Surgical interventions for cam-type FAI include osteoplasty of the anterior portion of the femoral neck-head junction (Fig. 12), relieving the cause of impingement, arthroscopic debridement of labral tears and possible removal of foreign bodies [57].
We believe the retroversion is the greater cause of impingement and obligate out-toeing when walking and sitting while the varus deformity is more related to the limb length inequality and trochanteric impingement.
An explanation for this difference is that orthopaedic surgeons commonly need to determine the cause of impingement when preparing for operative treatment.
The orthopaedic surgeon has the highest percentage in correctly diagnosing impingement and is significantly more accurate than radiologist 2. Furthermore, the orthopaedic surgeon is significantly the most accurate observer in determining the cause of impingement.
The description of a safe technique for surgical dislocation of the hip and MRI studies describing the alpha angle and decreased head-neck offset as potential causes of idiopathic impingement were also published prior to 2003, laying the foundation for this concept and its treatment.
The proximal femoral abnormalities characteristic of SCFE are a well-known cause of femoroacetabular impingement (FAI) [6, 7, 8].
Cam hip shape morphology is a recognised cause of femoroacetabular impingement (FAI) and is associated with hip osteoarthritis.
Cam-type FAI may be congenital or due to developmental dysplasia of the hip, slipped capital femoral epiphysis, trauma or avascular necrosis [14] but contrary to slipped capital femoral epiphysis and growth abnormalities of the femur congenital dysplasia is a rare cause of cam impingement because the head-neck junction in these patients is usually normal.
Intraoperatively, during the second revision, a large amount of ectopic bone was found in the lesser trochanter area (Fig. 4b), which is a possible cause of stem impingement and, in particular, the neck stem interface, which may lead to dissociation due to repetitive stresses and micromovement in the area.
