The hip prosthesis stems of the LCU System follow the concept of a straight stem with tapered lateral shoulder and an osteoconductive coating.4 The straight profile with rectangular cross-section provides the implant with proximal stability. The HX coating promotes bone integration.1 Two types of stem are available for the purpose of adaptation to the patient’s anatomy2:
The following materials and coatings are used for the hip prosthesis stems of the LCU System:
A tapered distal end reduces distal bone contact and facilitates introduction of the stem into the medullary canal.1,5,6
The self-anchoring shape of the stem is an optimization of the standard design in the proximal region in order to promote mechanical stability and favorable load transmission to the bone surface. The horizontal ribs in the proximal section of the stem serve to counteract subsidence of the stem and to promote primary stability. The distal region has vertical ribs to counteract the rotational forces.7
Meta-diaphyseal support and fixation provided by a large medial curvature with a 100 mm radius of curvature for anatomical adaptation is the prerequisite for primary and secondary stability.
The primary stability of the implant is additionally enhanced by the characteristic metaphyseal V-shape, while the rectangular cross-section neutralizes torsion forces.1,5
The flat, tapering prosthesis neck allows a large scope of movement between prosthesis stem and acetabular cup.2 The 12/14 taper is designed for the use of modular LINK prosthesis heads made of ceramic or metal with various lengths and diameters.
Furthermore, the highly polished neck region reduces abrasion in the event of unintentional contact with the acetabular cup9.