NMES and TENS For knee osteoarthritis

Osteoarthritis (OA) refers to a clinical syndrome of joint pain accompanied by varying degrees of functional limitation and reduced quality of life. It is the most common form of arthritis, and one of the leading causes of pain and disability worldwide. The most commonly affected peripheral joints are the knees, hips and small hand joints. Pain, reduced function and effects on a person’s ability to carry out their day-to-day activities can be important consequences of osteoarthritis.

Osteoarthritis is characterised pathologically by localised loss of cartilage, remodelling of adjacent bone and associated inflammation. A variety of traumas may trigger the need for a joint to repair itself. Osteoarthritis includes a slow but efficient repair process that often compensates for the initial trauma, resulting in a structurally altered but symptom-free joint. In some people, because of either overwhelming trauma or compromised repair, the process cannot compensate, resulting in eventual presentation with symptomatic osteoarthritis; this might be thought of as ‘joint failure’. This in part explains the extreme variability in clinical presentation and outcome that can be observed between people, and also at different joints in the same person.

Here’s the evidence….

NMES has been shown to be effective in patients with knee OA by enhancing the effectiveness of an exercise program.

Does neuromuscular electrical stimulation enhance the effectiveness of an exercise programme in subjects with knee osteoarthritis? A randomized controlled trial. Elboim-Gabyzon M et al. Clin Rehabil. 2013 Mar;27(3):246-57.

  • To determine whether NMES applied to the quadriceps femoris muscle will enhance the effectiveness of an exercise programme in patients with knee osteoarthritis.
  • Randomized trial with parallel intervention treatment groups.
  • 50 participants (mean age 68.9 years) with symptomatic idiopathic knee OA and radiographic evidence (grade ≥ II Kelgren’s classification).
  • participants were randomized into one of two groups receiving 12 biweekly treatments
  • an exercise-only group, or an exercise combined with NMES group (75 Hz).
  • Pain VAS score and quadriceps activation improved significantly more in NMES group.  Other parameters improved similarly and significantly in both groups.
  • The authors conclude that electrical stimulation treatment to the quadriceps femoris enhanced the effectiveness of an exercise programme in alleviating pain and improving voluntary activation in patients with knee osteoarthritis.

 TENS has been shown to be effective for knee OA

Comparison of Intra-articular Hyaluronic Acid Injections With Transcutaneous Electric Nerve Stimulation for the Management of Knee Osteoarthritis: A Randomized Controlled Trial. Chen WL et al.  Arch Phys Med Rehabil. 2013 Aug;94(8):1482-9.

  • to compare the effects of intra-articular hyaluronic acid and TENS in the treatment of patients with knee osteoarthritis.
  • Prospective, randomized controlled trial.
  •  patients were randomly assigned to HA group (n=27) who received intra-articular HA injection into the affected knee once a week for 5 consecutive weeks, or TENS group (n=23) who received a 20- minute session of TENS (on acupoints – mixed freq. 3Hz/20Hz) 3 times a week for 4 consecutive weeks.
  • All subjects were assessed at baseline, and at 2 weeks, 2 months, and 3 months after the treatments were completed.
  • Pain and Lequesne index were significantly more improved in TENS group.  Knee ROM improved significantly only in TENS group.  Other outcomes improved significantly and similarly in both groups.  Improvements were maintained at 3 months follow-up.
  • The authors conclude that TENS on acupoints was more effective than intra-articular HA injection in improving the VAS for pain and the Lequesne index in patients with moderate to severe knee OA.

NMES in knee OA patients improves quadriceps architecture, strength and function and improves health status.

Neuromuscular electrical stimulation (NMES) reduces structural and functional losses of quadriceps muscle and improves health status in patients with knee osteoarthritis. Vaz et al. J Orthop Res. 2012 Nov 8.

  • to identify the associations of knee OA with quadriceps muscle architecture and strength, and to quantify the effects of a NMES training program on these parameters.
  • Experimental study: Part 1: comparison OA patients vs. healthy controls.  Part 2: comparison OA patients before vs. after NMES treatment
  • 20 OA patients and 10 healthy subjects
  • 12 (of the 20) OA patients participated in an 8-week NMES program (24 sessions of 18 min – 3x/wk – 400µs/80Hz).
  • Outcomes included: muscle architecture (thickness, fascicle length, and pennation angle of the vastus lateralis muscle), maximal isometric knee extensor torque and WOMAC index.
  • OA patients had significantly smaller vastus lateralis thickness and fascicle length than healthy subjects and also had a 23% smaller knee extensor torque compared to the healthy control subjects.
  • NMES training significantly increased all these parameters and also improved WOMAC scores.
  • The authors conclude that OA patients have decreased strength, muscle thickness, and fascicle length in the knee extensor musculature compared to control subjects. NMES training appears to offset the changes in quadriceps structure and function, as well as improve the health status in patients with knee OA.

A home-based NMES program is effective in knee OA demonstrating equivalent results to resistance training program and better adherence and less resource intensive than traditional physical therapy.

Effects of home-based resistance training and neuromuscular electrical stimulation in knee osteoarthritis: a randomized controlled trial. Bruce-Brand et al. BMC Musculoskelet Disord. 2012 Jul 3;13:118.

  • To compare the effects of home-based resistance training (RT) and NMES on patients with moderate to severe knee OA.
  • randomised control trial.
  • 41 patients with symptomatic, moderate to severe knee OA.
  • patients were randomised to 6 week programs of RT, NMES (50Hz, on/off cycle10s/50s) or a control group receiving standard care.
  • outcomes were primary outcome was functional capacity measured using a walk test, stair climb test and chair rise test.  Additional outcomes were self-reported disability, quadriceps strength and cross- sectional area.
  • Similar, significant improvements in functional capacity for the RT and NMES groups at week 8 compared to week 1 (p ≤ 0.001) and compared to the control group (p < 0.005), and the improvements were maintained at week 14 (p ≤ 0.001)
  • Cross sectional area of the QFM increased 5.4% in NMES and 4.3% in RT group.
  • Adherence was 91% and 83% in the NMES and RT groups respectively.
  • The authors concluded that home-based NMES is an acceptable alternative to exercise therapy in the management of knee OA, producing similar improvements in functional capacity.