Preoperative prediction model for risk of readmission after total joint replacement surgery: a random forest approach leveraging NLP and unfairness mitigation for improved patient care and cost-effectiveness.

BACKGROUND: The Center for Medicare and Medicaid Services (CMS) imposes payment penalties for readmissions following total joint replacement surgeries. This study focuses on total hip, knee, and shoulder arthroplasty procedures as they account for most joint replacement surgeries. Apart from being a burden to healthcare systems, readmissions are also troublesome for patients. There are several studies which only utilized structured data from Electronic Health Records (EHR) without considering any gender and payor bias adjustments. METHODS: For this study, dataset of 38,581 total knee, hip, and shoulder replacement surgeries performed from 2015 to 2021 at Novant Health was gathered. This data was used to train a random forest machine learning model to predict the combined endpoint of emergency department (ED) visit or unplanned readmissions within 30 days of discharge or discharge to Skilled Nursing Facility (SNF) following the surgery. 98 features of laboratory results, diagnoses, vitals, medications, and utilization history were extracted. A natural language processing (NLP) model finetuned from Clinical BERT was used to generate an NLP risk score feature for each patient based on their clinical notes. To address societal biases, a feature bias analysis was performed in conjunction with propensity score matching. A threshold optimization algorithm from the Fairlearn toolkit was used to mitigate gender and payor biases to promote fairness in predictions. RESULTS: The model achieved an Area Under the Receiver Operating characteristic Curve (AUROC) of 0.738 (95% confidence interval, 0.724 to 0.754) and an Area Under the Precision-Recall Curve (AUPRC) of 0.406 (95% confidence interval, 0.384 to 0.433). Considering an outcome prevalence of 16%, these metrics indicate the model's ability to accurately discriminate between readmission and non-readmission cases within the context of total arthroplasty surgeries while adjusting patient scores in the model to mitigate bias based on patient gender and payor. CONCLUSION: This work culminated in a model that identifies the most predictive and protective features associated with the combined endpoint. This model serves as a tool to empower healthcare providers to proactively intervene based on these influential factors without introducing bias towards protected patient classes, effectively mitigating the risk of negative outcomes and ultimately improving quality of care regardless of socioeconomic factors.

Predicting Pulmonary Embolism in Total Joint Arthroplasty Patients A Pilot Study.

Postoperative venous thromboembolism (VTE) is a common and costly complication following total joint arthroplasty (TJA). Development of a refined thrombophilic screening panel will better equip clinicians to identify patients at high-est risk for developing VTEs. In this pilot study, 62 high-risk TJA recipients who had developed pulmonary emboli (PE) within 90-days of surgery were eligible to participate. Of these patients, 14 were enrolled and subsequently adminis-tered a pre-determined panel of 18 hematologic tests with the aim of identifying markers that are consistently elevated or deficient in patients developing PE. A separate cohort of seven high-risk TJA recipients who did not report a symp-tomatic VTE within 90-days of surgery were then enrolled and Factor VIII and lipoprotein(a) levels were assessed. The most common aberrance was noted in 10 patients (71.4%) who had elevated levels of Factor VIII followed by five patients (35.7%) who had elevated levels of lipoprotein(a). Factor VIII was significantly prevalent (p < 0.001) while lipoprotein(a) failed to achieve statistical significance (p = 0.0708). Of the patients who were within normal limits of Factor VIII, three-fourths were "high-normal" with Fac-tor VIII levels within 5% of the upper limit of normal. This study demonstrates the potential utility of this hematologic panel as part of a perioperative screening protocol aimed at identifying patients at risk for developing VTEs. However, future larger scale studies assessing the capabilities and limitations of our findings are warranted.

Insulin resistance and osteocalcin associate with the incidence and severity of postoperative delirium in elderly patients undergoing joint replacement.

AIM: While insulin sensitivity plays an important role in maintaining glucose metabolic homeostasis and cognitive function, its impact on postoperative delirium (POD) remains unclear. This study aimed to investigate the association between POD and indicators of insulin sensitivity, including insulin resistance and osteocalcin. METHODS: A total of 120 elderly patients undergoing joint replacement were recruited and divided into delirium and non-delirium groups. Plasma and cerebrospinal fluid (CSF) samples were collected for the analysis of biomarkers, including insulin, uncarboxylated osteocalcin (ucOC), total osteocalcin (tOC), and glucose. Insulin resistance was assessed through the homeostatic model assessment of insulin resistance (HOMA-IR). MAIN RESULTS: Out of the total, 28 patients (23.3%) experienced POD within 5 days after surgery. Patients with delirium exhibited higher levels of preoperative HOMA-IR and ucOC in CSF and plasma, and of tOC in CSF (P = 0.028, P < 0.001, P = 0.005, P = 0.019). After adjusting for variables, including age, Mini-Mental State Examination score, surgical site and preoperative fracture, only preoperative ucOC in CSF and HOMA-IR were significantly linked to the incidence of delirium (OR = 5.940, P = 0.008; OR = 1.208, P = 0.046, respectively), both of which also correlated with the severity of delirium (P = 0.007, P < 0.001). Receiver operating curve analysis indicated that preoperative HOMA-IR and ucOC in CSF might partly predict POD (area under the curve [AUC] = 0.697, 95% confidence interval [CI] = 0.501-0.775, AUC = 0.745, 95% CI = 0.659-0.860). CONCLUSIONS: We observed that preoperative elevated HOMA-IR and ucOC in CSF were associated with the incidence and severity of POD. While these preliminary results need confirmation, they suggest a potential involvement of insulin resistance and osteocalcin in the pathological mechanism of POD. Geriatr Gerontol Int 2024; 24: 421-429.

Complications after total wrist arthroplasty.

We reviewed the incidence and management of complications after total wrist arthroplasty, as reported in the literature, with so-called fourth-generation implants and other recent designs. While early intraoperative and postoperative complications, including fractures, tendon lacerations, infection, nerve compression, tendonitis, stiffness and chronic regional pain syndrome, had an acceptable incidence, late complications, such as periprosthetic osteolysis and implant loosening, occurred more frequently. Implant survival at 10 years was in the range of 70%-80% in most publications. Several of the implants have been modified or withdrawn. Instability and dislocation were frequent after a pyrocarbon spacer. Failed arthroplasties can be salvaged by revision arthroplasty or total wrist arthrodesis. Revision arthroplasty has a lower survival rate than primary arthroplasty and does not clearly offer important significant advantages over total wrist arthrodesis in terms of patient-reported outcome measures. Further development of prosthetic design, new materials and more knowledge on patient-related risk factors are needed.

Rates of venous thromboembolism and use of thromboprophylaxis after major orthopedic surgery in patients with congenital hemophilia A or B: a systematic review.

BACKGROUND: Venous thromboembolism (VTE) is a well-recognized complication after total joint replacement (TJR). Persons with hemophilia A or B are considered at low postoperative VTE risk due to their coagulation factor deficiencies, and administering pharmacologic thromboprophylaxis is often considered contraindicated. However, using factor replacement therapy could increase the postoperative VTE risk. OBJECTIVES: To analyze best available evidences of VTE rates in persons with hemophilia A or B undergoing lower limb TJR and the use of postoperative pharmacologic thromboprophylaxis. METHODS: We systematically screened 4 online biomedical databases to identify studies reporting VTE rates in patients with hemophilia after TJR. Case reports and case series with less than 10 patients were excluded. RESULTS: Twenty-six observational studies were included in this systematic review, reporting 1181 TJRs in patients with hemophilia A or B. Eight studies had VTE rates as the primary outcome. Five studies reported screen-detected VTE, while 21 reported symptomatic VTE events. Overall, 17 VTE events were reported (1.4%; 95% CI, 0.9%-2.3%), including 10 (6.6%) after 151 surgeries with postoperative VTE screening and 7 (0.7%) after 1080 surgeries without postoperative screening. Thromboprophylaxis protocols were specified in 21 studies; postoperative thromboprophylaxis was used in 15 (1.3%) surgeries. This information was not available for 29.0% of the analyzed population. CONCLUSION: Despite the low thromboprophylaxis use in patients with hemophilia, rates of symptomatic VTE after TJR appeared to be low. We also highlighted the need to better report the thrombotic outcome in persons with hemophilia to face the ongoing changes in the hemophilia landscape.

Impingement-related osteolysis in Motec total wrist arthroplasty: an explant analysis and review of the literature.

We present five cases of osteolysis in the Motec total wrist prosthesis, three around the radial implant, one around the metacarpal implant and one around both. Three of these were progressive and required revision, and biomechanical explant analyses of these revised prostheses were performed. Ex vivo testing of the contact points of the Motec implants was also performed at maximum extension. Here, impingement occurs between the metacarpal screw and the dorsal rim of the cup (non-articulating surfaces) with the short-necked prosthesis, leading to metacarpal screw damage, titanium debris formation and osteolysis. An analysis of three previously published cases suggests that this may have been the likely mode of failure in those cases. This complication is preventable by avoiding use of the short-neck prosthesis.Level of evidence: IV.

Complication rates and modes of short and medium-term failure in Motec total wrist arthroplasty: an international cohort study.

The aim of this study was to analyse the short- and medium-term complications of the Motec total wrist arthroplasty (TWA). Identifying exact modes of failure and their causes should allow surgeons to avoid or mitigate these risks in the future. Retrospective analysis of prospectively collected data from six hand surgeons at five international centres provided details of 171 Motec TWAs. The mean follow-up was 5.8 years (range 18 months to 12 years). There were 33 (19%) complications within our cohort, with a revision rate of 8.2% (14 revisions). There was no difference in complication rates between metal-on-metal and metal-on-polymer articulations. Failure of osseointegration was the most common complication. Problems with soft tissue balancing, implant impingement related osteolysis, bony impingement and metacarpal fracture were found to be other preventable causes of failure in this series. Elimination of these preventable complications will improve survival rates for this implant.Level of evidence: IV.

Shoulder arthroplasty for inflammatory arthritis is associated with higher rates of medical and surgical complications: a nationwide matched cohort analysis from 2016-2020.

BACKGROUND: Inflammatory arthritis (IA) represents a less common indication for anatomic and reverse total shoulder arthroplasty (TSA) than osteoarthritis (OA). The safety and efficacy of anatomic and reverse TSA in this population has not been as well studied compared to OA. We analyzed the differences in outcomes between IA and OA patients undergoing TSA. METHODS: Patients who underwent primary anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) from 2016-2020 were identified in the Premier Healthcare Database. Inflammatory arthritis (IA) patients were identified using International Classification of Diseases, Tenth Revision, diagnosis codes and compared to osteoarthritis controls. Patients were matched in a 1:8 fashion by age (±3 years), sex, race, and presence of pertinent comorbidities. Patient demographics, hospital factors, and patient comorbidities were compared. Multivariate regression was performed following matching to account for any residual confounding and 90-day complications were compared between the 2 cohorts. Descriptive statistics and regression analysis were employed with significance set at P < .05. RESULTS: Prior to matching, 5685 IA cases and 93,539 OA controls were identified. Patients with IA were more likely to be female, have prolonged length of stay and increased total costs (P < .0001). After matching and multivariate analysis, 4082 IA cases and 32,656 controls remained. IA patients were at increased risk of deep wound infection (OR 3.14, 95% CI 1.38-7.16, P = .006), implant loosening (OR 4.11, 95% CI 1.17-14.40, P = .027), and mechanical complications (OR 6.34, 95% CI 1.05-38.20, P = .044), as well as a decreased risk of postoperative stiffness (OR 0.36, 95% CI 0.16-0.83, P = .002). Medically, IA patients were at increased risk of PE (OR 2.97, 95% CI 1.52-5.77, P = .001) and acute blood loss anemia (OR 1.27, 95% CI 1.12-1.44, P < .0001). DISCUSSION AND CONCLUSION: Inflammatory arthritis represents a distinctly morbid risk profile compared to osteoarthritis patients with multiple increased surgical and postoperative medical complications in patients undergoing aTSA and rTSA. Surgeons should consider these potential complications and employ a multidisciplinary approach in preoperative risk stratification of IA undergoing shoulder replacement.

Total Wrist Replacement Outcomes in the Asian Pacific Population - A Single-Centre Result.

Background: Total wrist replacement (TWR) is rarely done in the Asia-Pacific region. The aim of this study is to report the surgical outcomes and experience of TWR in patients with advanced arthritis. Methods: This is a retrospective review of all TWR patients in the Department of Orthopaedics and Traumatology, Prince of Wales Hospital, Hong Kong, which is a university tertiary centre, from January 2004 to March 2023. Recorded demographic parameters include gender, age upon surgery, pathology, types of implants and follow-up period. The surgical outcome parameters include range of motion, grip strength, wrist function assessment, radiological and clinical complications and any related secondary operations. Postoperative X-ray and clinical notes were reviewed. All wrist function assessments were performed by specialised occupational therapists according to protocol. Results: The study included a total of 12 wrists of 10 patients, all Chinese-Asian, with a mean age of 61.4 years at surgery. Larsen grade V arthritis constituted 50% and grade IV 16.7% of the patients, amongst which 33% had volar subluxation. The mean follow-up period was 97.4 months (21-205 months). The mean grip strength was 64.2% of the unaffected side. The mean postoperative Disabilities of Arm, Shoulder and Hand (DASH) score was 41.12% and patient-rated wrist/hand evaluation (PRWE) score 18.0. Complication incidence was 16.67% for loosening, 8.3% for metallosis and 8.3% for infection. One patient required conversion to total wrist arthrodesis due to metallosis. No patient suffered from dislocation, periprosthetic fracture and infection. Conclusions: TWR is an effective and safe alternative to total wrist arthrodesis with comparable outcomes. Our series outcomes are satisfactory and in line with literature. With meticulous soft tissue release and balancing, volar subluxation can also be corrected and may not be a contraindication. Level of Evidence: Level IV (Therapeutic).

Trial of Vancomycin and Cefazolin as Surgical Prophylaxis in Arthroplasty.

BACKGROUND: The addition of vancomycin to beta-lactam prophylaxis in arthroplasty may reduce surgical-site infections; however, the efficacy and safety are unclear. METHODS: In this multicenter, double-blind, superiority, placebo-controlled trial, we randomly assigned adult patients without known methicillin-resistant Staphylococcus aureus (MRSA) colonization who were undergoing arthroplasty to receive 1.5 g of vancomycin or normal saline placebo, in addition to cefazolin prophylaxis. The primary outcome was surgical-site infection within 90 days after surgery. RESULTS: A total of 4239 patients underwent randomization. Among 4113 patients in the modified intention-to-treat population (2233 undergoing knee arthroplasty, 1850 undergoing hip arthroplasty, and 30 undergoing shoulder arthroplasty), surgical-site infections occurred in 91 of 2044 patients (4.5%) in the vancomycin group and in 72 of 2069 patients (3.5%) in the placebo group (relative risk, 1.28; 95% confidence interval [CI], 0.94 to 1.73; P = 0.11). Among patients undergoing knee arthroplasty, surgical-site infections occurred in 63 of 1109 patients (5.7%) in the vancomyin group and in 42 of 1124 patients (3.7%) in the placebo group (relative risk, 1.52; 95% CI, 1.04 to 2.23). Among patients undergoing hip arthroplasty, surgical-site infections occurred in 28 of 920 patients (3.0%) in the vancomyin group and in 29 of 930 patients (3.1%) in the placebo group (relative risk, 0.98; 95% CI, 0.59 to 1.63). Adverse events occurred in 35 of 2010 patients (1.7%) in the vancomycin group and in 35 of 2030 patients (1.7%) in the placebo group, including hypersensitivity reactions in 24 of 2010 patients (1.2%) and 11 of 2030 patients (0.5%), respectively (relative risk, 2.20; 95% CI, 1.08 to 4.49), and acute kidney injury in 42 of 2010 patients (2.1%) and 74 of 2030 patients (3.6%), respectively (relative risk, 0.57; 95% CI, 0.39 to 0.83). CONCLUSIONS: The addition of vancomycin to cefazolin prophylaxis was not superior to placebo for the prevention of surgical-site infections in arthroplasty among patients without known MRSA colonization. (Funded by the Australian National Health and Medical Research Council; Australian New Zealand Clinical Trials Registry number, ACTRN12618000642280.).

Venous thromboembolism in orthopedic surgery: Global guidelines.

Venous thromboembolism (VTE) is a severe complication that can occur after major orthopedic procedures. As VTE-related morbidity and mortality are a significant concern for both medical professionals and patients, and preventative measures are typically employed. Multiple organizations, including the American College of Chest Physicians (ACCP) and the American Academy of Orthopedic Surgeons (AAOS), have developed guidelines for VTE prophylaxis specifically in patients undergoing joint replacement procedures. However, recently, the International Consensus Meeting (ICM) was convened, which brought together over 600 experts from 68 countries and 135 international societies. These experts, spanning a range of medical disciplines including orthopedic surgery, anesthesia, cardiology, hematology, vascular, and internal medicine, conducted a comprehensive review of the literature using a strict Delphi process to generate practical recommendations for VTE prophylaxis across all types of orthopedic procedures. This review article summarizes some of the recommendations of the ICM.

Risk of Infection After Septic and Aseptic Revision Total Knee Arthroplasty: A Systematic Review.

BACKGROUND: The causes of primary total knee arthroplasty (TKA) failure can be divided into septic and aseptic etiologies. It is unclear whether the etiology affects the infection rate after revision TKA. This systematic review was conducted to evaluate whether there is a difference in infection rates between septic and aseptic revision TKA. We hypothesized that infection rates would be higher after septic revision TKA. METHODS: The PubMed and Embase databases and the Cochrane Library were searched to find studies evaluating infection rates following septic and aseptic revision TKA. We included studies that compared the postoperative infection rates of a group that received revision TKA for aseptic failure and a group that received 1- or 2-stage revision TKA for septic failure. Studies on re-revision TKA and on revision surgery after partial knee arthroplasty were excluded, as were studies of debridement, antibiotics, and implant retention (DAIR). RESULTS: Twelve studies were included in this systematic review. In studies in which 1- or 2-stage revision TKA was performed for septic failure, septic revision TKA had a significantly higher infection rate than aseptic revision TKA (odds ratio [OR], 6.83; 95% confidence interval [CI], 1.54 to 30.33; p = 0.01). Similarly, in studies in which 2-stage revision TKA was performed for septic failure, septic revision TKA had a significantly higher infection rate than aseptic revision TKA (OR, 4.14; 95% CI, 2.33 to 7.36; p < 0.00001). In the comparison of revision TKA for aseptic loosening and septic revision TKA, septic revision TKA had a higher infection rate than aseptic revision TKA (OR, 4.45; 95% CI, 2.28 to 8.70; p < 0.0001). CONCLUSIONS: Overall, septic revision TKA had a higher infection rate than aseptic revision TKA. Even when 2-stage revision TKA was performed for septic failure, the infection rate was higher after septic revision TKA than after aseptic revision. Surgeons should explain the relatively high infection rates to patients undergoing revision TKA for septic failure of their primary joint replacement. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Effects of depressive symptoms on osteoporotic bone metabolism and prognosis of joint replacement surgery in elderly male patients with femoral neck fracture.

OBJECTIVE: To investigate the effect of depressive symptoms on osteoporotic bone metabolism and prognosis of joint replacement surgery in elderly male patients with femoral neck fractures. METHOD: 102 elderly male patients with femoral neck fractures hospitalized in the Beijing Hospital from January 2017 to January 2019 were included. The patients with femoral neck fractures were divided into the depression group and the control group. The observation indicators included: bone mineral density, serum alkaline phosphatase, serum calcium, serum phosphorus, 25-hydroxy-vitamin D, osteocalcin, Type I procollagen amino-terminal propeptide, serum ß-isomer of C-terminal telopeptide of type I collagen, hip function scores, and pain visual analogue scale at pre- and post-operative examinations. RESULTS: The BMD was significantly lower in the depressed group than in the control group [either for lumbar spine or hip, P < 0.05]. Serum 25-(OH)-D levels and serum OC levels were lower (both P < 0.05) in the depression group, while serum -CTX levels were higher in the depression group than in the control group (P < 0.05). Depression severity (GDS score) was negatively correlated with BMD (r = -0.456, P < 0.05), 25(OH)D (r = -0.546, P < 0.05), and OC (r = -0.215, P < 0.05), while positively correlated with ß-CTX (r = 0.372, P < 0.05). The Harris scores of the depression group were lower than the control group (P < 0.001). In the control group, VAS scores decrease at 12 months postoperatively while in the depressed group, VAS scores increased (P < 0.001). CONCLUSION: Depression is a risk factor for low bone mineral density and fracture, and adversely affects functional recovery and pain relief after artificial femoral head replacement. Special care should be taken for those patients with depressive symptoms in orthopedic practice.

Rank-Ordered List of Cost-effective Strategies for Preventing Prosthetic Joint Infection in Total Joint Arthroplasty in an Academic US Hospital.

Although the overall rate of prosthetic joint infection (PJI) is low, it remains a major complication associated with total joint arthroplasty (TJA). PJI represents a significant economic burden to the health care system that is projected to increase commensurate with increasing joint replacement volumes. This review provides a rank-ordered list of cost-effective strategies that are performable intraoperatively and have data supporting their efficacy at preventing PJI after TJA. This study may be helpful in assisting surgeons, ambulatory surgery center owners, and hospital acquisition committees to make reasonable and cost-conscious decisions in the face of changing reimbursement. [Orthopedics. 2023;46(6):327-332.].

Does radiolucency really predict loose components in revision shoulder arthroplasty?

OBJECTIVE: The number of shoulder arthroplasties is increasing along with the need for revision surgeries. Determining the stability of the implant is crucial in preoperative planning. This study aims to investigate whether radiolucent lines (RLL) in preoperative radiographs predict component loosening. MATERIALS AND METHODS: Preoperative radiographs of 93 cases in 88 patients who underwent shoulder arthroplasty revision were evaluated regarding the presence of RLL. Correlation analyses were performed for radiographic findings and demographic factors (age, gender, BMI, prior surgeries) compared to intraoperative findings. RESULTS: The presence of RLL around the humeral component correlated with loosening (p < 0.001, Phi 0.511), and the distal zones 3 and 5 showed the strongest correlation (Phi 0.536). While RLL in only one zone did not predict loosening (p = 0.337), RLL present in two or more zones showed correlation with loosening (p < 0.001). Risk factors associated with loosening were a higher age at the time of revision surgery (p = 0.030) and the number of zones with RLL (p < 0.001). The glenoid component was loose in 39.0% of the cases; 5.5% of the glenoid components with RLL were stable. Nevertheless, the presence of RLL was highly associated with loosening (p < 0.001, Phi 0.603). A longer time between implantation and revision correlated with loosening of the glenoid component (p = 0.046). CONCLUSION: While RLL do not predict loosening of the implant in general, occurrence in more than one zone correlates with loosening. If located in distal zones and with increasing number of zones with RLL, the correlation becomes even stronger and loosening is more likely.

Diagnostic accuracy of sonication fluid cultures from prosthetic components in periprosthetic joint infection: an updated diagnostic meta-analysis.

BACKGROUND: Periprosthetic joint infection (PJI) is the most serious complication following total joint arthroplasty (TJA) and has a significant impact on patients and the national healthcare system. To date, the diagnosis of PJI is still confronted with dilemmas. The present study investigated the validity of sonication fluid culture (SFC) for removing implants in the diagnosis of PJI after joint replacement. METHODS: From database establishment to December 2020, relevant literature was retrieved from the PubMed, Web of Science, Embase and Cochrane Library databases. Two reviewers independently performed quality assessment and data extraction to calculate the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), area under the curve (AUC) and diagnostic odds ratio (DOR) to evaluate the diagnostic value of overall SFC for PJI. RESULTS: A total of 38 eligible studies including 6302 patients were selected in this study. The pooled sensitivity, specificity, PLR, NLR, and DOR of SFC for PJI diagnosis were 0.77 (95% confidence interval [CI], 0.76-0.79), 0.96 (95% CI, 0.95-0.96), 18.68 (95% CI, 11.92-29.28), 0.24 (95% CI, 0.21-0.29), and 85.65 (95% CI, 56.46-129.94), respectively, while the AUC was 0.92. CONCLUSION: This meta-analysis showed that SFC was of great value in PJI diagnosis, and the evidence of SFC on PJI was more favorable but not yet strong. Therefore, improvement of the diagnostic accuracy of SFC is still necessary, and the diagnosis of PJI continues to warrant a multiplex approach before and during a revision procedure.

What is the Safe Distance Between Hip and Knee Implants to Reduce the Risk of Ipsilateral Metachronous Periprosthetic Joint Infection?

BACKGROUND: Periprosthetic joint infection (PJI), the most common cause of revision after TKA and THA, is a devastating complication for patients that is difficult to diagnose and treat. An increase in the number of patients with multiple joint arthroplasties in the same extremity will result in an increased risk of ipsilateral PJI. However, there is no definition of risk factors, micro-organism patterns, and safe distance between knee and hip implants for this patient group. QUESTIONS/PURPOSES: (1) In patients with hip and knee arthroplasties on the same side who experience a PJI of one implant, are there factors associated with the development of subsequent PJI of the other implant? (2) In this patient group, how often is the same organism responsible for both PJIs? (3) Is a shorter distance from an infected prosthetic joint to an ipsilateral prosthetic joint associated with greater odds of subsequent infection of the second joint? METHODS: We designed a retrospective study of a longitudinally maintained institutional database that identified all one-stage and two-stage procedures performed for chronic PJI of the hip and knee at our tertiary referral arthroplasty center between January 2010 and December 2018 (n = 2352). Of these patients, 6.8% (161 of 2352) had an ipsilateral hip or knee implant in situ at the time of receiving surgical treatment for a PJI of the hip or knee. The following criteria led to the exclusion of 39% (63 of 161) of these patients: 4.3% (seven of 161) for incomplete documentation, 30% (48 of 161) for unavailability of full-leg radiographs, and 5% (eight of 161) for synchronous infection. With regard to the latter, per internal protocol, all artificial joints were aspirated before septic surgery, allowing us to differentiate between synchronous and metachronous infection. The remaining 98 patients were included in the final analysis. Twenty patients experienced ipsilateral metachronous PJI during the study period (Group 1) and 78 patients did not experience a same-side PJI (Group 2). We analyzed the microbiological characteristics of bacteria during the first PJI and ipsilateral metachronous PJI. Calibrated, full-length plain radiographs were evaluated. Receiver operating characteristic curves were analyzed to determine the optimal cutoff for the stem-to-stem and empty native bone distance. The mean time between the initial PJI and ipsilateral metachronous PJI was 8 ± 14 months. Patients were followed for a minimum of 24 months for any complications. RESULTS: The risk of ipsilateral metachronous PJI in the other joint secondary to a joint implant in which PJI develops can increase up to 20% in the first 2 years after the procedure. There was no difference between the two groups in age, sex, initial joint replacement (knee or hip), and BMI. However, patients in the ipsilateral metachronous PJI group were shorter and had a lower weight (1.6 ± 0.1 m and 76 ± 16 kg). An analysis of the microbiological characteristics of bacteria at the time of the initial PJI showed no differences in the proportions of difficult-to-treat, high virulence, and polymicrobial infections between the two groups (20% [20 of 98] versus 80% [78 of 98]). Our findings showed that the ipsilateral metachronous PJI group had a shorter stem-to-stem distance, shorter empty native bone distance, and a higher risk of cement restrictor failure (p < 0.01) than the 78 patients who did not experience ipsilateral metachronous PJI during the study period. An analysis of the receiver operating characteristic curve showed a cutoff of 7 cm for the empty native bone distance (p < 0.01), with a sensitivity of 72% and a specificity of 75%. CONCLUSION: The risk of ipsilateral metachronous PJI in patients with multiple joint arthroplasties is associated with shorter stature and stem-to-stem distance. Appropriate position of the cement restrictor and native bone distance are important in reducing the risk of ipsilateral metachronous PJI in these patients. Future studies might evaluate the risk of ipsilateral metachronous PJI owing to bone adjacency. LEVEL OF EVIDENCE: Level III, therapeutic study.

Hyponatremia Is an Overlooked Sign of Trouble Following Total Joint Arthroplasty.

BACKGROUND: Hyponatremia is a common electrolyte abnormality in arthroplasty patients. This issue, underrecognized by surgeons, can impact the postoperative course of patients. There are, however, little data on the implications of sodium disturbances following total joint arthroplasty (TJA). The primary aims of this study were to (1) report the rate of hyponatremia following TJA, and (2) examine the impact of hyponatremia on the perioperative course of TJA patients. METHODS: This was a retrospective analysis of 3,071 primary and revision TJAs performed between 2015 and 2017. Based on preoperative and postoperative sodium values (pre-post), patients were classified into 4 groups: normonatremic-normonatremic (Group 1), normonatremic-hyponatremic (Group 2), hyponatremic-normonatremic (Group 3), and hyponatremic-hyponatremic (Group 4). Primary end points were length of stay (LOS), postoperative discharge, in-hospital complications, and 90-day readmissions. RESULTS: The distribution of cases was 84.6% Group 1, 9.4% Group 2, 2.1% Group 3, and 3.8% Group 4. Overall, 13.2% of patients had hyponatremia after TJA. Older age, hip arthroplasty, general anesthesia, higher Charlson Comorbidity Index, congestive heart failure, revision surgery, and history of stroke, liver disease, and chronic kidney disease were risk factors for postoperative hyponatremia. Patients with postoperative hyponatremia (Groups 2 and 4) had greater likelihoods of having a 90-day complication and non-home discharge and greater LOS. CONCLUSIONS: Postoperative hyponatremia was a relatively common occurrence in patients undergoing TJA, and was associated with greater LOS, complications, and non-home discharge. Surgeons should identify patients at risk for developing sodium abnormalities in order to optimize these patients and avoid increased resource utilization. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Problematic opioid use among osteoarthritis patients with chronic post-operative pain after joint replacement: analyses from the BISCUITS study.

OBJECTIVES: Opioids are commonly used to manage pain, despite an increased risk of adverse events and complications when used against recommendations. This register study uses data of osteoarthritis (OA) patients with joint replacement surgery to identify and characterize problematic opioid use (POU) prescription patterns. METHODS: The study population included adult patients diagnosed with OA in specialty care undergoing joint replacement surgery in Denmark, Finland, Norway, and Sweden during 1 January 2011 to 31 December 2014. Those with cancer or OA within three years before the first eligible OA diagnosis were excluded. Patients were allocated into six POU cohorts based on dose escalation, frequency, and dosing of prescription opioids post-surgery (definitions were based on guidelines, previous literature, and clinical experience), and matched on age and sex to patients with opioid use, but not in any of the six cohorts. Data on demographics, non-OA pain diagnoses, cardiovascular diseases, psychiatric disorders, and clinical characteristics were used to study patient characteristics and predictors of POU. RESULTS: 13.7% of patients with OA and a hip/knee joint replacement were classified as problematic users and they had more comorbidities and higher pre-surgery doses of opioids than matches. Patients dispensing high doses of opioids pre-surgery dispensed increased doses post-surgery, a pattern not seen among patients prescribed lower doses pre-surgery. Being dispensed 1-4,500 oral morphine equivalents in the year pre-surgery or having a non-OA pain diagnosis was associated with post-surgery POU (OR: 1.44-1.50, and 1.11-1.20, respectively). CONCLUSIONS: Based on the discovered POU predictors, the study suggests that prescribers should carefully assess pain management strategies for patients with a history of comorbidities and pre-operative, long-term opioid use. Healthcare units should adopt risk assessment tools and ensure that these patients are followed up closely. The data also demonstrate potential areas for further exploration in improving patient outcomes and trajectories.