System Dynamics to Model the Unintended Consequences of Denying Payment for Venous Thromboembolism after Total Knee Arthroplasty

Background: The Hospital Acquired Condition Strategy (HACS) denies payment for venous thromboembolism (VTE) after total knee arthroplasty (TKA). The intention is to reduce complications and associated costs, while improving the quality of care by mandating VTE prophylaxis. We applied a system dynamics model to estimate the impact of HACS on VTE rates, and potential unintended consequences such as increased rates of bleeding and infection and decreased access for patients who might benefit from TKA. Methods and Findings: The system dynamics model uses a series of patient stocks including the number needing TKA, deemed ineligible, receiving TKA, and harmed due to surgical complication. The flow of patients between stocks is determined by a series of causal elements such as rates of exclusion, surgery and complications. The number of patients harmed due to VTE, bleeding or exclusion were modeled by year by comparing patient stocks that results in scenarios with and without HACS. The percentage of TKA patients experiencing VTE decreased approximately 3-fold with HACS. This decrease in VTE was offset by an increased rate of bleeding and infection. Moreover, results from the model suggest HACS could exclude 1.5% or half a million patients who might benefit from knee replacement through 2020. Conclusion: System dynamics modeling indicates HACS will have the intended consequence of reducing VTE rates. However, an unintended consequence of the policy might be increased potential harm resulting from over administration of prophylaxis, as well as exclusion of a large population of patients who might benefit from TKA

Mason type II and III radial head fracture in patients older than 65: is there still a place for radial head resection?

Purpose: To evaluate the clinical outcomes of radial head excision for multifragmentary radial head fracture in patients over 65 years old. Methods: We retrospectively examined 30 patients over 65 years of age treated with radial head excision for comminuted radial head fractures. Patients were evaluated through clinical examinations, administrative questionnaires (DASH—Disabilities of the Arm, Shoulder and Hand; MEPS—Mayo Elbow Performance Score, VAS—Visual Analog Scale) and plain films. Results: The mean follow-up was 40 months (range 24–72 months); 27 out of 30 patients claimed to be satisfied. The mean DASH score was 13 (range 3–45.8) and mean MEPS was 79 (range 65–97). The radiographic evaluation showed 21 cases of elbow arthritis; only two of them complained about pain. Heterotopic ossification was evident in six cases with functional impairment in only one patient. Six patients with increased ulnar variance had clinical distal radio-ulnar joint instability. Discussion: Radial head excision has been considered a safe surgical procedure with satisfactory clinical outcomes. Development in biomechanical studies and prosthetic replacement of the radial head question the validity of radial head excision. In current literature, there are neither long-term follow-up studies on radial head prosthesis outcomes nor studies which consider elderly patient samples. Conclusion: Radial head resection remains a good option when a radial head fracture occurs in elderly patients, taking into account the influence of poor bone quality and comorbidities on the outcome. Radial head excision is not indicated in the presence of associated lesions, because of the risk of residual elbow instability; complications associated with advanced age must be considered and a strict follow-up granted