The Comparison Of TAD Measurement In Intertan For Intertrochanteric Fracture

Objective: A research and comparison on TAD(Tip-Apex Distance)measurement after intertrochanteric fracture fixed by a new generation of proximal nailInterTan,confirming the association between the TAD and cut-out of the InterTan lagscrew from the femoral head.Methods: We divided125intertrochanteric fracture patients fixed by InterTaninto A、B、C、D、E five groups(25patient in every group) randomly in First AffiliatedHospital of Dalian Medical University orthopedic trauma department from June2009toJune2012,use five different methods to measure the TAD value on the day,6weeks,12weeks,24weeks,36weeks after sugery. TAD(A): Regard the lag screw andcompression screw as a combine screw, measure the distance from the apex of combinescrew central axis line to the apex of femoral head. TAD(B): Define the InterTan apex Bas a point of intersection between combine screw central axis line and the line from thelag screw apex to the compression screw apex. TAD(B) is the distance when connectingthe apex B to the apex of femoral head. TAD(C): Connect the apex of lag screw to theapex of compression screw, make a vertical line from the midpoint of the line to thecombine screw central axis line,define it as InterTan apex C. TAD(C) is the distancewhen connecting the apex C to the apex of femoral head. TAD(D): Connect the apex oflag screw to the apex of compression screw, define the midpoint of the line as InterTanapex D, TAD(D) is the distance when connecting the apex D to the apex of femoralhead. TAD(E): Connect the apex of lag screw to the apex of femoral head, define thedistance as TAD(E). Mesure the mean TAD(A)、TAD(B)、TAD(C)、TAD(D)、TAD(E)after surgery separately，analysis with completely randomized design data analysis ofvariance. Compare the InterTan lag screw cut out between the TAD>23mm group (92cases) and TAD <23mm group (n=33) with t test. All data was analyzed by SPSS17.0,P <0.05was considered statistically significant, P <0.01was considered notablestatistically significant. Results: The mean TAD of five groups were compared by SPSS17.0withcompletely randomized design data analysis of variance shows that there is also nostatistically significant(P＞0.05).There is3InterTan cut-out cases in the TAD>23mm group, and2cases whenTAD＞25mm(TAD=26.0mm、28.1mm),1case when TAD＞30mm(TAD=30.3mm). TheComparison between InterTan cut-out group and no cut-out group shows that there isstatistically significant(P＜0.05).Conclusion:TAD affect the the InterTan lag screw cut-out, when TAD＞23mm,the greater the TAD value, the greater possibility of cut-out.There is no differents whenTAD(E) compare with other measurements,so TAD(E) can be used as a simplifiedmethod to assess Intertan TAD.