IMPORTANCE OF A THIN CEMENT MANTLE - AUTOPSY STUDIES OF 8 HIPS

0The question whether thin cement mantles around cemented femoral comp onents led to an increased frequency of cracks in the cement was asked . Microscopically, multiple cross sections of eight femurs retrieved a t autopsy from clinically successful total hip replacements after prol onged in vivo service containing well fixed Harris Design 2 cemented f emoral components were studied. None of the components were loose by r adiographic criteria, All were fixed solidly when loaded in vitro in s imulated stair climbing and gait, as assessed by high resolution micro motion sensors, The specimens were sectioned transversely at 5-mm incr ements. The cross sections were examined under a dissecting microscope at x100. A thin mantle arbitrarily was defined as a mantle of less th an 1 mm in thickness. The analysis of the contact radiographs showed t hat the routine anteroposterior and lateral radiographs underestimated the prevalence of thin cement mantles and mantle defects. Although ov erall on all the cross sections 9% of the aggregated cement mantles wa s classified as having thin cement, 92 of the 101 cement cracks occurr ed in areas of the mantles that were less than 1 mm thick.