Preoperative Emergency Department Visits Are Predictive of 90-Day Postoperative Emergency Department Visits and Discharge Disposition in Total Knee Arthroplasty Patients.

The increasing number of patients undergoing total knee arthroplasty (TKA) has resulted in efforts to better understand patient utilization of healthcare services in the 90-day postoperative period. The primary purpose of this study was to examine whether emergency department (ED) visits in the year prior to elective TKA were predictive of postoperative ED visits in the 90-day global period following surgery. A retrospective chart review was performed for all patients undergoing TKA from June 1, 2011 to December 31, 2015 at a Veterans Affairs hospital. Total number of ED visits in the year prior to surgery and 90 days following surgery were tabulated. Binary and ordinal logistic regression analyses were utilized to determine if preoperative ED visits were predictive of postoperative ED visits. The significance level was set to α = 0.05. Overall, 611 eligible TKA procedures were performed. The logistic regression model for postoperative ED visits was significant (p < 0.001), with the number of preoperative ED visits (1 vs. 0: p < 0.001; 2 vs. 1: p = 0.012) and presence of diabetes (p = 0.007) both predicting the likelihood of a postoperative ED visit. Healthcare changes that are redefining the concept of quality of care to include the postoperative care episode, coupled with an increasingly aging population in need of TKA, will continue to challenge orthopaedic surgeons to provide safe, competent, and cost-effective care to patients. The results of this study demonstrate that a patient's propensity to visit the ED prior to TKA is predictive of a tendency to do so postoperatively and is of use to surgeons when evaluating and counselling patients who will be undergoing a TKA.

Dynamic tracking influenced by anatomy in patellar instability.

BACKGROUND: The current study was performed to correlate anatomical parameters related to trochlear dysplasia, tibial tuberosity position, and patella alta with in vivo patellar tracking for subjects with recurrent patellar instability. METHODS: Eight subjects with recurrent patellar instability that failed conservative treatment were evaluated using computational reconstruction of in vivo knee motion. Computational models were created from dynamic CT scans of the knee during extension against gravity. Shape matching techniques were utilized to position a single model of each bone (femur, patella and tibia) to represent multiple positions of knee extension. Patellar tracking was characterized by the bisect offset index (lateral shift) and lateral tilt. Anatomical parameters were characterized by the inclination of the lateral ridge of the trochlear groove, the lateral distance from the tibial tuberosity to the posterior cruciate ligament attachment (lateral TT-PCL distance), and the Caton-Deschamps index. Stepwise multivariable linear regression analysis was used to relate patellar tracking to the anatomical parameters at low (<20°) and high flexion angles. RESULTS: At low flexion angles, both lateral trochlear inclination and lateral TT-PCL distance were significantly correlated with bisect offset index (p=0.02). Only lateral trochlear inclination was significantly correlated with lateral tilt (p<0.001). At high flexion angles, bisect offset index and lateral tilt were correlated with only lateral TT-PCL distance (p≤0.02). CONCLUSION: Parameters related to trochlear dysplasia and tibial tuberosity position were both related to patellar tracking, but the relationship changed with the flexion angle. CLINICAL RELEVANCE: The anatomical parameters related to patellar tracking can be used to evaluate the risk of continued instability and guide surgical treatment.