Intra-articular guanethidine injection for resistant shoulder pain: a preliminary double blind study of a novel approach.

OBJECTIVE To study the effect of intraarticular (IA) sympathetic blockade for the relief of resistant shoulder pain. METHODS Eighteen patients with shoulder pain resistant to conventional treatment were allocated randomly to two groups, to receive either IA guanethidine 20 mg or IA saline. They were assessed for pain, and range of active movements, before injection and at one, four, and eight weeks after injection. RESULTS There were no significant differences between groups, but the group receiving guanethidine showed greater improvement in pain relief at all three follow up visits compared with those receiving placebo (9% v 7% at one week; 15% v 6% at four weeks and 36% v 16% at eight weeks). The improvement reached significance (p < 0.05) at the eight week visit compared with baseline. The range of movement was not significantly improved in either group. CONCLUSION The results suggest that IA guanethidine produced measurable improvement in resistant shoulder pain and that further studies of this novel approach are indicated.