Fast Track Total Knee Arthroplasty: Local Infiltration Analgesia vs Femoral Nerve Block

Inclusion Criteria: * American Society of Anesthesiologists (ASA) physical health status I-II * patient presents with non-inflammatory primary knee osteoarthritis (radiological confirmation) * patient is planned for a primary unilateral posterior-stabilized tri-compartmental cemented total knee replacement (Genesis II - PS) * patient is scheduled for fast track protocol * patient plans to be available fot follow-up through one year post-operative * written informed consent Exclusion Criteria: * any contra-indication for locoregional anesthesia * any contra-indication for spinal anesthesia * traumatic osteoarthritis requiring TKA * an active, local infection or systemic infection * known hypersensitivity to amide-type local anesthetics * known intolerance or contraindication for opioids, nonsteroidal antiinflammatory drugs (NSAIDs) or paracetamol * a Body Mass Index \> 40 kg/m2 * inability to walk independently (inability to walk at least 10 consecutive meters without a walking aid) * scheduled for contralateral TKA within one year postoperative * scheduled for another operation within 3 months postoperative * physical, emotional or neurological conditions that would compromize compliance with postoperative rehabilitation and follow-up * chronic opioid analgesic therapy * chronic gabapentin or pregabalin analgesic therapy * rheumatoid arthritis