Search. The hip (acetabulofemoral joint) is a synovial joint formed by articulation between the femur and acetabulum of the pelvis. The head of the femur is cover by type II collagen (Hyaline cartilage) and proteoglycan.The acetabulum is the concaved portion of the ball and socket joint.The acetabulum has a ring of fibrocartilage called the labrum that deepens the acetabulum and improves stability of the hip joint.earch. The hip (acetabulofemoral joint) is a synovial joint formed by articulation between the femur and acetabulum of the pelvis. The head of the femur is cover by type II collagen (Hyaline cartilage) and proteoglycan.