Our primary hypothesis is that TENS decreases pain with movement by reducing hyperalgesia. Minimizing the severe pain experienced during required activities in the immediate postoperative period will promote functional recovery and prevent the development of new chronic pain syndromes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
317
Subjects randomized to the placebo group will use an EMPI TENS Select device that emits a current for 45 seconds then shuts off. They will be asked when they first feel the current, then the device will be turned down a half-point to provide "treatment" at a sub-sensory level. This unit displays an active indicator light suggesting to the subject that the unit is actively emitting current. At discharge, subject will be sent home with an adequate supply of batteries and asked to change batteries when the device goes below 4 bars, further suggesting that the device is actively working.
High-frequency intense TENS provided with the EMPI Select TENS. The generator emits a balanced, asymmetrical, biphasic waveform and has buttons for variation of frequency and amplitude. A rate modulation frequency of 50pps and 150pps every 0.5 seconds will be used with a pulse width of 150 microseconds (μs).
University of Iowa
Iowa City, Iowa, United States
Self-Reported Pain With Movement
While subject's knee extension is measured, they report their pain on 0-20 Numeric Rating Scale (where 0 is "no pain" and 20 is "pain as bad as you can imagine").
Time frame: 1 day post-op
Self-reported Pain With Walking (From Iowa Gait Test)
Subjects are instructed to walk as quickly as they safely can for 15 seconds. Their pain was assessed with a Numeric Rating Scale (where 0 is "no pain" and 20 is "pain as bad as you can imagine").
Time frame: 2 days post-op
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