Clinical evaluation begins with the patient's history, including knowledge of the patient's previous fracture type and surgeries performed. One should determine whether any complications exist from prior procedures. A history of the patient's functional status, activity level, and expectations is also useful for counseling.
During the physical examination, the clinician should assess gait pattern, abductor function, leg length discrepancy, rotational profile of the lower extremity, previous incisions, and neurovascular status. Inspection of incisions can establish what prior approach was used, soft-tissue quality, and the risk of subsequent wound healing complications.
Previous surgical notes and radiographs can provide useful information regarding the prior approach, types of implant used, intraoperative complications, and abductor muscle status. This information can determine what surgical approach is appropriate for reconstruction and what instruments can facilitate implant removal.
Preoperative radiographic evaluation begins with a low AP view of the pelvis as well as AP and lateral radiographs of the affected hip. These images are used for digital templating to allow accurate prediction of implant sizing[5,6] (Figure 2) The goal of reconstruction, as with routine primary hip arthroplasty, is to restore hip mechanics to as normal as possible. The contralateral, uninvolved hip is often useful for preoperative planning. The low AP view of the pelvis establishes derangements of hip biomechanics, including leg length, femoral offset, hip center of rotation, and trochanteric integrity.
Radiograph showing templating. Preoperative templating is vital to plan component positioning, fixation, and sizing. It is imperative for selecting femoral stem fixation that will obtain adequate stability and bypass prior bone defects. Templating also assists in managing leg length and offset restoration.
In patients with prior acetabular trauma, Judet views (Figure 3) can provide further evaluation of acetabular bone integrity. If the medial wall has been affected because of prior disruption from anterior and/or posterior column trauma, the surgeon must be constantly aware of this intraoperatively because reaming to the acetabular floor will place the cup medial to the anatomic position. For patients with prior femoral trauma, full length femur views can assist in evaluating femoral deformities and the distal extent of retained implants.
Judet views. In cases of prior acetabular fractures, Judet views can provide useful information on fracture healing and the integrity of the anterior and posterior columns.
Radiographs can make the surgeon aware of heterotopic ossification, either for purposes of planning excision or perioperative prophylaxis. This heterotopic ossification is classified according to the Brooker staging system. Previous implants can be evaluated to determine whether they are well fixed or loose, and whether removal is necessary for proper implant positioning. Acetabular and femoral bone deficiencies (Figure 1, A) can be assessed and classified according to the American Academy of Orthopaedic Surgeons or Paprosky systems.
CT with three dimensional reconstructions can provide additional information in cases of extensive heterotopic ossification, acetabular deformities, the integrity of the columns, or torsional deformities of the proximal femur that cannot be adequately assessed with radiographs.
Active infection is an absolute contraindication for total hip arthroplasty and must be excluded preoperatively. Laboratory evaluation includes erythrocyte sedimentation rate and C-reactive protein, which are sensitive screening markers just as for revision joint arthroplasty. If these are increased, the hip joint is aspirated or a biopsy of the prior surgical site is performed. If an active infection is found, surgery should proceed in staged fashion. A two-stage protocol would commence with implant removal, débridement, and resection arthroplasty or antibiotic spacer placement. Definitive reconstruction can be performed later if infection is eradicated.
J Am Acad Orthop Surg. 2019;27(8):275-285. © 2019 American Academy of Orthopaedic Surgeons