You may be experiencing symptoms of osteoarthritis (OA) but it’s also possible that you have a hip condition such as femoroacetabular impingement (FAI). Femoroacetabular impingement (FAI) refers to some portion of the soft tissue around the hip socket getting pinched or compressed. Femoroacetabular tells us the impingement is occurring where the femur (thigh bone) meets the acetabulum (hip socket).
There are several different types of impingement. They differ slightly depending on what gets pinched and where the impingement occurs. Anatomic abnormalities of the femur and/or the acetabulum predispose the person to damage of the soft tissue structures inside the joint. Vigorous, repetitive hip motion creates abnormal contact and collision that result in hip pain.
The pain comes on slowly at first. Symptoms remain centered around the hip but can travel down the leg (rarely going into the buttocks or past the knee). Rest usually does relieve symptoms of osteoarthritis but when femoroacetabular impingement is present, symptoms are made worse by prolonged hip flexion (sitting). If this is the problem, you may lose hip motion (especially hip flexion and internal rotation). An X-ray will show the changes in the hip typically associated with femoroacetabular impingement (FAI).
For an accurate diagnosis, you will need to see your primary care physician or an orthopedic surgeon. The physician who examines you will assess three areas: 1) symptoms of FAI, 2) positive hip impingement test pain with hip flexion and internal rotation), and 3) imaging findings seen with FAI (e.g., increased alpha angle, bone cysts from impingement, increased lateral center-edge angle).