Background: Although pain is often a symptom that precedes total knee arthroplasty (TKA), the procedure itself is associated with considerable postoperative pain lasting days to weeks. Postoperative pain control is an important factor in determining recovery time, hospital length of stay, and rehabilitation success. Several brain stimulation technologies including transcranial direct current stimulation (tDCS) have demonstrated promise as treatments for a variety of pain conditions. The present study examined the effects of 4 sessions of tDCS on post-TKA pain and opioid consumption.
Materials and methods: Forty patients undergoing unilateral TKA were randomly assigned to receive a total of 80 minutes of real (n=20) or sham tDCS (n=20) with the anode over the knee representation of the motor strip (C1h or C2h corresponding to the target knee) and cathode over the right dorsolateral prefrontal cortex (F3; located by the EEG 10-20 System). Patient-controlled analgesia ( hydromorphone) use was tracked during the ∼48 hours postsurgery.
Results: Patients in the real tDCS group used an average of 6.6 mg (SD=5.3) of patient-controlled analgesia hydromorphone, whereas those in the sham group used 12.3 mg (SD=6.6; t37=2.93, P=0.006). Despite using less opioid medication, participants in the real tDCS group reported no pain exacerbation or worse mood with respect to those in the sham tDCS group.
Conclusions: Results from this pilot feasibility study suggest that tDCS may be able to reduce post-TKA opioid requirements. Although these results are preliminary, the data support further research in the area of adjunctive cortical stimulation in the management of postsurgical pain.