Total knee replacement (TKR) reduces disability and improves quality of life of patients with osteoarthritis. However, the treatment is also associated with severe postoperative pain at the surgical site due to the immune response generated after the tissue injury and leads to delayed wound healing, infection, and poor results. The study compares the different analgesia approaches to manage the pain and perforin-Expressing Lymphocytes.

Surgical stress and pain induce a pro-inflammatory reaction accompanied by down-regulation of the immune system. This down-regulation may intensify the number of postoperative complications, like extended wound healing or infections. To maintain the immune balance, natural killer (NK) cells and T lymphocytes are the crucial components of cellular immunity. This study aimed to investigate three types of postoperative analgesia impact on the protection and cytotoxic potential of NK cells, T lymphocytes, and their subpopulations, as well as NKT cells, among patients following total knee replacement (TKR) to discover the most efficient analgesic approach for alleviating immune suppression.

A total of forty-eight patients selected and randomly categorised into three groups; Group 1 (epidural analgesia), Group 2 (sciatic and femoral nerve block), or Group 3 (multi-modal systemic analgesia). The assessment of pain was done at rest, on movement back, quickly after, 24 and 72 h of the treatment. At the corresponding time points, blood samples were accumulated, and peripheral blood mononuclear cells were separated. The proportions of NKT cells, NK cells, T lymphocytes and their perforin expression, were concurrently identified and investigated by flow cytometry.

Less pain was experienced by the patients of group 1 and 2 as compared to group 3. Also, the proportions of NKT cells, NK cells, T lymphocytes, and their perforin expression were noticed to be lowered in group 3 as compared to group 1 and 2. 

The outcomes of the present study validated that regional analgesia is more efficient in managing perforin expression in peripheral blood lymphocytes and cell-mediated immunity among the patients after TKR.