Intra-Articular Anaesthesia
==========================+

- giving intra-articular (IA) morphine in a dose of about 1 mg
  will give significant pain relief, and is blocked by IA
  naloxone, suggesting that there are indeed local opioid
  receptors.  [Stein, C et al.  Analgesic effect of
  intraarticular morphine after arthroscopic knee surgery.  N
  Engl J Med 1991;325:1123.]