2 patients were excluded, 1 in the PA group, owing to posterior dislocation before the 3-month test, and 1 in the AA group, in whom the liner had dislocated perioperatively. 2 patients experienced adverse events that did not compromise participation in the study: 1 in the PA group had an accidental dural puncture and 1 in the AA group had a cardiac arrest during surgery, but was successfully resuscitated with no sequelae.