The use of an individual acetabular component for acetabular defect: a clinical case

Hovakim A.  Aleksanyan; Алексанян Оваким Аргамович; Hamlet A.  Chragyan; Чрагян Гамлет Ашотович; Sergey V.  Kagramanov; Каграманов Сергей Владимирович; Ruslan A.  Khanmuradov; Ханмурадов Руслан Агамуратович; Nikolay V.  Zagorodniy; Загородний Николай Васильевич

doi:10.17816/vto159380

The use of an individual acetabular component for acetabular defect: a clinical case

Authors: Aleksanyan H.A.¹, Chragyan H.A.¹, Kagramanov S.V.¹, Khanmuradov R.A.¹, Zagorodniy N.V.¹
Affiliations:
1. Priorov National Medical Research Center of Traumatology and Orthopedics
Issue: Vol 30, No 2 (2023)
Pages: 209-217
Section: Clinical case reports
URL: https://journals.eco-vector.com/0869-8678/article/view/159380
DOI: https://doi.org/10.17816/vto159380
ID: 159380

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Abstract

BACKGROUND: The incidence of total hip replacements is increasing every year. Acetabular defects are becoming more frequent, with Paprosky type IIIA and above becoming more common. Recently, customized 3D-printed constructs have been used to remodel severe defects. We wanted to demonstrate the possibility of treating a patient with a severe acetabular defect by performing a one-stage revision endoprosthesis using a customized design.

CLINICAL CASES DESCRIPTION: A 69-year-old patient underwent primary total hip replacement of the right hip joint with a Biomet endoprosthesis for coxarthrosis in 2010. In 2011 — on the left side with a Zimmer endoprosthesis. In 2013 — revision endoprosthesis of the right hip joint due to instability was preformed. In the postoperative period, there were repeated dislocations with subsequent closed repositioning. In 2015, revision endoprosthetic replacement with a Burkh-Schneider antiprotrusion ring was done for recurrent dislocation. In november 2017, she was diagnosed with instability of the right total hip joint, for which she underwent revision hip replacement with a customized acetabular component.

HHS score before revision arthroplasty was 18 points, 1 month after surgery — 75 points, after 3 months — 65, after 6 months — 82, after 4 years — 74. Quality of life was assessed using the WOMAC scale: 92 points before surgery, 38 points 1 month after surgery, 31 points in 3 months, 15 points in 6 months, and 35 points in 4 years. As of the last visit, the patient moves with a cane, and still has a limp due to scar remodeling and gluteal muscles atrophy.

CONCLUSION: In case of severe acetabular defects, the use of individual components allows achieving reliable "implant–bone" fixation, which leads to improved functional results. However, in chronic pelvic bone integrity defects, the use of an individual acetabular component does not always achieve reliable stabilization. All existing methods for solving this problem are currently ambiguous and require further improvement.

Keywords

hip joint, revision arthroplasty, individual design

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BACKGROUND

The number of total hip replacements is increasing annually, and the number of revision hip replacements is expected to nearly double in the next 10 years [1]. In revision hip arthroplasty, the surgeon is more often confronted with acetabular defects, with Paprosky type ≥IIIA defects becoming more common. Thus, according to Christie et al., such defects account for 14% of revision cases [2]. Technologies for creating customized acetabular components have been steadily developing since the late 70s and now include computer-aided design and three-dimensional (3D) printing of implants using additive manufacturing technology [3]. Previously, 3D printing was only used to create models of the pelvis or implant, and the final implant was manufactured from forged titanium by milling.

Through a clinical example, we wanted to demonstrate the possibility of treating a patient with a severe acetabular defect with a one-stage revision endoprosthesis using a customized design.

CLINICAL CASE

A 69-year-old patient underwent primary total hip replacement of the right hip joint with a Biomet endoprosthesis for right-sided coxarthrosis in 2010. In 2011, a similar operation using a Zimmer endoprosthesis was performed for left-sided coxarthrosis. In 2012, pain in the right hip joint region appeared and began to progress. In 2013, a revision hip replacement of the right hip joint was performed for acetabular component instability. Postoperatively, the patient noted repeated dislocations of the head of the right hip joint endoprosthesis with subsequent closed repositioning. In 2015, a revision hip replacement with a Burkh–Schneider antiprotrusion ring was performed for recurrent dislocations of the head of the right hip joint. Eighteen months after surgery, pain in the operated joint recurred. In November 2017, the patient was admitted to the endoprosthesis department of the N.N. Priorov National Medical Research Center of Traumatology and Orthopedics. The assessment of the right hip joint function according to the Harris hip scale (HHS) was 18 points, the severity of pain syndrome according to the visual analog scale (VAS) was 74 points (for a more accurate assessment, the scale was measured in millimeters), and the patient’s social adaptation according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scale was 92 points. Radiographs of the pelvic bones in a straight projection were obtained (Fig. 1).

Fig. 1. Preoperative radiograph of a 69-year-old patient: type IIIB acetabular defect according to W.G. Paprosky.

For a more detailed visualization of the defect of the bones forming the acetabulum, multispiral computed tomography (CT) with 3D reconstruction was performed (Fig. 2).

Fig. 2. 3D reconstruction of the right acetabulum by imaging using multislice computed tomography.

Given the severity of the acetabular defect and the extreme difficulty of reconstruction using standard components, a customized acetabular component was used. In collaboration with “Endoprint” engineers, a 3D model of the implant was created in accordance with the bony defect of the acetabulum (Fig. 3).

Fig. 3. 3D model of the implant: a — the porous part of the implant, which fills the structure of the bone defect; b — hemispherical part of the endoprosthesis with holes for screws; c — the direction of the screws, taking into account the density of the bone tissue.

The final digital model of the implant was printed on a 3D printer (Fig. 4), sterilized by autoclaving, and inserted (Fig. 5). The implant position was assessed on postoperative radiographs (Fig. 6). Postoperatively, the patient received symptomatic, anticoagulant, antibacterial, and rehabilitation therapy, and the wound healed with primary tension. The patient was discharged on day 7 after surgery.

Fig. 4. 3D model of the implant: a — the porous part of the implant, which fills the structure of the bone defect; b — hemispherical part of the endoprosthesis with holes for screws; c — the direction of the screws, taking into account the density of the bone tissue.

Fig. 5. Stage of implant placement.

Fig. 6. Postoperative control X-ray.

Three months after surgery, the patient came for a follow-up examination. Radiographs showed migration of the sciatic and brow bones from the flanges of the construct (Fig. 7). The patient still had pain syndrome in the operated joint area, which was 28 (mm) points on the VAS scale. On the HHS scale, the hip joint function was assessed at 75 points. The social adaptation score on the WOMAC scale was 38 points. Considering the clinical and radiological picture, the patient was offered surgery for screw removal from the lower flanges and correction of the sciatic flange of individual design with a high-speed bur. The patient refused the proposed surgery.

Fig. 7. Postoperative control X-ray after 3 months.

Six months after surgery, no negative dynamics on control radiographs were observed. The HHS, WOMAC, and VAS scores were 82, 15, and 30 (mm) points, respectively. Despite a slight increase in the severity of pain syndrome according to the VAS score, the patient noted improvement in the bearing capacity and functional results of the operated limb. No significant changes in the evaluation scales were noted at the subsequent follow-up examinations (1 year after surgery and once a year thereafter). At the time of writing, >4 years have elapsed since the operation. Data obtained four years after surgery did not show negative dynamics on control radiographs (Fig. 8). The pain syndrome slightly increased and corresponds to 32 (mm) points on the VAS scale. On the HHS scale, the hip joint function corresponded to 74 points, and social adaptation according to the WOMAC scale corresponded to 35 points. The patient is under dynamic observation.

Fig. 8. Postoperative control X-ray 4 years after the operation.

DISCUSSION

The need for revision arthroplasty is increasing annually, and its incidence is expected to nearly double in the next 10 years [1]. According to Christie et al., who reported their centers’ 6-year data (1922–1998), Paprosky type IIIA and IIIB defects accounted for 14% (78 hips) of the total number of revision hip replacements [2].

Different reconstruction options have been previously used to repair severe acetabular bone defects; however, unsatisfactory results reported in the published literature. Hip arthroplasty with one-staged restoration of acetabular integrity using plate and screw metallosteosynthesis resulted in revision in 47% of cases within 3 weeks to 124 months after the surgery [4].

In other studies using the antiprotrusion ring, the net reoperation rate was 29%–66% of cases [5–7].

The cup-cage technique is another option for the reconstruction of severe bone defects, including acetabular disruption. In the mid-term follow-up period, satisfactory results were obtained in 89% of cases [8, 9]. Complications included the dislocation of the endoprosthesis head, periprosthetic infection, and paresis of the peroneal portion of the sciatic nerve [8].

When porous tantalum augments were used during the 5-year follow-up period, only 2 out of 58 cases required revision because of aseptic loosening. In six cases, radiographic signs of progressive osteolysis of the bone in the third DeLee–Charnley zone were observed. A significant improvement in function after the 5-year follow-up was evidenced by the Meyo hip scores [10].

Another option for the reconstruction of large acetabular bone defects is the use of structural allografts combined with a tantalum-coated acetabular component. In one study, 1 of 20 patients had asymptomatic migration of the acetabular component that did not require revision [11]. The other group included 58 patients (59 hips) with Paprosky type II–III acetabular defects in whom bone alloplasty combined with a cementless cup was used for reconstruction. In this group, revision was required in three cases: two with type IIIB defects and one with a type IIIA defect. Reoperations were performed after 4, 7, and 9 years for aseptic loosening of the acetabular component [12]. In 20 patients in whom a two-cup design was used for acetabular reconstruction, no cases of aseptic loosening occurred during the follow-up period (2.4 years). Complications included dislocation of the endoprosthesis head in six cases, deep infection in four cases, and delayed wound healing in three cases [13].

In the early stages of development, 3D-printing technology allowed for the creation of plastic models of the affected side of the pelvis, which were used to produce a clay prototype of the implant. The resulting prototype was then subjected to final modeling, from which a custom-made implant was fabricated from the forged titanium with the option of applying hydroxyapatite plasma spraying or porous coatings to the contact surface to stimulate osseointegration. The results improved but were still far from ideal. The failure rates ranged from 7.4% to 35% in 16 months to 7 years [2, 14–21].

The fabrication process of modern custom designs includes the creation of digital models that the surgeon can adjust online without viewing the physical model. This allows for wider dissemination of the technology and shortens the design time. Previously, the interval from CT scan to implant placement was 2–3 months [14]. In our experience, this interval is 3–4 weeks. In addition, the entire acetabular implant, including the porous base, is now printed using additive manufacturing technology, in which each titanium layer is fused using electron beam melting to ensure the strength of the implant.

Only a few published studies have demonstrated the results of current customized designs. At a conference in 2016, Hooper showed promising results with fewer revisions after 2 years than previous customized implants. Similar results were demonstrated in a study of nine patients. In this group, the median follow-up period was 28.8 months, the implant survival rate was 88.8%, and revision was required in one patient with bilateral pelvic bone integrity failure, which the authors believe led to unsatisfactory outcomes [22]. In a 2018 retrospective study with a mean follow-up period of 38 months of 36 patients, 1 had recurrent dislocations, 1 had revision for deep infection, 1 had early implant migration requiring stabilization, and 2 had radiological signs indicating lack of osseointegration. No cases of aseptic loosening were reported in this group at the time of publication [23].

With the improvement in the technological process abroad, the cost of customized implants has improved. In 2001, Joshi et al. reported that the cost of making an implant using clay models was $5,000, whereas in 2012, Taunton et al. used computer models and made implants from forged titanium, which cost $12,500. In 2021, Angela Yao et al. reported that the cost of a customized implant using 3D-printing technology was AU$19,000 [24]. Our experience with customized designs has demonstrated that with the improvement and adoption of 3D-printing technology, the cost of these implants has significantly decreased.

CONCLUSION

In severe acetabular defects, the use of customized components can achieve reliable “implant–bone” fixation, which leads to improved functional results. In chronic pelvic bone integrity defects, the use of an individual acetabular component does not always achieve reliable stabilization. All existing methods for solving this problem are currently ambiguous and require further improvement.

ДОПОЛНИТЕЛЬНО

Вклад авторов. Все авторы подтверждают соответствие своего авторства международным критериям ICMJE (все авторы внесли существенный вклад в разработку концепции, проведение исследования и подготовку статьи, прочли и одобрили финальную версию перед публикацией).

Источник финансирования. Авторы заявляют об отсутствии внешнего финансирования при проведении исследования и подготовке публикации.

Конфликт интересов. Авторы декларируют отсутствие явных и потенциальных конфликтов интересов, связанных с проведённым исследованием и публикацией настоящей статьи.

Информированное согласие на публикацию. Авторы получили письменное согласие пациентов на публикацию их медицинских данных и фотографий (24.11.2017 г.).

ADDITIONAL INFO

Author contribution. All authors made a substantial contribution to the conception of the work, acquisition, analysis, interpretation of data for the work, drafting and revising the work, final approval of the version to be published and agree to be accountable for all aspects of the work.

Funding source. This study was not supported by any external sources of funding.

Competing interests. The authors declare that they have no competing interests.

Consent for publication. The patients gave their written consent (24.11.2017) for publication of their medical data and images.