Dynamic Hip Screw For The Treatment Of Postoperative Intertrochanteric Femur Fractures Between The Angle Of Inclination Change Related Risk Factors And Intervention Means Of Clinical Research

Objective:To discuss the relationship among the postoperative change of the angle of inclination(AI) and preoperative fracture type,the relevant management,postoperative bone loss after treating intertrochanteric femur fractures(IFF) with Dynamic Hip Screw(DHS).After following up, the possible AIuses of AI loss have been demonstrated,and according to them the intervention measures to prevent or reduce the occurrence have been proposed for clinical reference.Methods:Sixty IFF(Evans type Ic) cases of our hospital from January 2004 to June 2005 were randomized to group A,B,C or D,all of which were treated with DHS.The medial proximate of the femur were not reconstructed in Group A and reconstructed in Group B.On the basis of group A,the calcium and vitamin D₃ were added into the treatment in group C.In group D,the calcium and vitamin D₃ were also used on the basis of group B.The postoperative bone mineral density(BMD),AI,the healing time and the function of the affected limbs were compared and analyzed.Resluts:Sixty cases of patients were followed up for one year,and the average healing time is 18.2 weeks(group A 20.2 weeks,group B 19.3 weeks, group C 17.8 weeks and group D 15.8 weeks).There was no significant difference between group A and B(P＞0.05).The healing time of group C and D were shorter than that of group A and B(group A and B vs.group C P＜0.05;group A and B vs.group D P＜0.01).It showed that group C and D were better than group A and B,and group D was the best.Determining the BMD of all groups,the values of one month after operation descended, and group A and B were significantly lower than group C and D(P＜0.05). The BMD of three months after operation have been improved,and group C and D have been almost recovered to the level of pre-operation,faster than group A and B.After six months the BMD of group A and B were still lower than the level of pre-operation,but the BMD of group C and D have reached or got close to the normal level.Compared with group A and B, the BMD of group C and D increased rapidly.The measurements of AI of the affected limbs shown that the average AI of the four groups didn't change one month after operation(P＞0.05).After three months,the AI of group A and C changed significantly greater than that of group B and D(P＜0.01).After 6 months,the AI of all groups were unchanged,and equal to that of three months after operation.Assessing the function of the affected hip according to the Harris score,the average rate of excellent and good results was 85.0%,80.0%in group A,86.7%in group B,80.0%in group C and 93.3%in group D.The total curative effect was satisfied. The rate of excellent and good results of group B and D was higher than that of group A and C,and group D was the best.Conclusion:In treating IFF,DHS is one of the best choices of the extramedullary fixation system because of the reliable mechanical stability properties.After DHS fixation,bone loss in the region trochanterica is serious,and may result in osteoporosis.So reconstructing the medial structure of the femur can be effectively restored the anatomy of the proximal femur,and using the calcium and vitamin D3 can improve bone quality.The combination of these two methods can reduce occurrence of AI changing after operation,shorten the healing time of the fracture,and regain satisfyingly the function of the hip.