Introduction: Despite significant advancements in total knee arthroplasty (TKA), some patients require revision surgery (R‐TKA) due to complications such as infection, mechanical loosening, instability, periprosthetic fractures, and persistent pain. This study aimed to explore the specific causes leading to R‐TKA, associated complications, including infection, mechanical failure, and wound issues, as well as costs, mortality rates, and hospital length of stay (LOS) using data from a large national database.Methods: Data from the nationwide inpatient sample (NIS), the largest publicly available all‐payer inpatient care database in the United States were analysed from 1 January 2016 to 31 December 2019. The study included 44,649 R‐TKA cases, corresponding to 223,240 patients, with exclusions for nonelective admissions. Various statistical analyses were used to assess clinical outcomes, including in‐hospital mortality, postoperative complications, LOS, and hospitalization costs.Results: Among 2,636,880 TKA patients, 8.4% underwent R‐TKA. R‐TKA patients had higher rates of chronic conditions, including mental disorders (36.4%) and renal disease (9.9%). Additionally, these patients often experienced instability, necessitating revision surgery. Infection (22.3%) was the primary reason for R‐TKA, followed by mechanical loosening (22.9%) and instability. Compared to primary TKA patients, R‐TKA patients exhibited higher in‐hospital mortality (0.085% vs. 0.025%), longer LOS (3.1 vs. 2.28 days), and higher total charges ($97,815 vs. $62,188). Postoperative complications, including blood transfusion (4.6% vs. 1.3%), acute kidney injury (4.4% vs. 1.8%), venous thromboembolism (0.55% vs. 0.29%), infection, and wound problems, were significantly higher in R‐TKA patients.Conclusions: This study provides detailed insights into t LOS, costs, and complications associated with specific etiologies of revision TKA. Our findings emphasize the need for targeted preoperative optimization and patient education. This approach can help reduce the incidence and burden of R‐TKA, improve patient care, optimize resource allocation, and potentially decrease the overall rates of complications in revision surgeries.Level of Evidence: Level III.

Knee cysts are a common finding in orthopedic practice, with diagnoses that range from benign fluid collections to more complex lesions requiring intervention. This comprehensive review explores the types of cysts around the knee, including popliteal (Baker's) cysts, meniscal cysts, proximal tibiofibular joint cysts, and ganglion cysts within the cruciate ligaments. The review highlights the mechanisms of formation, clinical presentations, diagnostic methods, differential diagnoses, and treatments for each cyst type. Imaging, particularly MRI, plays a critical role in accurate diagnosis, helping differentiate cysts from other pathologies, such as tumors and vascular lesions. Treatment options vary, from conservative management for asymptomatic cases to surgical interventions, such as arthroscopic cyst removal, for symptomatic cysts or those associated with intra-articular pathologies. Emerging biological treatments, including platelet-rich plasma (PRP) and mesenchymal stem cell (MSC) therapies, show promise for addressing underlying joint degeneration and inflammation associated with certain cysts, particularly those linked to osteoarthritis. This review underscores the importance of tailored, evidence-based approaches in managing knee cysts to optimize patient outcomes. Keywords: Knee Cysts, Popliteal Cyst, Meniscal Cyst, Proximal Tibiofibular Joint Cyst, Joint Pathology

Background: Obesity is a major risk factor for osteoarthritis (OA) and negatively impacts both short-term and long-term outcomes following total knee arthroplasty (TKA). Bariatric surgery has been proposed as a strategy to improve surgical outcomes in obese patients; however, its effects on postoperative complications, hospital stay, healthcare costs, and revision rates remain insufficiently explored. This study investigates whether bariatric surgery before TKA is associated with improved outcomes. Methods: This retrospective cohort study utilized data from the Nationwide Inpatient Sample (NIS) from 2016 to 2019, including 2,519,099 TKA patients, of whom 56,291 had a history of bariatric surgery. Propensity score matching was applied to balance baseline characteristics between groups. Statistical analyses compared the length of hospital stay (LOS), total healthcare costs, postoperative complications, and revision rates. Results: Patients with a history of bariatric surgery exhibited significantly lower rates of sepsis, deep vein thrombosis (DVT), pulmonary embolism (PE), acute kidney injury (AKI), and ileus compared to those without. Additionally, these patients had a shorter LOS and slightly lower total hospital charges. However, the bariatric surgery group had higher rates of blood loss anemia, intraoperative fractures, and blood transfusions. Revision surgery rates were also higher in the bariatric surgery group, with mechanical loosening and prosthesis instability being more common etiologies. Conclusions: Bariatric surgery is associated with fewer early postoperative complications and shorter hospital stays in TKA patients, suggesting potential perioperative benefits. However, increased risks of blood loss anemia, intraoperative fractures, and revision surgery highlight the need for further research on long-term outcomes and alternative weight-loss strategies, such as pharmacologic interventions.

Background: Periprosthetic fractures following total hip arthroplasty are serious complications occurring in up to 2.4% of primary cases, contributing to significant morbidity, extended hospital stays, and elevated healthcare costs. Predicting these fractures remains a challenge despite advances in surgical techniques and prosthetic materials. Methods: This study analyzed 1,634,615 cases of primary THA from the NIS database (2016–2019) using propensity score matching to compare outcomes between patients with and without intraoperative periprosthetic fractures. Predictive models, including logistic regression, decision tree, and deep neural network, were evaluated for their ability to predict fracture risk. Results: Patients with periprosthetic fractures exhibited a 14-fold increase in pulmonary embolism risk, a 12-fold increase in infections, and a 5-fold increase in hip dislocations. Fractures extended hospital stays (3.8 vs. 2.5 days) and added approximately USD 32,000 in costs per patient. The predictive models yielded low accuracy (AUC max = 0.605), underscoring the complexity of predicting periprosthetic fractures. Conclusions: Intraoperative periprosthetic fractures in THA significantly elevate complication rates, costs, and length of stay. Despite extensive modeling efforts, accurate prediction remains difficult, highlighting the need to focus on preventive strategies, such as improved surgical techniques and real-time intraoperative monitoring.

Background: This study investigates the rising trend of total hip arthroplasty (THA) in patients under 55 years old, commonly referred to as “younger” THA patients. Traditionally a procedure for older adults with osteoarthritis, THA is increasingly performed on younger patients. Methods: Using data from the Nationwide Inpatient Sample (NIS) from 2016 to 2019, we analyze the factors driving this trend, including the causes of hip issues, patient characteristics, and coexisting medical conditions. The study examines in-hospital mortality, length of stay, post-surgical complications, and hospitalization costs for 231,630 THA patients aged 18–54.9, identified using ICD-10 codes. Results: Statistical analysis revealed that younger patients (aged 18–34.9) had higher rates of chronic anemia, inflammatory bowel disease, sickle cell disorders, connective tissue disorders, and coagulation defects compared to patients aged 35–44.9 and 45–54.9. They also experienced the longest hospital stays (2.08 days) and highest costs ($70,540). Significant odds ratios were found for sickle cell disorders (36.078), coagulation defects (1.566), inflammatory bowel disease (2.582), connective tissue disorders (11.727), hip dislocation (3.447), and blood transfusion (1.488) in younger patients compared to other THA patients. Conclusions: Comprehensive analysis of these unique needs is crucial for optimizing care, tailoring treatment, managing co-existing conditions, and personalizing recovery strategies to improve outcomes and quality of life for younger THA patients.