Medacta Corporate | AMIStem

First stem specifically designed for AMIS

THE LOGICAL EVOLUTION
OF THE HIP STEM DESIGN

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.

BONE PRESERVING, AMIS FRIENDLY

  1. First stem specifically designed for AMIS
  2. Proven stability for both cementless and cemented versions in biomechanical tests[5,6]
  3. Reduced bone removal due to the optimised length
  4. Easier stem introduction due to the reduced lateral flare. Overall dimensions reduced by 33% compared to standard straight rectangular stems [8]

AMIStem-H

11 STANDARD sizes, from 00 to 9, with 135° neck-shaft angle
9 LATERALIZED sizes, from 0 to 8, with 127° neck-shaft angle

AMIStem-H Collared

Collared stems are available both in standard and lateralized option.
11 STANDARD sizes, from 00 to 9, with 135° neck-shaft angle
9 LATERALIZED sizes, from 0 to 8, with 127° neck-shaft angle

AMIStem-C

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]

AMIStem-H Collared is an additional option to the AMIStem System which is now even more flexible and able to include all patient needs and bone anatomies.

COLLAR
The collar width increases with size.
May assist in the prevention of subsidence in patients that present Dorr Type C bone.

NECK
The mirror polished surface treatment minimises soft tissue damage and liner wear, making the AMIStem-H Collared 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.

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.

ONE TRAY IS ENOUGH!

  • The same tray to implant AMIStem-H, AMIStem-H Collared and AMIStem-C.
  • Both standard and lateralised trial necks fit onto the broaches for a quick and precise trial reduction.
  • Offset broach handles available.
  • High quality sharp broaches for a precise preparation of the medullary cavity.
  • Optional monoblock motorised broaches available for use with femoral stem trials.
  • Dedicated AMIS instrumentation.

REDEFINING THR: THE AMIS SYNERGY

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:

  • The definitive MIS approach: AMIS;
  • Dedicated AMIS instrumentation;
  • The AMIS Mobile Leg Positioner: the original orthopaedic extension table included as part of the instrumentation that makes the surgery easier and reproducible;
  • The AMIS Education Program based on Medacta’s proven educational methods.

AMIS & AMIStem

Thanks to its unique design, AMIStem is the logical femoral stem for the AMIS approach:

REDUCED SHOULDER +
OPTIMISED LENGTH =
EASIER STEM INTRODUCTION 
THROUGH AMIS

 

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.