CRONO THR

CHRONO, new hip prosthesis of completely Italian design and manufacture, cutting-edge technology of human derivation, designed to overcome the limits of the prostheses currently on the market and improve clinical performance in terms of ease and safety of implantation (thanks to a new instrumentation), primary stability, speed of osseointegration, long life thanks to the reduced wear of the polyethylene particularly useful in young patients, easy replacement of the polyethylene element subject to wear, greater joint excursion, greater resistance to dislocations.

In the dogs, unlike humans, hip replacement is also performed in young subjects due to severe forms of hip dysplasia that cannot be treated in other ways. With the increase in the number of prostheses implanted in young and particularly active patients, it is of fundamental importance on the one hand to prevent and reduce biomechanical complications such as joint instability and postoperative dislocation and on the other to ensure a long duration of the plant by limiting mechanical wear to a minimum.

The Arthemidex Chrono prosthetic implant has been studied and designed with these specific objectives: rapid osseointegration, long life, reduced wear, better range of motion, greater resistance to dislocations.

Stem and Cup with Trabecular Structure Integration Interface

The trabecular structure is designed to ensure maximum primary stability and the fastest and best osseointegration possible to date.

The trabecular structure of the CHRONO prosthetic system mimics that of bone tissue with a porosity and modulus of elasticity in compression, comparable to that of cancellous bone.

The additive manufacturing techniques with which components can be produced by superimposing layers starting from a 3D CAD file, have allowed the realization of the porous material in continuity and completely integrated with the underlying solid structure. It is therefore not a coating but a continuous structure with which the prosthetic components of the CHRONO hip prosthetic system are made.

The presence of the trabecular structure increases the primary stability and the forces at the interface with the cancellous and cortical bone by improving the biological fixation and loading of the bone tissue surrounding the prosthetic components. The high primary stability guaranteed by the trabecular structure makes the additional primary stabilization obtained through the use of screws or other similar systems non-functional and unnecessary.

Chrono femoral stem

The femoral stem entirely made with the additive technology of selective fusion by laser beam of Ti6Al4V titanium powder (ISO 5832/3, ASTM F1472, ASTM B348), is characterized by its quadrangular section shape that gives resistance to torsion ensuring stability primary of the implant and its osseointegration. The tapered and blunt diaphyseal region favors wedging into the medullary canal and centering the stem. The absence of sharp edges eliminates the risk of concentrating efforts on the distal cortices.

From a FEM (Finite Element Analysis) analysis performed on the CHRONO femoral stem, it is found that in the most stressed area (femoral neck), the stresses acting on the resistant section are considerably lower than the yield strength of the material.

Product features: 12 SIZES

Dual mobility Chrono cup

The concept of double mobility involves the use of an acetabular cup within which a movable insert is articulated, where in turn the head of the femoral stem is articulated.

The dual mobility cup, introduced in human medicine to reduce the risk of dislocation, is based on the principle of using a larger diameter of the femoral head to improve implant stability.

The goal of the double joint is essentially to provide the maximum possible joint excursion using large heads, thus reducing the risk of dislocation, but at the same time reducing the wear that would occur using large heads.

In addition, the dual mobility system allows greater flexibility of angulation during installation while still guaranteeing flat functionality and stability with a greater range of motion than traditional systems.

Chrono acetabular cup

Entirely made with the additive technology of selective melting by laser beam of Ti6Al4V titanium powder (ISO 5832/3, ASTM F1472, ASTM B348), at the equatorial level it is characterized by the presence of the trabecular structure which allows to gain primary stability and secondary biological fixation through bone regrowth.

The cup has a hemispherical geometry with polar crushing of the cup, which generates an equatorial distribution (with slight oversizing) of the forces acting on the cup and favors the stabilization of the implant increased by the surface characteristics in contact with the host tissue.

The polar flattening allows the insertion of the cup which can advance until contact with the host tissue at equatorial level and the achievement of primary stability.

The inner surface of the cup is smooth and ensures perfect sliding of the special polyethylene insert. The thin ceramic coating in titanium nitride (TiN) obtained using the cathode arc (PVD) physical vapor deposition technique ensures greater hardness of the joint surface and improves wear resistance.

Product features: 6 SIZES

Chrono insert

The insert is made of very high molecular weight polyethylene (UHMWPE) (ISO 5834/2).

Spherical in shape congruent with the inside of the cup, it allows perfect articulation. The press-fit head locks into the insert by means of a special antiluxation retentive mechanism.

Standard head

The Chrono system is completed with standard spherical heads made of medical steel compliant with ISO 5832/9.

The geometric characteristics comply with the ISO7206-2 standard. The fixing to the stem is done by means of a cone-morse.

Extra long heads are available which allow for greater neck extension.

Product features: 4 SIZES

BIOMECHANICS

The dual-mobility acetabular component increases the range of motion of the hip (ROM). The system moves through the design of two joints. In the first joint, the head is "hooked", but mobile, inside the polyethylene (PE), and takes on the mechanical role of a bearing.

The overall ROM of the dual-mobility Chrono system is given by the movement of the head of the femoral stem that articulates in the movable polyethylene insert increased by the movement of the movable insert that begins to articulate with the metal cup only when the neck of the femoral stem enters conflicting with the insert by rotating it inside the TiN-coated cup surface.

• Chrono Prosthetic System

• Chrono Prosthetic Leaflet