First stem specifically designed for AMIS
The AMIStem has been developed to facilitate broaching and stem insertion when utilising the AMIS approach without compromising implant stability. Based on the clinical experience of straight, rectangular, cementless hip stems,[1,2,3,4] the AMIStem incorporates features which simplify the AMIS approach.
10 STANDARD sizes, from 0 to 9, with 135° neck-shaft angle
8 LATERALIZED sizes, from 1 to 8, with 127° neck-shaft angle
9 STANDARD sizes, from 0 to 8, with 135° neck-shaft angle
9 LATERALIZED sizes, from 0 to 8, with 127° neck-shaft angle
NECK
The mirror polished surface treatment minimises soft tissue damage and liner wear, making the AMIStem-H suitable for double mobility liners.
Increasing size by size to restore anatomy.
SHAPE
The triple tapered design provides good axial and rotational stability with optimal fixation with bone. [5,7]
The rectangular cross-section facilitates effective stability but also promotes the preservation of bone vascularisation, since the diaphysis is not completely filled. [2,3,4]
SURFACE TREATMENT
The horizontal and vertical macrostructures increase stability and enhance the contact surface area by 10-15%. [8]
TIP
The double tapered distal tip reduces the risk of stress peak in the diaphysis.
MATERIAL
AMIStem-H and AMIStem-H Collared are made of Titanium- Niobium alloy in accordance with ISO 5832-11. Their surface presents a 80 μm thick Hydroxyapatite (HA) coating after a superficial sand-blasting of 4 to 7 μm roughness.
The HA coating has chemical characteristics similar to that of the human bone which stimulates the bony ongrowth. [4, 9, 10, 11, 12]
SURFACE TREATMENT
The mirror polished surface does not cause cracks or gaps in the cement mantle. [6]
AMIStem-C is made of high nitrogen stainless steel, in accordance with ISO 5832-9 and has a mirror polished surface.
The anterior approach, strengthened by several years of clinical experience, is the only technique which follows a path both intermuscular and internervous and therefore reduces considerably the risk of damaging periarticular structures such as muscles, tendons, vessels and nerves.Medacta International is the world leader for educating and supporting surgeons in their pursuit of Anterior Minimally Invasive Surgery (AMIS).
Reference Centers, located throughout the world, provide the necessary AMIS educational experience and Medacta offers continuous support for surgeons, as well as constantly improving and developing the industries most specialised instrumentation platform.Using AMIStem you can enter Medacta International’s world of AMIS.
Discover:
Thanks to its unique design, AMIStem is the logical femoral stem for the AMIS approach:
CLINICAL EXPERIENCE OF STRAIGHT RECTANGULAR CEMENTLESS STEM
[1] Quadra cementless. 3 years follow up, Dr. Moreau, 2008. Data on file: Medacta
[2] 20 years of Zweymüller cement free hip endoprosthesis Jatros Orthopädie - Jahrgang 5 Dez. 1999 - ISSN 0941-4770
[3] Zweymüller K., 20 vears of Zweymüller hip endoprosthesis Hans Huber Verlag 2002 ISBN 3-456-8343 1-4 pp 29-39
[4] Bonnomet et al., Comportement d'un tige fémoral droite en arthroplastie totale primaire non cimentée de la hance chez les patients de moins de 65 ans Rev de Chir Orthop 2001, 87, 802-814
AMISTEM PROVEN STABILITY
[5] Heidelberg Lab-Report, Orthopädische Universitätsklinik Heidelberg, 2008. Data on file: Medacta
[6] Orthopaedic Research Laboratory Radboud University Nijmegen Medical Centre, Experimental assessment of the stability of the Cone stem relative to the AMIStem-C, April 2010. Data on File: Medacta
[7] Zweymüller K., 20 vears of Zweymüller hip endoprosthesis Hans Huber Verlag 2002 ISBN 3-456-8343 1-4 pp 11-25
[8] Data on file: Medacta
[9] Hardy et al. Bonding of Hydroxyapatite Coated Femoral Prostheses JBJS vol 73-B, No5, Sept. 1991.
[10] Hardy et al. Aspects Radiologiques de l’Arthroplastie Fémorale Revetue d’Hydroxyapatite et correspondence Histologiques Acta Orthop. Bel. Vol 59, Suppl I, 1993.
[11] Hardy et al. Projection d’Hydroxyapatite sur Prothèses Articulaires : Progrès ou Illusion ? Acta Orthop. Bel. Vol 59, Suppl I, 1993.
[12] Fraissinet P, Hardy D et al. Histological analysis of the bone-prosthesis interface after implantation in humans of prostheses coated with hydroxyapatite. The journal of Orthop Surg. 1993; 7(3): 246-53.
