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.

AIMS/UNASSIGNED:The aim of this study was to assess the variations in the positioning of components between sides in patients who underwent staged bilateral total hip arthroplasty (THA), and whether these variations affected patient-reported outcome measures (PROMs). METHODS/UNASSIGNED:A retrospective review included 207 patients who underwent staged bilateral THA between June 2017 and November 2022. Leg length, the height and anteversion of the acetabular component, and the coronal and sagittal angles of the femoral component were assessed radiologically and compared with the contralateral THA. The effect of the surgical approach and the technology used on this variation was also assessed. Linear regression was used to investigate the variations between the two THAs and the PROMs. RESULTS/UNASSIGNED:Between the two sides, the mean leg length varied by 4.6 mm (0.0 to 21.2), the mean height of the acetabular component varied by 3.3 mm (0.0 to 13.7), the mean anteversion varied by 8.2° (0.0° to 28.7°), the mean coronal alignment of the femoral component varied by 1.1° (0.0° to 6.9°), and the mean sagittal alignment varied by 2.3° (0.0° to 10.5°). The use of the direct anterior approach resulted in significantly more variation in the alignment of the femoral component in both the coronal (1.3° vs 1.0°; p = 0.036) and sagittal planes (2.8° vs 2.0°; p = 0.012) compared with the use of the posterior approach. The posterior approach generally led to more anteversion of the acetabular component than the anterior approach. The use of robotics or navigation for positioning the acetabular compoment did not increase side-to-side variations in acetabular component-related positioning or leg length. Despite considerable side-to-side variations, the mean Hip disability and Osteoarthritis Outcome, Joint Replacement (HOOS JR) score was not affected by variations in the postioning of the components. CONCLUSION/UNASSIGNED:Staged bilateral THA resulted in considerable variation in the positioning of the components between the two sides. The direct anterior approach led to more variations in anteversion of the acetabular component and sagittal alignment of the femoral component than the posterior approach. The use of computer navigation and robotics did not improve the consistency of the positioning of the components in bilateral THA. Variations in the positioning of the components was not associated with differences in PROMs, indicating that patients can tolerate these differences.

BACKGROUND:Optimal femoral stem alignment and femoral canal fill have been associated with improved osteointegration in patients undergoing cementless total hip arthroplasty (THA). Direct anterior approach (DAA) has become more popular among new surgeons, and the ability to achieve appropriate stem alignment and canal fill due to limited surgical exposure may pose added risks. To mitigate these concerns, several modern tissue sparing stem designs have been designed. This study aimed to compare implant canal fill and alignment between two of the leading DAA-friendly femoral stems available. METHODS:This was a multi-center, retrospective study of patients who underwent DAA THA with either A (n = 149) or B stem (n = 85) between 2021 and 2023 and had a minimum one-year follow-up. Radiographic measures of proximal femoral morphology, including canal calcar ratio (CCR), Morphological Cortical Index (MCI), and Dorr Class (based on the CCR), as well as postoperative measures including femoral canal fill ratio (CFR), signs of osteointegration and stem alignment were analyzed and compared between stem types. RESULTS:, p = 0.082). Spot weld formation was significantly higher in stem A group (59.7% vs. 37.6%, P = 0.001). CONCLUSION/CONCLUSIONS:For patients with similar femoral morphology undergoing DAA THA, the stem A group demonstrated superior anatomical fit in the metaphyseal region, as evidenced by CFR, spot weld formation and implant positioning. Further longer follow up research is needed to elucidate these findings and their correlation to clinical outcomes.

BACKGROUND:Two-stage revisions for chronic periprosthetic joint infections (PJIs) often include antibiotic-loaded cement spacers to control for infection and preserve function. While studies have reported on complications (dislocations, readmissions, and reoperations) after static versus articulating spacer types, there is a paucity of evidence about whether the degree of spacer constraint in articulating spacers affects these complications. This study aims to address a key gap in understanding as to whether the level of spacer constraint affects complications in two-stage revision THA utilizing articulating spacers. QUESTIONS/PURPOSES/OBJECTIVE:(1) Among patients receiving nonconstrained versus constrained articulating antibiotic spacers during first-stage revision THA for PJI, are there differences in major complications, such as dislocation, loosening, periprosthetic fracture, reinfection, and unplanned revisions? (2) After second-stage reimplantation, do patients who received a nonconstrained versus constrained liner during the first stage show differences in the risk of complications, reoperations, and readmissions? METHODS:This is a retrospective review of 539 patients who underwent two-stage revision THA for PJI at a single-specialty, urban academic referral center between July 2011 and March 2023. Of these 539 patients, 72% (388) were excluded for undergoing a full component revision (femoral or acetabular) for any reason before their first stage, 3% (15) for receiving static spacers, and 6% (35) for receiving prefabricated femoral mono-block stems as part of their first stage. Those who underwent only liner exchange were not excluded. The remaining 19% (101 of 539) of patients were included in the final analysis and categorized by degree of liner constraint: 32 were in the nonconstrained group and 69 were in the constrained group. All surgeons included in this study specialize in adult reconstruction and are fellowship trained, and the selected level of constraint was solely based on their routine practice for articulating spacer construct. Baseline characteristics and clinical data, including age, self-reported gender, race, BMI, American Society of Anesthesiologists score, smoking status, surgical history, and perioperative details, were collected. There were no differences in baseline characteristics between the groups except for smoking status. A priori power analysis determined that 150 patients (75 per group) would be needed to detect a statistical difference in the risk of dislocation between groups, assuming a 20% dislocation risk for the constrained group, at a 0.05 alpha level, and 80% power. RESULTS:Between patients receiving nonconstrained versus constrained liners, there were no differences in complications after the first stage of revision. Three percent (1 of 32) of the nonconstrained liners developed dislocations compared with 3% (2 of 69) in the constrained group (relative risk [RR] 1.1 [95% confidence interval (CI) 0.09 to 12.3]; p > 0.99). Three percent (1 of 32) of the nonconstrained group developed periprosthetic fractures compared with 7% (5 of 69) in the constrained group (RR 0.4 [95% CI 0.05 to 3.69]; p = 0.72). Similarly, 3% (1 of 32) versus 7% (5 of 69) had persistent infection (RR 0.4 [95% CI 0.05 to 3.69]; p = 0.72). One incident of loosening occurred in the constrained group. There were also no differences in spacer revision incidence: 10% (3 of 32) of the nonconstrained group and 10% (7 of 69) of the constrained group underwent an unplanned revision after the first stage (RR 1.0 [95% CI 0.29 to 3.91]; p = 0.91). For the second stage, dislocation was 14% (3 of 21) in the nonconstrained group and 10% (5 of 52) in the constrained group (RR 1.1 [95% CI 0.2 to 5.9]; p > 0.99). When comparing periprosthetic fractures, 10% (2 of 21) of the nonconstrained group developed periprosthetic fractures compared with 4% (2 of 52) in the constrained group (RR 2.2 [95% CI 0.3 to 16.6]; p = 0.78). Nineteen percent (4 of 21) in the nonconstrained group had persistent infection compared with 12% (6 of 52) in the constrained group (RR 1.5 [95% CI 0.39 to 5.74]; p = 0.81). The occurrence of readmission after the second stage was 19% (4 of 21) in the nonconstrained group compared with 15% (8 of 52) in the constrained group (RR 1.1 [95% CI 0.3 to 3.9]; p > 0.99). Twenty-four percent (5 of 21) of patients in the nonconstrained group required a surgery-related emergency department visit compared with 13% (7 of 52) in the constrained group (RR 1.6 [95% CI 0.4 to 5.6]; p = 0.64). The incidence of reoperation was 14% (3 of 21) in the nonconstrained group and 13% (7 of 52) in the constrained group (RR 0.9 [95% CI 0.2 to 3.8]; p > 0.99). CONCLUSION/CONCLUSIONS:Our results indicated no differences in the risk of dislocations, reinfections, reoperations, and readmissions between patients undergoing constrained versus nonconstrained articulating spacers for two-stage revision THA. Because constrained liners are typically preferred in patients at higher risk of instability, our findings suggest that their use does not necessarily increase the risk of complications. However, because of the small sample size, larger studies are needed to demonstrate whether there is superiority of liner constraint in this patient population. LEVEL OF EVIDENCE/METHODS:Level III, therapeutic study.

BACKGROUND:Methylene blue (MB), a phenothiazine dye with antimicrobial activity, is used to stain soft tissues and guide thoroughness of debridement during revision total knee arthroplasty (rTKA) for periprosthetic joint infection (PJI). The purpose of this study was to determine if instillation of MB prior to arthrotomy impacts culture yield in TKA PJI. METHODS:We retrospectively reviewed 266 patients diagnosed with TKA PJIs according to the 2018 International Consensus Meeting (ICM) criteria from January 2018 - March 2023 at a single academic hospital. Demographics, perioperative outcomes, and preoperative and intraoperative culture positivity were compared between patients who received intraoperative MB (MB group; n = 26) and those who did not (nMB group; n = 241). A record of detected organisms was included in the analysis. RESULTS:There was no difference in preoperative aspiration culture positivity between groups. However, the MB group had a higher percentage of preoperative to intraoperative culture concordance (89.5 vs. 69.9%; P = 0.04). Although the overall rate of intraoperative culture positivity did not differ significantly between groups, the MB group had more intraoperative cultures obtained per patient (4.9 vs. 4.5; P = 0.02) and higher numbers of positive intraoperative cultures per patient. Concordance rates for patients in both groups with positive preoperative and negative intraoperative cultures were similar (10.5 vs. 16.5%, P = 0.50). Among patients with negative preoperative cultures, intraoperative culture positivity was more discordant in the MB group (0 vs. 18.8%; P = 0.03). There was no difference in the number of patients that received antibiotics following aspiration (68.4 vs. 49.6%; P = 0.12). CONCLUSION/CONCLUSIONS:While MB use did not affect overall culture positivity, it could interfere with intraoperative pathogen detection in patients with negative preoperative cultures. In these cases, MB should be avoided to decrease inaccuracies in intraoperative culture yield. If preoperative cultures are positive, MB may improve surgical debridement and likelihood of infection eradication.

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:Modern surgical protocols, particularly the use of tranexamic acid (TXA), have reduced, but not eliminated, blood transfusions surrounding total hip arthroplasty (THA). Identifying patients at risk for transfusion remains important for risk reduction and to determine type and screen testing. METHODS:We reviewed 6,405 patients who underwent primary, unilateral THA between January 2014 and January 2023 at a single academic institution, received TXA, and had preoperative hemoglobin (Hgb) values. We compared demographics, baseline Hgb levels, and surgical details between patients who were and were not transfused. Data were analyzed utilizing multivariate regression and receiver operating characteristic curve analysis. RESULTS:The overall perioperative and intraoperative transfusion rates were 3.4 and 1.0%, respectively. Patients who were older, women, and American Society of Anesthesiologists class >II demonstrated an increased risk of transfusion. Risk of transfusion demonstrated an inverse correlation with preoperative Hgb levels, a bimodal association with body mass index, and a direct correlation with age, surgical time, and estimated blood loss on multivariate analysis. The receiver operating characteristic analysis demonstrated a preoperative Hgb cutoff of 12 g/dL for predicting any transfusion. Above the threshold of 12 g/dL, total and intraoperative transfusions were rare, with rates of 1.7 and 0.3%, respectively. Total and intraoperative transfusion rates with Hgb between 11 and 12 g/dL were 14.3 and 4.6%, respectively. Below 11 g/dL, total and intraoperative transfusion rates were 27.5 and 10.1%, respectively. CONCLUSIONS:In the age of TXA, blood transfusion is rare in THA when preoperative Hgb is >12 g/dL, challenging the need for universal type and screening. Conversely, patients who have Hgb < 11.0 g/dL, remain at substantial risk for transfusion. Between Hgb 11 and 12 g/dL, patient age, sex, body mass index, American Society of Anesthesiologists classification, anticipated estimated blood loss, and surgical time may help predict transfusion risk and the need for a perioperative type and screen. LEVEL OF EVIDENCE/METHODS:III.

BACKGROUND/UNASSIGNED:Electronic medical record portals enable real-time communication between patients and surgeons after total knee arthroplasty (TKA). This study evaluated the impact of message timing and frequency on postoperative outcomes and patient-reported outcome measures (PROMs). MATERIALS AND METHODS/UNASSIGNED:We retrospectively reviewed 9,353 primary TKAs performed at a single academic institution. Of these, 1,219 patients sent messages within 2 weeks of surgery (early), 507 sent messages between 2 and 8 weeks (late), and 7,627 did not message. RESULTS/UNASSIGNED:< .001). There was no difference in PROMs regardless of message timing, and there was no association between the number of messages sent and perioperative outcomes or PROMs. CONCLUSION/UNASSIGNED:Older age and longer LOS were associated with less patient-initiated contact after TKA. Older patients may be less familiar with digital platforms and less likely to send messages. Early messaging may reflect heightened recognition of postoperative issues, enabling counseling or intervention and reducing readmissions. These findings underscore the importance of preoperative education and equitable access, though long-term effects of messaging warrant further study.

INTRODUCTION/BACKGROUND:Discharge disposition after total joint arthroplasty may be predictable. Previous literature has attempted to improve upon models such as the Risk Assessment and Prediction Tool (RAPT) in an effort to optimize postoperative planning. The purpose of this study was to determine whether preoperative laboratory values and other previously unstudied demographic factors could improve the predictive accuracy of the RAPT. METHODS:All patients included had RAPT scores in addition to the following preoperative laboratory values: red blood cell count, albumin, and vitamin D. All values were recorded within 90 days of surgery. Demographic variables including marital status, American Society of Anesthesiologists (ASA) scores, body mass index, Charlson Comorbidity Index, and depression were also evaluated. Binary logistic regression was used to determine the significance of each factor in association with discharge disposition. RESULTS:Univariate logistic regression found significant associations between discharge disposition and all original RAPT factors as well as nonmarried patients (P < 0.001), ASA class 3 to 4 (P < 0.001), body mass index >30 kg/m2 (P = 0.065), red blood cell count <4 million/mm3 (P < 0.001), albumin <3.5 g/dL (P < 0.001), Charlson Comorbidity Index (P < 0.001), and a history of depression (P < 0.001). All notable univariate models were used to create a multivariate model with an overall predictive accuracy of 90.1%. CONCLUSIONS:The addition of preoperative laboratory values and additional demographic data to the RAPT may improve its PA. Orthopaedic surgeons could benefit from incorporating these values as part of their discharge planning in THA. Machine learning may be able to identify other factors to make the model even more predictive.