A Study to Evaluate Long-Term Safety of Multiple Doses of Tapentadol (CG5503) Prolonged-Release (PR) and Oxycodone Controlled-Release (CR) in Patients With Chronic Pain

Inclusion Criteria: * Clinical diagnosis of knee or hip osteoarthritis with history of pain at the reference joint for at least 3 months or clinical diagnosis of low back pain of benign origin for at least 3 months * Must be dissatisfied with their current analgesic therapy (e.g. Non-steroidal anti-inflammatory drugs NSAIDS, COX-2 inhibitors, opioids, paracetamol/acetaminophen * Have a pain intensity \>4 on Numerical Rating Scale Exclusion Criteria: * Life-long history of seizure disorder or epilepsy * Any of the following within one year: mild/moderate traumatic brain injury, stroke, transient ischemic attack, and brain neoplasm * Severe traumatic brain injury within 15 years (consisting of more than one of the following: brain contusion (injuries resulting in hemorrhage), intracranial hematoma, unconsciousness or post traumatic amnesia lasting for more than 24 hours) or residual sequelae suggesting transient changes in consciousness * History of malignancy within past 2 years, with exception of a successfully treated basal cell carcinoma * Presence of significant pain associated with conditions other than osteoarthritis or low back pain that could confound the assessment or self-evaluation of pain