Fig. 6

Treatment methods for patients with long-term unreduced hip joint dislocation, secondary osteoarthritis and pseudoarthrosis. a Type A places the acetabular component at the position of the original acetabulum (similar to standard total hip arthroplasty). b Type B1 places the acetabular component at the position of the original acetabulum, with local structural bone grafting (or augment) on the posterior-superior wall of the acetabulum (similar to total hip arthroplasty in patients with DDH). c Type B2 places the acetabular component of small size (commonly 38 mm–42 mm) at the position of the original acetabulum without structural bone grafting (similar to total hip arthroplasty in patients with DDH). d Type C places the acetabular component at the position of the original acetabulum, with massive structural bone grafting (or acetabular augmentation). If the original acetabulum cannot be identified during surgery, the acetabular component can be placed at the position of the pseudoacetabulum with a restrictive liner or dual mobility hip system