Garland A, Bülow E, Lenguerrand E, et al. - This study was intended to construct and externally validate a parsimonious statistical prediction model of 90-day mortality after elective total hip arthroplasty (THA), and to provide a web calculator for clinical usage. Researchers enrolled 53,099 patients with cemented THA due to osteoarthritis from the Swedish Hip Arthroplasty Registry for model derivation and internal validation, as well as 125,428 patients from England and Wales recorded in the National Joint Register for England, Wales, Northern Ireland, the Isle of Man, and the States of Guernsey (NJR) for external model validation. They assessed discriminative ability by the area under the receiver operating characteristic curve. Model calibration was evaluated by using a calibration belt. They established a parsimonious model that may facilitate individualized risk evaluation prior to one of the most common surgical interventions. In addition, they have published a web calculator to aid clinical decision-making.