Hip Impingement

Technical Name: Femoro-acetabular Impingement (FAI)

AKA Name: Hip impingement

Short Summary:

In the normal ball and socket hip joint the smooth surfaces should move without causing pain or damage.  In some individuals the ball or the socket can be shaped abnormally which can result in damage to the hip joint itself or surrounding tissues that can therefore cause pain during movement.

What is impingement?

During the development of the hip joint in some individuals the ball forms with a slight flattening resulting in a ‘bump’ at the edge of the ball and in others there is an over growth of bone at the rim of the socket.  In either of these situations there is a subtle mismatch in the congruency of the ball and socket joint and results in some rubbing together of bone and tissue at the front of the hip.   Surrounding the edge of the socket is a structure called the ‘labrum’ that acts like a washer to help stabilize the ball in the socket.  Rubbing together of the ‘bony bump’ on this labrum can cause damage or a ‘tear’ that then generates pain and discomfort with movements of the hip.

There are two types of impingement that in some patients can co-exist:

  • Cam impingement – is where there is a subtle ‘bump’ on the ball (femoral head) which results in it not moving smoothly into the socket during movement.  This then can cause damage to the labrum and cartilage within the socket.
  • Pincer impingement – is where there is an overgrowth of bone from the superior rim of the socket (acetabulum) that again can cause excessive pressure and damage on the labrum of the hip socket.

What are the symptoms?

Patients often describe pain at the front of the hip and in the groin especially with movements including bending (flexing) and twisting.  As symptoms progress then you may find increasing difficulty in undertaking exercise such as cycling and certain swimming stokes.  Some patients experience the pain when sitting for long periods of time where others find it worse when standing or twisting.   

How is it diagnosed?

A detailed history is important in helping move towards the diagnosis of FAI.  Investigations normally start with an X-ray of the hips to look for any abnormality of the bones around the hip joint.  To investigate the soft tissue structures further it is common to then undergo an MRI scan sometimes with an injection of a dye into the hip joint to highlight the structures around the hip joint itself.  The MRI scan gives much more detail about the labrum, cartilage and soft tissue structures around the hip joint. 

How is it treated?

  • Non-operative treatment – this approach is successful in a large number of cases that starts with oral analgesia and a targeted physiotherapy rehabilitation regime.  If the symptoms persist then an injection into the hip joint can help improve things.
  • Operative treatment – if non-operative treatment has failed to improve symptoms significantly then the option of keyhole (arthroscopic) surgery may be discussed with you.  This is carried out through small incisions around the hip to repair or re-shape the labrum that is damaged and in some cases re-shape the bone around the femoral head (ball).     

Important: this information given above is only a guideline as is not complete.  For more information or to book an appointment please contact us.