Biochemical markers of bone metabolism in bone marrow edema syndrome of the hip.

The aim of this study was to evaluate bone metabolism in patients with bone marrow edema syndrome of the hip. In 37 consecutive patients undergoing core decompression of the femoral head, biochemical markers of bone metabolism were measured in aspirates from cancellous bone and in samples obtained simultaneously from peripheral blood. The diagnosis was made by means of radiographs, magnetic resonance imaging (MRI), and core biopsy specimens. Undecalcified microtome section were available for histopathological evaluation. Bone specific alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen Type I N-terminal propeptide (PINP), and C-terminal cross-linking telopeptide (ICTP) were studied. Mean serum levels of analytes were 13.1 ng/mL (OC), 11.2 ng/mL (bone ALP), 4.7 ng/mL (ICTP), and 38.8 ng/mL (PINP). In samples obtained from cancellous bone, mean concentrations of all markers were elevated significantly. The mean bone to serum ratios for bone ALP and OC were 14.1 (P=0.005) and 4.1 (P=0.002), respectively. For collagen Type I metabolites, bone to serum ratios averaged 16.3 (P=0.001) for ICTP and 9.6 (P=0.001) for PINP. Markers of bone formation correlated with each other in serum as well as in aspirates from cancellous bone. Elevation of all markers in aspirates from cancellous bone pointed at increased bone turnover, which correlated with histopathological findings of irregularly woven bone, osteoid seams, and lining cells. Mean serum concentrations of all markers, however, were not different from healthy individuals and thus did not provide any useful clue in the diagnosis of this disease. The lack of osteonecrotic regions in our specimens, the marked increase of bone turnover in samples obtained from edematous lesions, and the fact that none of the patients developed osteonecrosis of the femoral head so far seem to further support the contention that transient bone marrow edema syndrome of the hip is a distinct clinical entity.