EMPERION◊ Design and Technology
Hip anatomy varies from patient to patient. The EMPERION Modular Hip System has been designed to address the different anatomical variants that a surgeon may encounter during either primary or revision hip arthroplasty.
The EMPERION Modular Hip System is designed with a polished cylindrical stem, optimized neck geometry, progressive offset options, distal flutes, coronal slot and a polished bullet tip. The EMPERION stem design is intended to promote stem stability while minimizing stress-shielding, micromotion, stiffness and thigh pain.
The sizing and terminology of the EMPERION stems were planned with simplicity in mind. The instruments are designed to allow you to implant the same size stem as the last reamer used. Thus, if the surgeon reams to 15 millimeters then a size 15 stem should be implanted. Each stem is oversized by 0.5mm as compared to the final reamer size in order to achieve an appropriate press-fit. The entire technique and procedure is then based off the distal stem diameter. The EMPERION stems are available in sizes ranging from nine to 23 millimeters in two-millimeter increments. For most stem sizes, there are three stem lengths available: primary, standard revision, and long revision. Each primary stem has two different offsets available. However, because of the special needs in revision procedures, the revision stems are only available with the high offset option. In addition, the revision stems have a neutral proximal body option and a +10 calcar replacement option. The long revision stems have a neutral option, a +10, and a +20 calcar replacement option available.
Note: The primary length stems can be used in revision surgeries, if you determine it is appropriate. 2
Each sleeve is designed with a tapered porous surface. The outer porous coating is covered with a hydroxyapatite (HA) layer, also known as POROUS PLUS◊ HA.
Although modularity increases the available intraoperative options, many times it also increases the system complexity. However, the EMPERION Modular Hip System keeps it simple. This simplicity continues with sleeve options and terminology. The EMPERION system has two sleeve length options available: a 40mm sleeve length (standard) and a 60mm sleeve length (tall). The tall sleeve extends further distally into the femoral canal thereby achieving fixation over a larger area that extends into the femoral diaphysis. This may be useful in revision situations where bone loss prevents adequate fixation from being achieved in the more proximal femur.
POROUS PLUS HA coating
POROUS PLUS HA coating uses RoughCoatTM porous coating technology with an HA application.
RoughCoatTM porous coating
The sintered-bead RoughCoatTM porous coating, manufactured from commercially pure titanium, has demonstrated several advantages over plasma-sprayed or simple textured surfaces:
• The irregularly layered beads of the RoughCoatTM porous coating enhance the 3-D interlock of the prosthesis.
• Studies have shown stems with sintered beads result in two to three times less polyethelene wear in the acetabular component than stems with plasma sprayed surfaces. 1
• Sintered beads have been shown to have greater bond strength than plasma-sprayed surfaces or diffusion bonded wire surfaces. 2,3,4
Mechanical testing has shown the optimal pore size for bone ingrowth to be between 50 and 400 microns. 5 The pore size of the RoughCoatTM porous coating on the EMPERION Modular Hip System is 200 microns.
For detailed information download the EMPERION Design Rationale.
5. Aldinger P. Insertion force study of the EMPERION and DePuy S-ROM modular hip system distal models using finite element analysis. Internal Smith & Nephew Data. 2006 May.
1. Bal BS, Vandelune D, Gurba DM, Jasty M, Harris WH. Polyethylene wear in cases using femoral stems of similar geometry, but different metals, porous layer, and modularity. J Arthroplasty. 1998 Aug;13(5):492-499.
2. Smith & Nephew Data. Bead pull-off testing of Ti-6AI-4V. In-House Test Data Summary. 1993 Feb.
3. Anderson P, Levine D. Adhesion of fiber metal coatings. ASTM STP 953: Quantitiative characterization and performance of porous implants
for hard tissue applications, J Lemons, ed, ASTM Special Publication, 1987.
4. Robinson T, Bearcroft J. Smith & Nephew Advanced Technology Report. 1993 May.
5. Bobyn JD, Pilliar RM, Cameron HU, Weatherly GC, Kent GM. The effect of porous surface configuration on the tensile strength of fixation of
implants by bone ingrowth. Clin Orthop Relat Res. 1980 Jun;(149):291-298.