Transcutaneous electrical nerve stimulation (TENS) significantly decreased movement pain postoperatively but not by 6 weeks after total knee arthroplasty compared to standard care. TENS and placebo-TENS results were not significantly different.
This study evaluated the efficacy of transcutaneous electrical nerve stimulation (TENS) in reducing pain and hyperalgesia and increasing function after total knee arthroplasty (TKA). We hypothesized that participants using TENS during rehabilitation exercises would report significantly lower pain during range-of-motion (ROM) activity and fast walking but not at rest, would have less hyperalgesia, and would have better function than participants receiving placebo-TENS or standard care. We also hypothesized that change in ROM pain would differ based on psychological characteristics (trait anxiety, pain catastrophizing, and depression) and treatment group. This prospective, randomized study used intent-to-treat analyses in 317 participants after primary, unilateral TKA. Assessors, blinded to treatment allocation, measured pain, function (ROM and gait speed), and hyperalgesia (quantitative sensory tests) postoperatively and 6 weeks after surgery. Analgesic intake, anxiety, depression, and pain catastrophizing were also assessed. TENS participants used it 1 to 2 times per day at 42 mA (on average) and had less pain postoperatively during active knee extension (P = .019) and fast walking (P = .006) than standard care participants. TENS and placebo-TENS were not significantly different. TENS participants who scored low on anxiety and pain catastrophizing had a greater reduction in ROM pain at 6 weeks than those who scored high on these factors (P = .002 and P = .03). Both TENS and placebo-TENS participants had less postoperative mechanical hyperalgesia (P = .03–.01) than standard care participants. Supplementing pharmacologic analgesia with TENS during rehabilitation exercises reduces movement pain postoperatively, but a placebo influence exists and the effect is gone by 6 weeks. Patients with low anxiety and pain catastrophizing may benefit most from TENS.
aThe University of Iowa College of Nursing, Iowa City, IA, USA
bDepartment of Biostatistics, The University of Iowa College of Public Health, Iowa City, IA, USA
cDepartment of Orthopedics and Rehabilitation, The University of Iowa College of Medicine, Iowa City, IA, USA
dSchool of Health Sciences, University of Ulster, Northern Ireland, UK
eDepartment of Physical Therapy and Rehabilitation Science, The University of Iowa College of Medicine, Iowa City, IA, USA
*Corresponding author. Address: College of Nursing, The University of Iowa, 50 Newton Rd, 318 CNB, Iowa City, IA 52242, USA. Tel.: +1 (319) 335 7036.
Article history: Received March 14, 2014; Received in revised form September 11, 2014; Accepted September 22, 2014.
ClinicalTrials.gov Identifier: NCT01364870.
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