Hip impingement, or Femoroacetabular impingement (FAI), is a condition where the bones in the hip joint are abnormally shaped, meaning the bones do not fit together perfectly. This causes the hip bones to rub against each other and causes damage to the joint.
In FAI, bone spurs develop around the thigh bone (femoral head) and along the acetabulum. The additional bone growth causes the hip bones to hit against each other, rather than moving smoothly within the joint. Over time, this can cause tearing of the labrum and a breakdown of articular cartilage (osteoarthritis).
Types of Femoroacetabular impingement (FAI)
- Pincer: form of impingement that occurs due to extra bone that extends out over the normal rim of the hip socket (acetabulum). This additional growth can cause damage to the labrum.
- Cam: describes a form of impingement where the femoral head is not round and cannot rotate smoothly inside the hip socket (acetabulum). This causes a bump to form on the edge of the thigh bone (femoral head) that grinds the cartilage inside the hip socket (acetabulum).
- Combined: meaning both the pincer and cam impingements are present.
Causes of Femoroacetabular impingement (FAI)
FAI occurs because the hip bones do not form normally during growth. It is the abnormal growth, or deformity, that causes the formation of cam bone spurs, pincer bone spurs, or both. The bone spurs form in the hip joint cause damage and pain to the joint. Activity level and exercise does not cause FAI.
People with FAI usually experience pain in the groin area. However, people may also experience pain toward the outside of the hip. People may experience a dull ache, or a sharp stabbing pain that occurs with turning, twisting, and squatting.
Your physician may order imaging tests to help further diagnosis the cause of your hip pain.
X-Rays: provide your physician with good images of the hip joint. From the x-ray, your doctor will be able to determine if your hip has abnormally shaped bones of FAI. X-rays can also show bone spurs and signs of arthritis.
Magnetic Resonance Imaging (MRI) Scans: studies used to take images of soft tissue, and help your physician locate any damage to the labrum and/or articular cartilage. Your physician may also inject dye, or contrast, into the hip joint to show damage more clearly. This is referred to as an MRI arthrogram.
Your physician will likely conduct an impingement test to try and recreate your hip pain. For this test, your doctor will bring your knee up towards your chest and rotate it inward towards your opposite shoulder. If the physician is able to recreate your hip pain, the test result is positive for impingement.
Conservative, nonsurgical treatment options can be used to address the symptoms of FAI. Changes in activity level may be recommended in order to avoid activities that cause symptoms. Medications can help ease any inflammation and reduce pain. Physical therapy can improve range of motion in your hip and strengthen the muscles that support the hip joint.
Most FAI issues can be treated with arthroscopic surgery. During this procedure your physician can correct the impingement by trimming the bony rim of the acetabulum and also by shaving down the bump on the femoral head. Additionally, your surgeon can clean out any damage to the labrum and articular cartilage during the procedure.
Post-Op Recovery for FAI Surgery
Following the procedure, patients are given crutches for 1-2 weeks to help minimize weight-bearing on the hip joint. A post-op appointment is usually held within 1-2 weeks after surgery to examine the patient’s progress and to remove sutures. Following the appointment, patients will typically begin a 6 week physical therapy program to improve strength and flexibility in the hip. After therapy is completed, and patients have been cleared by their physician, most patients can resume normal activities. However, it may take 3-6 months for patients to experience no soreness or pain in the hip joint.