A study published in Scientific Reports has demonstrated that popliteal plexus block (PPB) is non-inferior to tibial nerve block (TNB) in facilitating rehabilitation after total knee arthroplasty (TKA). The research, conducted at Daiyukai General Hospital, compared the two nerve block techniques in terms of time to achieve rehabilitation goals, pain management, and functional outcomes.
The study enrolled 136 patients undergoing unilateral TKA for knee osteoarthritis. Participants were randomized to receive either PPB or TNB preoperatively, with all surgeons, nurses, and physiotherapists blinded to the allocation. The primary endpoint was the time to rehabilitation goal, defined as achieving a Numeric Rating Scale (NRS) score ≤4 at rest with scheduled analgesics, walking 30 meters with a walker, and demonstrating voluntary performance of 90° knee flexion.
Regional Anesthesia Techniques
Both PPB and TNB were performed by an experienced anesthesiologist using ultrasound guidance. For TNB, 10 mL of levobupivacaine 0.25% was administered on the medial side of the tibial nerve in the popliteal fossa. For PPB, 10 mL of levobupivacaine 0.25% was injected between the vastus medialis and adductor magnus muscles at the distal end of the adductor canal.
Key Findings
The results indicated that PPB was non-inferior to TNB in achieving the primary endpoint. The mean time to reach rehabilitation goals was comparable between the two groups. Secondary endpoints, including NRS scores at rest and during knee flexion, active knee range of motion (ROM), additional analgesic requirements, and straight leg raise (SLR) success, were also similar between the PPB and TNB groups.
Maximum voluntary isometric contraction (MVIC) of foot movement was assessed to evaluate potential motor deficits. No significant differences were observed between the groups at 6 and 24 hours postoperatively, suggesting similar effects on motor function.
Implications for Postoperative Pain Management
These findings suggest that PPB can be considered an effective alternative to TNB for postoperative pain management and rehabilitation following TKA. The study's rigorous methodology, including blinding and standardized rehabilitation protocols, strengthens the validity of the results. According to the researchers, PPB offers a comparable approach to TNB with similar functional outcomes and pain control.
