Arthroscopic treatment of iliopsoas impingement (IPI) after total hip replacement

The purpose of the study was to present our arthroscopic surgical technique and the results in patient with an iliopsoas impingement (IPI) syndrome after a hip replacement. Between 1999 and 2011, 35 patients with the clinical picture of an IPI after total hip replacement were diagnosed and treated arthroscopically. The age was ranged from 58 to 82 years. All patients underwent conservative treatment for at least 6 months without success. The indication for the arthroscopic procedure was the failure of the conservative therapy as well as typical clinical signs as painful hip flexion, a positive local anesthesia test and radiological evidence of the presence of a prominent anterior acetabular component. The arthroscopic treatment was performed in all patients with anterior capsulotomy and partial capsulectomy of the hip joint. After identification of the pathology an arthroscopic release of the iliopsoas tendon in the region of the proved lesion was performed. The average follow-up period was 3.6 years (6 months to 12 years). In all patients osseous integrated acetabular components were found. In six cases there was a surface replacement, in three cases it was a cementless screw-in cup and in the other three cases it was a cementless modular press-fit cup. 8 out of 12 patients suffered from a hip dysplasia with a secondary osteoarthritis. After establishing an anterior capsular window arthroscopically, the iliopsoas tendon could be visualized in all cases. In addition to multiple local tendinitis all patients already showed mechanical limitation with partial rupture of variable extent in the iliopsoas tendon. During the arthroscopy the lesion was detected at the level of the anterior prominent acetabular component as well as distal to it. 10 out of 12 patients reported immediately after postoperative mobilization that the typical preoperative complaints have disappeared. Two patients still had residual pain. In one of those patients this was relieved by the time of the follow-up examination. Clinically a temporary weakness of hip flexion in the first days of the postoperative period was detected. In the first follow-up 6 weeks later there was no evidence of weakness in any of the patients. An arthroscopic release of the iliopsoas tendon with evidence of iliopsoas impingement after total hip replacement gives predictably good results. A clinically relevant weakness of hip flexion is not expected after the procedure.