Hip impingement

Right now, you probably have lots of questions: How serious is hip impingement? What’s the best treatment? What do we do next? We’ve provided some answers to your questions on this site, and our experts at Children’s Hospital Boston can explain your child’s condition fully when you meet with us.

Background: the normal hip joint

The hip joint is one of the body's most reliable structures, providing movement and support without pain or problems in most people for a lifetime. The hip’s simple ball-and-socket anatomy—with the ball-shaped femoral head rotating inside a cup-shaped socket called the acetabulum—usually works well with amazingly little friction, and little or no wear.

The well-fitting surfaces of the femoral head and acetabulum, which face each other, are lined with a layer of cartilage, lubricated by a thin film of fluid. Friction inside a normal hip is less than one-tenth that of ice gliding on ice.

What is hip impingement?

Hip impingement is a condition of the hip joint in which the hip’s normally smooth gliding motion is disturbed by bony deformities, causing friction between the thigh bone (femur) and the bone socket (acetabulum), which can wear away at the cartilage and can also damage the labrum, the joint’s fibrous seal.

What causes hip impingement?

Deformities of the thigh bone (cam impingement), acetabulum (pincer impingement) or a combination of the two abnormalities can cause hip impingement.

• Pincer impingement occurs when there’s direct contact between the thigh bone head-neck junction and a section of the acetabular rim.
   
• Cam impingement is caused by a squeezing or jamming of an abnormally shaped thigh bone head (femoral head) and head-neck junction into the socket (acetabulum) during certain types of motion, such as tying one's shoe, or riding a bike.
   
• Impingement of the hip can also be caused by conditions such as Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, misshapen thigh bone head, abnormally tilted head with bump on the thigh bone neck or post-traumatic deformities. 

What are the signs and symptoms of hip impingement?

Some signs and symptoms can include:

How common is hip impingement?

Hip impingement is essentially a wear-and-tear condition, affecting about 20 percent of the total population. It’s more common among younger athletes—especially those in sports requiring turning, twisting and squatting motions—and physically active people. Sometimes babies are born with the condition (congenital).

How serious is hip impingement?

Hip impingement can cause significant pain, loss of hip motion and early arthritis. Treatment is surgical.

Who’s at risk for developing hip impingement?

How does a doctor diagnose hip impingement?

In addition to a complete medical history and physical exam, procedures for diagnosing hip impingement may include:

• x-rays
• MRI (magnetic resonance imaging)

How does Children’s treat hip impingement?
Specific treatment for hip impingement is determined by your child’s doctor based on:

• his age, overall health and medical history
• the type, extent and severity of the impingement

Treatment may include conservative approaches such as:

• rest
• activity restrictions
• anti-inflammatory and pain medications
• exercises and physical therapy

If these don’t alleviate your child’s discomfort, doctors may perform:

• arthroscopic or open surgery (the surgical approach and techniques depend on the cause of the condition and the degree of cartilage damage that’s already occurred)
  • Most impingements that need surgery are treated arthroscopically.
  • Open surgery can be needed if the impingement involves an abnormal angle of the hip joint.
  • Surgical techniques address the elements of hip impingement—including damaged cartilage, labral tear and friction between the ball and socket.

Will my child be OK?

The long-term result of surgery depends on the amount of cartilage damage present at the time of surgery. Perfect outcomes are possible with early joint-preserving treatments before the cartilage is damaged. But even surgery may not be able to fully repair impingement if the cartilage has already been severely damaged. This is why diagnosing and treating your child’s hip impingement early in its development greatly increases the likelihood of a successful outcome, in which your child can resume full activities, including sports.

What new research is Children’s doing regarding developmental hip conditions?

Developmental hip conditions such as hip impingement, slipped capital femoral epiphysis, hip dysplasia and Legg-Calve-Perthes disease can lead to premature arthritis in young adults with resulting pain and disability. Children’s many research studies focus on understanding the mechanical forces (pathomechanics) that adversely change the hip’s structure and function. With better understanding, we can improve existing therapies and develop new therapies for these conditions.

The clinical and basic science researchers at Children’s Orthopedic Centerare recognized throughout the world for their achievements in the field. Our breakthroughs mean that we can provide your child with the most innovative care available.

For more on Children’s extensive orthopedic research, see Research & Innovation.

FAQ

Q: What is hip impingement?
A: Hip impingement is a condition of the hip joint in which the hip’s normally smooth gliding motion is disturbed by bony deformities, causing friction between the thigh bone (femur) and the bone socket (acetabulum), which can wear away at the cartilage and can also damage the labrum, the joint’s fibrous seal.

Q: If my child has hip impingement, will he be OK?
A: The long-term result of surgery depends on the amount of cartilage damage present at the time of surgery. Perfect outcomes are possible with early joint-preserving treatments before the cartilage is damaged. But even surgery may not be able to fully repair impingement if the cartilage has already been severely damaged. Diagnosing and treating your child’s hip impingement early in its development greatly increases the likelihood of a successful outcome, in which your child can resume full activities, including sports.    

Q: What are the signs and symptoms of hip impingement?
A: Some signs and symptoms can include:

• stiffness in the groin or front of the thigh
• inability to flex the hip beyond a right angle
• pain in the groin during/after the hip has been flexed, such as running, jumping or prolonged sitting

Q: How does Children’s treat hip impingement?
A: Conservative approaches to treatment may include:

• rest
• activity restrictions
• anti-inflammatory and pain medications
• exercises and physical therapy

If these don’t alleviate your child’s discomfort, doctors may perform:

• arthroscopic or open surgery (the surgical approach and techniques depend on the cause of the condition and the degree of cartilage damage that’s already occurred)
  • Most impingements that need surgery are treated arthroscopically.
  • Open surgery can be needed if the impingement involves an abnormal angle of the hip joint.
  • Surgical techniques address the elements of hip impingement—including damaged cartilage, labral tear and friction between the ball and socket.

Q: How long will it take for my child to heal?

A: After surgery, your child will need to limit his weight-bearing, perhaps with crutches or a walker, for a few weeks. Physical therapy will help him restore his muscle strength. He’ll probably be able to resume full activities, including sports, after three or four months.

Q: If my child has hip impingement, what should I ask my Children’s doctor?
A: Some of the questions you may want to ask include:

• Could you describe what’s wrong with my child’s hip joint?
• Are other tests needed to confirm this diagnosis?
• Is there, or could there be, damage to his tissues or blood vessels?
• Does my child need treatment? Does he need surgery?
• Will hip impingement affect his growth plate and the normal growth of his leg?
• How long will it take for him to heal?
• Will he need to use crutches? If so, when, and for how long?
• Will he need rehab or physical therapy?
• Will there be restrictions on my child’s activities? If so, for how long?
• Could there be long-term effects? Pain? Arthritis?
• How long should my child be followed by his care team?
• What can we do at home?

Q: How is hip impingement usually diagnosed?
A: Besides a complete medical history and physical exam, tests for hip impingement may include:

• x-rays
• MRI (magnetic resonance imaging)

Q: If my child has hip impingement in one hip, can he develop it in the other hip, too?
A: Hip impingement can develop in one hip, or both.

Q: What are the causes and risk factors for hip impingement?
A: Hip impingement is caused by the abnormal development of the bones of the hip joint that ultimately causes damage to the joint’s cartilage. While exercise itself probably doesn’t cause hip impingement, young athletes with the condition may experience pain sooner than their less active peers.

• Babies may be born with hip impingement (congenital).
• Children, teens and adults may develop hip impingement (acquired).
• Most likely, hip impingement develops from a combination of genetics and environment.
• The condition is somewhat common in teen and young-adult athletes
  • Significant athletic activity, including contact sports, before skeletal maturity in the teen years is a possible but unproven cause.
• There’s some evidence that cam impingement may be more common in males, while pincer impingement may be more common in females.

Q: What’s the long-term outlook for a child who has hip impingement?
A: The long-term result of surgery depends on the amount of cartilage damage present at the time of surgery. Perfect outcomes are possible with early joint-preserving treatments before the cartilage is damaged. But even surgery may not be able to fully repair impingement if the cartilage has already been severely damaged. This is why diagnosing and treating your child’s hip impingement early in its development greatly increases the likelihood of a successful outcome, in which your child can resume full activities, including sports.

Q: What is Children’s experience treating hip problems in children and teens?
A: At Children’s, we’re known for our clinical innovations, breakthrough research and leadership in treatment for hip impingement and other hip problems. We offer the most advanced diagnostics and treatments—several of which were pioneered and developed by Children’s own researchers and clinicians.

Teens and young adults with hip problems usually need diagnostic and surgical techniques that differ significantly from what’s indicated for younger children. Children’s Child and Adult Hip Preservation Program is the only program of its kind in the world. We offer the extensive experience and advanced techniques of clinicians and researchers dedicated to finding better ways to care for adolescents and young adults with hip problems.

Causes

Hip impingement is caused by the abnormal development of the bones of the hip joint that ultimately causes damage to the joint’s cartilage. While exercise itself probably doesn’t cause hip impingement, young athletes with the condition may experience pain sooner than their less active peers.

• Babies may be born with hip impingement (congenital).
• Children, teens and adults may develop hip impingement (acquired).
• Most likely, hip impingement develops from a combination of genetics and environment.
• The condition is somewhat common in teen and young-adult athletes.
  • Significant athletic activity, including contact sports, before skeletal maturity is a possible but unproven cause.
• There’s some evidence that cam impingement may be more common in males, while pincer impingement may be more common in females.

Signs and symptoms

Some signs and symptoms can include:

• stiffness in the groin or front of the thigh
• inability to flex the hip beyond a right angle
• pain in the groin during/after the hip has been flexed, such as running, jumping or prolonged sitting

When to seek medical advice

Contact your child’s doctor if he:

• has stiffness in the groin or front of the thigh
• is unable to flex the hip beyond a right angle
• has pain in the groin during/after the hip has been flexed, such as running, jumping or prolonged sitting

Questions to ask your doctor

If your teen or child is diagnosed with hip impingement, you may feel a bit overwhelmed. It can be easy to lose track of the questions that occur to you. Lots of parents find it helpful to jot down questions as they arise—that way, when you talk to your child’s doctors, you can be sure that all your concerns get addressed.

Some of the questions you may want to ask include:

• Could you describe what’s wrong with my child’s hip joint?
• Are other tests needed to confirm this diagnosis?
• Is there, or could there be, damage to his tissues or blood vessels?
• Does my child need treatment? Does he need surgery?
• Will hip impingement affect his growth plate and the normal growth of his leg?
• How long will it take for him to heal?
• Will he need to use crutches? If so, when, and for how long?
• Will he need rehab or physical therapy?
• Will there be restrictions on my child’s activities? If so, for how long?
• Could there be long-term effects? Pain? Arthritis?
• How long should my child be followed by his care team?
• What can we do at home?

Who’s at risk

Risk factors that increase the likelihood of hip impingement include the following:

• Babies may be born with hip impingement (congenital).
• Children, teens and adults may develop hip impingement (acquired).
• Most likely, hip impingement develops from a combination of genetics and environment.
• The condition is somewhat common in teen and young-adult athletes
  • Significant athletic activity, including contact sports, before skeletal maturity in the teen years is a possible but unproven cause.
• There’s some evidence that cam impingement may be more common in males, while pincer impingement may be more common in females.

Complications

The vast majority of surgical treatments for hip impingement at Children’s occur without major complications. But patients who’ve had surgery for the condition are at a very small risk for infection, bleeding or poor bone healing (malunion).

Long-term outlook

The long-term result of surgery depends on the amount of cartilage damage present at the time of surgery. Perfect outcomes are possible with early joint-preserving treatments before the cartilage is damaged. But even surgery may not be able to fully repair impingement if the cartilage has already been severely damaged. This is why diagnosing and treating your child’s hip impingement early in its development greatly increases the likelihood of a successful outcome, in which your child can resume full activities, including sports.

For teens

If you’re a teen with a developmental hip problem, you have a lot to cope with. Besides the typical issues any teenager faces—from social acceptance to body changes and more—you may also be dealing with pain; medical appointments and procedures; and limiting some of your activities for a period of time.

If you’re an athlete or an active person, to be experiencing pain or sitting on the sidelines for a while can be depressing and frustrating. If you feel down, angry or anxious through this important time in your life, speak to your doctor, parent or counselor to get help—they’re all on your team, and they want to help you. And remember that Children’s Child and Adult Hip Preservation Program is always here for you, too.

Hip impingement glossary

• acetabulum: hip socket; a part of the pelvis
   
• arthritis (osteoarthritis): joint inflammation, resulting in pain, swelling, stiffness and limited movement. Arthritis can occur when a joint’s cushioning cartilage wears away
   
• arthroscopy: minimally-invasive procedure to repair a damaged joint; through a small incision, a scope “sees” the joint and the surgeon uses instruments for repair
   
• avascular necrosis (osteonecrosis): a condition in which poor blood supply to a bone leads to bone death; the head of the femur is a common site of this condition in a condition called Legg-Calvé-Perthes disease. This disease can be associated with hip impingement.
   
• The Center for Families at Children’s: dedicated to helping families find the information, services and resources they need to understand their child’s medical condition and take part in their care
   
• cam impingement: one of the types of hip impingement; the femoral head is not round and cannot rotate smoothly inside the acetabulum. A bump forms on the edge of the femoral head that grinds the cartilage inside the acetabulum
   
• cartilage: smooth, rubbery tissue that cushions the bones of a joint and other areas; allows the bones to move easily without pain
   
• diagnosis, diagnostics: identifying disease or injury through examination, testing and observation
   
• femoral acetabular impingement (FAI, hip impingement): medical term for hip impingement; a mechanical disorder of the hip in which the hip’s usually smooth gliding motion is disturbed by bony deformities, causing friction between the thigh bone (femur) and the bone socket (acetabulum), which can wear away at the cartilage and tear the labrum.
   
• femoral head: round-headed top of the thigh bone (femur)
   
• femur: the thigh bone, the longest and strongest of your child’s bones. The rounded top of the femur (femoral head) joins the hip socket (acetabulum) to form the hip joint
   
• hip impingement: another term for femoral acetabular impingement (FAI); a mechanical disorder of the hip in which the hip’s usually smooth gliding motion is disturbed by bony deformities, causing friction between the thigh bone (femur) and the bone socket (acetabulum), which can wear away at the cartilage and tear the labrum.
   
• labrum: a gristle-like, fibrous lining around the rim of the hip socket (acetabulum) whose cushioning characteristics provide hip joint stability and reduce friction in the joint; can be torn in hip impingement
   
• MRI (magnetic resonance imaging): a diagnostic procedure that uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within the body
   
• onset (of signs or symptoms): the first appearance of signs or symptoms
   
• open reduction surgery: a procedure in which the doctor repositions the hip bone into the socket through an incision into the patient’s body
   
• orthopedic surgeon, orthopedist: a doctor who specializes in surgical and non-surgical treatment of the skeletal system, spine and associated muscles, joints and ligaments
   
• orthopedics: the medical specialty concerned with diagnosing, treating, rehabilitating and preventing disorders and injuries to the spine, skeletal system and associated muscles, joints and ligaments
   
• osteonecrosis (avascular necrosis): the death of a bone due to loss of blood supply
   
• pincer impingement: one of the types of hip impingement; extra bone extends out over the normal rim of the acetabulum. The labrum can be damaged under the prominent rim of the acetabulum.
   
• physical therapy: a rehabilitative health specialty that uses therapeutic exercises and equipment to help patients improve or regain muscle strength, mobility and other physical capabilities
   
• slipped capital femoral epiphysis (SCFE): a hip joint condition in which a weakness of the growth plate (physis) in the upper end of the thigh bone (femur) causes the head, or "ball," of the thigh bone (femoral head, epiphysis) to slip off the neck of the thigh bone, much as a scoop of ice cream can slip off the top of a cone. SCFE is actually a fracture of the growth plate. It is often associated with hip impingement.
   
• x-rays: a diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film

  Unique expertise in problems of the adolescent hip

  Many teens and young adults with hip problems need diagnostic and surgical techniques that are significantly different from what’s indicated for younger children. Children’s Child and Adult Hip Preservation Program, led by Michael Millis, MD, and Young-Jo Kim, MD, is the only program of its kind in the world. We offer the extensive experience and advanced techniques of clinicians and researchers dedicated to finding better ways to care for adolescents and young adults with hip problems.