What is Spastic Hip Dysplasia?
Spastic hip dysplasia is a hip disorder in which the acetabulum, the hip socket, doesn't cover the femoral head properly. As a result, the patient suffers from abnormal hip development which typically includes either partial or complete hip dislocation. Spastic hip dysplasia is caused by spasticity induced by cerebral palsy, a neuromuscular disorder that impairs muscle movement and coordination. Spasticity causes exaggerated reflexes and muscle stiffness, causing abnormal joint function and dislocation.
Spastic hip dysplasia usually occurs in infants and children and can be corrected with timely diagnosis and treatment.
Anatomy of the Hip
The hip joint is a ball-and-socket structure in which the head of the femur forms the ball, and the pelvic acetabulum forms the socket. The joint surface is covered by smooth articular cartilage that cushions and enables smooth movement of the joint. A fibrous cartilage ring called the labrum lines the acetabular socket. It deepens the cavity, increasing the stability and strength of the hip joint.
What are the Causes of Spastic Hip Dysplasia?
Spastic hip dysplasia may develop due to various reasons. These include:
- Pelvic obliquity or the misalignment of the pelvis
- Scoliosis or an abnormal spine curvature
- Neurological defects such as cerebral palsy
- Hemiplegia: Paralysis in one side of the body due to spinal cord injury or brain damage
- Tetraplegia, also called quadriplegia: Paralysis that affects all four limbs and sometimes parts of the chest, abdomen, and back
- Congenital defect (present at birth) due to a defective gene
- Heredity
- Injury due to a fall, motor vehicle accident, or trauma
What are the Symptoms of Spastic Hip Dysplasia?
The symptoms of spastic hip dysplasia may include:
- Mild to severe pain
- Muscle asymmetry: The muscle on one side of the body is smaller, larger, weaker, or stronger than the corresponding muscle on the other side of the body
- Abnormal gait or walking style
- Abnormal posture
- Difficulty standing or walking
- Difficulty stretching or rotating the legs or hip
- Leg or limb length discrepancy
In older children and young adults, symptoms of spastic hip dysplasia may include:
- Hip instability
- Hip labral tear
- Osteoarthritis
- Activity-related groin pain
How is Spastic Hip Dysplasia Diagnosed?
For infants, changes in behaviour, difficulty communicating, or refusal to eat can be taken as warning signs. During hip examination, the doctor may look for a compromised range of motion of the hip, the presence of uneven skin folds around the thigh, and leg-length differences. Depending on the patient’s age and condition, the doctor may also order an X-ray or ultrasound to confirm the diagnosis.
What are the Treatment Options for Spastic Hip Dysplasia?
Spastic hip dysplasia can be treated through a variety of methods that include either a non-surgical conservative approach or open surgery. The treatment aims to keep the femoral head in good contact with the acetabulum so that the hip can develop normally. Your doctor will decide the treatment based on your child’s age and the severity of the condition.
Non-Surgical Treatment
The first line of treatment for spastic hip dysplasia is conservative management. This includes:
- Passive stretching
- Immobilizing the joint using a brace or a splint
- Pavlik harness is a soft brace that holds the ball of the hip joint firmly in its socket for several months and is usually recommended for infants
- Use of orthoses to help in movement or walking assistance
- Physical therapy to increase mobility and muscle strength
- Medications to minimize pain and inflammation
- Treatments to alleviate spasticity may include:
- Botulinum toxin injections
- Antispasmodic agents
- Muscle relaxant drugs
Surgical Management
Surgery is recommended for children with severe spastic hip dysplasia and those who do not respond well to conservative therapy. Surgery may involve any of the following procedures:
Selective Dorsal Rhizotomy (SDR):
This procedure involves cutting the nerve rootlets in the spinal cord that are responsible for sending abnormal signals to the hip muscles to help correct muscle spasticity.
Tendon/Muscle Release:
This surgery involves cutting or excision of the muscle or tendon in the hip joint to correct the stiffness and asymmetry created due to muscle spasms. Adductor, iliopsoas, and medial hamstring muscles/tendons are primarily worked upon during this surgery. Surgical release treats muscle stiffness, reduces pain, and improves range of motion.
Pelvic/Femoral Osteotomy:
This procedure involves cutting and aligning the proximal part of the femur (thigh bone) with the acetabulum to restore hip function.
Multilevel Surgery:
This type of surgery involves the soft tissues, femur, and pelvis at the same time to correct morphological abnormalities and stabilize the hip joint.
Total Hip Arthroplasty or Hip Resection:
In this surgery, the hip joint is partially or completely replaced with hip implants. This is recommended when the patient suffers from severe pain or severe spasticity. It is highly effective in minimizing pain and improving patient comfort.
