Three-Dimensional Hands-on Total Hip Arthroplasty Simulation After Surgically Treated Acetabular Fractures: A Technical Note on 8 Cases

Abstract

Delayed total hip arthroplasty after surgically treated acetabular fractures can be a complex procedure because of disturbed anatomy, bone defects and in situ osteosynthesis material. Assessing and classifying acetabular bone defects, especially with in situ osteosynthesis material, can be challenging with standard radiological techniques. This report describes the use of multicoloured 3-dimensional–printed acetabular models to simulate acetabular component positioning to optimize preoperative surgical planning.

Introduction

Acetabular fractures are a challenging problem and often requires surgical treatment to restore joint congruency by open reduction and internal fixation (ORIF) [1,2]. Anatomical restoration of the acetabular joint is important in postoperative outcomes; however, due to the complexity of the fracture many patients develop post-traumatic osteoarthritis and avascular necrosis [3,4]. Delayed total hip arthroplasty (THA) could be used as a salvage procedure when these patients present with disabling complaints [5,6]. This procedure could be complex because of in situ osteosynthesis material (plates and screws), scar tissue, heterotopic ossification, bone defects, disturbed bony anatomical landmarks [7]. Removal of osteosynthesis material can be difficult especially when implanted through an anterior intrapelvic approach and is often preferred to leave in situ when fracture-related infection (FRI) has been ruled out. Unfortunately, postoperative outcomes are worse than THA for primary osteoarthritis patients [8].

Recently, there is an increase in 3-dimensional (3D) printing in the medical field. With inhospital 3D printing, it is easier to understand patient-specific pathology compared to standard imaging techniques [9]. It has been shown that 3D prints are helpful to understand the complex pathology of acetabular fractures [10,11]. In post-traumatic reconstruction cases, the surgeon is also better informed about disturbed anatomical landmarks and possible interference with osteosynthesis material. Therefore, 3D printing might be an excellent tool to practice hands-on simulation of the surgical procedure on patient-specific models [[12], [13], [14]].

The aim of this surgical technique report is to describe the use of multicoloured 3D-printed acetabular models to enhance preoperative workup and preparation for complex THA after surgically treated acetabular fractures.

Office tip

In the period of 2021-2023, preoperative computed tomography (CT)-based 3D prints were used in 8 patients that underwent THA as a late salvage procedure after initially treated with ORIF for acetabular fractures in a single hospital (level 1 trauma center, Tilburg, The Netherlands). Written informed consent was obtained from the patients for publication of their deidentified cases. All patients were operated by the same surgeon using the posterolateral approach. Three surgeries were performed for avascular necrosis, 4 surgeries for post-traumatic osteoarthritis and 1 patient suffered from failed osteosynthesis. In total, 2 patients had acetabular protrusion and 1 patient had a FRI. Preoperatively, active infection has been ruled out by standard workup and perioperative tissue samples were taken for cultures. In none of the patients there were any signs of active FRI. Patient characteristics are summarized in Table 1.

Table 1.

Patient demographics and surgical details.

Patient no.	Sex	Age	Year of trauma	Side	Judet-Letournel classification	ORIF acetabulum	Indication THA	Year of THA	Implants used
1	M	62	2021	R	Both column	Anterior intrapelvic approach, quadrilateral surface plate	AVN with acetabular protrusion	2021	Trabecular metal revision shell, Highly crosslinked polyethylene liner, Taperloc (Zimmer-Biomet, Warsaw)
2	M	65	2022	R	Both column	Anterior intrapelvic approach, quadrilateral surface plate, straight pelvic plate	AVN, girdlestone after FRI acetabulum	2023	Avantage cup, Muller lateral straight stem (Zimmer-Biomet, Warsaw)
3	M	62	2023	L	Anterior column + posterior hemitransverse	Anterior intrapelvic approach, quadrilateral surface plate, symphysis pubis plate	Post-traumatic osteoarthtritis	2023	Continuum acetabular system, Taperloc (Zimmer-Biomet, Warsaw)
4	M	41	2022	L	Posterior wall	Kocher-Langenbeck approach, Straight pelvic plates	Failed osteosynthesis/ secondary fracture dislocation	2022	Continuum acetabular system, Taperloc (Zimmer-Biomet, Warsaw)
5	M	73	2022	L	Both column	Anterior intrapelvic approach, quadrilateral surface plate	Post-traumatic osteoarthtritis	2023	Avantage cup, Muller lateral straight stem (Zimmer-Biomet, Warsaw)
6	M	33	2022	L	Both column	Anterior intrapelvic approach, quadrilateral surface plate	AVN with acetabular protrusion	2023	Continuum acetabular system, Taperloc (Zimmer-Biomet, Warsaw)
7	V	26	2019	R	Both column	Anterior intrapelvic approach, quadrilateral surface plate	Post-traumatic osteoarthtritis	2023	Continuum acetabular system, Taperloc (Zimmer-Biomet, Warsaw)
8	M	81	2019	R	T-shaped	Anterior intrapelvic approach, quadrilateral surface plate	Post-traumatic osteoarthtritis	2024	Avantage cup, Muller lateral straight stem (Zimmer-Biomet, Warsaw)

AVN, avascular necrosis.

A patient-specific live-sized acetabular 3D model was created by importing the DICOM archives of standard multislice CT (Philips Brilliance iCT 256, 1.0 mm slice thickness) in Mimics (Materialise Mimics 25.0). Different tissue structures were segmented with automatic and semiautomatic tools. Bone, osteosynthesis material and soft tissue were distinguished using thresholding based on grayscale images. The files were uploaded to 3D-matic (version 18.0) and exported as 3D object in stereolithography format to the 3D print software (Bambu Studio version 1.6.2.4) (Fig. 1).

Figure 1.

(a and b): Example of 3D-reconstructed acetabulum after failed acetabular fracture ORIF.

The 3D model was printed using butenediol vinyl alcohol copolymer (BVOH) BASF filament (support material), polylactic-acid (PLA) white for bone tissue and PLA red for osteosynthesis material with the Bambu lab X1 carbon printer. The default printing setting was 0.2 mm layer height, 0.42 mm line thickness, 0.84 mm shell thickness (2 lines) and a fill density of 15%. After obtaining the robust 3D-printed model, the BVOH BASF filament was largely removed by hand and finished by placing the model in water. Eventually, the BVOH BASF filament dissolves in water and the PLA model remained.

For each patient, the actual operation was simulated on the 3D model by the primary surgeon. First, the acetabular 3D model was positioned for a posterolateral approach and the acetabulum was reamed. According to the standard procedure, the acetabulum was first medialized and enlarged step-by-step such that the dome was filled (Figure 2, Figure 3, Figure 4). Attention was paid for any interference with osteosynthesis material, this was easily noticed because osteosynthesis material was colored red (Figs. 3 and 4). The model was inspected for bone defects, acetabular wall integrity and screw interference and the last reamer was left in place to assess stability of the potential implant. Finally, the surgical plan was documented and the required materials for the operation were obtained. For example, a standard procedure could be performed when there was no interference with osteosynthesis material (Fig. 2). However, when interference with osteosynthesis material was noticed, the surgeon had to decide to continue peripheral reaming without further medialization, to ream in between the osteosynthesis material or to remove osteosynthesis using a metal cutting burr (Figs. 3 and 4). Uncemented acetabular cups, with or without screw fixation, could be implanted when enough acetabular medialization was achieved during reaming (Figs. 2 and 3). When osteosynthesis material prevented further medialization and could not be easily removed, acetabular preparation was continued with the use of small reamers and bone curettes and a cemented acetabular cup was implanted with or without bone grafting (Fig. 4).

Figure 2.

Images of patient no. 6. (a and b) Radiograph and CT scan demonstrates a nonunion of a both column fracture with AVN of the femoral head with acetabular protrusion. (c-e) A 3D-printed acetabular model was created, after stepwise reaming the surgeon concluded that there was no interference with osteosynthesis material and adequate acetabular bone stock to support a cementless cup. (f) Peroperatively, an apical bone defect was grafted with autologous bone graft and an uncemented trabecular metal-coated acetabular cup size 60 was placed. This was according to the preoperative formed surgical plan. AVN, avascular necrosis.

Figure 3.

Images of patient no. 7. (a and b) Radiograph and CT scan demonstrates ORIF of a both column acetabulum fracture with post-traumatic osteoarthritis and possible interference of osteosyntheses material. (c-e) In the 3D-printed model, the intra-articular screw is clearly visible and could be easily removed peroperatively using a metal-cutting burr. After stepwise reaming, the surgeon concluded that there was no interference with other osteosynthesis material, so the decision was made to leave the osteosynthesis material in situ. (f) Peroperative image demonstrated the single intra-articular screw, this was removed with a metal cutting burr and further medialization was achieved by stepwise reaming. The acetabulum was reconstructed with an uncemented trabecular metal coated acetabular cup size 52. (g): Postoperative radiograph.

Figure 4.

Images of patient no. 8. (a and b) Radiograph and CT scan demonstrates ORIF of a both column acetabulum fracture with post-traumatic osteoarthritis and possible interference of osteosyntheses material. (c-e) In the 3D-printed model, osteosynthesis material (3 screws) was visible and could not be easily removed. Acetabular preparation was continued with the use of small in between the screws and enough medialization was achieved. (f) Preoperative image demonstrated the osteosynthesis material, the acetabulum was reconstructed according to the preoperatively formed plan with an uncemented dual mobility cup size 60 without bone grafting. (g) Postoperative radiograph.

Three patients received a cemented acetabular dual-mobility cup and in one of these patient’s acetabular reconstruction was performed by bone impaction grafting. An uncemented acetabular trabecular metal cup was placed in 4 patients and in 1 of these patients an acetabular defect was restored with bone impaction grafting. In 1 patient, a highly cross-linked polyethylene liner was cemented in a trabecular metal revision shell after 2 acetabular defects were restored with bone impaction grafting (Table 1). In all cases the preoperative plan was fully carried out.

Discussion

Delayed THA after ORIF for acetabular fractures is a complex procedure and associated with increased risk of postoperative complications [15]. Therefore, surgeons must be optimally prepared to minimize time of surgery and improve acetabular component positioning.

In this report, the use of a multicoloured 3D-printed acetabular model was described as a hands-on workup tool to understand the complex disturbed anatomy of failed ORIF acetabular fractures in 8 patients. In this way, the reaming procedure and acetabular cup positioning can be simulated preoperatively. Removal of acetabular osteosynthesis material can be difficult and is associated with severe complicates such as vascular and nerve injuries [16]. Therefore, it is preferred to leave osteosynthesis material in situ. With conventional workup using x-ray and CT-scans, it often remains uncertain if osteosynthesis material or wall integrity will hamper optimal up placement. By foreseeing possible problems such as screw interference in a 3D-printed model, the surgeon is preoperatively well informed and a detailed operation plan can be accurately made. In this way, one can adapt on fixation techniques, removal of osteosynthesis material or adjust on cup placement. In our opinion, this has big advantages, not only to perform the operation successfully, but also to start complex procedures with more confidence. It is important to note, that the value of surgical simulation on 3D-printed acetabular models as an addition to standard workup depends on personal preferences and experience of the orthopaedic surgeon as well. The aim of this technical note, however, was not to demonstrate how different problems were solved, but to demonstrate that anticipating on them could be very helpful. In addition, it might lead to less ordering of special implants, which reduces costs and environmental burdens [17].

The CT-based 3D acetabular models used in this study can be printed at relatively low costs: For example, the total print cost of the acetabular 3D model in patient 8 was 30.89 euro and total printing time was 1 day 11 hours 14 minutes. A CT scan is routinely ordered in all complex arthroplasty cases, such as failed ORIF acetabular fractures, as part of standard preoperative workup in our hospital. Therefore, the CT scan itself did not result in additional costs.

Several other studies reported on 3D-printed acetabular models for surgical simulation of complex THA procedures [[12], [13], [14],18]. To the best of our knowledge, our technical note was the first to use 3D-printed acetabular models in THA patients after failed ORIF of acetabular fractures. Jiang et al. [14] demonstrated in a pilot study that 3D models improved surgical planning in complex THA patients. They used 3D-printed models for surgical simulation as an adjunct to surgical planning. This allowed them to trial multiple approaches to the same surgical problem and gave insight in possible complications. They also conclude that it provides valuable teaching opportunities for trainees and streamline operative logistics. Although 2 patients with acute acetabular fractures were included, they did not include THA patients after failed ORIF for acetabular fractures.

Maryada et al. [12] used 3D-printed models in 27 THA patients to predict cup size and bone defects. They concluded that acetabular cup size was accurate in 25 patients and acetabular bone defects were accurate in all patients. Although 2 patients were post acetabular fractures, they did not mention anticipating on in situ osteosynthesis material.

Ivanov et al. [11] used 3D-printed models to facilitate optimal preoperative planning of surgical treatment of complex acetabular fractures. They reported a significant decrease in operative time, blood loss, radiation and improved outcomes compared to conventional treated patients.

Summary

This technical note demonstrates that multicoloured 3D-printed acetabular models could be used to simulate acetabular component positioning in complex THA patients after surgically treated acetabular fractures. We think that this could be beneficial in preoperative planning, surgical confidence and patient outcomes. Future studies should investigate if it actually leads to less complications and improved patient reported outcomes.

CRediT authorship contribution statement

Luuk A. de Wert: Writing – review & editing, Writing – original draft. S. Bossers: Writing – review & editing, Writing – original draft. Vito van Dal: Writing – review & editing, Methodology. Pieter-Jan Scheerlinck: Writing – review & editing, Writing – original draft. Hilco P. Theeuwes: Writing – review & editing. Olav P. van der Jagt: Writing – review & editing, Visualization, Conceptualization.

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.2026.101956.