Postoperative pain belongs to the acute pain category and accompanies every surgery. Total knee arthroplasty is an example of repair surgery that can relieve the patient from the chronic pain associated with irreversible damage of the knee. The concept of multimodal analgesia applied so far in patients after orthopaedic surgery has involved the use of different classes of analgesics and different analgesia techniques. However, none of the analgesics was administered directly into the operation wound. The aim of the study was to evaluate the efficiency of an analgesic mixture including non-steroidal anti-inflammatory drugs (NSAIDs) and opioid injected directly into the operation wound. The study included 40 patients with rheumatoid arthritis (RA) and osteoarthritis (OA) who underwent TKA under spinal anaesthesia with the use of 20 mg of bupivacaine 0.5% spinal heavy at the L3-L4 level (Table I). The control group consisted of patients who received 0.4 mg of spinal morphine. This group of patients did not participate in the study. Apart from the basic parameters such as HR, RR, and Sp02, the pain according to VAS (Fig. 2, 3) was also evaluated as well as the drainage (Fig. 5) and the wound healing process 7 days after the surgery (clinical evaluation). The results describing the analgesia time in different groups showed that the longest time of analgesia occurred in the group that received 0.4 mg of spinal morphine, whereas the direct injection of analgesic mixture into the operation wound allowed for 5 hours analgesia (Fig. 1). The use of the analgesic mixture has reduced the use of postoperative systemic opioids. No negative effects on the process of wound healing were found (Fig. 4). The analgesic mixture allowed for the adequate postoperative pain analgesia.