Context:​ Quadriceps activation deficits have been reported in patients with tibiofemoral osteoarthritis (TFOA). Transcutaneous electrical nerve stimulation (TENS) has been reported to immediately increase quadriceps activation in people with TFOA, yet there is no data to determine the effectiveness of TENS in increasing muscle activation over an extended period of time.

Objective:​ To determine if sensory TENS augmented with therapeutic exercise and daily activities for 4-weeks, will increase voluntary quadriceps activation in patients with TFOA compared to placebo TENS and exercise, and receiving exercise only.

Design:​ Blinded, Randomized Controlled Trial.

Setting:​ University laboratory setting.

Participants:​ Thirty–six patients with radiographically assessed TFOA were randomly assigned to the TENS, Placebo TENS, and the control groups. Five participants did not complete the intervention and 1 participant did not perform follow-up strength or activation testing.

Intervention(s):​ Participants completed a supervised 4-week lower extremity exercise program. TENS and placebo TENS were worn throughout the rehabilitation sessions as well as during daily activities.

Main Outcome Measures:​ Quadriceps central activation ratio was assessed in 70° of knee flexion and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were evaluated at baseline and at 2 weeks and 4 weeks of the intervention.

Results:​ Quadriceps activation was significantly higher in the TENS group compared to the control at 2 weeks and the placebo at 4 weeks. WOMAC scores decreased for all three groups over time.

Conclusions:​ This study provides evidence that TENS can be used to increase quadriceps activation in patients with TFOA.