 epochs and batch size 4 with mean squared error ±1.82°. The model's regression agrees with the hypothesized change in preoperative to planned coronal alignment: valgus measurements are translated to neutral/aligned targets while varus alignments are translated to varus alignment of lesser severity. Evaluative statistics demonstrate this method for planning knee morphologies is significantly more accurate than making predictions about the mean (RMSE 1.440; R-squared 0.444; Nash Sutcliffe 0.579). CONCLUSION/CONCLUSIONS:This study's model provides accurate predictions for target knee alignment morphologies. Future work is warranted to evaluate this method's usefulness for planning robotic TKA.

BACKGROUND:High body mass index (BMI) is a risk factor for tibial baseplate loosening following total knee arthroplasty (TKA) but may not adequately correlate with stresses at the tibial baseplate. In this study, we aimed to determine an optimal cutoff of a weight-to-tibial baseplate surface-area ratio (weight/SA) for predicting aseptic tibial baseplate loosening. We further examined whether tibial stem extensions have a protective effect. METHODS:We identified 16,368 patients who underwent primary, elective TKA from June 2011 to March 2023. Patient demographics, including age, sex, and race, implants used, and revision surgeries were extracted. Revisions were manually reviewed to confirm revision indications. The exact surface areas of tibial baseplates were obtained from manufacturers. Receiver operating characteristic (ROC) analysis of patients without tibial stem extensions was utilized to examine the utility of BMI and weight/SA for predicting aseptic tibial baseplate loosening. Optimal weight/SA and BMI cutoffs for predicting loosening were determined. The effect of tibial stem extensions on loosening was then examined in patients at or above (n = 7,698; 3.7% with stem extension) and below (n = 8,670; 1.3% with stem extension) the determined weight/SA cutoff. RESULTS:There were 16,368 patients in the final sample (median age, 67 years; 68.9% female; 54.1% White). Weight/SA (area under the curve [AUC] = 0.653; p < 0.001) was a better predictor of aseptic tibial baseplate loosening requiring revision compared with patient BMI (AUC = 0.624; p < 0.001). The optimal weight/SA cutoff for predicting loosening was 0.0162 kg/mm2 (sensitivity = 0.747, specificity = 0.537). Multivariable logistic regression demonstrated that being at or above the weight/SA cutoff (odds ratio [OR] = 3.17; p < 0.001) but not the BMI cutoff (p = 0.911) was a significant predictor of revision for tibial baseplate loosening in patients without stem extensions. No cases of revision for aseptic tibial baseplate loosening in patients with stem extensions occurred either at or above or below the cutoff. The rate of revision for aseptic tibial baseplate loosening in patients without stem extensions was 0.3% for patients below and 1.0% for patients at or above the weight/SA cutoff. CONCLUSIONS:The ratio of weight-to-tibial baseplate surface area was more predictive of revision for aseptic tibial baseplate loosening following TKA compared with BMI alone. For patients with obesity with small tibial baseplate sizes, utilization of a tibial stem extension may protect against tibial loosening. LEVEL OF EVIDENCE/METHODS:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Tranexamic acid (TXA) is a renally-excreted antifibrinolytic commonly utilized in total joint arthroplasty (TJA). This study examined whether TXA administration affected clinical outcomes and kidney function in patients who had end-stage renal disease (ESRD) undergoing TJA or hemiarthroplasty. METHODS:Through a retrospective chart review, we identified 123 patients: 40 who underwent primary elective total knee arthroplasty (TKA; 65% received TXA), 34 who underwent primary elective total hip arthroplasty (THA; 52.9% TXA), and 49 who underwent nonelective THA or hemiarthroplasty (44.9% TXA) from January 2011 to February 2024. All patients had ESRD and/or were on dialysis, with no difference in percentage on dialysis between TXA groups (TKA: 65.4 versus 64.3%; THA: 55.6 versus 50.0%; nonelective/hemiarthroplasty: 86.4 versus 85.2%, P values ≥ 0.586). Demographic and perioperative characteristics, including preoperative hemoglobin, TXA administration, dose, and route of administration (ROA; intravenous, topical), were extracted. Pre- and postoperative (≤ 7 days) creatinine, perioperative transfusions, revisions, and 90-day emergency department (ED) visits, readmissions, and mortalities were recorded and compared between TXA groups. RESULTS:In the total sample and all cohorts, change in pre- to postoperative creatinine and incidence of postoperative acute kidney injury (AKI), per Kidney Disease Improving Global Outcomes (KDIGO) guidelines, did not significantly differ based on receiving TXA (P values ≥ 0.159). Among patients receiving TXA, change in creatinine did not significantly differ by dose (P values ≥ 0.428) or ROA (P values ≥ 0.256). There were no statistically significant differences in 90-day ED visits, readmissions, or mortalities based on receiving TXA (P values ≥ 0.055). Thromboembolic events occurred in four patients (one TXA, three no TXA, P = 0.617), and perioperative transfusions occurred in two patients (one TXA, one no TXA, P = 0.882) in the nonelective/hemiarthroplasty cohort, with none in the elective cohorts. CONCLUSIONS:The administration of TXA does not portend a significant increase in complications for patients who have ESRD undergoing TJA or hemiarthroplasty for fracture, suggesting TXA should not be contraindicated in this population.

BACKGROUND:A tourniquet is commonly used during total knee arthroplasty (TKA) to improve surgical field visibility and minimize blood loss. While the short-term effects of tourniquet use on postoperative outcomes have been studied extensively and found to be minimal, its influence on longer-term outcomes remains underexplored. This study examined tourniquet use in TKA with up to five-year follow-up. METHODS:In this post hoc analysis of a randomized controlled trial, 227 patients who underwent primary TKA in the tourniquet (T) group (n = 112) or no tourniquet (NT) group (n = 115) were evaluated. Clinical outcomes and patient-reported outcome measures (PROMs) were compared between the two groups. RESULTS:The T group had non-significant trends toward reduced blood loss (131.8 versus 116.7 ml, P = 0.098) and shorter operative time (97.8 versus 95.7 minutes, P = 0.264), with slightly higher postoperative day-one Visual Analog Scale (VAS) pain scores (3.1 versus 3.6, P = 0.197). Length of stay (2.0 versus 2.1 days, P = 0.837) and home discharge rate (88.7 versus 92.0%, P = 0.340) were comparable. The NT group had three 90-day readmissions, while none occurred in the T group (2.7 versus 0%, P = 0.081). The active range of motion at the final follow-up was similar between groups (108.3 versus 106.5 degrees, P = 0.457). All-cause revision rates at five years were comparable between the NT and T groups (5.2 versus 3.6%, P = 0.546). Kaplan-Meier survivorship analysis revealed comparable aseptic implant survival at five years (P = 0.769). There were no significant differences in Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR), Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity, PROMIS pain interference, or PROMIS physical health scores at three months, one year, and five years postoperatively. CONCLUSION/CONCLUSIONS:Using a tourniquet during primary TKA was not associated with differences in clinical or patient-reported outcomes at up to five-year follow-up. These findings suggest that tourniquet use in TKA can be left to the surgeon's discretion.

INTRODUCTION/UNASSIGNED:Previous studies have demonstrated the use of technology in total hip arthroplasty (THA) provided favorable outcomes. This study sought to describe the effect preoperative two-dimensional low-dose (2DLD) full-body radiographs had on the prevention of adverse outcomes following THA. METHODS/UNASSIGNED:We reviewed 11,814 cases of patients who underwent primary, elective THA from 2016 to 2021. Patient demographics and clinical data were compared between patients who did or did not have preoperative standing and sitting 2DLD images (29.5% vs. 70.5%, respectively) using Chi-squared test and multivariate logistic regressions. RESULTS/UNASSIGNED: < 0.001). Multivariate analysis demonstrated preoperative 2DLD images to be significantly associated with lower odds of dislocation, independent from surgical approach, coexisting spinal fusion, and utilization of dual-mobility implants. CONCLUSION/UNASSIGNED:Preoperative 2DLD images were independently associated with decreased risk for dislocations. Even in a higher risk cohort with spinal fusion, the rate of dislocation in the 2DLD cohort was significantly lower.

BACKGROUND:With the increasing utilization of total hip arthroplasty (THA) in patients who have a high comorbidity burden (HCB), coinciding with modifications to reimbursement models over the past decade, an evaluation of the financial impact of HCB on THA over time is warranted. This study aimed to investigate trends in revenue and cost associated with THA in HCB patients. METHODS:Of 13,439 patients who had primary, elective THA between 2013 and 2021 at our institution, we retrospectively reviewed 978 patients considered to have HCB (Charlson comorbidity index ≥ 5 and American Society of Anesthesiology scores 3 or 4). We collected patient demographics, perioperative data, revenue, cost, and contribution margin (CM) of the inpatient episode. We analyzed changes as a percentage of 2013 values over time for these financial markers. Linear regression determined trend significance. The final analysis included 978 HCB patients who had complete financial data. RESULTS:Between 2013 and 2021, direct costs increased significantly (P = .002), along with a nonsignificant increase in total costs (P = .056). While revenue remained steady during the study period (P = .486), the CM decreased markedly to 38.0% of 2013 values, although not statistically significant (P = .222). Rates of 90-day complications and home discharge remained steady throughout the study period. CONCLUSIONS:Increasing costs for HCB patients undergoing THA were not matched by an equivalent increase in revenue, leading to dwindling CMs throughout the past decade. Re-evaluation of reimbursement models for THA that account for patients' HCB may be necessary to preserve broad access to care. LEVEL OF EVIDENCE/METHODS:III.

INTRODUCTION/UNASSIGNED:Total hip arthroplasty (THA) using computer-assisted navigation (N-THA) and robot-assisted surgery (RA-THA) has been increasingly adopted to improve implant positioning and offset/leg-length restoration. Whether clinically meaningful differences in patient-reported outcomes (PROMs) compared to conventional THA (C-THA) are achieved with intraoperative technology has not been established. This systematic review aimed to assess whether published relative PROM improvements with technology use in THA achieved minimal clinically important differences (MCIDs). METHODS/UNASSIGNED: 2786) studies, respectively, for analyses. RESULTS/UNASSIGNED:Statistically significant improvements in postoperative PROM scores were reported in 2/6 (33.3%) studies comparing N-THA with C-THA, though only 1 (16.7%) reported clinically significant relative improvements. Statistically significant improvements in postoperative PROMs were reported in 6/10 (60.0%) studies comparing RA-THA and C-THA, though none reported clinically significant relative improvements. Improved radiographic outcomes for N-THA and RA-THA were reported in 83.3% and 70.0% of studies, respectively. Only 1 study reported a significant improvement in revision rates with RA-THA as compared to C-THA. CONCLUSIONS/UNASSIGNED:Reported PROM scores in studies comparing N-THA or RA-THA to C-THA often do not achieve clinically significant relative improvements. Future studies reporting PROMs should be interpreted in the context of validated MCID values to accurately establish the clinical impact of intraoperative technology.

BACKGROUND:The impact of increased patient comorbidities on the cost-effectiveness of total hip arthroplasty (THAs) is lacking. This study aimed to compare revenue, costs, and short-term (90 days) surgical outcomes between patients who have and do not have a high comorbidity burden (HCB). METHODS:We retrospectively reviewed 14,949 patients who underwent an elective, unilateral THA between 2012 and 2021. Patients were stratified into HCB (Charlson Comorbidity Index ≥ 5 and American Society of Anesthesiology scores of 3 or 4) and non-HCB groups, and were further 1:1 propensity matched based on baseline characteristics. Perioperative data, revenue, costs, and contribution margins (CMs) of the inpatient episode were compared between groups. Also, 90-day readmissions and revisions were compared between groups. Of the 11,717 patients who had available financial data (n = 1,017 HCB, n = 10,700 non-HCB), 1,914 patients were included in the final matched analyses (957 per group). RESULTS:Total (P < .001) and direct (P < .001) costs were significantly higher for HCB patients. Comparable revenue between cohorts (P = .083) resulted in a significantly decreased CM in the HCB patient group (P < .001). The HCB patients were less likely to be discharged home (P < .001) and had significantly higher 90-day readmission rates (P = .049). CONCLUSIONS:Increased THA costs for HCB patients were not matched by increased revenue, resulting in decreased CM. Higher rates of nonhome discharge and readmissions in the HCB population add to the additional financial burden. Adjustments to the current reimbursement models should better account for the increased financial burden of HCB patients undergoing THA and ensure access to care for all patient populations. LEVEL OF EVIDENCE/METHODS:III.

BACKGROUND:Computer navigation and robotic assistance may reduce total hip arthroplasty (THA) dislocations by improving the accuracy and precision of component positioning. We investigated dislocation rates for THAs using conventional techniques, robotic assistance, and computer navigation, while controlling for surgical approach, dual mobility (DM) use, and fluoroscopic guidance. METHODS:We reviewed 11,740 primary THAs performed between June 2016 and December 2022, including 5,873 conventional, 1,293 with robotic-arm assistance, and 4,574 with navigation. The approach was posterior in 6,580 (56.0%), anterior in 4,342 (37.0%), and lateral in 818 (7.0%). A DM was used in 10.4%. Fluoroscopy was used in 3,653 cases and only with the anterior approach. Multivariate analyses yielded odds ratios (OR) for dislocation and revision. Additional regression analyses for dislocation were performed for approach and DM. RESULTS:Raw dislocation rates were as follows: conventional 1.2%, robotic 0.4%, navigation 0.9%, anterior with fluoroscopy 0.4%, anterior without fluoroscopy 2.3%, posterior 1.3%, and lateral 0.5%. Upon multivariate analysis, use of robotics was found to be associated with significantly reduced dislocation risk compared to conventional (OR: 0.3), as did anterior (OR: 0.6) compared to posterior approach; navigation and lateral approach were not found to be associated with a significant reduction in risk. For the anterior approach, multivariate analysis demonstrated that fluoroscopy significantly reduced dislocation risk (OR: 0.1), while DM, robotics, and navigation were not significant. For the posterior approach, the dislocation risk was lower with robotics than with conventional (OR: 0.2); the use of navigation or DM did not demonstrate a significant reduction in risk. CONCLUSIONS:The use of robotics was associated with a reduction in dislocations for this cohort overall. Further, fluoroscopy in the anterior approach and robotic assistance in the posterior approach were both associated with decreased dislocation risk. The role of imageless computer navigation and DM implants requires further study.