Revision tha

Editor's Notes

• #2: In many patients, failure of total hip arthroplasty can be traced to one or more technical problems that occurred at the time of the primary procedure. - Revision requires more operative time and more blood loss, and the incidences of infection, thromboembolism, dislocation, nerve palsy, and perforation and fracture of the femur are higher.
• #3: Before proceeding with surgery, referral to other surgeons or a specialty center for additional opinions may be helpful. Every effort should be made to determine the cause of pain before considering exploration or revision.
• #4: - septic loosening- the findings of the history and physical examination are suggestive of infection, resorption of bone is considerable, the endosteal surface of the bone is scalloped, periosteal elevation is present, and the ESR or the CRP level is high. - The diagnosis of loosening is made by the clinical evaluation based on the history, physical examination, and radiographic findings. Pain associated with loose total hip components typically occurs with the first few steps a patient takes (“start-up” pain). A loose acetabular component usually produces pain in the groin, whereas a loose femoral component may cause pain in the thigh or the knee. Ancillary studies are seldom required, but comparison of previous radiographs often is helpful. If the bone loss associated with the loosening, or particle-induced osteolysis is severe or progressive, revision should be considered because symptoms are likely to worsen and further resorption of bone would make the procedure more difficult and the result less favorable.
• #5: - Poor-quality films often lead to underestimation of bone loss because areas of thinned cortex cannot be distinguished from adjacent cement.
• #6: A variety of short- and long-stem femoral components, calcar replacement stems, or stems with extended neck lengths are necessary to correct limb-length discrepancy, bone loss, and intraoperative femoral fracture. Acetabular components of 70 to 75 mm sometimes are needed to fill large acetabular deficiencies. Rarely, deficits are so irregular or the femur is so deformed that a custom-made component is the only solution.
• #21: - This task is delayed until after the acetabular component has been revised because persistent bleeding from the femoral canal obstructs the view of the acetabulum and adds to the operative blood loss.
• #35: A segmental deficiency is a complete loss of bone in the supporting rim of the acetabulum, including the medial wall. A cavitary deficiency is a volumetric loss in the bony substance of the acetabular cavity.
• #36: (Redrawn from Paprosky WG, Perona PG, Lawrence JM: Acetabular defect classification and surgical reconstruction in revision arthroplasty: a 6-year follow-up evaluation, J Arthroplasty 9:33, 1994.)
• #43: - When segmental and cavitary deficits occur simultaneously, the segmental defect is reconstructed first to restore the rim. Any remaining cavitary deficits are filled with particulate cancellous graft.
• #44: Pelvic discontinuity results from a transverse fracture of the acetabulum with complete separation between the superior and inferior halves. Antiprotrusio cages have been used for combined deficiencies and pelvic discontinuities with insufficient host-bone contact or stability for a hemispherical socket.
• #52: - Biomechanical studies have shown that the stress pattern of a tubular bone returns to normal at a distance of two bone diameters distant to a defect.