The question „Where is the incision in the minimally invasive anterior Hüftzugang?“ is at the center of modern Hüftendoprothetik. For many patients, who undergo a Hüftprothese, it is essential to know, how the minimally invasive approach is performed anatomically, where exactly the skin is cut and what advantages this modern surgical pathway offers – especially compared to classic procedures.

In this comprehensive guide, we explain to you in detail:

• What does "minimally invasive" really mean in hip surgery
• The two established approaches AMIS and ALMIS
• Where the incision is made, anatomical orientation, and practical significance
• Why the anterior-lateral area is chosen more frequently today
• Why the muscle gap under the skin is crucial
• And why a treatment with a hip specialist like Prof. Dr. Kutzner at the Endoprotheticum Rhein-Main in Mainz is sensible
• 
  

What does "minimally invasive" mean in hip access?

A minimally invasive approach means:
The surgeon wählt a path with a small incision and minimal tissue trauma, to implant the artificial hip joint. In this process:

• the soft tissue is treated gently
• Muscle and nerve tissue not cut, but held aside
• the operation duration and postoperative pain are reduced
• the rehabilitation is accelerated

Goal is a smaller incision, less postoperative pain and faster patient mobilization compared with traditional approaches with großen skin incisions and extensive muscle injuries. The minimally invasive approaches AMIS and ALMIS are führende techniques in this field.

The AMIS approach – „anterior minimally invasive approach“

What is AMIS?

The term AMIS stands for Anterior Minimally Invasive Surgery – in German: anterior minimally invasive approach to the hip joint.

The concept:

• The operation is performed from the front („anterior“) at the hip joint
• The incision is relatively small – typically approx. 8–12 cm long
• The muscles and tendons are not cut, but only pushed aside
• It is performed through a natural muscle gap operated, the so-called Hueter interval – between the Musculus tensor fasciae latae (TFL) and the Musculus rectus femoris or Sartorius.

Where is the incision in the AMIS access?

The incision for the AMIS approach is placed front-laterally over the hip region – also at the front thigh side, in the area between the groin and the lateral hip bone. It runs over the muscle groups, but not through them, so that the underlying muscles are spared.

Why this is important:

• Through this incision the hip joint can be safely reached, without cutting muscles
• The natural gap between the muscles is used anatomically
• This results in less tissue trauma
• The patient can be mobilized more quickly
• Pain is often less severe than with classical approaches
• The hospital stay is often shorter

This gentle Schnittführung is a central advantage of AMIS method gegenüber herkömmlichen techniques.

How does the access proceed anatomically?

Anatomically, the AMIS approach uses a muscle-sparing plane:

• Lateral: Musculus tensor fasciae latae
• Medial: Rectus femoris muscle or Sartorius muscle
• No muscle transection, but only retraction medially and laterally
• This exposes the joint and implants the prosthesis

This intermuskuläre and internervöse Wegführung reduces injuries to muscle and nerve tissue significantly.

Why is a cut in the anterior-lateral area more common today?

In modern Hüftendoprothetik the trend has clearly moved towards anterior or anterolateral Zugänge developed – especially in minimally invasive surgeries such as AMIS and ALMIS.

Anatomical advantages

• The musculature at the front and side is thinner and easier to shift than, for example, the strong musculature in the rear area
• By using existing Muskellücken less tissue is damaged
• Es können more important Stabilitätsmuskeln (abductors) be spared
• The nerves and vessels are located in this area in such a way that they are less endangered with correct technique
• The natural gap and internervous plane allows for direct access without cutting through muscle bellies

Practical advantages

• Less postoperative pain
• Faster mobilization
• Lower risk of gait disorders such as permanent limping
• Small scar due to minimal incision
• Faster return to daily activities

It is important to understand: The skin incision is only the outer entry point. Crucial for the gentle effect of the minimally invasive approaches is the choice of the muscle and tissue layer beneath the skin – namely the natural muscle gap, through which the access is guided. As a result, muscles and tendons are maximally spared, and the hip joint can be reached safely.

Why a direct incision over the groin in anterior hip access has disadvantages

During the anterior minimally invasive approach (AMIS) is fundamentally characterized by muscle preservation and rapid rehabilitation, recent years have shown that a too far anterior skin incision – directly over the inguinal fold – brings several relevant disadvantages. These experiences have led many specialized hip surgeons today to prefer the lateral approach where the incision is placed slightly more laterally, the anterior muscle gap is still utilized.



Increased risk of nerve damage to the lateral femoral cutaneous nerve

A cut very far anterior, near the groin, frequently leads to immediate proximity to Nervus cutaneus femoris lateralis (N. CFFL). This sensitive skin nerve runs in the area of the Spina iliaca anterior superior (SIAS) and extends from there fan-shaped over the upper outer thigh.

With a purely anterior, very medial approach, it can therefore lead to:

• mechanical irritation
• Overstretching
• Compression by retractors
• or even direct injury

of the lateral femoral cutaneous nerve occur.

The consequences are often stressful for patients:

• Numbness in the area of the anterolateral thigh
• Paresthesias (tingling, burning, crawling sensation)
• Neuropathic pain, which can persist for months or even permanently

Especially with early AMIS-like techniques, where the skin incision was placed very far forward on the inguinal ligament, significantly increased rates of these nerve injuries were described.

Through the currently preferred anterolateral incision approach the at‑risk nerve is protected much better, because the surgical pathway runs slightly more laterally and the critical nerve zone at the SIAS is avoided more safely.

Hygienic disadvantages in robust or obese patients

A central, often underestimated factor is the anatomical situation in the inguinal fold. A skin incision directly over the groin is located:

• in a warm skin area
• with natural moisture
• with high bacterial colonization
• and in many people in a deep skin fold, which is difficult to clean

In patients with obesity this problem is significantly increased:

• The groin fold lies deeper, the skin overlaps more strongly
• A humid, poorly ventilated environment develops
• The wound area is difficult to access
• Dressing changes are more complicated
• The risk of wound healing complications, macerations and superficial infections increases markedly

Therefore clinical experience and current surgical trends clearly show:
The anterior, directly over the groin placed incision is often disadvantageous for strong and obese patients and is associated with higher complication rates.

Why the anterior-lateral incision has become established today

For these reasons many specialized hip surgeons – including Prof. Dr. Kutzner – today a modified, laterally shifted incision line, which:

• further away from the groin fold lies
• significantly better hygiene enables
• the more safely spares the N. cutaneus femoris lateralis
• but under the skin still the true anterior access über die natürliche Muskellücke (Hueter-Intervall) nutzt

That means:
The operative approach remains minimally invasive and muscle-sparing, but the skin incision is intelligently relocated to reduce risks.

How important is the experience of the surgeon?

Very important! Minimally invasive surgical techniques such as AMIS und ALMIS require a specific training, experience and excellent anatomical knowledge. The reason:

• The incision is small, so the view is more limited than with large approaches
• Orientation in the muscle-sparing planes requires high precision
• The correct placement of the implant despite the small opening is technically demanding

Therefore, the choice of a specialized hip surgeon is one of the most important factors for an optimal result.

Recommendation: Hip specialist like Prof. Dr. Kutzner at Endoprotheticum Rhein-Main

When it comes to minimally invasive Hüftendoprothetik with AMIS or ALMIS is, the experience of the operator is decisive für safety and outcome Qualität.

 Prof. Dr. med. Karl Philipp Kutzner at Rhein-Main Endoprosthetic Center in Mainz belongs to the leading experts in hip endoprosthetics.
 He has extensive experience in minimally invasive approaches such as AMIS and ALMIS and combines state-of-the-art surgical technique with individualized patient care.