Data regarding the surgery will be collected. Intraoperative data includes type of arthroplasty performed (total hip or total knee arthroplasty), type of anaesthesia (spinal, general or other anaesthesia), use of femoral nerve block, intraoperative drug use, tourniquet time, intra-articular injections and blood transfusion (number of pints transfused). Occurrence of hypotension, which is defined as a mean arterial pressure <60mmHg, and its duration will also be recorded.