Anteversion and Retroversion describe the rotation of an organ or part of it.
What is Anteversion?
Anteversion means rotated forwards (towards the front of the body)
What is Retroversion?
Retroversion means rotated backwards (towards the back of the body)
The version is in comparison to a reference position.
For example, the normal uterus is typically slightly anteverted but in certain cases it may be retroverted.
In musculoskeletal science, the terms are important in hip and shoulder.
For example, in hip the neck of femur is anteverted slightly. An increase anteversion or retroversion can cause problems in the alignment and gait.
Normal humeral head has 30º of retroversion to the frontal axis of the elbow joint. The femoral head has 12 to 15º of anteversion to the line connecting posterior aspect of both femoral condyles
The acetabulum in a similar manner is slightly anteverted.
Knowing right anteversion is important in designing of arthroplasty implants and placement during surgery.
Femoral Anteversion and Retroversion
Femoral Anteversion or Hip Anteversion
Femur neck is normally anteverted with respect to rest of femur [see the diagram]. It is considered abnormal only if it is significantly different from the average value of a patient of the same age. Femoral neck anteversion is also called anteversion of hip.
Definition of Femoral Anteversion
It 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.
Normal femoral anteversion ikn adults is 15 and 20 degrees from the frontal plane of the body.
The term medial femoral torsion is also used to describe femoral neck anteversion and is thought to result from medial or internal rotation of the limb bud in early intrauterine life.
Femoral anteversion is the most common cause of children walking with their toes inward (in-toeing) in children older than 3 years of age.
With abnormal anteversion of femur, parent might notice that his or her child is walking with the toes turned inward. A child might also trip or fall more commonly than normal children. The child rarely has pain.
Abnormal femoral anteversion is a developmental abnormality. The normal child is born with 31-40 degrees of femoral anteversion. This gradually decreases to 10 to 15 degrees at adolescence and generally improves with further growth. Therefore, no treatment is necessary if the anteversion is within this normal range.
If the anteversion does not decrease with age, femoral derotation osteotomy may be performed.
Change in Femoral Anteversion Angle with Age
- Newborn – 31 degrees
- 5 years – 26 degrees
- 9 years – 21 degrees
- 16 years – 15 degrees by 16 years of age.
How to Measure?
Most femoral torsion problems are evaluated with computerized tomography. This involves 3 images or scans—2 proximal and 1 distal. One image defines the location of the center of the femoral head, the second image defines the base of the femoral neck, and the third image defines the distal femoral condylar axis.
The angle in the transverse plane between the intersection of the plane of anteversion and the condylar plane defines the angle of anteversion.
- Children with an intoeing or outtoeing gait have an increased or decreased femoral neck anteversion angle respectively
- Decreased femoral neck anteversion is thought to be a factor in developing slipped capital femoral epiphysis though more studies are required on this topic.
- Patients who had decreased femoral neck anteversion angle angles also were more likely to have osteoarthritis of the hip.
- An increase or decrease in the femoral anteversion may alter the hip’s congruity and place abnormal stress on the acetabular labrum and could lead to injury.
Femoral Retroversion or Retroversion of Hip
When femoral neck anteversion is less than average range [ 15-20 degrees], it is called femoral retroversion or hip retroversion.
If the anteversion is less than normal average or the inclination of the femoral neck is in opposite direction. Femoral neck retroversion is present when the head and neck of the femur are angled less than the average anteversion angle along the frontal plane of the body.
In some cases, the femoral head and neck may even be angled backward from the frontal plane of the body.
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