Patient-Specific 3D Printed Hemipelvic Reconstruction with Constrained Total Hip Arthroplasty Following Type I + II Internal Hemipelvectomy for Ewing’s Sarcoma

Patient Overview

A 20-year-old male with metastatic Ewing’s sarcoma of the left hemipelvis presented following induction chemotherapy. Imaging revealed extensive involvement of the iliac wing and acetabulum, requiring a Type I + II internal hemipelvectomy. Given the complexity of the defect and the patient’s young age, a patient-specific 3D printed hemipelvic implant was designed to restore pelvic anatomy, preserve limb function, and provide a stable foundation for hip reconstruction.

The Clinical Challenge

Reconstruction after periacetabular tumor resection remains one of the most demanding procedures in orthopedic oncology. Conventional reconstruction techniques, including biological grafts and standard pelvic prostheses, often present significant challenges such as: 

• Implant instability 
• Limited fixation due to bone loss 
• Infection risk 
• Limb-length discrepancy 
• Delayed rehabilitation 
• Variable functional outcomes 

For this patient, the goal was to achieve complete tumor resection while restoring pelvic continuity and enabling an early return to mobility.   

Personalized Surgical Planning 

A patient-specific implant solution was developed by JMS design team to address the defects and support reconstruction.  A CT-based three-dimensional model of the pelvis was created to enable comprehensive preoperative planning. 

This digital workflow facilitated the design of: 

• Planning of resections planes 
• Patient-specific resection guides for precise osteotomies 
• A customized porous Titanium hemipelvic implant 
• Optimized iliosacral fixation 
• A constrained total hip arthroplasty (THA) construct 

The implant was engineered to restore native hip biomechanics while maximizing primary stability and long-term biological fixation. 

Custom Implant Design 

The patient-specific implant incorporated several advanced design features to match the patient’s anatomy and support durable reconstruction. 

Key Design Features 

• Anatomically matched Type I + II hemipelvic implant 
• Porous titanium surface to promote osseointegration 
• Press-fit tapered iliosacral peg for primary stability 
• Multiple locking screw trajectories into the sacrum and residual pelvis 
• Cement-locking grooves for acetabular fixation 
• Compatibility with constrained total hip arthroplasty components 

Surgical Procedure 

1. Tumor Resection 

The procedure was performed using an extended iliofemoral approach. Patient-specific cutting guides were secured with Kirschner wires, allowing precise osteotomies according to the preoperative plan. Careful dissection preserved the surrounding neurovascular structures, including the S1 nerve root. Following completion of the osteotomies, the tumor was removed as the **en bloc**. 

2. Reconstruction 

The customized implant was first trialed on the patient-specific pelvic model and native pelvis before definitive implantation. Using a patient-specific drilling guide, the iliosacral junction was prepared, and a tapered porous peg was inserted to achieve immediate press-fit fixation. 

Final fixation was achieved with multiple locking screws placed into the: 

• Sacrum 
• Residual ilium 
• Superior pubic ramus 
• Ischium 

A constrained acetabular component was cemented into the custom implant, followed by implantation of an uncemented porous-coated femoral stem and a 28-mm femoral head.

Clinical Outcome 

Postoperative imaging demonstrated: 

• Stable implant positioning 
• Restoration of pelvic continuity 
• Secure iliosacral fixation 
• Anatomical restoration of the hip center 
• Stable constrained hip articulation 

Why Patient-Specific Reconstruction? 

Customized 3D printed implants offer several advantages over conventional reconstruction techniques by enabling: 

• Accurate restoration of patient anatomy 
• Precise implant fit 
• Optimized screw placement 
• Improved primary fixation 
• Enhanced biological integration through porous surfaces 

Clinical Significance 

This case highlights the value of combining patient-specific surgical planning, customized 3D printed reconstruction, and constrained total hip arthroplasty for the management of complex pelvic tumors. 

The personalized approach enabled accurate tumor resection, stable reconstruction, restoration of pelvic biomechanics, and rapid postoperative rehabilitation, demonstrating the potential of patient-specific technology to improve outcomes following extensive pelvic oncologic surgery.