The primary objective is to evaluate whether local infiltration analgesia (LIA) will reduce oxycodone consumption during the first 48 postoperative hours in patients undergoing total knee arthroplasty (TKA).

The goal of LIA is to gain an effective and safe pain control during the first postoperative days. The study is a single-center, randomized controlled trial, which will be performed in Coxa Hospital for Joint Replacement in Tampere, Finland. The injectant mixture consists of 150 mg levobupivacaine mixed with 30 mg ketorolac and 0.5 mg adrenaline with occasional variations if the patient is unusually small, very elderly, infirm or has a history of significant intolerance to analgesics or anesthetic agents. The RKA mixture is diluted with normal saline. Total volume of the solution is 100 ml depending on the size of the wound. The normal saline injection are used in the control group in the same manner than in the RKA group.

Inclusion Criteria:

• Patients requiring primary TKA for primary OA
• Patients aged 75 years or less
• Patients suitable for all applicable devices

Exclusion Criteria:

• Rheumatoid arthritis or other inflammatory diseases
• Patients requiring bone grafting during surgery
• Unwilling to provide informed consent
• BMI > 35
• ASA > 3
• Renal dysfunction
• Allergic to ASA
• Previous high tibial osteotomy or previous osteosynthesis
• > 15 degrees varus / valgus malalignment
• Physical, emotional or neurological conditions which would comprise the patient´s compliance with postoperative rehabilitation and follow-up (e.g. drug or alcohol abuse, serious mental illness, general neurological conditions such as Parkinson, MS, etc.)
• Known sensitivity to materials in the devices