Feasibility of a randomized trial comparing exercise-based rehabilitation to no exercise-based rehabilitation after total knee arthroplasty: DRAW-TKA hybrid 1 RCT.

Objective: Trials comparing the effectiveness of exercise-based rehabilitation against no exercise-based rehabilitation are needed, but their feasibility is unclear. The DRAW-TKA feasibility trial aimed to assess recruitment-, retention-, harms-, and procedural feasibility to inform a full-scale effectiveness trial. Design: This pragmatic, multicentre, parallel, two-arm feasibility trial included participants scheduled for total knee arthroplasty due to osteoarthritis, aged ≥18, who could read and write Danish. Participants were recruited pre-operatively from two hospitals. At discharge, participants were encouraged to be physically active and randomised (one-to-one) to "Referral to exercise" (usual care) or "No exercise". Recruiters, outcome assessors, and intervention-deliverers were masked to allocation. The primary feasibility criteria were based on recruitment rate, retention, participation barriers, and data completeness. Secondary criteria on harms, procedural feasibility, and intervention acceptance. Results: Between Aug 22nd Conclusion: The trial's scientific rationale - allocation to exercise, or no exercise - introduced significant risk of selection and attrition bias in this clinical context, severely limiting the generalisability. Although recruitment was predominantly feasible, further adaptations are required to warrant full-scale initiation.NCT05935020.