Fig 3. Cox cumulative hazard function for knee replacement during extended follow-up by HRQoL trajectory groups.

The time to KR (months between the dates of baseline visit and the date of KR) in relation to membership in the trajectory groups. Participants without a recorded KR event were censored. The Cox regression was carried out in an unadjusted mode. HRQoL change (MIC, a minimally important reduction in KOOS QoL) trajectory groups: no change in KOOS QoL (green line); improving KOOS QoL after decline (blue line); slowly worsening KOOS QoL (yellow line); rapidly worsening KOOS QoL (red line).