Femoral Acetabular Impingement (FAI): A Comprehensive Guide to Diagnosis

Femoral Acetabular Impingement (FAI)

Femoral Acetabular Impingement (FAI) is a condition that affects the hip joint, causing pain and discomfort. It occurs when the bones of the hip joint are not shaped correctly, causing them to rub against each other during movement. This friction can damage the joint, leading to pain and reduced mobility.

FAI is a common cause of hip and groin pain, especially among people between the ages of 20 and 45. It can be caused by a variety of factors, including genetics, overuse, and trauma. Symptoms of FAI can include pain in the hip or groin area, limited range of motion, and a clicking or locking sensation in the hip joint.

Diagnosing FAI can be challenging, as the symptoms can be similar to those of other conditions. However, with the right diagnostic tools, including imaging tests and a thorough physical examination, doctors can accurately diagnose FAI and develop a treatment plan that is tailored to the individual patient.

Key Takeaways

  • FAI is a condition that affects the hip joint, causing pain and discomfort.
  • It can be caused by a variety of factors, including genetics, overuse, and trauma.
  • Accurate diagnosis is essential for developing an effective treatment plan.

Understanding Femoral Acetabular Impingement

Femoral acetabular impingement (FAI) is a condition that occurs when there is an abnormal shape of the ball and socket of the hip joint. This abnormality can lead to abnormal contact and rubbing of the bones during movement, which can cause pain and damage to the hip joint.

There are three types of FAI: cam, pincer, and mixed morphology. Cam FAI occurs when there is an abnormality in the shape of the femoral head, which can cause it to rub against the acetabulum. Pincer FAI occurs when there is an overgrowth of bone around the acetabulum, which can cause it to rub against the femoral head. Mixed morphology FAI is a combination of both cam and pincer FAI.

Picture of the different types of FAI
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FAI can affect people of all ages, but it is most common in young adults and athletes. It can be caused by a variety of factors, including genetics, structural abnormalities, and repetitive hip movements.

Symptoms of FAI can include hip pain, stiffness, and limited range of motion. These symptoms can worsen with physical activity and can affect a person’s ability to perform daily activities.

To diagnose FAI, a doctor will perform a physical exam and may order imaging tests, such as X-rays or an MRI. Treatment for FAI may include physical therapy, pain management, and in some cases, surgery.

Overall, understanding the causes and symptoms of FAI is important in order to receive an accurate diagnosis and appropriate treatment.

Causes and Risk Factors for Acetabular Impingement

Femoroacetabular Impingement occurs when the bones of the hip joint are not shaped properly, causing them to rub against one another.

FAI can develop during childhood and adolescence when the bones are still developing. It can also occur later in life due to injury or overuse. Some people are born with a deformity that can lead to FAI. Others may develop a bump on the femoral head or the rim of the acetabulum due to injury or wear and tear.

Femoral Acetabular Impingement (FAI): A Comprehensive Guide to Diagnosis

FAI can also have a genetic component. If a family member has FAI, there is a higher chance that an individual will also develop it.

Athletes, particularly those who participate in sports that require repetitive hip movements, are at a higher risk of developing FAI. Women are also more likely to develop FAI than men, possibly due to differences in hip anatomy.

Risk factors for FAI include a history of hip problems, such as hip dysplasia, and certain occupations that require repetitive hip movements. Being overweight can also increase the risk of developing FAI.

It is important to note that not everyone with FAI will experience symptoms. However, if left untreated, FAI can lead to hip labral tears, cartilage damage, and osteoarthritis.

Symptoms of Femoroacetabular Impingement

The symptoms of FAI can vary from person to person. Some people may experience no symptoms at all, while others may experience severe pain and limited mobility.

The most common symptom of FAI is hip pain, which can be felt in the groin, thigh, or buttock. The pain is often described as a dull ache or a sharp stabbing pain. The pain may be worse during certain activities, such as running, jumping, or twisting.

Possible Pain Referral in Patients with FAI

In addition to hip pain, people with FAI may experience stiffness in the hip joint. They may also have a limited range of motion, making it difficult to perform activities that require bending or twisting at the hip. Some people may also limp due to the pain and stiffness.

Another symptom of FAI is clicking, catching, or locking of the hip joint. This can occur when the bones of the hip joint rub against each other, causing a snapping or popping sensation. The clicking, catching, or locking may be more noticeable during certain activities, such as walking up stairs or getting out of a chair.

Prolonged sitting can also exacerbate the symptoms of FAI. People with FAI may experience increased pain and stiffness after sitting for long periods of time. This can make it difficult to perform activities that require sitting for extended periods, such as driving or working at a desk.

Overall, if you are experiencing hip pain, stiffness, or limited mobility, you must see a healthcare professional for an accurate diagnosis and treatment plan.

Diagnosing FAI: The Process

Diagnosing FAI involves comprehensively evaluating the patient’s medical history, physical examination, and imaging tests.

The first step in the diagnosis process is to identify the source of the patient’s pain. The doctor or medical professional, such as a physical therapist, will ask the patient about the location, duration, and intensity of the pain. They will also ask about any activities that may worsen the pain, such as walking, running, or sitting for extended periods.

Next, the doctor will perform a physical exam to assess the range of motion and strength of the hip joint. They may also perform an impingement test, such as the FADIR (Flexion, Adduction, and Internal Rotation) test, which involves bending the hip and rotating it inward to see if it causes pain.

The doctor will also take a detailed medical history to determine if the patient has any underlying medical conditions that may contribute to the pain.

X-rays are often used to diagnose FAI because they can show any abnormalities in the shape of the hip joint. However, imaging tests such as magnetic resonance imaging (MRI), computed tomography (CT) scans, or magnetic resonance arthrography may be necessary to get a more detailed view of the hip joint. These tests can show any damage to the labrum or cartilage, which may be contributing to the patient’s pain.

MRI of a Labral Tear and FAI
MRI of a Labral Tear with FAI

Advanced imaging techniques are typically done if conservative care, such as physical therapy, is not successful in treating the patient’s pain. Patients may get frustrated that an MRI is not ordered right away, but this is often not necessary for most cases.

In some cases, a CT scan may be necessary to get a more detailed view of the bones in the hip joint. This can help the doctor determine if surgery is necessary to correct any abnormalities in the joint.

Even at this point, it’s important to make sure that the pain is truly coming from the FAI and not muscular compensations or weakness. An orthopedic doctor will likely inject the hip and area of impingement. If this takes the pain away and it matches the imaging studies, then your pain is likely due to FAI. If the injection does not change the pain, then the true cause of pain may be due to muscular dysfunction that needs to be teased out.

Types of Femoroacetabular Impingement

There are three types of FAI: cam impingement, pincer impingement, and combined impingement.

Cam Impingement

Cam impingement occurs when the femoral head is not shaped properly, causing it to rub against the acetabulum. This type of impingement is characterized by a bony bump on the femoral head, which prevents it from fitting properly into the acetabulum. This can cause damage to the articular cartilage and labrum, leading to pain and discomfort in the hip joint.

Pincer Impingement

Pincer impingement occurs when extra bone extends out over the normal rim of the acetabulum. This type of impingement can cause the labrum to be crushed under the prominent rim of the acetabulum. Pincer impingement can also damage the articular cartilage and labrum, causing pain and discomfort in the hip joint.

Combined Impingement

Combined impingement is a combination of both cam and pincer impingement. This type of impingement can cause significant damage to the hip joint, leading to pain, discomfort, and limited mobility.

Associated Conditions of FAI

FAI can lead to various associated conditions, including hip osteoarthritis, labral tears, and avascular necrosis.

Hip osteoarthritis is a common condition that can develop due to FAI. This condition occurs when the articular cartilage in the hip joint begins to wear away, causing the bones to rub against each other. This can lead to pain, stiffness, and swelling in the hip joint.

Labral tears are another commonly associated condition with FAI. The labrum is a ring of cartilage that surrounds the acetabulum (socket) of the hip joint. When the femoral head (ball) pinches up against the acetabulum, damage to the labrum can occur, causing hip stiffness and pain.

Avascular necrosis is a more severe associated condition that can occur if FAI is left untreated. This condition occurs when the blood supply to the femoral head is disrupted, causing the bone tissue to die. This can lead to a collapse of the femoral head and severe joint damage.

Other conditions that can be associated with FAI include:

  • Slipped capital femoral epiphysis
  • Dysplasia
  • Joint degeneration
  • Perthes disease.

Slipped capital femoral epiphysis occurs when the ball at the top of the femur slips out of place within the hip socket. Dysplasia is a condition where the hip joint does not develop properly, leading to an increased risk of joint damage. Degeneration occurs when the hip joint wears down over time, leading to arthritis. Perthes disease is a condition that affects children where the blood supply to the femoral head is disrupted, causing bone tissue to die.

Treatment Options for FAI

Once an FAI diagnosis has been made, there are several treatment options that can be explored. The underlying problem with FAI is a bony abnormality, so treatment will depend on the severity of the impingement and the presence of symptoms.

Rest and Activity Modification

In mild cases of FAI, rest and activity modification may be enough to alleviate symptoms. This may include avoiding activities that exacerbate pain, such as high-impact sports or activities that require repetitive hip flexion. Rest may also be recommended to reduce inflammation and allow the hip joint to heal.

Physical Therapy

Physical therapy is highly recommended to help improve hip joint function and alleviate pain. A physical therapist can develop a customized exercise program that includes stretching and strengthening exercises specific to FAI to improve the range of motion and reduce pain. They may also use manual therapy techniques to help improve joint mobility.

single leg bridge

Injection Therapy

Injection therapy may be used to reduce inflammation and alleviate pain. This may include the use of local anesthetics or corticosteroids to target the affected joint. Nonsteroidal anti-inflammatory medications (NSAIDs) may also be prescribed to help reduce inflammation and pain.

Surgery

In severe cases of FAI, surgery may be recommended. The goal of surgery is to reshape the bones of the hip joint to reduce impingement and improve joint function. There are two types of surgery for FAI: arthroscopic surgery and open surgery. Arthroscopic surgery is less invasive and involves smaller incisions, while open surgery involves a larger incision and may be recommended for more complex cases.

Overall, treatment options for FAI will depend on the severity of the impingement and the presence of symptoms. Rest and activity modification, physical therapy, injection therapy, and surgery may all be recommended to help alleviate pain and improve joint function.

Surgical Treatments

When conservative treatments fail to provide relief, surgical intervention may be necessary for patients with FAI. Surgery for FAI can be performed using hip arthroscopy or open surgery.

In hip arthroscopy, the hip is distracted and an arthroscope (a video camera about the size of a pen) is used to look in the joint to see and treat damage that is found using two to five incisions that are about ΒΌ inch in size. Often, all of the components of FAI such as bone spurs, labral tears, and cartilage damage can be treated with hip arthroscopy. Recovery time is typically shorter with hip arthroscopy than with open surgery.

Open surgery may be necessary for patients with more advanced stages of FAI. During an open operation, a larger incision is made to allow the surgeon to see and repair the damage. This type of surgery may be recommended if the hip joint is severely damaged or if there are significant bone abnormalities that cannot be corrected with arthroscopy.

Both arthroscopic hip surgery and open surgery have their own risks and benefits. Patients should discuss the options with their surgeon to determine which procedure is best for their individual case.

Overall, surgical treatment for FAI has advanced significantly in recent years, and with proper diagnosis and treatment, patients can often return to their normal activities without pain.

Recent Research and Advances

Recent research and advances in the diagnosis and treatment of Femoral Acetabular Impingement (FAI) have been promising. One study found that siblings of individuals with FAI were more likely to have the condition themselves, suggesting a genetic component to FAI. This information can be useful in identifying individuals who may be at higher risk for developing FAI and can aid in early detection and treatment.

Magnetic Resonance Imaging (MRI) and CT scans have become increasingly important in the diagnosis of FAI. MRI can provide detailed images of the soft tissue structures around the hip joint, such as the labrum and cartilage, while CT scans can provide detailed images of the bony structures of the hip joint. These imaging techniques can aid in the diagnosis of FAI and help determine the appropriate treatment plan.

Advances in arthroscopic surgical techniques have also improved the treatment options for FAI. Arthroscopic surgery is a minimally invasive procedure that allows surgeons to access the hip joint and make repairs without the need for large incisions. This technique can reduce recovery time and improve outcomes for patients with FAI.

Overall, recent research and advances in the diagnosis and treatment of FAI have provided valuable insights into the condition and improved treatment options for patients. With continued research and advancements, it is likely that even more effective treatment options will become available in the future.

Frequently Asked Questions

Conclusion

Femoroacetabular impingement (FAI) is a condition that can cause hip and groin pain, especially among people between the ages of 20 and 45. It occurs when the bones of the hip joint are not shaped properly, causing them to rub against one another. FAI can be diagnosed through physical examination, imaging tests, and arthroscopy.

If left untreated, FAI can lead to early osteoarthritis of the hip. However, with proper diagnosis and treatment, most people with FAI can return to their normal activities without pain or limitations. Treatment options include rest, physical therapy, medication, and surgery.

It is important to note that not all hip pain is caused by FAI, and not all people with FAI experience symptoms.

Therefore, it is important to seek medical attention if you experience hip or groin pain, especially if it is persistent or severe.

In conclusion, if you suspect that you may have FAI, it is important to consult with a healthcare professional who can provide an accurate diagnosis and recommend appropriate treatment options. With proper care, most people with FAI can manage their symptoms and maintain their quality of life.

About the Author

Mark Davis, DPT, OCS
Mark Davis is a physical therapist passionate about helping his patients improve their mobility and reduce pain. He has over 15 years of experience in the field and has worked with patients of all ages and backgrounds. Mark earned his orthopedics specialist certification and loves treating all things musculoskeletal. Mark is dedicated to providing personalized care and developing individual treatment plans to meet his patients’ needs. He enjoys playing golf and spending time with his family in his free time.