9.1.1 Cause

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  Most commonly due to an underlying osteoarthritis.

  
  
• 
  

  A common presentation in the athlete with a femoral–acetabular impingement (CAM and pincer lesion).

  
  
• 
  

  May be secondary to trauma or overuse.

9.1.2 Presentation

Pain felt in the groin with referral into the anterior thigh region. Occasionally pain may radiate into the lower lumbar region.

If the cause of pain is osteoarthritis, the hip presents in a classic capsular pattern of restriction with a painful loss of the following:

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  Most internal rotation with a hard end feel.

  
  
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  Less extension.

  
  
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  Least abduction.

If the cause of pain is a femoral–acetabular impingement, pain may be reproduced with flexion, abduction, and internal rotation of the hip.

9.1.3 Equipment

See Table  9‑1.

9.1.4 Anatomical Considerations

The safest and easiest technique is to use an anterolateral approach. The clinician need not worry about any major blood vessels or nerves if this technique is used. The needle is directed toward the femoral head or the anterior femoral recess.

9.1.5 Procedure

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  The patient is positioned in the supine position with the knee flexed on a pillow to 20 degrees. The hip is in slight abduction.

  
  
• 
  

  The probe is positioned over the anterior aspect of the hip joint in the transverse oblique plane. This should be in the same plane as the femoral neck and approximately 45 degrees to the long axis of the femur.

  
  
• 
  

  The needle is directed along the long axis of the probe from an inferolateral aspect superomedially.

  
  
• 
  

  The target is the anterior aspect of the femoral head or the anterior femoral recess.

9.1.6 The Injection

See Fig.  9‑1 and Fig.  9‑2.

9.1.7 Notes

Using an anterolateral approach the femoral neurovascular structures are easily avoided. If there are concerns as to the position of these vessels, they may be imaged prior to injection by moving the probe medially and utilizing the Doppler function. Once the femoral neurovascular structures are seen, the probe can be moved back into line with the femoral neck and the injection can be given with confidence.

In the patient with mild to moderate osteoarthritis of the hip, injection may allow sufficient symptomatic relief to initiate a programme of rehabilitation.

As an alternative to corticosteroid injection a hyaluronan may result in longer-term symptomatic relief. Hyaluronan may be of particular benefit in the active patient with mild degenerative change.

In the patient with a mild femoral–acetabular impingement, injection of corticosteroid may be sufficient to settle symptoms so long as other factors such as tightness within the iliopsoas complex are addressed. In more severe cases of femoral–acetabular impingement, surgery may be required to address bony change or damage to the anterosuperior labrum. However, even in more severe cases of femoral–acetabular impingement, injection may be of diagnostic benefit and an indicator of the likely benefit of surgery.

9.2.1 Cause

Most commonly, an overuse injury particularly associated with sports and activities involving repeated flexion of the hip such as cycling.

9.2.2 Presentation

Pain is felt in the groin and anterior thigh and exacerbated with abduction and end-range flexion. Signs and symptoms can be difficult to distinguish from a femoral–acetabular impingement without imaging.

9.2.3 Equipment

See Table  9‑2.