Participants will be randomized to receive an injection treatment of either a compound of 1 ml triamcinolone 20mg/ml (Lederspan), Meda AB, Solna, Sweden) and 1 ml lidocaine hydrochloride 10mg/ml (Xylocain), Astra Zeneca, Södertälje, Sweden) or 0.99 ml saline solution 9mg/ml, 1 ml lidocaine hydrochloride and 0.01 ml fat emulsion (Intralipid), Fresenius Kabi, Uppsala, Sweden), the latter to make the solution opalescent as Lederspan.