A 69-year-old woman underwent primary total hip arthroplasty (THA) using a direct anterior approach without apparent complications ( Fig. 51.1 ). She presented to a local emergency department complaining of increased right hip pain and an inability to bear weight on the affected limb. She denied any preceding trauma or injury. Radiographs revealed significant subsidence of the stem without an obvious fracture ( Fig. 51.2 ), and after a discussion with the primary surgeon, she was discharged to her home with instructions not to bear weight on the leg. She presented to the emergency department 1 week later with severe pain, an inability to ambulate, and drainage from the incision. Radiographs ( Fig. 51.3 ) revealed a periprosthetic fracture with subsidence. The patient was treated conservatively with protected weight bearing for 6 weeks.
She presented to my office approximately 1 year after the initial surgery complaining of an inability to ambulate because of pain and significant shortening of the limb. She could perform transfers with difficulty and could ambulate minimally with a 1-inch external shoe lift placed by the operating surgeon. On physical examination, she appeared to be nontoxic, and using a walker, she ambulated with an obvious Trendelenburg lurch. Her incision was well healed with no signs of infection, but she described hip, groin, and thigh pain with hip range of motion and weight-bearing activities. Radiographs revealed obvious subsidence of the stem, a healed malunion of the proximal metaphysis of the femur, and significant shortening of the limb ( Fig. 51.4 ). Results of the laboratory workup for infection were negative.
After discussing the treatment options with the patient, she underwent revision THA through her previous direct anterior incision. The femoral component was revised with a modular, tapered, distal-fitting stem (Reclaim Modular Revision Hip System, DePuy, Warsaw, Ind.) ( Fig. 51.5 ). Exposure was augmented with an iliac wing osteotomy ( Fig. 51.6 ) to improve femoral access. Postoperatively, no hip precautions were instituted, and no abduction wedge or knee immobilizer was used. Weight bearing was protected by 50% solely for the iliac wing osteotomy for 2 weeks, and the patient was able to ambulate with the use of a cane at 3 weeks. Follow-up radiographs at 3 months ( Fig. 51.7 ) revealed complete healing of the osteotomy and incorporation of the stem, which resolved the patient’s pain and leg length discrepancy and restored a near-normal gait and unrestricted activity.
Chapter Preview
Chapter Synopsis
Use of the direct anterior approach (DAA) in complex revision total hip arthroplasty (THA) is described in this chapter. The DAA has become the preferred approach for an increasing number of surgeons.
Important Points
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The surgical approach chosen for revision THA depends on many variables, including anticipated deformities and defects, the surgeon’s experience, and prior surgical approaches.
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No surgical approach is appropriate for all situations, and surgeons should be comfortable with many and choose the best one for the patient.
Clinical/Surgical Pearls
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Precise preoperative planning is essential to determine and anticipate defects.
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Advantages of the DAA include use of the true internervous-intermuscular plane, tissue sparing (i.e., limited soft tissue stripping), limited or no hip precautions (depending on defects and fixation), and a decreased dislocation rate.
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The DAA is extensile proximally (i.e., true Smith-Peterson incision) with or without an iliac wing osteotomy and is extensile distally with or without an extended trochanteric osteotomy.
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Improved component positioning is possible with supine positioning of the patient and use of intraoperative fluoroscopy.
Clinical/Surgical Pitfalls
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The DAA has a steep learning curve.
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The procedure is easier to perform on a specialized orthopedic table.
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It is not applicable when posterior wall or column acetabular reconstruction is required.
Introduction
Surgical exposure is the key to any hip procedure, especially complex revision surgery. Delineation of the anatomy and bony defects allows safe removal of existing components and enables reconstruction with accurate component positioning. No single approach is appropriate for all situations, and surgeons should be comfortable with many to address the patient-specific needs of each case.
Traditionally, the posterior approach with or without a femoral osteotomy has been the workhorse for revision THA. It is easily adaptable to the primary situation, and it offers wide exposure of the femur and acetabulum. However, recovery can be delayed due to soft tissue stripping, osteotomy nonunion, and dislocation (rates up to 28%). With increased interest in the DAA because of the potential benefits of accelerated recovery and lower dislocation rates, some surgeons are expanding its application to primary and complex revision THAs of the femoral and acetabular components. The case study illustrates the utility of the extensile nature of the DAA in complex reconstruction.
Indications and Contraindications
Indications for revision THA include aseptic loosening, septic loosening, progressive osteolysis, and recurrent dislocation with component malposition. Contraindications for revision utilizing the DAA include acetabular revision work in which defects in the posterior column or wall may require stabilization of the posterior column. On the femoral side, the anterior approach must be used with caution when a well-fixed, distally fitting stem requires removal.
Equipment
As with any revision THA, a vast complement of tools and implants must be available to address the challenges that may be encountered with the DAA. Existing components should be identified for specialized removal tools that may be required or for matching implants that will be retained. Flexible osteotomes, high-speed burs, and ultrasonic cement removal devices should be available in the operating room to facilitate component removal.
Implants designed to address any accompanying bone loss, such as wedges, augments, modular stems, flexible reamers, and cable systems, are necessary. Algorithms based on the Paprosky classification of bone loss are used to select reconstructive options for the femur and acetabulum (see Chapter 42 , Chapter 45 ). Unique to the DAA is a specialized orthopedic table that greatly enhances femoral exposure and that consistently ensures proper positioning of the femur. The hanaSSTX orthopedic surgery table and PROfx pelvic reconstruction orthopedic fracture table from Mizuho OSI (Union City, Calif.) are widely used.
Surgical Technique
Preoperative Planning
Preoperative planning is essential for revision THA. A detailed history and physical examination should consider the symptoms and cause of failure, the implants used, and the approach and complications related to the primary operation. Hospital records and previous operative reports should be obtained if possible. The physical examination should assess previous skin incisions, gait patterns, muscle function, leg length discrepancy, and neurologic status.
Infection should be ruled out with a complete blood cell (CBC) count and determinations of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values. Bone scans using tracer-labeled white blood cells may be helpful, and culture of a hip aspirate should be considered in cases of abnormal blood work results or a previous history of sepsis.
Standard preoperative imaging should include an anteroposterior pelvis radiograph and a true lateral radiograph of the affected hip. Judet oblique views of the pelvis can help to determine the stability of the pelvic columns and identify a pelvic discontinuity. Computed tomography (CT) may also assist in identifying areas of suspected bone loss.
Anatomy and Approach
Just as in a primary THA through a DAA, the initial approach in revision procedures uses the Smith-Peterson incision distal to the anterior superior iliac spine (ASIS) or the Heuter approach, which exposes the hip without detachment of muscle from the bone. The superficial interval is between the tensor fascia muscle (i.e., superior gluteal nerve) and the sartorius muscle (i.e., femoral nerve), and the deep interval is between the tensor or gluteus minimus muscle (i.e., superior gluteal nerve) and the rectus femoris muscle (i.e., femoral nerve) ( Fig. 51.8 ).
Proximally, exposure can be enhanced by subperiosteal dissection of the tensor muscle from the iliac crest for approximately 2 to 3 cm through the primary incision or more extensively by completing the Smith-Peterson approach with extension of the skin incision along the iliac crest and performing an iliac wing osteotomy. Distally, the femoral exposure can be enhanced by extending the original incision distally and proceeding with standard lateral approach to the femur with mobilization of the vastus lateralis muscle anteriorly. Alternatively, a second lateral skin incision can be made to expose the femur directly.
Procedure
The patient is brought into the operating room, and while a general or spinal anesthetic is being administered, pneumatic compression stockings are applied to both legs, and padded traction boots are placed. The patient is transferred to the hanaSSTX table, the boots are placed in the leg spars, and the peroneal post is positioned. It is important to place the patient as level as possible with gentle pressure on the post for proper orientation. Appropriate antibiotics and tranexamic acid can be administered before the skin incision is made. The use of a cell saver can be considered in selected cases. The legs are placed in slight abduction and neutral rotation with the toes pointed to the ceiling. No traction is applied at this point and throughout most of the case.
Draping should allow wide exposure of the entire iliac crest, abdomen to the umbilicus, and thigh down to the knee ( 
).Prior skin incisions should be used if possible, as in this case, but if the previous surgery was not performed anteriorly, the incision is initially positioned approximately 2 to 3 cm lateral and 1 cm distal to the ASIS and extended distally and slightly posterior for 10 to 12 cm. Extension of the incision proximally can be accomplished by gently curving the incision along the border of the iliac crest. Care should be taken when crossing the hip flexion crease, especially in obese patients, because wound healing can be an issue. Distal extension is easily performed by continuing the incision to the midpoint of the femur and then extending it along the lateral aspect of the femur.
After penetrating the subcutaneous tissue, the fascia overlying the tensor muscle should be identified and carefully incised the length of the skin incision, taking care not to damage the underlying muscle. The superficial interval between the tensor and the sartorius muscles is developed. This is typically accomplished with blunt finger dissection ( 
) in cases of previous posterior or lateral approaches, but it can be more difficult in previous anterior cases. The muscle may be scarred down to the fascia, and more careful dissection with Bovie electrocautery or a Cobb elevator may be required.
Hibbs retractors are placed, and the deep fascia of the tensor muscle is incised to develop the deep interval between the tensor and rectus muscles. In cases of previous posterior or lateral primary approaches, this is easily done, but the vessels of the ascending branch of the lateral circumflex complex must be identified and coagulated or ligated ( Fig. 51.9 ). In previous cases that used an anterior approach, these vessels should have been ligated. The insertion of the vastus lateralis muscle on the intertrochanteric ridge should be identified because it marks the base of the femoral neck.
