Comparison of the Efficacy, Tolerability and Safety of actiTENS to Those of Level 2 Analgesic Treatments.

This is a phase 3, multicentre, prospective, single-blind on principal efficacy criterion, 2 parallel groups, randomized, controlled clinical study comparing efficacy and safety of actiTENS versus systemic level 2 analgesics recommended for the treatment of moderate or severe, nociceptive, chronic pain in patients suffering from osteoarthritis of the knee.

Osteoarthritis (OA) is a debilitating chronic condition requiring long-term treatment of pain and inducing functional impairment. More specifically knee osteoarthritis (KOA) is a common disease associated with significant morbidity. Its prevalence increases with age dramatically. KOA is frequently associated with pain which can worsen with daily activities. The goals of KOA treatments are to provide pain relief and to improve function and quality of life. For the American college of Rheumatology and despite the frequent use of TENS in treating patients with KOA, questions remained regarding its efficacy. Consequently TENS needs additional clinical studies to demonstrate its efficacy in management of painful osteoarthritis.

The main objective of this study is to demonstrate the efficacy and to the safety of TENS in the management of chronic, nociceptive pain in patient suffering from KOA.

Eligibility Criteria:
Inclusion Criteria:

* Adult \> or = 55 years.
* Being monitored by a rheumatologist in private practice or in a hospital.
* Presenting nociceptive pain:

  * chronic (for at least 3 months),
  * secondary to knee osteoarthritis confirmed by x-ray: stage 2 and over according to Kellgren and Lawrence.
* Of moderate to severe intensity equal to or above 4 on a numerical scale of 0-10.
* In a situation of analgesic therapy failure for level 1 analgesics:

  * paracetamol and NSAIDS,
  * Prescribed at therapeutic dose : 4 g/d of paracetamol and 1200 mg/d of ibuprofen or equivalent (analgesic dose),
  * For at least 2 weeks,
* Requiring a level 2 prescription.
* Affiliated to social security insurance.
* Informed of the concept and agreeing to use the TENS as a non-medicinal analgesic treatment.
* Capable of understanding how to use the TENS and the level 2 analgesic treatments.
* Intellectually and physically able to participate in the study in the opinion of the investigator.
* Owns a Smartphone to be able to download the actiTENS application.

Exclusion Criteria:

* Current or previous allergy to the actiTENS electrodes.
* On-going or planned pregnancy and absence of effective contraception (except for menopausal women).
* Neuropathic pain with a DN4 result \> 4/10 or with a positive response to one or more questions in the DN4 clinical examination.
* Osteoarthritis flare.
* Surgery planned in the following 6 months.
* History of multiple operations on the knee concerned.
* Medicinal or non-medicinal treatments which could influence the pathology being studied.
* Modification of medicinal or non-medicinal treatments planned in the following 6 months.
* Current participation in another study.
* Presence of another painful condition which could perturb the evaluation.
* Patient with an absolute contraindication to TENS or level 2 systemic analgesic treatments recommended for the treatment of chronic pain of moderate or severe intensity.
* Patient unable to express his/her consent or deprived of liberty.
* Patient with cognitive disorder or behaviour rendering him/her unsuitable to follow the instructions for this study.
* Patient not affiliated to a social security system.