Randomized Controlled Trial

Intra-articular injection versus portal infiltration of 0.5% bupivacaine following arthroscopy of the knee: a prospective, randomised double-blinded trial.

J Bone Joint Surg Br. 2009 May 1;91(5):601-3.
Randomized Controlled Trial

Intraarticular tramadol-bupivacaine combination prolongs the duration of postoperative analgesia after outpatient arthroscopic knee surgery.

Anesth. Analg. 2008 Jul 1;107(1):292-9.
Review

Intra-articular clonidine for post-operative analgesia following arthroscopic knee surgery: a systematic review and meta-analysis.

Knee Surg Sports Traumatol Arthrosc. 2014 Sep 1;22(9):2076-84.