Trauma: Acetabular Fractures and Pelvic Discontinuity via the Direct Anterior Approach

Key Learning Points

Determine the best strategy for managing a patient with a periprosthetic acetabular fracture.
How to expand the direct anterior approach (DAA) to the hip for management of acetabular fractures.
Technical details of the modified Paprosky acetabular distraction technique for use with chronic acetabular fractures.
Postoperative care of the patient with an operatively treated periprosthetic acetabular fracture.

Introduction

There are four common situations in which surgeons would encounter acetabular fractures during their use of the DAA to the hip. During either primary or revision surgery, the surgical team may fracture the native acetabulum, impacting an acetabular component. Surgeons may also encounter chronic acetabular fractures as pelvic discontinuities in revision surgery. Similarly, although rare, surgeons may see patients who have an acute acetabular fracture around an existing acetabular component or have an unrecognized iatrogenic fracture that presents with acetabular component failure in the early postoperative period. Finally, surgeons may encounter patients who are over 60 years old who have an acetabular fracture and may benefit from concomitant open reduction and internal fixation (ORIF) plus acute total hip arthroplasty (THA).¹ We address each of these scenarios in this chapter.

Iatrogenic Acetabular Fractures in Total Hip Replacement

Although rare, iatrogenic acetabular fractures do occur in the setting of primary THA. The standard advice has been to take a radiograph and proceed with plating of the posterior column of the acetabulum and then place a multihole revision acetabular component with multiple screws. However, in our experience, this is rarely feasible in practice because most of these fractures occur at hospitals or surgery centers where there are no implants or instruments available for acetabular fracture fixation. The surgeons themselves may also not be comfortable with the exposure and reduction techniques necessary to repair the posterior column.

The key principle when dealing with periprosthetic acetabular fractures is to be able to wedge a stable multihole acetabular component between the subchondral bone attached to the ischium and the subchondral bone attached to the anterior inferior iliac spine (AIIS; Figure 33.1).

FIGURE 33.1 The two critical points for acetabular component stability are the subchondral bone attached to the AIIS and the subchondral bone attached to the ischium.

These are illustrated with red arrows. The anterior wall and posterior wall (yellow arrows) are not as important for acetabular component stability.

(Reprinted with permission from Theodore Manson, MD and the R Adams Cowley Shock Trauma Center.)

Many times in iatrogenic fractures, the posterior column is nondisplaced. If the posterior column is nondisplaced, adequate acetabular component stability can be achieved by wedging a slightly larger than normal (2-4 mm) acetabular multihole component in between the ischium and the AIIS (Figure 33.2). After placement of the acetabular component and confirmation of the appropriate position, multiple screws are placed both superior and inferior to the equator of the acetabular component to gain fixation into both the ilium and the ischium.

FIGURE 33.2 A and B, An older patient who presented with a displaced left subcapital femoral neck fracture and a nondisplaced posterior column fracture due to a high-speed motor vehicle collision. This was managed using a standard multihole component with screws both superior and inferior to the equator of the acetabular component but without concomitant ORIF of the acetabulum. A standard DAA was used. C-E, A separate but similar patient who had a displaced right subcapital femoral neck fracture and a nondisplaced posterior column and posterior wall acetabular fracture. These intraoperative anteroposterior and Judet fluoroscopic images show the multiple screws superior and inferior to the acetabular component. F-H, Postoperative images of the same patient. The obturator oblique shows that the posterior wall component has been bone grafted but has not been treated with ORIF. AP, anteroposterior.

(Reprinted with permission from Theodore Manson, MD and the R Adams Cowley Shock Trauma Center.)

If the posterior column of the acetabulum is displaced and mobile, then concomitant ORIF plus THA is required (Figure 33.3). This can be accomplished through the DAA as will be described later. However, in many cases, the surgical team will not be comfortable with proceeding with this type of fixation and the instruments and implants may also not be available. In these cases, leaving the patient with a temporary hip resection without arthroplasty implants and facilitating transfer to a tertiary facility are preferable.

FIGURE 33.3 A radiograph of a patient who was involved in a high-speed motor vehicle collision 3 years after a left THA.

This iliac oblique image shows a displaced posterior column acetabular fracture and probable shift of the original acetabular component. With this degree of displacement, ORIF is required before acetabular revision.

(Reprinted with permission from Theodore Manson, MD and the R Adams Cowley Shock Trauma Center.)

Concomitant Open Reduction and Internal Fixation Plus Total Hip Arthroplasty

Acetabular fractures around a hip replacement where the posterior column is displaced can occur either as iatrogenic fractures during THA or as a postoperative fracture. As mentioned previously, if the posterior column is mobile and displaced, then these acute fractures are usually best managed by ORIF plus concomitant THA. The surgical goal is to restore a fixed relationship between the subchondral bone attached to the ischium and the subchondral bone attached to the AIIS (see Figure 33.1).

Through a DAA to the hip, this can usually be accomplished by placing a 3.5-mm reconstruction plate inside the false pelvis along the pelvic brim with long 3.5-mm screws securing the posterior column fracture line. The surgical approach used for reduction fixation can be in extension of the DAA to the hip, which is known as the Levine approach to the hip.¹^,²^,³

The details of this approach have been published in a previously reported technique article on concomitant ORIF plus THA.¹ The Levine approach essentially extends the DAA up to the anterior superior iliac spine. Releasing the inguinal ligament and the sartorius from the anterior superior iliac spine and subperiosteal elevation of the iliacus muscle give excellent access to the internal surfaces of the pelvis for reduction and fixation of acetabular fractures (Figure 33.4). There does not need to be anatomic reduction of the fracture, but the column does need to be approximated so that union may occur. Usually, large reduction clamps are used to clamp the posterior column fracture line, and then long 3.5-mm screws are placed under fluoroscopic guidance to stabilize the posterior column (Figures 33.5 and 33.6).

FIGURE 33.4 This photograph of a cadaver dissection shows the Levine extended approach to the acetabulum.

The sartorius and inguinal ligament have been released subperiosteally from the anterior superior iliac spine, and the iliacus muscle has also been elevated subperiosteally from the internal surfaces of the ileum. In this cadaver dissection, the rectus tendon has also been released as well, but in practice this is rarely necessary.

(Reprinted with permission from Theodore Manson, MD and the R Adams Cowley Shock Trauma Center.)

FIGURE 33.5 A–C, This was an older patient involved in a high-speed motor vehicle collision who sustained a right acetabular fracture with dome and femoral head impaction. These postoperative radiographs show the anteroposterior, iliac, and obturator oblique views of the patient, who underwent concomitant ORIF plus THA through the Levine anterior approach. Notice the relative simplicity of the fixation construct, which consists of a single pelvic brim plate with long screws securing the anterior to posterior columns of the acetabulum. This stabilizes the relationship of the AIIS and ischium before acetabular component placement with multiple screws.

(Reprinted with permission from Theodore Manson, MD and the R Adams Cowley Shock Trauma Center.)

FIGURE 33.6 A different but similar older patient who was injured in a bicycle collision sustaining a left acetabular fracture that also had both dome and femoral head impaction.

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