A total of 159 patients will be needed (53 patients per arm, 3 arms in total). Dexamethasone (brand name: Mephameson) is the steroid drug that we perioperative administer in two different ways: intra-venous (IV) dexamethasone (9mg) in arm-A, intra-articular (IA) dexamethasone (9mg) in arm-B. No steroid supplementation will be provided in the control group (arm-C).

The primary objective of the study is to compare the effect on post-operative pain of I.V. and I.A. perioperative dexamethasone supplementation for total knee arthroplasty (TKA).

The secondary objectives of the studies will be the comparison between I.V. and I.A. peri-operative dexamethasone supplementation in terms of post-operative pain and function, opioids and analgesic drugs consumption, knee range of motion, systemic inflammatory response, time to mobilisation, length of stay, and patient satisfaction.

Moreover, both I.V. and I.A. steroid supplementation protocols will be compared to routine analgesia protocol (no steroid supplementation group) in order to document their advantages over the absence of steroid supplementation.

The safety of I.V. and I.A. peri-operative dexamethasone will be evaluated and compared recording all the steroid supplementation related complications. In particular, the risk of hyperglycaemia-related complications and post-operative infections will be documented. The safety of both I.V. and I.A. steroid supplementation protocols will be verified comparing them to the no-treatment group in terms of incidence of complications.

Overall study duration will be 12 years: 2 years to enroll all the patients and 10 years to complete the last follow-up. Primary data analysis is planned after the completion of the 1-year follow-up visits.