Effect of different postoperative flexion regimes on the outcomes of total knee arthroplasty: randomized controlled trial

Purpose: A consistent limb position strategy could be an attractive and easier alternative to reduce blood loss and increase range of motion following total knee arthroplasty. The aim of this study was to understand the proper amount of flexion required to improve functional outcomes with limited patients’ discomfort. Methods: Eighty-five patients undergoing total knee arthroplasty were randomly assigned to receive mild (30° of knee flexion) or high-flexion protocol (70° of knee flexion), 48 h after surgery. The same daily rehabilitation scheme was followed. Total blood loss, hidden blood loss, haemoglobin and haematocrit levels, fixed flexion deformity, range of motion and limb circumference at the superior patellar pole were evaluated preoperatively and 7 days after surgery. Results: Demographics, blood parameters and preoperative range of motion did not show any significant difference between the two groups. No complications were recorded in both groups. High-flexion group had greater rate of dropout due to excessive patients’ discomfort. A significantly lower Hb at day 1 was found in the high-flexion group. No differences were recorded regarding the remaining parameters. Conclusion: No significant differences were found between the high-flexion and mild-flexion protocols; however, mild-flexion protocol was better tolerated by patients. We therefore recommend a 30° flexion protocol to be routinely used 48 h postoperatively after total knee arthroplasty. This is an easy strategy to improve functional outcomes, which is a fundamental issue considering the steady increase in knee prostheses utilization. Level of evidence: Randomized controlled trial, Level II.