The purpose of this retrospective review was to evaluate the effectiveness of a hydraulic distention technique (hydroplasty) combined with a therapy program for treatment of idiopathic frozen shoulder. Over a two-year period, 60 patients with idiopathic frozen shoulder were identified as having undergone the hydroplasty procedure and therapy protocol at the authors' hand center. Distention of the glenohumeral joint was achieved by an injection of a 10-mL combination of bupivacaine (Marcaine), lidocaine (Xylocaine), and corticosteroid followed by injection of 30 mL of chilled sterile normal saline. Therapy was initiated immediately after the surgeon had completed the hydroplasty. The mean active range of motion improvement was as follows: flexion 28 degrees, abduction 42 degrees, internal rotation 22 degrees, and external rotation 26 degrees. There was no significant difference in outcomes between diabetics and nondiabetics or subjects with symptoms less than six months' duration compared with subjects with symptom duration greater than six months. At discharge, only two (3%) of the subjects reported persistent pain during sleep. The hydroplasty procedure combined with a therapy program is a successful treatment for idiopathic frozen shoulder.