Abstract
Starting in 1977 a new cemented stem made of titanium alloy (with vanadium) was designed regarding some principle: rectangular shape, smooth surface covered with thin layer of titanium oxide, filling the medullar cavity. As a consequence: a thin layer of cement. It was designed with a collar. Initial Cementing technique used dough cement, vent tube and finger packing; then we applied cement retractor low viscosity cement and sometimes Harris Syringe. At the moment we went back to initial technique plus a cement retractor made of polyethylene. Many papers looked at long term follow up results depicting about 98 to 100 percent survivors at 10 years and 95 to 98% at 20 years (Hernigou, Hamadouche, Nizard, El Kaim).
Clinical as well as radiological results are available.
Radiological results depicted some radiolucent lines that appeared at the very long term. They could be related to friction between the stem and the cement. As advocated by Robin Ling, he called “French paradox” the fact that if a cemented prosthesis is smooth and fills the medullary cavity, long term excellent results could be expected.
This was the case with stainless steel Kerboull shape, the Ling design (Exeter)and the Ceraver design.
The majority of these stems were implanted with an all alumina bearing system. And in some occasion, when revision had to be performed, the stem was left in place (108 cases over 132 revisions)
Our experience over more than 5000 stems implanted is outstanding (see figure 1: aspect after 30 years).
Discussion other experience with cemented titanium stem were bad (Sarmiento, Fare). We suspect that this was related either to the small size of this flexible material, or to the roughness of its surface.
If one uses titanium cemented stem it must be large enough and extra smooth.
