Medacta Corporate | AMIS (Anterior Minimally Invasive Surgery)

More than an
Anterior Approach

Procedures performed


Total Hip Replacement is a safe and clinically proven surgical procedure.
Implant manufacturers and orthopaedic surgeons have been working in partnership on Total Hip Replacement for many years, the former improving and mastering the materials used, and the latter refining the implantation techniques.

Medacta International is committed to becoming a preferred partner for new technologies such as in total hip arthroplasty through the minimally invasive anterior approach (the AMIS approach = Anterior Minimally Invasive Surgery).

A true Minimally Invasive Surgery (MIS) is characterized by a reduced skin incision and the preservation of muscles and tendons.

The anterior approach follows the principles of MIS. Other approaches advertised as minimally invasive (posterior, lateral, or double incision approach) are associated with muscles and/or tendons injury and thus are only reduced skin incision techniques.

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 to damage periarticular structures such as muscles, tendons, vessels and nerves.

For this reason the AMIS approach is the ideal approach for atraumatic surgery which is fundamental for a fast recovery.



The preservation of all muscles ensures:

  • Shorter stays in the hospital.
  • Shorter rehabilitation.
  • Reduced risk of dislocation.
  • Immediate post-operative muscle tone preservation.
  • Decreased post-operative pain.
  • Less blood loss.
  • Faster return to daily activities.
  • Reduction of scar tissues.


Thanks to the AMIS technique risks are decreased when compared to a standard technique both in the short and in the medium term.

In fact, it has been demonstrated that:
After Total Hip Replacement, trochanteric soft tissue abnormalities may be associated with residual trochanteric pain and limping, in other words with symptomatic patients. Defects of the abductor tendons and fatty atrophy of the gluteus medius and the posterior part of the gluteus minimus muscle are rare in asymptomatic patients.[1,2]
The use of the anterior approach for primary Total Hip Replacement shows, at one year after surgery, better functional results and a smaller extent of injury in the muscle and tendon units compared to other approaches.[3,4]

This means: the AMIS approach shows that at one year after surgery there is less symptomatic muscle degeneration compared with other approaches.

Therefore the AMIS technique should provide better results in the short and medium term and an improved long term quality of life for your patients.

In addition, the preservation of muscle and soft tissue should prove advantageous in revision


Specific instrumentation and a leg positioner are required for the AMIS success.
Medacta, in collaboration with the orthopaedic world, developed a set of instruments and the AMIS, with the objectives of:

  • Reducing errors
  • Reducing the learning curve
  • Simplifying the implementation of this technique

Medacta offers a choice of instruments for the AMIS:

AMIS Charnley

A modified Charnley retractor with hooks designed for ideal exposure of the operative site, especially the acetabulum.

AMIS Hohmann

The “femur lifter” with an atraumatic tip ideally exposes and raises the femoral stem.

AMIS Starter

The curved Starter rasp is used to open the femoral medullary canal, for correct rasp positioning.

AMIS Cup​ Impactor

An offset impaction handle is used for implanting the cup in an atraumatic manner.

AMIS Broach Handle

This rasp handle gives a firm hold during femoral preparation, decreasing the risk of malpositioning of the stem.

Offset Reamer Handle

The offset reamer handle provides high-quality reaming in a reduced operative site.


A Medacta patented design complying with ISO standards, the AMIS Mobile Leg Positioner is not a complete table but just an extension which easily adapts to any operating table.

What for?
Simplifying surgery during AMIS implantation:

  • Easy extraction of the femoral head, and optimum exposure of the femur.
  • Reduction aid and possibility of testing without removing the shoe.
  • Multiple tasks (traction, flexion, hyper-extension, rotation, adduction).
  • Easy handling by one person.
  • Reduced surgical team.

AMIS Mobile Leg Positioner makes everything easier and reproducible!


[1] Abductor Tendons and Muscles Assessed at MR Imaging after Total Hip Arthroplasty in Asymptomatic and Symptomatic Patients. C. Pfirmann et al., Radiology 2005, 235: 969-976.
[2] MR Imaging of the abductor tendons and muscles after total hip replacement in asymptomatic and symptomatic patients. PD Dr. C. Dora, EFORT 2007.
[3] Der anteriore Zugang für die minimal-invasive HTEP. PD Dr. C. Dora; Leading Opinions Sept 2006, 1/2006.
[4] Soft-tissue changes in hip abductor muscles and tendons after total hip replacement: COMPARISON BETWEEN THE DIRECT ANTERIOR APPROACH AND THE TRANSGLUTEAL APPROACHES. Bremer AK, Kalberer F, Pfirrmann CWA, Dora C, Journal of Bone and Joint Surgery – British Volume. 2011–July; 93-B:886-9.
[5] Revision Total Hip Arthroplasty Performed Through the Hueter Interval. Mast NH, Laude F, Journal of Bone and Joint Surgery – American Volume. 2011–May; 93-A Suppl 2: 143-8).

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