Hip dysplasia of humans
Table of contents
Introduction
I. Basic facts about hip dysplasia
II. Two major types of hip dysplasia
1. Congenital hip dysplasia
2. Developmental hip dysplasia
III. Methods of detecting CHD and DHD
Conclusion
Introduction
The main goal of this paper is to give a clear explanation and define such medical
term as “hip dysplasia”, speak about its diagnosis and prognosis
and ways of detecting. Though this disease affects not only humans but also
animals (especially dogs), only human hip dysplasia will be discussed in this
paper. This term is often used to describe health problems of human beings connected
with wrong formation of the hip joint. Hip dysplasia, also known as hip dislocation,
has several types, such as Congenital hip dislocation, Congenital dislocatable
hip and Developmental dysplasia of hip. More often hip dysplasia can be found
in newborn babies or very young children. However, there are some cases when
the disease is not detected in time. Because there are several types of hip
dysplasia this work will also discuss peculiarities of each type and differences
between them.
I. Basic facts about hip dysplasia.
The first point of hip dysplasia that is necessary to discussis the definition
of this term and short history of it. According to Webster’s dictionary
dysplasia is defined as abnormal growth or development, that’s why hip
dysplasia is an abnormal development of hip, which causes instability of hip
joint and dislocation of the thigh bone from the socket in the pelvis [1]. Usually
this disease is innate, though recent researches have shown that it develops
during the first weeks - months and sometimes year of life. That’s why
it has been called developmental hip dysplasia. According to historical evidences
hip dysplasia was known as early as the time of Hippocrates. Nowadays there
are two types of hip dysplasia known in medicine congenital dysplasia and developmental
dysplasia. So, what is hip dysplasia? According to medical researches displasia
is a result of abnormal development of the hip when the relationship between
the thigh bone, called femur, and shallow socket, called acetabulum is disrupted.
Acetabulum is the large cup-shaped cavity at the junction of pelvis and femur
[1]. Because of this disruption neither femur nor acetabulum develops in a proper
way. Before a baby is born its hip must be developed in a way in which femur
is located right in the center of acetabulum, in its turn acetabulum must cover
the head of femur. In cases of hip dysplasia wrong development of the acetabulum
makes femoral head ride in an upward direction out of the joint socket. This
is especially noticed when a certain weight is put on the hip [3]. In the event
when a baby was born healthy and had no hip displasia there’s a possibility
of getting developmental hip displasia during the next six weeks of baby’s
life, which are considered to be a critical period for hip joint formation.
That’s why it’s very important to hold a proper examination in order
to identify the disease or a possibility of getting it in future. If proper
examination wasn’t done or a mistaken diagnosis was established there’s
a high chance of future morbidity that might cause more serious health problems,
such as the development of osteoarthritis [2].
According to scientific researches and statistics hip dypslasia more often can
be found in females than in males, it’s more frequently detected in infants
with breech presentation and very rarely in Afro-American people [5]. Though
hip dysplasia has been a subject of study for many years still doctors hesitate
on the matter what causes hip dislocation. It’s been noticed that hip
dysplasia runs in families, and usually girls are under risk of getting the
disease. That’s why it’s possible to assume that among factors causing
hip dysplasia is certain genetic information. Also factors of the environment
make cause hip dysplasia due to the different rate of the disease in different
countries. In order to find out whether a baby has hip dysplasia pediatricians
usually do the Barlow or the Ortolani tests. In cases when hip dysplasia is
not detected right away, by the age of one a child might be lame [4].
II. Two major types of hip dysplasia
As it has been mentioned above there are two major types of hip dysplasia known
nowadays: congenital and developmental. Congenital hip dislocation also known
as CHD is a malformation of hip joint that can be detected exactly after the
birth. Congenital hip dysplasia has some basic features such as different length
of legs and their asymmetry, uneven thigh fat folds and degraded mobility on
the side which was affected.
It’s hard to identify what causes CHD, but clinical studies have shown
that congenital hip dislocation runs in families, and affects more women than
men. Also there’s a large chance for a baby to have CHD in cases of breech
position births. First born children are more likely to have CHD than second
and third ones. A great role in the development of CHD also plays hormonal swing
of mother. Very often children having CHD don’t show any features of the
disease, that’s why a thorough physical examination is strongly recommended
on the second day of life of infant. There are two basic methods used in medicine
for detection of congenital hip dysplasia. They are the Barlow test and the
Ortolani test. The main principle used in both methods is moving infant’s
hips in order to determine whether femoral head is able to move in and out of
the hip joint. Other methods used to detect CHD are X-ray analysis and ultrasonographic
detection, which will be discussed later in the work [6].
While examining an infant pediatrician may diagnose several types of CHD. The
first one is congenital hip dislocation, which means that hip is already dislocated
at birth. The second one is congenital dislocatable hip, which means that hip
is in the correct place at birth, but it can dislocate completely under any
kind of stress. The third diagnose is congenital subluxatable hip, which means
that hip can dislocate only partially under stress. And the last one is acetabular
dysplasia, which is a situation when acetabulum is shallow and causes hip instability
[4].
Correct treatment of congenital hip dysplasia will help to avoid almost all
health problems associated with it in future. If CHD is not properly treated
shortly after birth the prognosis of the disease is the following. A child may
grow with a limp or waddling gait. Unless surgery is done a child might have
difficulties in walking and experience a lot of pain.
Second type of human hip dysplasia is Developmental hip dysplasia, also known
as DHD, which is a modern medical term used for hip dysplasia showing that in
some cases infants having normally developed hips develop hip dysplasia during
the first months of life. Usually it happens not later than during the first
year of life. In order to prevent the development of the disease it’s
necessary to hold an examination of a newborn baby. In cases if no signs of
the disease were found during the first examination, other examination when
an infant is one, two, four, six, nine and 12 months old are also required.
If during this examinations limited abduction is detected, it could be a trustworthy
sign of DHD. The best method of detecting DHD is arthrography of the hip, however
this type of examination is not advised to use in newborn babies. There are
other methods used by pediatricians to evaluate state of health of a child,
such as radiography and ultrasonography, though radiography is not effective
when used in children younger than four months, because it cannot show the full
picture yet. However, ultrasonography is rather effective in small infants,
and is able to show different abnormal findings if they are present. Usually
ultrasonography is used if physical examination detected some sort of abnormalities
and in high-risk newborns. Speaking about factors that influence the development
of DHD they are similar to those influencing CHD. They are family tendency,
breech presentations and some orthopedic problems, such as clubfoot deformity
and other congenital conditions and diseases. Among obvious symptoms of developmental
hip dislocation are infant’s legs of different length, uneven thigh folds
and wider space between legs in comparison with normal [7].
Developmental hip dislocation may result in even more complicated problems ending
up in the development of osteoarthritis. Health problems caused by DHD are knee
pain, back pain, abnormal gait and limping [8].
III. Methods of detecting CHD and DHD
Nowadays, clinical examination for hip dysplasia is established in many countries
of the world. The primary method of detecting hip dysplasia is physical examination;
however its accuracy is still under the question. As it has been mentioned above,
there are two methods of detecting hip dysplasia known as Ortolani and Barlow
tests. These tests have been common techniques for finding hip abnormalities
in newborns. However, these tests cannot be performed in a baby who is constantly
moving, because its muscle activity restrains movements of the affected hip.
These methods are proved to be more effective when done in the newborn period
[9].
Non-physical methods of detecting CHD and DHD in babies are ultrasound examination,
radiographic assessment or x-ray examination, and computed tomography scan.
Ultrasound examination was used to detect hip dysplasia in 1978 for the first
time. The main principle of this method is based on classification of infants’
hips according to their shape and depth of acetabulum. According to this method
there are four types of hips. The first type is considered to be normal; the
second type is used to represent a hip with slightly shallow acetabular cup,
and if a child is older than three months this is considered to be abnormal;
the third type of hip is subluxated; the last is the fourth type, which is used
to represent a dislocated hip. It is believed that results of ultrasonography
very much depend on operator conducting the examination, on his/her professional
skills; and that ultrasound examination provides best results when a baby is
4-6 weeks old.
Radiography or x-ray examination is usually held when a child is already 3-5
months old. The test is usually performed in a hospital radiology department
by a qualified clinician. Sometimes there’s a need to take several pictures
in order to get different views of joint. However, there’s a disadvantage
of this method, because x-ray examination can be made at the age when hip dysplasia
can be hardly treated without any surgery [9].
The next method of detecting hip dysplasia is computed tomography, which is
diagnostic method using a combinations of x-rays and computer technology. This
method is effective at examination of any part of body not only hips [7].
Conclusion
Having spoken about hip dysplasia of humans, its diagnosis, prognosis, and methods
of detecting it’s necessary to make a conclusion. Although this disease
is rather rare in occurrence: its incidence is 4 per 1000 live-births in the
general population [4], it’s necessary to examine all newborns during
their first days of life and continue regular examination until they start walking.
This will prevent the development of hip dysplasia, because only detected in
time it can be treated successfully. Otherwise, if it’s not noticed in
time hip dysplasia can lead to the development of more serious health problems
such as limping and osteoarthritis. Though it’s impossible to hold any
prenatal examination to detect CHD, it’s necessary to pay more attention
to infants born with breech presentation, because they have the highest risk
of getting hip dysplasia.
Bibliography
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2. http://www.emedicine.com/radio/topic212.htm
3. http://www.healthatoz.com/healthatoz/Atoz/ency/congenital_hip_dysplasia.jsp
4. http://www.orthoseek.com/articles/hipdys.html
5. http://www.learningradiology.com/notes/bonenotes/conghipdysplasiapage.htm
6. http://www.arthritis-symptom.com/a-c/congenital-hip-dysplasia.htm
7. http://www.lpch.org/DiseaseHealthInfo/HealthLibrary/orthopaedics/ddh.html
8. http://www.cs.nsw.gov.au/rpa/neonatal/html/newprot/ddh7.htm
9. http://www.aafp.org/afp/990700ap/177.html
