Previous Acetabular Fracture

Key Points

• Preoperative planning to template implant position and size: The acetabular component should be lateralized to its anatomic location if the inferior hemipelvis has been displaced medially as a result of prior fracture.

• Identify the sciatic nerve: If the sciatic nerve is directly in the operative field required for acetabular reaming or is in close proximity to retained hardware that requires removal, then the nerve should be mobilized and protected.

• Selectively remove intraarticular retained hardware: If prior infection has occurred, or if concern has arisen that bacterial colonization of retained hardware is present, then staged removal of hardware followed by delayed total hip arthroplasty (THA) is appropriate. Hardware may be embedded in bone. If retained screws protrude into the reamed acetabular cavity and impinge on the acetabular cup, the hardware may limit seating and subsequent ingrowth of the component and should be removed. Hardware that directly protrudes into the acetabulum requires removal. Reaming can be performed before hardware is removed; if intraarticular plates and screws are encountered, they should be removed.

• Bone graft acetabular defects or fill defects with modular porous metal augments: Primary support of the acetabular cup on host bone is necessary to provide implant stability and osteointegration. Contained cavitary defects are effectively treated with morselized autograft from acetabular reamings or the femoral head. Peripheral defects, if present and if they compromise the stability of the implant, can be augmented with structural femoral head autograft or metal augments.

• Use a large cementless cup or cage with screw fixation: Although areas of bone deficiency typically are present after prior acetabular fracture, the remaining bone may be relatively sclerotic, which generally provides adequate mechanical support for a cementless cup with screw fixation. Ingrowth into the porous coating can be compromised owing to poor vascularity of bone after prior fracture and newer porous metal cups may provide better long-term durability. However, if the bone quality is poor or segmental peripheral bone loss is present, then a reconstruction cage may be necessary to gain adequate fixation to the pelvis.

• Radiation therapy or nonsteroidal anti-inflammatory drugs (NSAIDs): After prior acetabular fracture and open reduction internal fixation (ORIF), heterotopic ossification (HO) can form. If a substantial amount of HO is removed during THA, then perioperative radiation therapy or postoperative treatment with NSAIDs should be used to minimize the risk of recurrent HO formation following THA.