In this sub-study of the 'Paracetamol and Ibuprofen in Combination' (PANSAID) trial, in which participants were randomised to one of four different non-opioids analgesic regimen consisting of paracetamol, ibuprofen, or a combination of the two after planned primary total hip arthroplasty, our aims were to investigate the distribution of participants' pain (mild, moderate or severe), integrate opioid use and pain to a single score (Silverman Integrated Approach (SIA)-score), and identify preoperative risk factors for severe pain. We calculated the proportions of participants with mild (VAS 0-30mm), moderate (VAS 31-60mm) or severe (VAS 61-100mm) pain and the SIA-scores (a sum of rank-based percentage differences from the mean rank in pain scores and opioid use, ranging from-200 to 200%). Using logistic regression with backwards elimination, we investigated the association between severe pain and easily obtainable preoperative patient characteristics. Among 556 participants from the modified intention-to-treat population, 33% (95% CI: 26-42) (Group Paracetamol+Ibuprofen (PCM+IBU)), 28% (95% CI: 21-37) (Group Paracetamol (PCM)), 23% (95% CI: 17-31) (Group Ibuprofen (IBU)), and 19% (95% CI: 13-27) (Group Half Strength-Paracetamol+Ibuprofen (HS-PCM+IBU)) experienced mild pain 6h postoperatively during mobilisation. Median SIA-scores during mobilisation were: Group PCM+IBU:-48% (IQR:-112 to 31), Group PCM: 40% (IQR:-31 to 97), Group IBU:-5% (IQR:-57 to 67), and Group HS-PCM+IBU: 6% (IQR:-70 to 74) (overall difference: p=0.0001). Use of analgesics before surgery was the only covariate associated with severe pain (non-opioid: OR 0.50, 95% CI: 0.29-0.82, weak opioid 0.56, 95% CI: 0.28-1.16, reference no analgesics before surgery, p=0.02). Only one third of participants using paracetamol and ibuprofen experienced mild pain after total hip arthroplasty and even fewer experienced mild pain using each drug alone as basic non-opioid analgesic treatment. We were not able, in any clinically relevant way, to predict severe postoperative pain. A more extensive postoperative pain regimen than paracetamol, ibuprofen and opioids may be needed for a large proportion of patients having total hip arthroplasty. SIA-scores integrate pain scores and opioid use for the individual patient and may add valuable information in acute pain research.