Variability of distal femoral rotational landmarks of osteoarthritic knees under three dimensional CT observation

DOU Yong; TIAN Wei; LIU Jian; YANG De-jing; YIN Xing-hua

doi:10.3969/j.issn.1002-266X.2014.16.005

Abstract：Objective To observe the variability of distal femoral rotational landmarks of osteoarthritic knees .Meth-ods Seventy-five patients ( 112 knees ) who underwent total knee arthroplasty for osteoarthritis were chosen , including 92 varus knees ( varus group ) , 20 valgus knees ( valgus group ); and 34 patients ( 68 knees ) with stage Ⅲ necrosis of the femoral head were selected as the normal group .A retrospective analysis of three-dimensional CT reconstruction of preoper-ative data of the three groups were conducted , and the mechanical femoral tibial angle ( mFTA) , the anatomical lateral dis-tal femoral angle (aLDFA), the anatomical medial proximal tibia angle (aMPTA), the femoral posterior condylar angle (PCA), condylar twist angle ( CTA), and the angles between Whiteside line and the PCL ( posterior condylar line, WPCL), SEA (surgical epicondylar angle, WSEA), CEA (clinical epicondylar angle, CEA) were measured.Results The mFTA, WPCL, WSEA, and WCEA in the varus group were larger than those of the normal group , while the aMPTA, PCA, and CTA were smaller .The aMPTA, PCA, CTA, WPCL, WSEA, and WCEA in the valgus group were larger than those of the normal group, while the mFTA and aLDFA were smaller than those of the normal group (all P<0.05).The PCA in the varus group was negatively correlated with mFTA ( r=-0.555 ) , and positively correlated with the aMPTA (r=0.450); the PCA in the valgus group was negatively correlated with the mFTA (r=-0.614) and aLDFA (r=-0.719), all P<0.05.When mFTA gradually increased to 15 °in the varus group, the PCA and CTA decreased , all P<0.05.Conclusions The Whiteside line had a lateral shifting trend in the osteoarthritic knees .The PCA, and CTA were smaller in the varus knees and were correlated with mFTA and aMPTA;the PCA, and CTA were larger in the valgus knees and were associated with mFTA and aLDFA .