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.

Introduction: The purpose of this study was to compare two methods for the quantification of bone marrow edema (BME) of the knee.

Materials and Methods: Forty-one patients with Bone Marrow Edema (BME) of the knee due to osteonecrosis, osteoarthritis, bone bruise or stress were included in the study. Coronal STIR images of the affected knees were obtained using either a 1.0 Tesla or a 1.5 Tesla Magnetic Resonance (MR) scanner. To monitor the BME’s progression, every knee was examined twice at a 3-month interval. Size and signal intensity of BME were semi-quantitatively assessed in consensus by two radiologists and two orthopaedic surgeons. Independently, size and signal intensity were calculated using a new computer assisted method based on grey value analysis and calculation of a threshold value between normal and edematous bone marrow. The results of the semi-quantitative method were correlated with those of the computer assisted method.

Results: The correlation coefficient was 0.89 (ìstrongî) for BME size and 0.72 (ìmedium to strongî) for BME signal intensity. For the progression of size and signal intensity, correlation coefficients of 0.78 (ìstrongî) and 0.67 (ìmediumî) were found.

Conclusion: Good correlation between semi-quantitative and quantitative methods of assessment of both size and intensity of BME was found. While the computer assisted method is time-consuming and reserved for scientific purposes, the semi-quantitative method is simple and offers to the experienced examiner a fast and simple means for BME recording in clinical practice.

Bone-marrow oedema syndrome (BMOS) of the hip gives a characteristic MRI pattern, in association with severe pain, non-specific focal loss of radiological density and a positive bone scan. In our MRI-controlled study, nine patients with non-traumatic BMOS in ten hips all had core decompression. Bone-marrow pressure measurements and intraosseous venography in five cases showed pathological values. All patients had immediate relief of pain, with return of MRI signals to normal after three months. Regular review was continued for at least 24 months with serial clinical radiological and MRI assessment. At a mean follow-up of 33 months all patients remained free of pain with normal radiographs and MR scans. The histological evaluation of undecalcified sections obtained from eight core decompressions confirmed the presence of bone-marrow oedema, with necrotic and reparative processes involving bone and marrow similar to those of early avascular necrosis but with no evidence of 'osteoporosis'. These findings support the assumption that BMOS may be the initial phase of non-traumatic avascular necrosis. In most patients BMOS will have a self-limiting course, but the duration of symptoms may be reduced by core decompression treatment.