Experimental Study For The Treatment Of Early Femoral Head Necrosis Using Lantern-shaped, Autograft Loaded Screw

Purpose: Femoral head necrosis is a disease that it is quite uncommon and difficult to treat. No consensus has been reached with regard to the early treatment of the disease until now at home and abroad, and the eventual goal is to delay or avert the total hip replacement for the treatment of the disease. The purpose of the study is to explore the efficacy in the treatment of the early femoral head necrosis using our self-designed, lantern-shaped auto-graft loaded screw, combined with traditional core decompression procedure.Materials and methods:Twenty-seven goats whose necrosis model was induced were involved in our study. Three of them were given the very necrosis model evaluation according to the literature described and the other was divided into three groups randomly. Eight goats were in each group. No intervention was carried out in group A. Core decompression was given to goats in group B. Lantern-shaped, loaded auto-graft screw was fixed in the femoral head of the goats in group C. X-ray and MRI were given to goats in group A at4,8,16weeks after the establishment of the model. X-ray and CT scans were carried out on goats in group B and C. Half of the goats were sacrificed to harvest the sample to observe the pathological results at8weeks. Biological test and analysis were given to the samples harvested before the pathological observation. All the data involved in the study was calculated utilizing the software of SPSS13.Results:It was established by the pathology of the femoral head necrosis after the model was made. Classic necrosis characteristics taking on pathology and radiography were found at eighth week after establishment of the model in goats in group A. At sixteenth week, severe traumatic hip arthritis occurred in one goat in group A. While no hip arthritis happened in group B and group C at sixteenth week after the second operation. We just observed variation of stiffness or inhomogeneous microscopic structure in the surface of the femoral head then. Surface of femoral head, density, and mechanical characteristic were almost normal in goats in group C at sixteenth week. It was shown pathologically that continuous trabecular bone walked through the cage and new bone was formed in lantern-shaped cage in goats in group C at sixteenth week. However, quantities of fibrous tissue existed pathologically in goats in group B at sixteenth week. Biological tests showed that compressive strength per unit exerted on femoral head axially in group A was significantly higher than that in group B and group C. And the strength in group B was also significantly higher than that in group A.Conclusions:Core decompression combined with lantern-shaped, auto-graft loaded screw almost uniformly delays or arrests the progression of the disease before articular collapse, and it could help obtain the balance between bone resorption and new bone formation, strengthen structural mechanics of the femoral head, provide structure support of articular cartilage. The lantern-shaped, auto-graft loaded screw that we have designed by ourselves combined with the animal study might make a guide on our selection in the treatment of early femoral head necrosis using this screw support device. But the long-term clinical efficacy still needs to be explored.