Analgesic Efficacy of Transcutaneous Electrical Nerve Stimulation Compared with Diclofenac Sodium in Osteo-arthritis of the Knee

Abstract

The role of drug treatment in osteo-arthritis is controversial. Comparatively few drugs are thought to affect the outcome of the disease process. Nevertheless non-steroidal anti-inflammatory drugs are, in most cases, the major weapon used by clinicians to relieve symptoms of the disease. There is some evidence that transcutaneous electrical nerve stimulation (TENS) is an effective and safe alternative to non-steroidal anti-inflammatory drugs in treatment of osteo-arthritis of the knee joint. It is non-invasive, non-toxic, inexpensive, portable and easy to apply. However there are conflicting reports of its efficacy, with little research to evaluate the effects of TENS as a primary single modality treatment, the relationship between the therapeutic benefits of TENS and pain severity has received little attention, and significant inter-subject variation in pain response can be expected. A single-blind trial of 60 patients was planned. Thirty-five completed the trial successfully. Before treatment a haemogram, blood chemistry tests and radiography of the affected knee were performed in addition to a thorough clinical examination where patients were selected for inclusion. After withdrawing all drugs for one week, patients were interviewed to record pain intensity on a simple descriptive scale and the distance they reported that they could walk comfortably. Each of the three phases of trial lasted for two weeks followed by a week's wash-out period. In phase 1 patients received both a placebo drug and placebo TENS. In phase 2 placebo TENS was combined with diclofenac sodium 50 mg three times a day. In phase 3 active TENS and the placebo drug were combined. Active TENS was applied in two 20-minute sessions daily for two weeks followed by assessment of pain intensity and the distance that patients reported they could walk. Though there was effective analgesia after placebo treatment as reported in many other studies, the analgesia produced by diclofenac sodium was greater (p < 0.05) when compared to the placebo. The analysis of phases 2 and 3, phases 2 and 1, and phases 3 and 1 revealed significant pain relief (p < 0.001) and improved walking (p < 0.001) after TENS in patients with mild to moderate pain and movement restriction. After phases 1 and 2 a marginal increase in ambulation (p < 0.05) was observed. TENS therapy was however not very effective in severely afflicted patients. The role of drug treatment in osteo-arthritis is controversial. Comparatively few drugs are thought to affect the outcome of the disease process. Nevertheless non-steroidal anti-inflammatory drugs are, in most cases, the major weapon used by clinicians to relieve symptoms of the disease. There is some evidence that transcutaneous electrical nerve stimulation (TENS) is an effective and safe alternative to non-steroidal anti-inflammatory drugs in treatment of osteo-arthritis of the knee joint. It is non-invasive, non-toxic, inexpensive, portable and easy to apply. However there are conflicting reports of its efficacy, with little research to evaluate the effects of TENS as a primary single modality treatment, the relationship between the therapeutic benefits of TENS and pain severity has received little attention, and significant inter-subject variation in pain response can be expected. A single-blind trial of 60 patients was planned. Thirty-five completed the trial successfully. Before treatment a haemogram, blood chemistry tests and radiography of the affected knee were performed in addition to a thorough clinical examination where patients were selected for inclusion. After withdrawing all drugs for one week, patients were interviewed to record pain intensity on a simple descriptive scale and the distance they reported that they could walk comfortably. Each of the three phases of trial lasted for two weeks followed by a week's wash-out period. In phase 1 patients received both a placebo drug and placebo TENS. In phase 2 placebo TENS was combined with diclofenac sodium 50 mg three times a day. In phase 3 active TENS and the placebo drug were combined. Active TENS was applied in two 20-minute sessions daily for two weeks followed by assessment of pain intensity and the distance that patients reported they could walk. Though there was effective analgesia after placebo treatment as reported in many other studies, the analgesia produced by diclofenac sodium was greater (p < 0.05) when compared to the placebo. The analysis of phases 2 and 3, phases 2 and 1, and phases 3 and 1 revealed significant pain relief (p < 0.001) and improved walking (p < 0.001) after TENS in patients with mild to moderate pain and movement restriction. After phases 1 and 2 a marginal increase in ambulation (p < 0.05) was observed. TENS therapy was however not very effective in severely afflicted patients.