Understanding Hip Joint Impingement: Causes, Symptoms, and Treatment of Femoroacetabular Impingement (FAI)

Cause

Femoroacetabular impingement (FAI) develops due to abnormal hip bone formation during growth in childhood. This structural irregularity, involving a cam or pincer bone spur or both, ultimately contributes to joint damage and discomfort. When hip bones are shaped this way, preventive measures are limited, making FAI a challenge to avoid. The prevalence of FAI remains uncertain, and while some individuals with FAI may lead active lives without issues, symptoms often indicate cartilage or labral damage and can signal a progression of the condition. Athletes and highly active individuals might experience symptoms earlier due to greater hip joint use, but physical activity itself does not cause FAI.

Symptoms

Common symptoms of FAI include:

• Pain
• Stiffness
• Limping

Pain is typically concentrated in the groin area but may also be felt on the outer hip. Movements such as turning, twisting, or squatting may trigger a sharp, stabbing sensation, though some individuals may experience a dull ache instead.

Home Remedies

When symptoms first appear, try identifying any activities that may have triggered the pain. Adjusting your movements and allowing your hip to rest can help alleviate discomfort. Over-the-counter anti-inflammatory medications, such as ibuprofen or naproxen, can also relieve pain. If symptoms continue, consult a healthcare provider to pinpoint the cause of the pain and discuss treatment options. Ignoring persistent symptoms may lead to increased hip joint damage from FAI.

Doctor Examination

At your initial consultation, the doctor will review your overall health and assess your hip symptoms. A thorough hip examination will follow.

Impingement Test

During the examination, your doctor may perform an impingement test. In this test, your doctor will bring your knee up toward your chest and rotate it inward toward the opposite shoulder. If this motion replicates your hip pain, it indicates a positive result for impingement.  

Impingement test.

Imaging Tests

To accurately diagnose femoroacetabular impingement (FAI), your doctor may recommend a series of imaging tests.

• X-rays: X-rays provide detailed images of bone structure, allowing your doctor to identify the abnormal bone shapes characteristic of FAI. They can also reveal early signs of arthritis.
• Computerized Tomography (CT) Scans: CT scans offer a more precise view than standard X-rays, enabling your doctor to closely examine the specific irregularities in your hip's shape.
• Magnetic Resonance Imaging (MRI) Scans: MRI scans produce clearer images of soft tissues, helping to detect damage to the labrum and articular cartilage. Adding a dye to the joint before the MRI can further enhance visibility of any damage.
• Local Anesthetic Injection: As a diagnostic measure, your doctor may inject a local anesthetic into the hip joint. Temporary relief from this injection can confirm FAI as the source of your pain.

Treatment

Nonsurgical Treatment

• Activity Modifications: Your doctor may suggest adjusting your daily activities and avoiding movements that trigger symptoms.
• Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Prescription-strength NSAIDs, such as ibuprofen, may be recommended to help manage pain and reduce inflammation.
• Physical Therapy: Targeted exercises can enhance hip mobility and strengthen muscles around the joint, helping to alleviate stress on the affected labrum or cartilage.

Surgical Treatment

If imaging tests reveal significant joint damage from FAI and nonsurgical treatments do not provide sufficient relief, your doctor may advise surgery as a treatment option.  

(Left)'X-ray shows a cam bump on the femoral head.'(Right)'After the bump has been shaved down during surgery.

Arthroscopy

Many issues related to femoroacetabular impingement (FAI) can be effectively addressed through arthroscopic surgery, a minimally invasive procedure using small incisions and specialized instruments. A tiny camera, called an arthroscope, allows the surgeon to see inside the hip joint. During an arthroscopic procedure, the surgeon can:

• Repair or remove damaged tissue from the labrum and articular cartilage
• Correct the FAI by reshaping the acetabulum's bony rim and smoothing the bump on the femoral head

In more severe cases, a traditional open surgery with a larger incision may be necessary to fully address the structural issues.  

(Left)'During arthroscopy, your surgeon inserts an arthroscope through a small incision about the size of a buttonhole.'(Right)'Other instruments are inserted through separate incisions to treat the problem.

 

Long-Term Outcomes

Surgery can effectively alleviate symptoms caused by femoroacetabular impingement (FAI), with joint correction often preventing further hip damage. However, surgical intervention may not completely reverse all existing damage, especially if treatment is delayed and the condition has progressed significantly. In some cases, additional issues could arise over time. While there remains a slight chance that surgery may not fully relieve symptoms, it currently represents the most effective option for managing painful FAI.

Future Developments

As surgical outcomes continue to improve, it is likely that doctors will begin recommending earlier intervention for FAI. Advancements in surgical techniques are ongoing, with some surgeons now utilizing computer-based navigation systems to assist in planning and guiding bone resection procedures for FAI correction.