Operative Techniques in Orthopaedic Surgery (4 Volume Set) 1st Edition

84. Revision Total Hip Arthroplasty With Well-Fixed Components

Trevor R. Pickering and Michael E. Berend

DEFINITION

images Well-fixed femoral and acetabular implants often have to be removed during revision total hip arthroplasty (THA).

images Conditions that necessitate removal of well fixed implants include:

images Infection

images Recurrent dislocations (malpositioned components)

images Limb-length discrepancy

images Severe osteolysis

images Polyethylene wear

images Locking mechanism failure

images Failure of other components in the hip such as a femoral stem fracture (FIG 1)

images The key point is to determine which components should be removed and which are well fixed and can be left at the time of revision THA.

ANATOMY

images Important anatomic considerations include the pelvic landmarks and the proximal femoral and diaphyseal anatomy.

images The pelvic landmarks that assist in component removal and positioning include the ischium, pubis, anterior and posterior acetabular columns, anterior inferior iliac spines, transverse acetabular ligament, sciatic notch, and acetabular walls.

images

FIG 1 • AP radiograph of a broken T-28 femoral stem. An extended trochanteric osteotomy (ETO) is used for distal well-fixed stem removal.

images Neurologic structures at risk include the sciatic nerve, which can be identified in three distinct anatomic locations:

images As it exits the sciatic notch

images Lying over the ischium posterior and inferior to the posterior acetabular column

images Beneath the femoral insertion of the gluteus maximus tendon insertion into the posterior femur.

images The superior gluteal nerve is at risk during component removal as it travels anteriorly along the ilium, approximately 4 to 5 cm superior to the tip of the greater trochanter, to innervate the gluteus medius muscle.

images The femoral nerve is well anterior to the hip for most approaches but may be at risk with further anterior dissection and retraction and with anterior supine approaches to the hip.

images The femoral artery and vein are well anterior to the dissection and usually are protected by the iliopsoas tendon and muscle belly.

images The proximal femoral anatomy includes the greater and lesser trochanter and the vastus ridge, which is a point of relatively weak bone in most revisions due to osteolysis, previous trochanteric osteotomies, or previous surgery in this area.

images The femoral diaphyseal anatomy includes the attachments of the vastus musculature at the vastus ridge and posteriorly at the linea aspera.

images These attachments often must be reflected during extended trochanteric osteotomies to aid in removal of wellfixed femoral implants (FIG 2).

images

FIG 2 • Bilateral acetabular component failure with superior displacement on the right hip and medial protrusio on the left. Both are indications for trochanteric osteotomy to facilitate exposure of the acetabulum and possible stem removal.

PATHOGENESIS

images Well-fixed implants may be removed because of polyethylene wear or in response to osteolysis that occurs as a result of particulate debris generating an inflammatory (macrophage) response and subsequent cellular activation with resulting bone resorption (FIG 3).

images Sepsis around a THA most commonly is caused by a grampositive organism and is best eradicated by component removal and two-stage treatment with intravenous antibiotics and a delay in reimplantation.

images The sepsis usually progresses rather quickly to the implant interfaces despite well-fixed implants and usually cannot be treated effectively with irrigation and joint débridement alone.

images Component removal with attention to bone preservation for subsequent reconstruction is crucial.

NATURAL HISTORY

images Retention of well-fixed components has been shown to lead to acceptable long-term performance on both the acetabular and femoral side during isolated component revision.2,5

PHYSICAL FINDINGS

images The physical examination of the patient undergoing revision THA includes:

images Gait

images Leg length

images Distal neurovascular examination

images Muscle strength about the hip and leg

images Skin examination and scars over the hip

IMAGING AND OTHER DIAGNOSTIC STUDIES

images The goal of diagnostic imaging studies is to identify which implants are well fixed, confirm that there is no infection, and see what bone stock is available for the revision reconstruction.

images

FIG 3 • AP radiograph of severe polyethylene wear and wellfixed components with significant osteolysis in the ilium.

images

FIG 4 • A. AP radiographs of a well-fixed uncemented stem and acetabular component with a metal-on-metal articulation. B. Judet oblique radiographs demonstrating anterior column deficiency and acetabular loosening with a well-fixed stem.

images Multiple plain radiographs, CT scanning with possible 3D reconstruction, scintigraphy (bone scans), and laboratory screening usually are sufficient.

images Biplanar radiographs of the entire implant and the joint above and below the prosthesis are essential.

images These should include the entire cement mantle on cemented femoral stems.

images Signs of ingrowth on uncemented stems have been well described3 (FIG 4A).

images Oblique, or Judet, views of the pelvis can demonstrate the anterior and posterior columns, because some defects may not be readily appreciated on routine anteroposterior (AP) radiographs (FIG 4B).

images In cases that demonstrate significant polyethylene wear or osteolysis, CT scanning may better demonstrate osteolytic lesion location and size.

images These findings are helpful in guiding plans for bone grafting of lytic lesions and identifying remaining bone stock.

images Plain radiographs usually greatly underestimate the extent of osteolysis involvement in the pelvis from polyethylene debris.

images Bone scan examination may demonstrate subtle implant loosening that may not be appreciated on plain radiographs or at the time of surgery and may help the surgeon decide whether to retain or remove implants that appear well fixed.

images Confirmation of a noninfected arthroplasty is critical prior to the revision THA.

images Confirmation is best accomplished by laboratory evaluation, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). The combination of a normal ESR and normal CRP has been demonstrated to have a very low (<1%) likelihood of being infected.6

images In cases of elevated ESR or CRP, aspiration of the hip is warranted, with examination of the cell count with differential and culture of the fluid.

SURGICAL MANAGEMENT

images Extended trochanteric osteotomy (ETO)

images Most well-fixed femoral components require some form of femoral osteotomy, which offers several advantages:

images Safe stem removal

images Exposure

images Deformity correction

images Soft tissue balance

images Bone grafting

images Increased union rate

images Decreased operating time

images Safer distal cement removal

images Removal of well-fixed acetabular components may be required in the face of infection, severe polyethylene wear and need for significant acetabular bone grafting, malalignment leading to severe impingement or instability, or perhaps to change to an alternate bearing surface.

images Care should be taken to preserve as much bone stock as possible during the removal for subsequent reconstruction.

images Osteotomes are available that facilitate acetabular component removal.

images These osteotomes are designed so that the rotation point is in the center of the acetabular component.

images Small and large osteotomes are available.

Preoperative Planning

images Appropriate removal instruments and surgical techniques are important considerations as one approaches the revision THA with well-fixed implants.

images When performing revision THA, multiple options for the implant must be on hand to match defects or needs that may be discovered intraoperatively.

Positioning

images In general, patients can be positioned supine or in the lateral decubitus position.

images In the anterior supine approach, the patient is positioned in the supine position and an anterior approach to the hip is performed in the interval between the tensor fascia lata and the sartorius muscles.

images An anterior or anterolateral approach to the hip can be performed in the supine or lateral position and is extensile in both the proximal and distal directions should additional exposure be required.

images The posterior approach to the hip is performed in the lateral decubitus position.

images At our institution, we use a pegboard positioner.

images An axillary roll is used to provide protection for the brachial plexus during surgery.

TECHNIQUES

APPROACH

Anterior Supine

images The patient is positioned in the supine position and an anterior approach to the hip is performed in the interval between the tensor fascia lata and the sartorius muscles (TECH FIG 1A,B).

images This technique is suitable for polyethylene exchange alone, in which the femoral component is well fixed and there is no significant need for bone grafting in the posterior aspect of the acetabulum (see Fig 3).

images Bone grafting is possible through the holes in the acetabular component or through a small “trap-door” above the acetabulum (TECH FIG 1C).

images This approach retains much of the posterior capsule and structures, which likely reduces the incidence of dislocation after revision.

images The femoral head is retracted posteriorly (TECH FIG 1D), and a new liner is inserted (TECH FIG 1E).

Lateral

images A direct lateral approach to the hip involves a split in the anterior third of the gluteus medius and minimus musculature.4

images

images

TECH FIG 1 • A. The same patient shown in Figure 3 has been placed in the supine position for anterior approach to the hip for isolated polyethylene exchange and bone grafting behind a well-fixed component. The old incision is marked, and the central third is used. B. Acetabular exposure with retractors in place before femoral head dislocation in this hip, which shows severe polyethylene wear and osteolysis. C. Bone graft is inserted through the screw holes in the acetabular component. D. New polyethylene liner is inserted with the femoral head in view and retracted posteriorly. E. New liner in place. (Courtesy of Roger Emerson, MD.)

EXTENDED TROCHANTERIC OSTEOTOMY

images The length of the osteotomy is determined by the amount of prosthesis that is well fixed or the distal extent of the cement column that needs to be removed. Approximately a third of the lateral portion of the femoral circumference is part of the osteotomy (TECH FIG 2A).

images The vastus lateralis remains attached to the lateral portion of the osteotomy but is reflected anteriorly to allow visualization of the lateral and posterior femoral cortex.

images An oscillating saw is used to perform the posterior portion of the osteotomy just superior to the linea aspera. The gluteus medius remains attached.

images The distal extent of the osteotomy is beveled in the distal and anteroposterior direction. Alternatively, the osteotomy can be performed with a high-speed burr with a thin tip (TECH FIG 2B).

images The anterior portion of the osteotomy is made with a small (¼-inch) osteotome perforated through the vastus musculature. Multiple perforations are made in the same plane to create the osteotomy.

images The capsule surrounding the prosthesis below the greater trochanter is released or excised and the “shoulder” of the prosthesis exposed.

images The entire extended trochanteric fragment is reflected anteriorly with care not to fracture the tip of the trochanteric fragment, because this is the weakest point in the osteotomized fragment (TECH FIG 2C).

images

images

TECH FIG 2 • A. AP view of the planned femoral osteotomy demonstrating the length of the osteotomy needed to remove the prosthesis or cement (or both). About one third of the lateral portion of the femoral circumference is part of the osteotomy. B. The vastus lateralis that remains attached to the lateral portion of the osteotomy is reflected anteriorly to allow visualization of the lateral and posterior femoral cortex. An oscillating saw is used to perform the posterior portion of the osteotomy just superior to the linea aspera. The distal extent of the osteotomy is beveled in the distal and AP direction. C. The anterior portion of the osteotomy is made with a ¼-inch osteotome perforated through the vastus musculature. The entire extended trochanteric fragment is reflected anteriorly, with care not to fracture the tip of the trochanteric fragment, which is the weakest point in the osteotomized fragment. D. Bennett and Charnley retractors retract soft tissue and the trochanteric fragment to visualize the femoral prosthesis. All tissue lateral to the psoas tendon can be removed if necessary. The cement–implant and cement–bone interfaces or the ingrowth interface is now accessible. E. The trial implants are inserted and a trial reduction performed before the trochanteric fragment is reattached. The osteotomy is reduced and secured with looped Luque wires.

images Curved Bennett-type retractors are inserted distal to the osteotomy for soft tissue retraction and the Charnleytype hip retractor anterior arm is carefully secured to the trochanteric fragment anteriorly to expose the femoral prosthesis (TECH FIG 2D).

images Anterior and medial capsular attachments are taken down to the level of the psoas tendon. All tissue lateral to the psoas tendon can be removed at this point if needed to allow visualization of the stem.

images Osteotomes, ultrasonic devices, or high-speed burrs now have access to the cement–implant and cement–bone interfaces or the ingrowth interface, as needed for removal.

images The femoral preparation for long-stem implant insertion is completed with flexible reamers and proximal femoral tapered reamers.

images The trial implants are inserted and a trial reduction performed with the trochanteric fragment not attached.

images ETO fixation is performed after the final implant is inserted. Often small amounts of trochanteric bone must be removed to facilitate appropriate osteotomy reduction and fixation with looped Luque wires (TECH FIG 2E).

ACETABULAR REMOVAL

images The goal in acetabular removal is to preserve as much of the remaining bone as possible. It is important not to gouge the acetabulum or to break off large pieces by aggressively twisting or pulling a well-secured cup.

images Acetabular osteotome systems facilitate cup removal by using the center of the acetabular polyethylene as a reference for osteotome insertion. Osteotomes match the radius of curvature of the cup. The center of rotation of the acetabular component allows thin osteotome insertion precisely in the bone implant interface (TECH FIG 3A).

images The osteotome blade is inserted and turned in a firm, controlled manner, maintaining its orientation to the rim of the cup.

images First, a small osteotome is inserted that matches the radius of the acetabular component. It is used to enter the bone–implant interface only around the rim of the ingrown acetabular component (TECH FIG 3B,C).

images Successively longer acetabular osteotomes are then used around the entire rim of the component to divide more medial ingrown interfaces (TECH FIG 3D).

images A handle permits the acetabular explant chisel to be rotated around the circumference of the component to further loosen the implant and remove the cup with minimal bone loss (TECH FIG 3E).

images

TECH FIG 3 • A. The acetabular osteotome used to remove cups allows thin osteotome insertion precisely in the bone implant interface. B. A small osteotome is first used to enter the bone–implant interface around the rim of the acetabular component. C. Osteotome shown with the implant removed. D. A longer acetabular osteotome removes the medial ingrown interfaces. E. Using the acetabular explant chisel on a handle, the implant is removed with minimal bone loss. (Courtesy of Zimmer, Inc., Warsaw, IN.)

images

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POSTOPERATIVE CARE

images Weight bearing is restricted to about 50% for 6 to 8 weeks if an implant has been reinserted and bone graft has been used.

images With polyethylene exchanges and component retention of osseointegrated implants, weight bearing as tolerated is recommended.

images When an implant is removed and an antibiotic-impregnated static spacer is inserted, foot-flat (essentially non–weight bearing) weight bearing is recommended. We combine this with a hinged knee brace locked in extension, which allows wound care but limits motion and provides additional support while allowing mobilization during the time of IV antibiotic therapy.

COMPLICATIONS

images Femoral fractures are common about the trochanteric region and in the diaphysis during removal of well-fixed femoral implants.

images Isolated component revision has a higher dislocation rate than primary revision THA.

images Acetabular deficiencies may be extensive in the face of polyethylene wear and osteolysis.

OUTCOMES

images Aribindi et al1 reported on the outcomes associated with THA revision with an extended trochanteric osteotomy in 122 cases with a minimum of 1 year of follow-up (average, 2.6 years).

images No non-unions, no migration greater than 2 mm

images All healed by 3 months

images 92% bone ingrowth, one stem revised for loosening

images Dislocation rate 10% (three required revision)

images 20% intraoperative fracture rate

REFERENCES

1.     Aribindi R, Paprosky W, Nourbash P, et al. Extended proximal femoral osteotomy. Instr Course Lect 1999;48:19–26.

2.     Berger RA, Quigley LR, Jacobs JJ, et al. The fate of stable cemented acetabular components retained during revision of a femoral component of a total hip arthroplasty. J Bone Joint Surg Am 1999;81A:1682–1691.

3.     Engh CA Jr, Hopper RH Jr, Engh CA Sr. Distal ingrowth components. Clin Orthop Relat Res 2004;420:135–141.

4.     Frndak PA, Mallory TH, Lombardi AV Jr. Translateral surgical approach to the hip. The abductor muscle “split.” Clin Orthop Relat Res 1993;(295):135–141.

5.     Moskal JT, Shen FH, Brown TE. The fate of stable femoral components retained during isolated acetabular revision: a six-to-twelveyear follow-up study. J Bone Joint Surg Am 2002;84A:250–255.

6.     Spangehl MJ, Masri BA, O'Connell JX, et al. Prospective analysis of preoperative and intraoperative investigations for the diagnosis of infection at the sites of two hundred and two revision total hip arthroplasties. J Bone Joint Surg Am 1999;81A:672–683.



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