Introduction: Bone marrow edema (BME) is a common cause of pain in the knee with restricted treatment options. The authors performed a double-blind, randomized, active-controlled study in order to explore the clinical effects of the prostacyclin analog iloprost (Schering AG, Germany)

Materials and Methods: Forty-one patients with painful bone marrow edema associated with osteonecrosis, osteoarthritis, bone bruise or axis deformities were evaluated. Patients were randomized either to iloprost (n=21, 15 male, 6 female; mean age 53 years) or to Tramadol (n=20, 12 male, 8 female; mean age 51 years). An individual dose adjustment was allowed within the range of 100–300 μg of iloprost, and 100–300 mg of Tramadol. The treatment duration was 4 weeks. The treatment period was followed by an 8-week treatment-free follow-up. During and after treatment, full weight bearing was allowed as tolerated. Efficacy of treatment was assessed by 10 cm visual analog scales for pain at rest and on exertion, Larson’s knee score, and magnetic resonance imaging.

Results: The results are presented below.

These clinical effects were sustained over the entire follow-up. At the end of study, 53% of iloprost patients showed healing of at least one BME affected bone as compared to only 19% of Tramadol patients. Regression of subchondral lesions occurred in 4 iloprost patients. No serious adverse events occurred; however, three Tramadol patients discontinued the treatment prematurely due to adverse events.

Discussion: The authors conclude that the oral application of the vasoactive drug iloprost results in substantial treatment effects on pain relief and joint function improvement. These effects were similar for iloprost and Tramadol. Iloprost treatment was associated more often with BME regression than Tramadol. Oral iloprost may offer a new and safe treatment option for patients with painful BME.