What is anteversion of the acetabular cup?
Anteversion of the revised acetabular component defined as the angle between a line connecting lateral anterior and posterior margins of the component and the sagittal plane defined as the plane perpendicular to a line connecting two identical points on either side of the pelvis.
What is acetabular cup?
The current acetabular implant is a cementless 2-component cup. A metal shell for bony ingrowth + a polyethylene liner (sometimes metal or ceramic) that snaps into the shell and articulates with the femoral head. The modern acetabular implant is a “press-fit” design (it is not cemented).
How is acetabular Retroversion treated?
Global acetabular retroversion is classically treated with open reverse periacetabular osteotomy. Given the low morbidity and recent success associated with the arthroscopic treatment of femoroacetabular impingement (FAI), there may also be a role for arthroscopic treatment of acetabular retroversion.
How common is acetabular Retroversion?
Acetabular retroversion is a common abnormality affecting 5 to 20% of the general population. It occurs in 16 to 25% of dysplastic hips and affects 31 to 49% of patients with Legg-Calvé-Perthes disease, and 36 to 76% of those diagnosed with slipped femoral epiphysis 2.
How do you measure anteversion on an acetabular cup?
Anteversion is between 23 degrees to 24 degrees when the ellipse bisects the total acetabular cross-section. This means that simply measuring the length of the short ellipse axis and the total length of the projected cross-section along the short axis provides the radiographic acetabular anteversion.
What is the angle of anteversion?
Femoral neck anteversion is defined as the angle between an imaginary transverse line that runs medially to laterally through the knee joint and an imaginary transverse line passing through the center of the femoral head and neck (Fig.
What is acetabular cup made of?
Requiring extreme precision, acetabular cups are composed of a titanium or cobalt chrome shell and Ultra High Molecular Weight Polyethylene liner.
How do you fix Retroverted hips?
An excessive femoral retroversion can place stress on hip and knee joints, often leading to joint pain and abnormal wear. In these situations, a surgical procedure known as a femoral osteotomy may be used. This surgery includes cutting and realigning the femur.
How is acetabular Retroversion diagnosed?
Radiographic evaluation is paramount in AR: the cross-over, the posterior wall and ischial spine signs are classic radiographic signs of AR. However, computed tomography (CT) evaluation permits a three-dimensional characterization of the deformity, being more reliable in its recognition.
What causes hip Retroversion?
Femoral retroversion is often a congenital condition, meaning children are born with it. It also appears to be related to the position of the baby as it grows in the womb. Torsional deformity can also occur after a fracture, if a broken bone heals with incorrectly (called malunion).
Where is the retroverted Cup of the acetabulum?
The inside of the ‘cup’ of the acetabulum is visible when looking at it face on. When the acetabulum is retroverted, it inclines or opens toward the posterior (i.e., the back of the body).
What do you need to know about acetabular retroversion?
Acetabular retroversion: Diagnosis and treatment Acetabular retroversion (AR) consists of a malorientation of the acetabulum in the sagittal plane. AR is associated with changes in load transmission across the hip, being a risk factor for early osteoarthrosis.
What happens if your acetabular cup tips too far forward?
Note that it is alternatively possible to have an acetabulum that is too anteverted, where the acetabular cup tips too far forward. If you have excessive acetabular anteversion (i.e., greater than ___ degrees anteverted), you may have labrum damage to the posterior edge of the acetabulum.
Which is the front edge of the acetabular cup?
The x-ray on the right shows a retroverted acetabulum. Again, the green line is the front edge of the acetabular cup and the yellow line is the rear edge of the cup. The entire acetabulum has been rotated forward so that there is excess coverage of the femur in the front of the cup and not enough coverage in the back.