Reducing readmissions after total joint arthroplasty (TJA) is challenging. Pre-operative risk stratification and optimization pre surgical care may be helpful in reducing readmission rates after primary TJA. Assessment of the predictive value of individual modifiable risk factors without a tool to properly stratify patients may not be helpful to the surgical community to reduce the risk of readmission. We developed a scoring system: Readmission Risk Assessment Tool (RRAT) as part of a Perioperative Orthopaedic Surgical Home model that allows for risk stratification in patients undergoing elective primary TJA at our institution. We analyzed the relationship between the RRAT score and readmission following primary hip or knee arthroplasty. The RRAT, which is scored incrementally based on the number and severity of modifiable comorbidities was used to generate readmission scores for a cohort of 207 readmitted and 2 cohorts of 234 (random and age-matched) non-readmitted patients each. Regression analysis was performed to assess the strength of association between individual risk factors, RRAT score and readmissions. We also calculated the odds and odds ratio (OR) at each level of RRAT score to identify patients with relatively higher risk of readmission.Introduction
Methods
In spite of extensive accounts describing the blood supply to the femoral head, the prediction of avascular necrosis is elusive. Current opinion emphasises the contributions of the superior retinacular artery but may not explain the clinical outcome in many situations, including intramedullary nailing of the femur and resurfacing of the hip. We considered that significant additional contribution to the vascularity of the femoral head may exist. A total of 14 fresh-frozen hips were dissected and the medial circumflex femoral artery was cannulated in the femoral triangle. On the test side, this vessel was ligated, with the femoral head receiving its blood supply from the inferior vincular artery alone. Gadolinium contrast-enhanced MRI was then performed simultaneously on both control and test specimens. Polyurethane was injected, and gross dissection of the specimens was performed to confirm the extraosseous anatomy and the injection of contrast. The inferior vincular artery was found in every specimen and had a significant contribution to the vascularity of the femoral head. The head was divided into four quadrants: medial (0), superior (1), lateral (2) and inferior (3). In our study specimens the inferior vincular artery contributed a mean of 56% (25% to 90%) of blood flow in quadrant 0, 34% (14% to 80%) of quadrant 1, 37% (18% to 48%) of quadrant 2 and 68% (20% to 98%) in quadrant 3. Extensive intra-osseous anastomoses existed between the superior retinacular arteries, the inferior vincular artery and the subfoveal plexus.
