In order to achieve the best outcomes in revision total hip arthroplasty (THA) surgery, extensive preoperative planning and an immaculate surgical technique are critical. Removal of the old implants, in combination with osteolytic bone defects, may have a profound impact on the quality of the bone and the soft tissues. Implant selection, surgical techniques, and the clinical outcomes are all potentially affected.

The etiologies for revision THA are variable and are well described elsewhere; they are associated with different potential failure mechanisms. Regardless of the etiology of failure, one of the most important factors for successful THA revision is the surgeon’s case experience and surgical skill.¹ The DAA has been in clinical use for many decades now. Extensive training and experience are critical to master the pitfalls of primary DAA THA. This is especially important to safely conduct revision procedures through the DAA. The DAA is safe and efficient and is both proximally and distally extensile, which allows the surgeon to deal with many different scenarios during the procedure. Different techniques have been proposed in the literature.^2,3,4

This chapter focuses on the techniques of removing well-fixed acetabular implants in revision THA. This chapter also includes some clinical case illustrations from the authors, who have extensive experience with revision DAA THA.^5,6,7

The majority of cup revisions are conducted for liner wear or aseptic loosening. In these cases, the acetabular component is more or less mechanically unstable and there is always some degree of quantitative bone loss. This bone loss can be either cavitary or with a structural rim and/or column deficiency.⁸ The removal of these loose acetabular components is technically not difficult, but addressing the underlying extensive bone loss can be a surgical challenge. On the contrary, the removal of a well-fixed acetabular component can be a technical challenge. Indications for the removal of a well-fixed acetabular component with adequate biological fixation are cup malpositioning with implant instability, squeaking, impingement with instability, adverse local soft tissue reactions, psoas impingement, an inadequate/outdated/unreliable historic polyethylene locking mechanism, or infection.

A good preoperative plan is mandatory to anticipate and accommodate for different scenarios during the procedure. Standard radiographic imaging will give information about the type of implant, the type of fixation, implant positioning, the presence of screws, and bone quality. Our radiographic assessment consists of anteroposterior standing pelvic radiographs (to assess the position), an ala view (to evaluate the posterior column integrity), and an obturator view (to evaluate the anterior column integrity). If more detailed information about the bone quality is required, a computed tomographic scan is often useful; this can then be used to visualize the pelvic bone and component in multiple planes, create 3-dimensional reconstructions using digital subtraction technology, or plan a custom implant to aid in the eventual reconstruction.

Obtaining adequate information about the implant is of paramount importance, and this may be derived from prior operative notes, implant records, or radiographic identification. The use of multiple methods of confirmation can greatly increase the preoperative accuracy of implant identification. This will allow the surgeon to identify the correct manufacturer, order the correct component sizes, and secure implant-specific extraction devices. Check the specific type of femoral neck taper of the retained implant because these may have changed over time, even for the same manufacturer. In case there is an issue of lateral or vertical femoral offset after the acetabular revision, a cement-in-cement femoral revision might be an option. The ideal patient should have a body mass index <30 kg/m² with no distinct skin folds and excessive fat or pannus covering the planned anterior
incision site. With sufficient surgeon experience and the knowledge derived from the earlier textbook chapter on managing obesity when using the DAA, the surgeon may consider the DAA for obese patients with a body mass index >30.

The detailed extensile acetabular exposure is described in a parallel chapter in this section of the textbook. Proper supine positioning of the patient is critical in order to achieve optimal exposure. The surgeon might place a pad underneath the ipsilateral knee to release the tension off the iliopsoas and to help the positioning of the retained femoral stem behind the acetabular wall. The positioning of the patient should place the hip at the bed hinge, which allows for intraoperative flexion and adduction of the operated leg (Figure 25.1). The use of a figure-4 leg position helps to mobilize the femoral stem trunnion lateral to the acetabulum; this technique was presented in the earlier head and liner exchange chapter within this section of the textbook.

For proper visualization, being able to strategically achieve a 360° circumferential view of the acetabular implant components is necessary. Full removal of all scar tissue and bony prominences around the peripheral acetabular rim should be performed for an adequate view of the implant/bone interface. It is important to have a sufficient inventory of appropriate anterior retractors, instruments, and implants.⁹ Many of the retractors are unique to DAA techniques. These retractors should be soft tissue friendly in order to prevent perioperative muscular damage; judicious retractor placement is important in order to prevent perioperative neurovascular complications. The retractors are placed in the standard position, similar to primary THA, in order to obtain a 360° view on the acetabulum. This can be significantly more difficult during acetabular revision due to scar tissues and the loss of bony support. The first retractor is put on the anterior acetabular wall just distal from the anterior inferior iliac spine, and the second is placed in the 6-o’clock position in the obturator foramen just posterior to the transverse acetabular ligament. The third retractor is put between the posterior wall and the posterior capsule.

In most instances, the standard longitudinal incision is sufficient for the correct view. If a more extensile visualization of the outer surface of the ileum is mandatory, release of the reflected head of the rectus and a partial release of the tensor muscle from the outer surface of the iliac crest are possible. (See parallel textbook chapters in this section regarding extensile exposures.) With a periosteal elevator, the origin of the tensor and gluteus minimus muscles can be released from the outer ilium in a posterior direction. For proper retraction of the retained femoral component, the standard superior capsular release from the proximal rim of the greater trochanter is performed. This gives a good release of the femur and allows for sufficient mobilization without applying extensive forces behind the posterior acetabular wall. Slightly flexing the hip and knee while also adding femoral external rotation will further facilitate the femoral retraction (see Figure 25.1). Protection of the femoral taper with a sleeve is advisable. Acetabular components are either cemented or cementless; in both cases, component extraction should prevent or minimize additional bone loss.