Hip Degeneration and FAI

Hip- Degenerative Pain

Hip Degeneration1

Avascular necrosis most commonly occurs in the hip joint often as a sequela of prior trauma, metabolic abnormality or vasculopathy. 

Early AVN may be radiographically occult. Early features include crescentic subchondral sclerosis which can later progress to subchondral collapse.

Crescentic subchondral lucency, articular surface collapse, and flattening of the femoral head distinguish this process, often leading to extensive secondary osteoarthritis and remodeling at the affected hip joint.

MRI is more sensitive for early changes of AVN

 

 

 

 

FINDINGS: Right hip joint space narrowing, subchondral sclerosis and cystic change with irregular flattening of the femoral head, consistent with advanced subchondral collapse in the setting of avascular necrosis. 

Hip Degeneration2

Acetabular protrusio

  • Medial displacement of the acetabulum and femoral head, such that the femoral head projects medial to the ilioischial line. (Fig A, B)

 

 

 

 

 

 

 

 

 

 

Coxa profunda

  • Medial displacement of acetabular socket which projects medial to ilioischial line. (Fig C)

Hip- FAI (femoroacetabular impingement)

Hip- FAI

FAI results from underlying morphologic abnormalities of the proximal femur and/or acetabulum which may cause repetitive abnormal contact and mechanical stress on the labrum and articular cartilage. 


Radiography can be used to identify abnormal morphology. CT and MRI are often used to obtain more detailed measurements and assess for associated soft tissue abnormalities to guide surgical treatment. 

  • Cam morphology- decreased femoral head-neck offset (fig a), best seen on Dunn lateral view
  • Pincer morphology- acetabular overcoverage (fig b), "crossover sign"
  • Mixed