Variability Comparison Of Different Reference Axises To Tibia Posterior Slope

Objective：Tibia posterior slope is measured to provide osteotomy reference fortotal knee arthroplasty(TKA).Methods：Tibia and fibula full-length lateral radiographs of60knees(32adultpatients) with osteoarthritis (IV period) are shot and different reference lines are used tomeasure the medial tibia posterior slope angle in order to calculate the coefficient ofvariation and obtain the most stable measurement reference.At the same time,seek areasonable measuring reference on the short X-ray film.Results：The measured data with reference to ATC (tibia anterior cortical line) is(11.84±3.69)°,coefficient of variation (C.V)0.312,which is minimum on the tibia andfibula full-length lateral radiographs. Measured data with reference to ATC on the shortX-ray film(below articular surface10cm) is (11.93±3.53)°，C.V0.296.All measuringresults has a high correlation with MA,which is recommended by American KneeAssociation and can better explain the importance of tibia posterior slope inmechanical conduction.Compared with other reference axises,measured data withreference to ATC on the short X-ray film is statistically significant (P<0.05)except forATC on the long X-ray film and TCAA (P>0.05).Measurement values of variousmethods between the left and right side, sex, age difference are not statisticallysignificant(P>0.05).Conclusion：ATC on the short X-ray film,combined with the other measuringmethods, can be used as an important reference in osteotomy in order to improveprognosis of TKA.