Experimental study of femoral head reshaping surgery for treatment of collapse stage of femoral head necrosis

[Objective]To assess the effect of femoral head reshaped surgery for treatment of collapse stage of femoral head necrosis in dogs.[Method]Experimental femoral head necrosis models were made in unilateral femoral head of 10 adult dogs.Under anaesthesia,the necrotic mass in the collapse area of femoral head necrosis was fully curreted through a passage from femoral neck to callapse head,a self-designed ball-tube apparatus enveloped with a cannula was put into under the curreted area,normal saline injected to fill the ball in the collapse cavity till the collapse area forced to reshape a spherical femoral head;After withdraw of normal saline,bone cement of calcium phosphate was injected into the reshaped cavity to maintain the reshaped femoral head.Finally the ball-tube apparatus was taken out.Preoperative and postoperative X-ray film of femoral head were taken to evaluate the reshaping.Femoral heads of experimental side and normal femoral head of contralateral side as control were take out after the dogs sacrifice for biomechanical examination of maximum compression strength.[Result]In experimental group,as compared to preoperative radiograms,the postoperative radiograms of 10 dogs showed the curreted necrotic cavity was fully filled with bone cement and reshape was maintained.The maximum comopression strength of femoral heads of control group was 49 Mpa to 60 Mpa,and that of experimental group was 49~54 Mpa with no statistical significant difference.[Conclusion]Femoral head reshaping surgery may be a method of choice for treatment of collapse stage of femoral head necrosis in experimental animal,but long-term effect should be evaluated thereafter.