Renal Osteodystrophy as a Risk Factor for Postoperative Complications after Knee Arthroplasty: A National In-Patient Sample Study.

ABSTRACT: Renal osteodystrophy (ROD), a skeletal complication of chronic kidney disease (CKD)-mineral and bone disorder, may influence perioperative outcomes after total knee arthroplasty (TKA), but its impact remains unclear. This study examined patient characteristics, hospital resource utilization, and postoperative complications in ROD patients undergoing primary TKA. We performed a retrospective cohort analysis of the National Inpatient Sample (2010-2019). Adults undergoing primary TKA were identified and stratified by ROD status. Propensity score matching (PSM; 1:20) was used to balance age, sex, race, comorbidities, and CKD stage. Outcomes included length of stay (LOS), hospital charges, and medical and surgical complications. Among 1,196,522 TKA patients, 283 (0.02%) had ROD. After matching (n = 5,337 controls), ROD patients had a longer median LOS (3 vs. 3 days; p < 0.001) and markedly higher median hospital charges ($58,550 vs. $18,004; p < 0.001). ROD was associated with increased odds of medical complications, including thrombocytopenia (OR: 3.2; 95% CI: 1.9-5.2), convulsion (OR: 6.9; 2.5-19.6), heart failure (OR: 2.3; 1.5-3.4), chest pain (OR: 3.4; 1.2-10.0), acute cerebrovascular disease (OR: 3.0; 1.4-6.4), stroke (OR: 3.3; 1.6-6.8), pneumonia (OR: 3.9; 1.7-9.0), and acute renal failure (OR: 2.3; 1.6-3.5). Surgical risks were also elevated, notably periprosthetic fracture (OR: 7.1; 2.2-22.9), joint dislocation (OR: 4.6; 1.7-12.3), and lower limb peripheral nerve injury (OR: 2.5; 1.4-4.7). ROD patients undergoing primary TKA incur greater hospital resource use and substantially higher rates of diverse medical and surgical complications. These findings highlight ROD as an independent risk factor warranting targeted preoperative risk stratification, multidisciplinary perioperative planning, and bone health optimization to improve outcomes and resource efficiency in this high-risk population.

ABSTRACT: The level of evidence is 3.

ABSTRACT: Trial registration is not applicable.