Hip impingement

The hip joint is a ball-and-socket joint which is formed by the thigh bone and the pelvis. In people with a healthy joint, the ball glides smoothly in the socket. But if the ball or the socket has an abnormal shape, it can interfere with the smooth motion. This leads to the problem called hip impingement (also called femoro-acetabular impingement). Due to a restricted movement, cartilage damage occurs over time causing pain and even arthritis. Osteoarthritis is majorly caused due to hip impingement, especially in people aged below 40 years.

Symptoms

In the early stages of hip impingement, often symptoms are not evident leading to an under diagnosis. In some patients, the hip impingement goes unnoticed for few years. Some of the typical symptoms include:

  • Stiffness in the hip, thigh, or groin
  • Limited range of motion (flexion of the hip beyond a right angle is not possible/difficult)
  • Pain in the groin region felt especially after the hip has been flexed (for example, after running, jumping or extended periods of sitting down)
  • Pain in the groin, hip, or lower back that occurs not only during activity but also while taking rest

Types of Hip Impingement

There are about two main types of hip impingement:

Cam impingement: This condition occurs due to the imperfection in the ball-shaped head of the thigh bone.
Pincer impingement: This condition occurs due to excessive coverage of ball by the socket.Also, both the types can co-exist in some cases.

Complications

If hip impingement is left untreated, it can lead to cartilage damage and thus, osteoarthritis.

A quick diagnosis helps the doctor in initiating the treatment as soon as possible. Diagnosis begins with taking a complete medical history. Following which, a physical examination is performed to check the range of motion of the hip joint. Further, your doctor will order one or more of the below imaging tests:

Test type Purpose of the test
X-ray To observe the two-dimensional image of the hip joint.
Computed tomography (CT) To observe a series of small images produced at different angles and construct a three-dimensional (3D) image of the hip joint. It shows detailed structures of the joint.
Magnetic resonance imaging (MRI) To observe the 3D image of the hip joint including soft tissue cartilage and labrum.

Treatment is based on the type of the hip impingement and its severity. In some patients, conservative therapies are successfully helpful in managing the condition. They include:

  • Resting the affected leg
  • Physiotherapy (certain exercises are recommended by your physical therapist to strengthen the muscles)
  • Reducing certain types of physical activity
  • Taking medications to manage pain and inflammation

  • If there is no relief with the above therapies, then you may have to undergo surgery. The type of surgery is based on the cause of the hip impingement and the extent of damage to the cartilage. The surgical procedures include:

  • Reshaping the ball or the socket using certain tools
  • Arthroscopy, which uses a light scope and tools inserted through the small incision made over the joint
  • Microfracture technique in which your surgeon cuts away the worn out cartilage or drill holes in the bone to stimulate the growth of such cartilage.
  • In the case of severe damage, hip replacement surgery can help to improve the function of the joint.

Hip impingement can occur in people of any age group, including adolescents and young adults.

Hip impingement occurs either due to the deformed femoral neck or femoral head or a large hip socket that covers femoral head to a greater extent.

Recurrent and repetitive movement of the hip joint (legs) beyond the range of motion can lead to hip impingement. This is more common in people who play certain sports such as football or hockey.

Any injury to the hip joint also can cause symptoms of hip impingement.

Other conditions that can cause hip impingement are:

  • Legg-Calve-Perthes disease - inadequate blood supply to the ball portion leading to the death of the tissue

  • Coxa vara - different growth paces of thigh bone and ball leading to deformity of the joint

  • Slipped capital femoral epiphysis -detachment of the ball from the thigh bone, commonly seen in obese children