Percutaneous Screws for Column Support During Total Hip Reconstruction of Metastatic Disease of the Acetabulum

Abstract

Reconstruction of the hip joint in the setting of metastatic lesions of the acetabulum is particularly challenging and can carry significant morbidity for patients who are already medically frail. Novel techniques to minimize morbidity and optimize function warrant exploration for these patients. Here, we present a 50-year-old woman was unable to walk secondary to metastatic breast cancer involving the acetabulum with articular disruption. A primary reconstruction technique was used that combined percutaneous stabilization of the acetabulum and cemented total hip arthroplasty using primary components. Existing reconstructive techniques for metastatic lesions of the acetabulum often require extensive open surgical approaches and revision components. Percutaneous acetabular stabilization combined with cemented total hip replacement may be a less-morbid and equally durable option.

Introduction

Approximately 1.9 million new cancer cases are expected to be diagnosed in 2023 with the bone being the third most frequent site of metastasis behind the lung and liver [1,2]. Lesions of the acetabulum caused by metastatic disease can result in pain, inability to ambulate, and pathologic fracture. Lesions with impending or completed fracture often require surgical management with a goal of providing a durable and pain-free hip joint [3]. In the setting of a combined periacetabular defect involving the roof and columns, reconstruction was traditionally accomplished through an extensive surgical approach with placement of Steinmann pins through the ilium and cementing of a flanged acetabular cup that incorporated the pins. Percutaneous bony stabilization is an attractive alternative fixation strategy to provide mechanical stability with limited soft-tissue dissection, which minimizes wound healing complications in this particular patient population. In this case report, the author presents a patient with extensive acetabular metastatic lesions who underwent percutaneous acetabular stabilization for periacetabular column support during the primary reconstructive hip surgery. A review of the literature did not reveal any other cases where this combined technique was used during a single stage surgery.

Written informed consent was obtained by the patient to present case and associated images in this manuscript.

Case history

Presentation

A 50-year-old woman with infiltrating ductal carcinoma of the breast who underwent a lumpectomy 8 years prior presented with debilitating right hip pain and inability to ambulate for 1 week. Plain radiographs revealed a lucent area at the right acetabulum that involved the weight bearing dome, the anterior column, the posterior column, and the medial wall (Fig. 1). A computerized tomography scan of the pelvis further defined the pelvic lesions and showed diffuse involvement of the ilium, complete involvement of the ischium and posterior wall, and involvement of the acetabular roof with intra-articular erosion (Fig. 2). She had not progressed to catastrophic fracture of the acetabulum but was increasingly bed bound. The risks and benefits of operative reconstruction of the hip were discussed at length with the patient, and she elected to proceed. Given the diffuse nature of the lesions and known primary tumor, preoperative biopsy was not conducted in this case.

Figure 1.

Plain radiograph of the pelvis demonstrating lucent regions of the right acetabulum around the weight bearing dome, the anterior column, and the ischium.

Figure 2.

Axial computerized tomography images of the right acetabulum demonstrating metastatic lesion involvement of the iliac wing, medial wall, ischium posterior wall and articular surface on the weight-bearing portion of the acetabulum, consistent with Harrington Class 3.

Operative technique

Surgical reconstruction was a 2-stage process starting with percutaneous insertion of periacetabular screws, followed by cemented total hip arthroplasty anchored on these screws. The patient was placed in a supine position on a flat radiolucent table and general anesthesia was administered. The inlet and obturator-outlet oblique views were used to visualize the anterior column, the acetabular dome, and the superior pubic rami to confirm the presence of a safe osseous fixation pathway. The guidewire for cannulated screw placement was started at the outer table of the ilium and guided down the length of the supraacetabular region, into the subchondral bone of the acetabulum, and anchored into the anterior cortex of the superior rami. Orthogonal fluoroscopic views of the anterior column were utilized to monitor safe placement of each screw, including the obturator oblique and the inlet views. Three percutaneously placed 5.5-mm fully threaded cannulated screws (Zimmer-Biomet, Warsaw IN) were placed (Fig. 3a and b). Two screws were placed in the superior rami, and 1 screw was placed in the supra-acetabular region.

Figure 3.

Intraoperative fluoroscopy of inlet (a) and obturator oblique (b) views after placement of 3 5.5-mm percutaneously placed cannulated screws supporting the anterior column and subchondral region of the acetabulum.

She was placed in the lateral position for the second-stage hip reconstruction via a standard posterior approach. There was no evidence of cartilage breakdown at the time of femoral head osteotomy. However, upon reaming of the acetabulum, we quickly encountered the metastatic lesions within the subchondral bone. These lesions were further debrided with a curette and rongeur. Given the destruction of the acetabulum by both the metastatic lesion and well as removal of the lesion, total hip arthroplasty was indicated. Reaming continued until the reamer contacted the percutaneously placed anterior column screws. A drill was used to make multiple keyholes in the acetabulum and around the anterior column screws. Polymethyl methacrylate cement was compressed into the previously made drill holes and around the screws, and an all-polyethylene acetabular cup (Zimmer ZCA, Zimmer-Biomet, Warsaw IN) was cemented in approximately 40 degrees of inclination and 20 degrees of anteversion. The femur was prepared in the standard fashion, and a cemented femoral stem (Zimmer Echo Cemented, Zimmer-Biomet, Warsaw IN) was placed. Hip stability was confirmed with trial head components before final implant insertion. The hip was thoroughly irrigated, and 1 gram of vancomycin powder was placed deep to the joint capsule prior to closure.

Postoperative course

Intraoperative pathology specimen confirmed metastatic breast cancer. She received palliative radiation to the right hip starting 4 weeks postoperatively, and subsequently initiated chemotherapy. She participated in a standard course of physical therapy with full weight bearing beginning on the first postoperative day and reported immediate pain relief. By 6 weeks postoperatively she reported no hip pain and was able to ambulate with occasional use of a cane. All follow-up radiographs showed adequate implant position, no evidence of aseptic loosening or component failure (Fig. 4a and b). She maintained posterior hip precautions for 3 months. By 6 months, she was at her functional baseline, and at the 2-year follow-up, she denied any recurrence of hip pain.

Figure 4.

Plain radiographs of AP (a) and frog-leg lateral (b) views of the right hip 16 months postoperatively demonstrating stable implant position without failure or loosening.

Discussion

Harrington classified several patterns of acetabular destruction based on tumor involvement of the acetabular roof, the medial wall, lateral cortices, and the anterior and posterior columns, and made treatment recommendations based on the size and location of the tumor within the periacetabular region [4]. His original reconstruction technique relied on affixing a cemented acetabular cup into Steinmann pins secured into the ilium through a wide iliac exposure. This technique has since been modified in many ways, but complications continue to occur in up to 32% of patients, including dislocation (8%), deep infection (5%), and wound healing problems (6%) [[5], [6], [7]]. Due to these challenges, there is a need for techniques that optimize stability of the periacetabular region through a soft-tissue-sparing approach that alleviates pain and allows for immediate weight bearing.

Percutaneous techniques for pelvic and acetabular fixation are well-described in trauma literature with detailed descriptions of safe osseus fixation pathways [[8], [9], [10]]. This method is attractive for addressing tumor-associated acetabular instability because in the fracture setting, they minimize blood loss, use smaller incisions, lower infection risk, minimize pain, decrease heterotopic ossification, and allow for faster rehabilitation compared to open approaches [11,12].

Yang et al. [13] described an alternative construct to the Harrington technique with 3 percutaneously placed cannulated screws within osseous fixation pathways for periacetabular lesions. Their series excluded lesions of the weight bearing surface, and their patients did not undergo concurrent arthroplasty. However, they were able to demonstrate safety and efficacy of percutaneous techniques with minimal blood loss and improvements in pain with immediate ambulation after surgery. Chang et al [14] utilized screw placement within osseous fixation pathways during the same setting as a cemented total hip arthroplasty to treat periacetabular tumors. In their series, an open intrapelvic approach was made via the “lateral window” of the ilioinguinal approach in order to place a posterior column screw when there was tumor involvement of the ischium. Additionally, they placed 1 screw per osseous pathway depending on tumor location. Nearly all patients were able to ambulate on day 1, and no intraoperative or postoperative complications were identified.

Current controversies and future considerations

Our highlighted technique utilized 3 screws within a single wide fixation pathway to support the anterior column and acetabular dome. Although percutaneous screw fixation for acetabular pathologic fractures is common, the ideal construct, number of screws, trajectory and overall support of the acetabular dome due to lytic erosion to allow safe mobilization is not fully understood. The location and size of lytic lesions creates a challenge to establish a stable base to support an arthroplasty component. The use of multiple screws has the mechanical advantage of greater screw spread and functions to create multiple segments of rebar within the cement-bone interface, which improves load distribution. One distinctive aspect of this case compared to the series by Chang et al. is that despite the involvement of the ischium in our case, posterior column fixation was not utilized, and as such, a completely percutaneous approach was used for screw placement. We posit that the use of several screws within the anterior column and supracetabular bone may make the addition of a posterior column screw unnecessary. The distinct advantage of this is that a separate open iliac approach to place an antegrade posterior column screw would not be needed – decreasing soft-tissue exposure, surgical time, and blood loss.

Summary

Treatment of acetabular defects due to tumors is a challenging problem that requires thorough understanding of the extent of destruction. Percutaneous techniques using multiple screws with concurrent cemented arthroplasty provides a stable construct that maximizes bone purchase and allows for early weight bearing. If multiple screws are placed in the anterior column and supra-acetabular region, additional posterior column augmentation may not be needed. Wound complications and infection are a primary concern due to adjuvant chemotherapy and radiation treatment, so soft-tissue-sparing approaches are advantageous. Additionally, collaborative discussions with all the oncologic providers for these patients is critical to properly coordinate timing of treatment modalities to avoid complications and optimize outcomes.

Key points

• •Percutaneous stabilization of lytic lesions of the acetabulum through osseus fixation pathways minimizes soft tissue disruption in tumor setting.
• •Percutaneous acetabular stabilization performed with simultaneous cemented total hip arthroplasty provides a linked construct to allow for early mobilization.
• •Distribution of purchase throughout subchondral bone of the anterior column of the acetabulum can effectively provide a stable base to fixate cemented arthroplasty components.

Conflicts of interest

The authors declare there are no conflicts of interest.

For full disclosure statements refer to https://doi.org/10.1016/j.artd.2024.101404.

Informed patient consent

The author(s) confirm that written informed consent has been obtained from the involved patient(s) or if appropriate from the parent, guardian, power of attorney of the involved patient(s); and, they have given approval for this information to be published in this case report (series).

CRediT authorship contribution statement

Justin E. Hellwinkel: Writing – original draft, Resources, Methodology. Anastasia Gazgalis: Writing – review & editing, Writing – original draft. Chima D. Nwankwo: Supervision, Investigation, Data curation, Conceptualization.