Hip dysplasia occurs when the two bones that come together in the hip joint — the pelvis and femur bones — are out of alignment. The condition can cause misalignment, movement, and flexibility issues for children and adults.
According to the International Hip Dysplasia Institute (IHDI), healthcare professionals refer to hip dysplasia in infants and children as developmental dysplasia of the hip (DDH). If they diagnose hip dysplasia in adults, they refer to it as acetabular dysplasia.
In people with the condition, their hip joint tends to wear out faster, which can lead to additional complications as time goes on.
This article discusses hip dysplasia, including its causes and symptoms. It also looks at treatment options, potential complications, and when to contact a doctor.
Hip dysplasia is a condition where the bones of the hip do not align properly.
The hip is a large ball-and-socket joint where the thighbone, or femur, fits snuggly into the socket, or acetabulum, of the pelvis in most people. In hip dysplasia, the socket is too shallow or small to fit the thighbone securely.
The severity of hip instability or looseness varies from person to person. According to the American Academy of Orthopaedic Surgeons (AAOS), there are three degrees of hip dysplasia:
- Subluxatable: This is the mildest form. The thighbone fits in the socket and can move around, but the joint will not dislocate.
- Dislocatable: The femur is inside the socket, but during a physical examination, a doctor can easily dislocate the joint.
- Dislocated: This is the most severe case, where the femur is outside the socket.
The AAOS states that the prevalence of hip dysplasia varies around the world. Approximately 1 in 2 infants per 1,000 have the condition at birth.
Doctors may refer to hip dysplasia using different terms, such as:
- neonatal hip instability
- acetabular dysplasia
Symptoms of hip dysplasia will depend on a person’s age. Below, we discuss signs and symptoms to watch for in infants, children, teenagers, and adults.
Infants and children
Some infants who are born with DDH do not present with any symptoms.
A person should contact a healthcare professional if they notice in a baby any of the following:
- The skin folds are uneven on the thigh.
- The length of the legs is different.
- The baby is less flexible or mobile on one side of the body.
Children living with hip dysplasia may show similar signs and symptoms, such as:
- uneven leg length
- unusual gait that can include toe walking, limping, or a waddling gait
- limited flexibility or mobility in one of the hips
Teenagers and young adults
According to the AAOS, hip dysplasia in adults typically stems from the development of DDH. Although healthcare professionals routinely screen for the condition, some cases are mild enough that they are left untreated or remain undetected.
In these cases, symptoms may not appear until a person has reached adolescence.
As a child grows, hip dysplasia is more likely to cause pain. The pain often results from a breakdown in the cartilage and other structures in the hip due to irregular wear and tear.
A person may also find that they limp when they walk.
Pain and limping are two most common signs of hip dysplasia in teenagers and young adults.
When pain occurs, it may:
- start as mild and infrequent and change in intensity and frequency over time
- be worse at the end of the day
- be in the groin but may also appear in the outer hip
A person may also experience a popping or crackling feeling in the hip.
Adults experience symptoms that resemble those in teenagers and young adults.
Some common symptoms include:
- pain in the groin
- increased pain while standing, walking, or moving
- popping or catching sensation in the hip during movement
- pain on the side of the hip
- pain during sleep time
- walking with a limp, which may be painful
Typically, infants develop DDH because it runs in their families. Additionally, according to a 2019 study, family history and postnatal swaddling are two main risk factors for developing DDH.
Experts do not fully understand the exact cause of hip dysplasia in adults.
Risk factors for DDH include:
The IHDI suggests the following method for swaddling:
- Place a square cloth down so that it is in the shape of a diamond. Fold back the top corner to create a straight edge.
- Place the baby onto the cloth, ensuring that the fabric is the same level as the shoulder.
- Bring the left arm down and wrap the cloth over the chest and arm. Tuck the cloth under the right side of the baby.
- Bring the right arm down and wrap the cloth over the chest and arm. Tuck the cloth under the baby’s left side.
- Twist or fold the bottom section of the cloth and tuck it behind the baby. At this point, ensure that the legs are bent upward and out.
If using a rectangular cloth, place the baby so that the shoulders are at the top of the long side.
It is important to make sure that the baby has enough space to move their hips.
Treatment will depend on the age of the person and the severity of the condition.
In infants, the goal of treatment is to get the head of the femur into the hip socket.
Infants and children
According to the AAOS, a healthcare professional will place the infant in a harness called the Pavlik harness. The baby will remain in it for 1–2 months.
- keep the thighbone in the socket
- tighten the ligaments that surround the joint
- promote hip socket formation
A healthcare professional will teach caregivers to perform daily tasks.
For babies aged 1–6 months, a harness is also necessary.
The amount of time a baby will need to wear the harness can vary. Typically, they may need to wear it full time for 6 weeks and part time for additional 6 weeks.
For those aged 6–24 months, a healthcare professional may recommend closed reduction and spica casting. A closed reduction involves resetting the bone, and a spica cast is a cast that covers one or both legs and the waist.
Surgery may be necessary if the closed reduction procedure is not successful or for those older than 2 years.
In older children, adolescents, and young adults, treatment options include both nonsurgical and surgical options. The goal of treatment is to prevent or delay the development of arthritis in the hip.
Adolescents and adults
Some common nonsurgical treatment options can include:
- Physical therapy: This aims to increase the range of motion in the hips and add strength to the joint.
- Observation: For mild cases, a doctor may recommend monitoring the condition.
- Lifestyle changes: These mainly include avoiding activities that may cause pain or discomfort.
- Use of medications: These include nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, or injections such as cortisone.
In some cases, a doctor may recommend surgery. There are several types of surgery that a doctor may conduct. The type they choose will depend on a person’s age, number of growing years left, presence of arthritis, and severity of the condition.
Periacetabular osteotomy is a common surgery. The procedure involves rotating the hip socket to make it more accommodating for the head of the femur to fit snugly in.
The diagnostic process will depend on a person’s age.
In infants, a pediatrician typically checks for hip dysplasia during all routine health visits. This can include a visual examination and physically moving the legs to check for signs of displacement.
A doctor may order an ultrasound of an infant’s hips if they have a higher risk of developing hip dysplasia.
In older children and adults, a doctor will also perform a visual examination. They will also likely move the legs and hips in different directions, often listening or feeling for clicking sensations.
If a doctor suspects hip dysplasia, they may order additional testing, such as:
Diagnosis in adults will also involve grading the condition. Doctors base grading on a person’s age, displacement of the hip, and deterioration of the hip joint.
Complications may be a result of either the condition itself or treatment options.
For instance, babies that have worn a cast may have delay in learning to walk, while those in the Pavlik harness may experience skin irritation, and one of their legs can be longer than the other.
In either case, the baby’s hip socket may still be shallow, and surgery may eventually be necessary.
Without treatment, hip dysplasia can lead to difficulty walking, pain, and osteoarthritis.
Any surgery carries a risk of complications. However, complications due to a procedure that addresses hip dysplasia are rare. They include:
When an infant has a high risk of developing DDH, doctors will likely take more steps to rule out its presence. Caregivers should take the baby to regular wellness visits, where a doctor will check for hip dysplasia.
Older children and adults should let a doctor know if they experience symptoms such as pain in the hips, difficulty walking, or limited mobility.
The doctor can check for the presence of hip dysplasia and recommend treatment as needed.
With successful treatment, a person should be able to maintain their mobility and lifestyle.
Hip dysplasia occurs when the thighbone does not fit properly in the hip socket. The condition can cause a disrupted gait, pain, and other symptoms.
Treatment can involve both surgical and nonsurgical options to help alleviate pain and help a person improve mobility and flexibility.