In a well-defined fast-track setup for total hip and knee arthroplasty, with a multimodal analgesic regimen consisting of intra-operative local anaesthetic infiltration and oral celecoxib, gabapentin and paracetamol for 6 days postoperatively, we conducted a prospective, consecutive, observational study. The purpose was to describe the prevalence and intensity of subacute postoperative pain and opioid related side effects, use of analgesics and functional ability 1-10 and 30 days postoperatively. Fast-track total hip and knee arthroplasty with early discharge (< 3 days) resulted in acceptable levels of pain and postoperative nausea and vomiting with concomitant low use of opioids in > 95% of patients after discharge before day 10 after total hip arthroplasty. However, after total knee arthroplasty 52% patients reported moderate pain (VAS 30-59 mm), and 16% severe pain (VAS > or = 60 mm) when walking 1 month after surgery with a concomitant increase in the use of strong opioids. These results emphasise the need for improvement in analgesia after discharge following total knee arthroplasty, to facilitate rehabilitation.