Simulation for Reduction of Transverse Acetabular Fractures in Sawbones Models

PURPOSE: The transversely oriented fracture lines are very difficult to reduce during operations, even after clear exposure of the fracture site, in acetabular fractures. The purpose of this study is to verify the quality of reduction between the different subtypes (transtectal, juxtatectal, and infratectal) of transverse fractures. This study also determined the proper type of clamps to use and the proper zone for achieving accurate reductions in Sawbones models. MATERIALS AND METHODS: Six fractures in 3 different subtypes of transverse fractures were artificially created. Ten different reduction clamps were applied for reduction of the fractures. Twelve holes around the fracture were drilled for the maintenance of the clamps. The fracture displacements were measured at the extra-articular area and the intra-articular joint portion. The pictures of the intra-articular fracture displacements were taken by a camera and these were uploaded and analyzed by the TraumaCad® computer program (Brainlab). RESULTS: The reduction quality was poor in order of transtectal, juxtatectal and infratectal. The intraarticular opening was more prominent in the transtectal subtype. The safe zone, when giving consideration of the neurovascular bundles, was a quadrilateral surface of the ilium. Drill holes are useful for maintenance of the reduction clamps. Reduction clamps with points (Weber clamp) were the best for maintenance and accurate reduction. Regarding the concerns of placement of clamps, the middle to posterior combination was the best. The upper hole among the posterior holes in the ilium was the most likely to well reduce the intra-articular opening. CONCLUSION: Transtectal was the more complicated subtype in the aspect of reduction quality. The Weber type reduction clamp was the best for reduction by centrally located holes in the quadrilateral surface and posteriorly located iliac holes in transverse acetabular fractures. The upper hole, among the posterior holes in the ilium, was the best for reduction of the fracture displacements in the intraarticular portion of acetabulum.

Association of Bone Marrow Sphingosine 1-phosphate Levels with Osteoporotic Hip Fractures

BACKGROUND: Sphingosine 1-phosphate (S1P) has been discovered to be a critical regulator of bone metabolism. Very recently, we found that higher circulating S1P levels were associated with higher rate of prevalent osteoporotic fracture in human. METHODS: This was a cross-sectional study of 16 patients who underwent hip replacement surgeries. Bone marrow fluids were obtained during hip surgeries, and the S1P levels were measured using a competitive enzyme-linked immunosorbent assay (ELISA) assay. Bone mineral densities (BMDs) at various skeletal sites were obtained using dual energy X-ray absorptiometry. RESULTS: Among 16 patients, 4 patients were undergone operations due to hip fractures, and the others were done by any other causes. Bone marrow S1P levels were significantly lower in patients with hip fractures than in those without, before and after adjusting for confounding factors (P=0.047 and 0.025, respectively). We failed to demonstrate significant associations between bone marrow S1P levels and any BMD values (gamma=0.026-0.482, P=0.171-0.944). CONCLUSIONS: In conjunction with our previous findings, these suggest that the effects of gradient between peripheral blood and bone marrow, but not S1P itself, may be the most critical on bone metabolism.