An Artificial Intelligence Chatbot is an Accurate and Useful Online Patient Resource Prior to Total Knee Arthroplasty.

BACKGROUND: Online information is a useful resource for patients seeking advice on their orthopaedic care. While traditional websites provide responses to specific frequently asked questions (FAQs), sophisticated artificial intelligence tools may be able to provide the same information to patients in a more accessible manner. Chat Generative Pretrained Transformer (ChatGPT) is a powerful artificial intelligence chatbot that has been shown to effectively draw on its large reserves of information in a conversational context with a user. The purpose of this study was to assess the accuracy and reliability of ChatGPT-generated responses to FAQs regarding total knee arthroplasty. METHODS: We distributed a survey that challenged arthroplasty surgeons to identify which of the 2 responses to FAQs on our institution's website was human-written and which was generated by ChatGPT. All questions were total knee arthroplasty-related. The second portion of the survey investigated the potential to further leverage ChatGPT to assist with translation and accessibility as a means to better meet the needs of our diverse patient population. RESULTS: Surgeons correctly identified the ChatGPT-generated responses 4 out of 10 times on average (range: 0 to 7). No consensus was reached on any of the responses to the FAQs. Additionally, over 90% of our surgeons strongly encouraged the use of ChatGPT to more effectively accommodate the diverse patient populations that seek information from our hospital's online resources. CONCLUSIONS: ChatGPT provided accurate, reliable answers to our website's FAQs. Surgeons also agreed that ChatGPT's ability to provide targeted, language-specific responses to FAQs would be of benefit to our diverse patient population.

The Financial Burden of Aspirin versus Oral Factor Xa Inhibitors for Thromboprophylaxis Following Total Knee Arthroplasty.

BACKGROUND: Aspirin and oral factor Xa inhibitor thromboprophylaxis regimens are associated with similarly low rates of venous thromboembolism following total knee arthroplasty (TKA). However, the rate of prosthetic joint infection (PJI) is lower with aspirin use. This study aimed to compare the cost differential between aspirin and factor Xa inhibitor thromboprophylaxis with respect to PJI management. METHODS: We used previously published rates of PJI following aspirin and factor Xa inhibitor thromboprophylaxis in primary TKA patients at a single, large institution. Prices for individual drugs were obtained from our hospital's pharmacy service. The cost of PJI included that of 2-stage septic revision, with or without the cost of 1-year follow-up. National data were obtained to determine annual projected TKA volume. RESULTS: The per-patient costs associated with a 28-day course of aspirin versus factor Xa inhibitor thromboprophylaxis were $17.36 and $3,784.20, respectively. Including cost of follow-up, per-patient costs for a 28-day course of aspirin versus factor Xa inhibitors increased to $73,358.76 and $77,125.60, respectively. The weighted average per-patient costs for a 28-day course were $237.38 and $4,370.93, respectively. The annual cost difference could amount to over $14.1 billion in the United States by 2040. CONCLUSIONS: The per-patient cost associated with factor Xa inhibitor thromboprophylaxis is as much as 1,980.6% higher than that of an aspirin regimen due to increased costs of primary treatment, differential PJI rates, and high costs of management. In an era of value-based care, the use of aspirin is associated with major cost advantages.

The Use of Aspirin for Venous Thromboembolism Prophylaxis in Patients Who Have Morbid Obesity Undergoing Primary and Revision Total Joint Arthroplasty.

BACKGROUND: Venous thromboembolism (VTE) poses a major clinical concern due to its life-threatening nature, and obese and morbidly obese patients are thought to be at an increased risk for VTE. The aims of this study were twofold; first, to explore VTE rates in patients who have a body mass index (BMI) > 40 undergoing primary and revision total joint arthroplasty, and second, to investigate aspirin (ASA) efficacy and safety. METHODS: We identified all patients (n = 4,672) who had a BMI > 40 who underwent primary and revision total joint arthroplasty from 2016 to 2022 at a single academic tertiary care center. Patients were stratified by BMI groups: 40 to 44.9 (n = 3,462), 45 to 49.9 (n = 935), and 50+ (n = 275). The primary outcome was any VTE event within 90 days postoperatively. The secondary outcome consisted of wound complications within 90 days postoperatively. RESULTS: The total VTE rate was 0.4% (n = 21) and did not differ statistically between the BMI groups (0.4 versus 0.4 versus 0.7%, P = .669). The VTEs consisted of 6 deep venous thromboses (DVTs), 14 pulmonary embolisms, and one concomitant deep venous thrombosis and pulmonary embolism. The VTE rates were not statistically different between patients who received aspirin 325 mg 0.5% (n = 9), aspirin 81 mg 0.2% (n = 1), aspirin + anticoagulant (AC) 0.5% (n = 6), and AC alone 0.4% (n = 5) (P = .954). In addition, wound complications did not differ significantly between patients who received ASA 325 mg, ASA 81mg, ASA + AC, or AC alone (1.6 versus 1.0 versus 1.8 versus 1.1%, P = .351). CONCLUSIONS: The use of aspirin 325 and 81 mg was found to have similar VTE rates as aspirin + ACs and ACs alone, with no significant increase in wound complications. In patients who have a BMI > 40, the use of aspirin is a safe option for VTE prophylaxis and should be prescribed in the context of the patient who has other risk factors for VTE.

Impact of Selective Posterior Cruciate Ligament Fiber Release on Femoral Rollback in Cruciate-Retaining Total Knee Arthroplasty: A Computational Study.

BACKGROUND: Partial or total release of the posterior cruciate ligament (PCL) is often performed intraoperatively in cruciate-retaining total knee arthroplasty (CR-TKA) to alleviate excessive femoral rollback. However, the effect of the release of selected fibers of the PCL on femoral rollback in CR-TKA is not well understood. Therefore, we used a computational model to quantify the effect of selective PCL fiber releases on femoral rollback in CR-TKA. METHODS: Computational models of 9 cadaveric knees (age: 63 years, range 47 to 79) were virtually implanted with a CR-TKA. Passive flexion was simulated with the PCL retained and after serially releasing each individual fiber of the PCL, starting with the one located most anteriorly and laterally on the femoral notch and finishing with the one located most posteriorly on the medial femoral condyle. The experiment was repeated after releasing only the central PCL fiber. The femoral rollback of each condyle was defined as the anterior-posterior distance between tibiofemoral contact points at 0° and 90° of flexion. RESULTS: Release of the central PCL fiber in combination with the anterolateral (AL) fibers, reduced femoral rollback a median of 1.5 [0.8, 2.1] mm (P = .01) medially and by 2.0 [1.2, 2.5] mm (P = .04) laterally. Releasing the central fiber alone reduced the rollback by 0.7 [0.4, 1.1] mm (P < .01) medially and by 1.0 [0.5, 1.1] mm (P < .01) laterally, accounting for 47 and 50% of the reduction when released in combination with the AL fibers. CONCLUSIONS: Releasing the central fibers of the PCL had the largest impact on reducing femoral rollback, either alone or in combination with the release of the entire AL bundle. Thus, our findings provide clinical guidance regarding the regions of the PCL that surgeons should target to reduce femoral rollback in CR-TKA.

Total knee arthroplasty survivorship and outcomes in young patients: a review of the literature and 40-year update to a longitudinal study.

INTRODUCTION: Growing numbers of younger patients are electing to undergo total knee arthroplasty (TKA) for end-stage osteoarthritis. The purpose of this study was to compare established literature regarding TKA outcomes in patients under age 55, to data from an ongoing longitudinal young patient cohort curated by our study group. Further, we aimed to provide a novel update on survivorship at 40 years post-TKA from our longitudinal cohort. METHODS: A literature search was conducted using the electronic databases PubMed, Embase, and Cochrane Library, using terms related to TKA, patients under age 55, and osteoarthritis. Demographic and outcome data were extracted from all studies that met the inclusion criteria. Data were divided into the "longitudinal study (LS) group," and the "literature review (LR) group" based on the patient population of the study from which it came. RESULTS: After screening, 10 studies met the inclusion criteria; 6 studies comprised the LR group, and 4 studies comprised the LS group. 2613 TKAs were performed among the LR group, and 114 TKAs were longitudinally followed in the LS group. The mean patient ages of the LR and LS groups were 46.1 and 51, respectively. Mean follow-up was 10.1 years for the LR group. Mean postoperative range of motion was 113.6° and 114.5° for the LR and LS groups, respectively. All-cause survivorship reported at 10 years or less ranged from 90.6% to 99.0%. The LS cohort studies reported survivorship ranges of 70.1-70.6% and 52.1-65.3% at 30 and 40 years, respectively. CONCLUSIONS: Young TKA patients demonstrated improved functionality at each follow-up time point assessed. Survivorship decreased with increasing lengths of follow-up, ultimately ranging from 52.1-65.3% at 40 years post-TKA. The paucity of literature on long-term TKA outcomes in this patient population reinforces the necessity of further research on this topic.

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.

Exposure to Extended Reality and Artificial Intelligence-Based Manifestations: A Primer on the Future of Hip and Knee Arthroplasty.

BACKGROUND: Software-infused services, from robot-assisted and wearable technologies to artificial intelligence (AI)-laden analytics, continue to augment clinical orthopaedics - namely hip and knee arthroplasty. Extended reality (XR) tools, which encompass augmented reality, virtual reality, and mixed reality technology, represent a new frontier for expanding surgical horizons to maximize technical education, expertise, and execution. The purpose of this review is to critically detail and evaluate the recent developments surrounding XR in the field of hip and knee arthroplasty and to address potential future applications as they relate to AI. METHODS: In this narrative review surrounding XR, we discuss (1) definitions, (2) techniques, (3) studies, (4) current applications, and (5) future directions. We highlight XR subsets (augmented reality, virtual reality, and mixed reality) as they relate to AI in the increasingly digitized ecosystem within hip and knee arthroplasty. RESULTS: A narrative review of the XR orthopaedic ecosystem with respect to XR developments is summarized with specific emphasis on hip and knee arthroplasty. The XR as a tool for education, preoperative planning, and surgical execution is discussed with future applications dependent upon AI to potentially obviate the need for robotic assistance and preoperative advanced imaging without sacrificing accuracy. CONCLUSION: In a field where exposure is critical to clinical success, XR represents a novel stand-alone software-infused service that optimizes technical education, execution, and expertise but necessitates integration with AI and previously validated software solutions to offer opportunities that improve surgical precision with or without the use of robotics and computed tomography-based imaging.

Spine or Hip First? Outcomes in Patients Undergoing Sequential Lumbar Spine or Hip Surgery.

BACKGROUND: Lumbar spine pathology frequently coexists in patients who have hip arthrosis. There is controversy on whether lumbar or hip pathology should be first addressed. The purpose of this study was to evaluate the outcomes of sequential lumbar spine (LSP) or hip arthroplasty (THA). METHODS: Using a large national database from 2010 to 2020, we reviewed the records of 241,279 patients who had concurrent hip arthritis and lumbar spine disease defined as spinal stenosis, lumbar radiculopathy, or degenerative disc disease. During the study period, 6,458 (2.7%) patients with concurrent hip/spine disease underwent sequential operative treatment of either the hip joint or lumbar spine within 2 years. The rates of subsequent surgery in either the hip or the spine, opioid requirements, and rates of hip dislocation were determined and analyzed using compared Chi-squared analyses. RESULTS: Patients undergoing THA first had lower risk of subsequent spinal procedure compared to patients who had spinal procedures first (5.7 versus 23.7%, P < .001). This disparity was maintained up to 5 years (P < .001). Opioid requirements at 1 year were highest in patients who underwent spinal procedures only (836 pills/patient) compared to any other group THA only (566 pills/patient), LSP and then THA (564 pills/patient), THA and LSP (586 pills/patient). Also, THA following LSP was associated with significantly higher rates of dislocation compared to patients undergoing THA first (3.2 versus 1.9%, P < .001). CONCLUSION: Total hip arthroplasty first in patients who have concurrent spine disease was associated with lower risk of subsequent surgery, opioid requirement, and risk of postoperative instability compared to patients having lumbar procedure first.

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.

Impact of preoperative opioid use on patient-reported outcomes following primary total knee arthroplasty.

PURPOSE: The previous literature suggests that 25-30% of patients who undergo total knee arthroplasty (TKA) are using opioids prior to their surgery. This study aims to investigate the effect of preoperative opioid use on clinical outcomes and patient-reported outcome measures (PROMs) following TKA. METHODS: We retrospectively reviewed 329 patients who underwent primary TKA from 2019 to 2020, answered the preoperative opioid survey, and had available PROMs. Patients were stratified into two groups based on whether they were taking opioids preoperatively or not: 26 patients with preoperative opioid use (8%) and 303 patients without preoperative opioid use (92%) were identified. Demographics, clinical data, and PROMs [Forgotten Joint Score (FJS-12), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR), and Veterans RAND-12 Physical and Mental components (VR-12 PCS and MCS)] were collected. Demographic differences were assessed with Chi-square and independent sample t-tests. Outcomes were compared using multilinear regression analysis, controlling for demographic differences. RESULTS: Preoperative opioid users had a significantly longer length-of-stay (2.74 vs. 2.10; p = 0.010), surgical time (124.65 vs. 105.69; p < 0.001), and were more likely to be African-American (38.5 vs. 14.2%; p = 0.010) compared to preoperative opioid-naive patients. Postoperative FJS-12 did not statistically differ between the two groups. While preoperative KOOS, JR scores were significantly lower for preoperative opioid users (41.10 vs. 46.63; p = 0.043), they did not significantly differ postoperatively. Preoperative VR-12 PCS did not statistically differ between the groups; however, both 3-month (33.87 vs. 38.41; p = 0.049) and 1-year (36.01 vs. 44.73; p = 0.043) scores were significantly lower for preoperative opioid users. Preoperative VR-12 MCS was significantly lower for preoperative opioid users (46.06 vs. 51.06; p = 0.049), though not statistically different postoperatively. CONCLUSION: At 8%, our study population had a lower percentage of opioid users than previously reported in the literature. Preoperative opioid users had longer operative times and length of stay compared to preoperatively opioid-naive patients. While both cohorts achieved similar clinical benefits following TKA, preoperative opioid users reported lower postoperative scores with respect to VR-12 PCS scores. LEVEL III EVIDENCE: Retrospective Cohort.

Inaccuracy of the intramedullary femoral guide: traditional instrumentation lacks precision and accuracy.

PURPOSE: The purpose of the study was to utilize a large-scale biomorphometric computer tomography (CT) database to determine the desirable starting point and angle for placement of the femoral intramedullary rod in the sagittal plane. METHODS: A CT-based modeling and analytics system (SOMA, Stryker, Mahwah, NJ) was used to evaluate 1029 entire-femur CT scans. From this, 19,464 simulations were run to test whether a 20 cm intramedullary rod, with a radius of 4 mm, would successfully pass through the femoral canal before contacting cortical bone. First, modelling included varying angles from 0-6 degrees in the sagittal plane, at 1-degree intervals. Next, the start point was adjusted with an assumed 3 degrees of induced flexion in comparison to the mechanical axis. RESULTS: A total of 5012 simulations were able to place the femoral intramedullary rod 20 cm into the canal. The angle of the rod that created the highest proportion of successful jig placement was at a 3-degree angle of induced flexion to the orthogonal plane of the transepicondylar axis (TEA), with 33.7% successful jig placements. The starting point for the greatest proportion of successful guide placements was 48.5% along the distance between the sTEA, slightly closer to the lateral side. In the AP plane, the average distance to the ideal start point was 12.1 mm anterior to the PCL. CONCLUSION: By examining over a thousand femoral CT scans, an angle of 3 degrees of induced flexion was identified in the sagittal plane with the highest proportion of successful placement of an intramedullary rod before cortical contact. It is important to note the high rate of failure in completely inserting the 20 mm rod. LEVEL OF EVIDENCE: This is a prospective computer based model.

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.

Total knee arthroplasty is associated with greater immediate post-surgical pain and opioid use than total hip arthroplasty.

BACKGROUND: As greater emphasis is being placed on opioid reduction strategies and implementation of multimodal analgesia, we sought to determine whether immediate post-surgical opioid consumption was different between THA and TKA. METHODS: A single-institution total joint arthroplasty database was used to identify patients who underwent elective THA and TKA from 2016 to July 2019. Baseline demographic data, operative time (defined by incision time), and American Society of Anesthesiologist (ASA) class were collected. Morphine milligram equivalents (MME) were calculated and derived from prospectively documented nursing opioid administration events, while visual analog scale (VAS) scores represented pain levels, both of which were collected as part of our institution's standard protocols. Activity Measure for Post-Acute Care (AMPAC) was used to determine physical therapy progress. RESULTS: A total of 11,693 cases were identified: 5,909 THA (50.53%) and 5784 (49.47%) TKA. THA patients tended to be slightly younger (63.38 years, SD 11.61 years, vs 65.72 years, SD 9.56 years; p < 0.01) and have lower BMIs (28.92 kg/m2 vs 32.52 kg/m2; p < 0.01). THA patients had lower ASA scores in comparison to TKA patients (p < 0.01). Aggregate opioid consumption (93.76 MME vs 147.55 MME; p < 0.01) along with first 24-h and 48-h usage was significantly less for THA as compared to TKA. Similarly, mean pain scores (4.15 vs 5.08; p < 0.01) were lower for THA, while AMPAC mobilization scores were higher (20.88 vs 19.29; p < 0.01) when compared to TKA. CONCLUSION: THA patients reported lower pain scores and were found to require less opioid medication in the immediate post-surgical period than TKA patients.

The influence of obesity on achievement of a 'forgotten joint' following total knee arthroplasty.

INTRODUCTION: Obesity has been associated with poorer outcomes following total knee arthroplasty (TKA); however, data remain sparse on its impact on patients' joint awareness following surgery. This study aims to investigate the impact of body mass index (BMI) on improvement in outcomes following TKA as assessed by the Forgotten Joint Score-12 (FJS-12). MATERIALS AND METHODS: We retrospectively reviewed 1075 patients who underwent primary TKA from 2017 to 2020 with available postoperative FJS-12 scores. Patients were stratified based on their BMI (kg/m2): < 30, 30.0-34.9 (obese class I), 35.0-39.9 (obese class II), and ≥ 40 (obese class III). FJS-12 and KOOS, JR scores were collected at various time points. Demographic differences were assessed with Chi-square and ANOVA tests. Mean scores between BMI groups were compared using univariate ANCOVA, controlling for observed demographic differences. RESULTS: Of the 1075 patients included, there were 457 with a BMI < 30, 331 who were obese class I, 162 obese class II, and 125 obese class III. There were no statistical differences in FJS-12 scores between the BMI groups at 3 months (27.24 vs. 25.33 vs. 23.57 vs. 22.48; p = 0.99), 1 year (45.07 vs. 41.86 vs. 40.51 vs. 36.22; p = 0.92) and 2 years (51.31 vs. 52.86 vs. 46.17 vs. 44.97; p = 0.94). Preoperative KOOS, JR scores significantly differed between the various BMI categories (49.33 vs. 46.63 vs. 44.24 vs. 39.33; p < 0.01); however, 3-month (p = 0.20) and 1-year (p = 0.13) scores were not statistically significant. Mean improvement in FJS-12 scores from 3 months to 2 years was statistically greatest for obese class I patients and lowest for obese class III patients (24.07 vs. 27.53 vs. 22.60 vs. 22.49; p = 0.01). KOOS, JR score improvement from baseline to 1 year was statistically greatest for obese class III patients and lowest for non-obese patients (22.34 vs. 25.49 vs. 23.77 vs. 27.58; p < 0.01). CONCLUSION: While all groups demonstrated postoperative improvement, those with higher BMI reported lower mean FJS-12 scores but these differences were not found to be significant. Our study showed no significant impact of BMI on postoperative joint awareness, which implies that obese patients, in all obesity classes, experience similar functional improvement following TKA. LEVEL III EVIDENCE: Retrospective Cohort Study.

Presence of back pain prior total knee arthroplasty and its effects on short-term patient-reported outcome measures.

PURPOSE: Back pain may both decrease patient satisfaction after TKA and confound outcome assessment in satisfied patients. Our primary objective was to determine whether preoperative back pain is associated with differences in postoperative patient-reported outcome measures (PROMs). METHODS: We retrospectively reviewed 234 primary TKA patients who completed PROMs preoperatively and 12 weeks postoperatively, which included a back pain questionnaire, the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) and the Forgotten Joint Score-12 (FJS-12). Cohorts were defined based on the severity of preoperative back pain (none, mild, moderate and severe) and compared. Demographics were compared using ANOVA and Chi-square analysis. Univariate ANCOVA analysis was utilized to compare PROMs while accounting for significant demographic differences. RESULTS: Both preoperative KOOS JR scores (none: 47.90, mild: 47.61, moderate: 44.61 and severe: 38.70; p = 0.013) and 12-week postoperative KOOS JR scores (none: 61.24, mild: 64.94, moderate: 57.48 and severe: 57.01; p = 0.012) had a statistically significant inverse relationship with regard to the intensity of preoperative back pain. Although FJS-12 scores at the 12-week postoperative period trended lower with increasing levels of preoperative back pain (p = 0.362), it did not reach statistical significance. Patients who reported severe back pain preoperatively achieved the largest delta improvement from baseline compared to those with lesser pain intensity (p = 0.003). Patients who had a 2-grade improvement in their back pain achieved significantly higher KOOS JR scores 12 weeks postoperatively compared to patients with either 1-grade or no improvement (63.53 vs. 55.98; p = 0.042). Both preoperative (47.99 vs. 41.11; p = 0.003) and 12-week postoperative (64.06 vs. 55.73; p < 0.001) KOOS JR scores were statistically higher for those who reported mild or no back pain pre-and postoperatively than those who reported moderate or severe back pain pre-and postoperatively. CONCLUSION: Knee pain and back pain both exert negative effects on outcome instruments designed to measure pain and function. Although mean improvement from pre- to postoperative KOOS JR scores for patients with severe pre-existing back pain was higher than their counterparts, this statistical difference is likely not clinically significant. This implies that all patients may experience similar benefits from TKA despite the presence or absence of back pain. Attempts to measure TKA outcomes using PROMs should seek to control for lumbago and other sources of body pain. Level of Evidence IIIRetrospective Cohort Study.

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.

Aspirin Use for Venous Thromboembolism Prevention Is Safe and Effective in Overweight and Obese Patients Undergoing Revision Total Hip and Knee Arthroplasty.

BACKGROUND: Venous thromboembolism (VTE), defined as pulmonary embolism or deep venous thrombosis, is a rare but serious complication following revision total hip arthroplasty (RTHA) and revision total knee arthroplasty (RTKA). Previous studies show that obesity may be associated with an increased risk for pulmonary embolism, wound complications, and infection. With no current universal standard of care for VTE prophylaxis, we sought to determine whether aspirin prescribed (ASA) is safe and effective in obese patients undergoing RTHA/RTKA. METHODS: A retrospective review of 1578 consecutive RTHA/RTKA cases (751 RTHAs and 827 RTKAs) was conducted identifying patients prescribed 325 or 81 mg ASA. Ninety-day postoperative VTE rates, bleeding, wound complications, deep infections, and mortality were collected. Cohorts were stratified according to body mass index (BMI): normal (18-24.9 kg/m2), overweight (25-29.9 kg/m2), obese (30-34.9 kg/m2), severely obese (35-39.9 kg/m2), and morbidly obese (≥40 kg/m2). RESULTS: The cohort comprised of 335 patients with a normal BMI, 511 were overweight, 408 obese, 232 severely obese, and 92 morbidly obese. Total VTE rates were statistically similar between BMI groups (0.90% vs 0.78% vs 0.74% vs 0.43% vs 0%, P = .89). There were no differences in bleeding rates (0.90% vs 0% vs 0% vs 0.43% vs 0%, P = .08), wound complications (0.30% vs 0.20% vs 0.25% vs 0% vs 0%, P = .93), infection (1.49% vs 1.57% vs 0.98% vs 1.29% vs 1.09%, P = .66), or mortality (0% vs 0.20% vs 0% vs 0% vs 0%, P = .72). CONCLUSION: ASA is safe and effective for VTE prevention in obese patients with similar complication rates to nonobese patients undergoing RTHA/RTKA.

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.

In a Bundled Payment Model, the Costs Associated With Total Joint Replacement in Those Aged Older Than 80 Years Are Significantly Greater.

BACKGROUND: The number of octogenarians requiring a total hip arthroplasty (THA) and/or total knee arthroplasty (TKA) will rise disproportionally in the coming decade. Although outcomes are comparable with younger patients, management of these older patients involves higher medical complexity at a greater expense to the hospital system. The purpose of this study was to compare the cost of care for primary THA and TKA in our bundled care patients aged ≥80 years to those aged 65-80 years. METHODS: A retrospective review of primary TKA (n = 641) and THA (n = 1225) cases from 2013 to 2017 was performed. Patient demographic and admission cost data were collected. Patients were grouped based on surgery type (ie, elective or nonelective THA/TKA) and age group (ie, older [≥80 years old] or younger [65-80 years old]). Multivariate regression analyses were used to account for demographic differences. RESULTS: Elective primary THA in the older cohort (n = 157) cost 24.5% more than the younger cohort (n = 1025) (P < .0001). Elective primary TKA cases in the older cohort (n = 87) cost 17.0% more than the younger cohort's (n = 554) (P < .0001). For nonelective THA cases, the older cohort's (n = 29) episodes cost 39.1% more than the younger cohort (n = 14) (P < .0001). When comparing the <80 elective THA cohort (n = 1025) to the ≥90 cohort (n = 10), the cost difference swelled to 58.7% (P < .0001). CONCLUSION: Although primary THA and TKA in ≥80-year-old patients yield similar outcomes, this study demonstrates that the additional measures required to care for older patients and ensure successful outcomes cost significantly more. Consideration should be given to age as a factor in determining reimbursement in a bundled payment system to reduce the incentive to restrict care to elderly patients.