Acetabular Femoral Conflict - Acetabular Femoral Impingement

, which originates from a "structural alteration of the" hip joint.
More precisely, the femoral-acetabular impingement is characterized by skeletal anomalies affecting the head of the femur and / or the acetabulum, which end up damaging the articular components (articular surfaces and acetabular labrum).
In most cases, femoroacetabular impingement is a congenital condition or resulting from abnormal skeletal development at a young age.
The symptom that best characterizes it is groin pain; to evoke this pain is, generally, the flexion movement of the hip in a range greater than 90 °.
For an accurate diagnosis of the disease, medical history, physical examination at a specialist and diagnostic imaging are essential.
Depending on the severity of symptoms and joint damage, treatment can be conservative or surgical.

painful of the musculoskeletal system, which affects the hip joint and is characterized by an abnormal contact between the head of the femur and the acetabulum.

Femoroacetabular impingement is also known as impingement femoroacetabular or FAI (from the English FemoroAcetabular Impingement).

Did you know that ...

An "other form of impingementSubacromial impingement of the shoulder is much more common than the femoroacetabular one, which specifically concerns the soft tissues interposed between the head of the humerus and the coracoacromial vault.

Hip joint: a brief review


Also known as the coxo-femoral joint, the hip is the important equal joint in the human body that connects the lower limb to the trunk.

In fact, it has as protagonists the head of the femur, the femur which is the bone of the thigh, and the acetabulum, which instead is a deep bone cavity belonging to the iliac bone (of the pelvis).

The head of the femur is an almost spherical bony protuberance, with a medial and slightly anterior orientation, which fits perfectly inside the acetabulum, which, as anticipated, is a cavity of the iliac bone.

Thanks to the combination of the femoral head and the acetabulum, the hip is a mobile and, at the same time, stable joint.

end of range; substantially, one or both components of the joint have a bone surplus due to which, at a certain degree of movement, they collide in an anomalous way.

Generally, the movement affected by the presence of the femoroacetabular impingement is the flexion of the hip (it is the movement that brings the knee closer to the chest).

The description of the pathophysiological mechanism that characterizes FAI dates back to 2005, so it is quite recent.

Femoro-Acetabular Impingement: Why Does It Cause Pain?


The presence of an obstacle to the physiological mobility of the hip could lead to damage to the articular cartilage and to the acetabular labrum.

The acetabular labrum is equipped with numerous nerve endings, therefore, when it is damaged, it causes pain.

As far as the articular cartilage is concerned, it is not innervated, but experts believe that the anomalous contact between the femoral head and the acetabulum increases the pressure on the bone placed under the articular cartilage, bone which, unlike the layer of cartilage , is rich in nerve endings, therefore also capable of evoking pain.

As stated, the damage to the aforementioned structures represents an "eventuality: in spite of an" articular alteration characteristic of FAI, in fact, some people do not show any symptoms of the condition, this is because the "anatomical anomaly is not such as to damage the lip. acetabular and articular cartilage.

Femoro-Acetabular Conflict: What Are the Causes?


In most cases, the femoroacetabular impingement is a congenital condition or deriving from an "anomaly of the skeletal development" of the young age, the cause of which, in both situations, is not well identifiable (genetic factors are suspected); in fact, therefore, in these specific cases, we are talking about a non-preventable condition.

To a much lesser extent, femoroacetabular impingement follows hip injuries.

Types of Femoro-Acetabular Conflict


There are three types of femoroacetabular impingement:

  • L"impingement "pincer", in which the joint anomaly consists of a "bone emergence that arises from the" acetabulum and, with the contribution of the femoral head, pinches the acetabular labrum.
  • L"impingement "cam", in which the joint anomaly consists of a head of the femur with a portion of extra tissue, which prevents a fluid relationship with the acetabulum and even erodes the cartilage of the latter.
  • L"impingement combined, in which both the anomalies described above are present.

Femur-acetabular conflict and physical activity: is there a correlation?

Physical activity does not cause femoroacetabular impingement; consequently, it is incorrect to assign exercise a role as a factor favoring the condition.

However, it should be noted that FAI carriers who perform daily physical activity are more likely to present symptoms related to the anomaly, compared to sedentary individuals also suffering from femoro-acromial impingement; this is explained by the fact that the articulation of particularly active people also tends to experience the widest range of motion, which, as previously analyzed, are those which then evoke pain.

correctly (due to pain).

It should be noted that femoroacetabular impingement is sometimes asymptomatic.

Pain: what causes it and what makes it worse?

Normally, in the presence of femoroacetabular impingement, the movement of the hip evokes pain; in particular, the most critical movement is the flexion of the joint (knee approaching the chest).

Another aspect that influences the painful symptomatology is, as stated on several occasions, the "range of motion: for example, a hip flexion movement at its maximum range, as happens for example when squatting up to bring the buttocks." in contact with the heels, it often causes pain.

Femoro-Acetabular Conflict: Complications

Over time, the presence of a femoral-acetabular impingement can cause significant damage to the acetabular labrum and / or favor the degeneration of the articular cartilage of the hip (arthrosis).

These events are responsible for chronic pain and some joint dysfunction.

or physiatrist).

The physical examination is very important, because it involves a series of diagnostic maneuvers (including the "impingement test) which help the doctor to understand if the present symptoms are actually connected to a pathology of the hip.

Then, the aforementioned clinical investigations are followed by diagnostic imaging tests, such as the classic radiography of the hip, nuclear magnetic resonance and CT scan.

Diagnostic imaging allows the doctor to establish whether the symptoms are actually due to a joint problem: in fact, by providing detailed images of the "hip joint", instrumental examinations allow to identify any skeletal anomalies at the joint level as well as possible degenerative phenomena. of the articular cartilage.

Imaging has a key role in the diagnosis of femoroacetabular impingement, because it is able to recognize the skeletal alterations characteristic of the pathology.

Finally, it should be noted that, in some circumstances, the injection of an anesthetic into the joint could be used for purely diagnostic purposes: an improvement in symptoms following the use of this anesthetic favors a diagnosis of FAI ( clearly, such a conclusion must be complemented by in-depth instrumental examinations).

, with the aim of relieving pain and inflammation typical of the first phase of joint pathology.
  • Limitation / suspension of all motor activities responsible for pain.For active people, this does not mean that they can no longer play sports, but simply that they opt for an "activity that does not cause pain (it could also mean avoiding, in a given sport, a certain exercise, replacing it with another that does not evoke discomfort).
  • Physiotherapy. Exercises to improve joint mobility and to strengthen the hip muscles improve the functionality of the suffering joint, with positive implications for painful symptoms.
    To get the maximum benefit from physiotherapy, it is good to rely on an expert physiotherapist, who knows the patient's clinical picture and the pathology from which he suffers.
  • Surgical Treatment

    Surgery is used when the femoral-acetabular impingement is extremely painful, also due to significant joint damage, and when the conservative treatment described above has proved ineffective.

    The main objectives of the surgical treatment are basically two:

    • Eliminate the bone anomalies that have compromised the joint anatomy;
    • Repair articular cartilage and acetabular labrum.

    The surgical technique normally adopted in the presence of femoral-acetabular impingement is arthroscopy, as it is a minimally invasive procedure, with overall short recovery times.

    There is, however, the possibility of resorting to more invasive surgical techniques, with a post-operative phase certainly more moonlight, such as traditional surgery ("open") and "arthroplasty, which involves the replacement of the" hip with a partial or complete prosthesis.

    Post-operative phase: Physiotherapy and Rehabilitation

    As after all surgical operations of an orthopedic nature, even after surgery for the femoral-acetabular impingement and rehabilitation physiotherapy.

    The duration of rehabilitation varies according to some parameters such as:

    • The extent of joint damage;
    • The invasiveness of surgery.

    Surgery: What are the Risks?

    Surgery for femoroacetabular impingement presents the classic risks of any surgical procedure.

    It should also be noted that, if the operation is particularly invasive on the femur, it could lead to a weakening of this bone and thus favor fractures on the femur.

    Antonio Griguolo

    Graduated in Biomolecular and Cellular Sciences, he obtained a Specialized Master in Journalism and Institutional Communication of Science
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