Characteristics of patients showing dislocation after total hip arthroplasty in an acute care hospital: A retrospective cohort study

Most previous studies on dislocation after total hip arthroplasty (THA) have focused on patient- and surgery-related factors without detailing the specific circumstances of dislocation events. Therefore, this study aimed to analyze dislocation cases and compare these relevant factors between patients who experienced dislocation and those who did not to inform targeted prevention measures during acute care hospitalization. This retrospective study examined the electronic medical records of 420 patients (445 joints) who underwent THA and rehabilitation at our hospital between April 1, 2018, and August 31, 2023. A total of 9 cases of dislocation in 6 patients were reported. Dislocation occurred most frequently in bed within the patient's room (5 cases; 55.6%), followed by in the rehabilitation room and the toilet (1 case each; 11.1%), and unknown locations (2 cases; 22.2%). Bed-related dislocations were associated with trunk rotation or external rotation of the hip joint; in 2 cases, the dislocation was already present when the patient awoke. The revision THA and THA indication rates, preoperative Functional Independence Measure scores, and locomotion status differed significantly between the patients who showed dislocation and those who did not. Revision THA, THA indications other than osteoarthritis, low Functional Independence Measure score at admission, and low locomotion status may increase the risk of dislocation. Furthermore, the findings suggest that dislocation prevention strategies during acute hospitalization should prioritize safe bed use and sleep positions.