By now femoroacetabular impingement (FAI), hip impingement,
is well documented in the literature, although far from all orthopedic surgeons
are qualified to diagnose and treat hip impingement. But a ‘new’ form of
impingement, called subspine or AIIS (anterior inferior iliac spine) impingement
is a diagnosis that is increasingly recognized.
Why is this important? Because
in patients who have femoroacetabular impingement (high alpha angle and/or
version), type II and type III shapes of the AIIS are associated with a
decrease in hip flexion and internal rotation.
