Aasvang EK, et al. - Researchers determined the incidence and associated factors for intraoperative failed spinal anaesthesia for lower limb arthroplasty in this sub-analysis of a prospective study on spinal anaesthesia for total hip- and knee arthroplasty (THA/TKA). Age, gender, American Society of Anaesthesiologist (ASA) score, height, weight, BMI, procedure, bupivacaine dosage and duration of time from spinal administration until end of surgery were analyzed for relation to failed spinal anaesthesia. In the failed spinal group, comprising significantly younger patients, operation time was longer vs no-failure group. No significant differences were found with regard to bupivacaine volume, gender, ASA-score, height, weight, BMI or THA vs TKA. A relatively frequent occurrence of failed spinal anaesthesia for THA and TKA was noted and identification of risk patients was not feasible. These results should be considered when choosing anaesthesia and included in the information to patients.