Sublimed SAS

This is a retrospective and transverse multicenter study to identify predictive factors for adherence to TENS by chronic pain patients followed in structures specialized in Chronic Pain management (SPC).
The study contains 2 parts:
* A retrospective part of data collection in the patient follow-up file of the SPC during the 6 months elapsed after the first rental prescription.
* A transversal part, aimed at collecting additional information on the use of TENS, satisfaction and quality of life during a telephone interview after 6 months of use.

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.