Taper Wedge Stem

The history of tapered wedge (TW)-type stems is long; the representative stems of the first generation are the TRI-LOCK stem (DePuy, Warsaw, IN, USA; Fig. 33.1a) and the Taperloc stem (Zimmer Biomet, Warsaw, IN, USA; Fig. 33.1b), which were developed in the early 1980s. The standard TW-type stems initially introduced in Japan were the Linear Hip System (approved and marketed in 1999; Fig. 33.1c) by SENKO MEDICAL INSTRUMENT Mfg. CO., LTD. and the CTiIITM (Corin, Cirencester, UK) (approved in 1996 and marketed in 2003; Fig. 33.1d). Later, in 2012, the short TW-type stem was introduced. The fixation concept is designed to fit the tapered medial and lateral cortical bone at the proximal metaphyseal end with the tapered coronal cross-section of the stem and to obtain rotational fixation with a flat shape with a thin anteroposterior width without a collar.