Knee pain during the first three months after unilateral total knee arthroplasty: a multi-centre prospective cohort study.

Many patients have an unfavourable pain outcome post total knee arthroplasty (TKA). This multi-centre prospective cohort study recorded weekly pain scores one week before TKA and 12 weeks post TKA. 96 patients were enrolled into the study. Patients kept a record of their weekly scores pre-operation and post-operation by using the visual acuity score. Pain was divided into "best" pain score (lowest pain score) and "worst" pain score (highest pain score). Patients with a pre-operative pain scores ≤ 4 were identified as an at risk group for poor pain outcome. Female gender, age and anaesthetics type were not identified as risk factors for poor pain outcome. Pain trajectory analysis also identified general patterns of pain response post TKA.