case_images: PMC11735376_01
case_images: Preoperative radiograph (A), CT scan (B), MRI scan (C), and SPECT scan (D) of the patient with Ewing's sarcoma involving the talus, accompanied by suspected involvement of the calcaneus.
case_images: OS-17-288-g006.jpg
case_images: PMC11735376_01_OS-17-288-g006.jpg
case_images: os14279-fig-0001
case_images: The radiograph revealed osteolytic bone destruction in the talus (Figure 1A). Computed tomography (CT) scan demonstrated a well-defined osteolytic lesion in the talus and a local bone destruction in the calcaneus (Figure 1B). Magnetic resonance imaging (MRI) revealed a primary lesion in the talus and calcaneus (Figure 1C). Single-photon emission computed tomography (SPECT) showed the signal concentration around the right ankle joint (Figure 1D). During the operation, the polyethylene models were used as navigation (Figure S1) and the metal model was used for resection marking (Figure S2).
case_images: Histopathological images showed small cell malignant tumors. (A) hematoxylin and eosin (H&E) stain x200 magnification; (B) immunohistochemistry (IHC) x40 magnification.
case_images: OS-17-288-g003.jpg
case_images: PMC11735376_01_OS-17-288-g003.jpg
case_images: os14279-fig-0002
case_images: Pathological biopsy of the right talus lesion suggests the diagnosis of Ewing sarcoma (Figure 2). During the operation, the polyethylene models were used as navigation (Figure S1) and the metal model was used for resection marking (Figure S2).
case_images: (A) Osteotomies were simulated on the virtual 3D models based on a combination of preoperative MRI and CT results; (B) the virtual 3D model of the 3D-printed customized talus-calcaneus prosthesis; (C) mediolateral view of the Simulating prosthetic replacement for the bone defect; (D) front view of the Simulating prosthetic replacement for the bone defect.
case_images: OS-17-288-g002.jpg
case_images: PMC11735376_01_OS-17-288-g002.jpg
case_images: os14279-fig-0003
case_images: Then the resection range was determined based on the extent of bone resection after evaluating the range from the MRI and the shape of the calcaneus and talus prosthesis were designed according to the shape of the bone defect (Figure 3A). Subsequently, the shape of the talus and calcaneus component of the prosthesis is generated by mirroring that of the contralateral side (Figure 3B,C). The prosthesis is composed of a UHMWPE part and a titanium alloy part, which are connected through a "snap-fit" design (Figure 3B).
case_images: Physical photos of the 3D-printed customized talus-calcaneus prosthesis, (A) side view; (B) vertical view; (C) prosthetic segment component of ultrahigh-molecular weight polyethylene (UHMWPE); (D) bottom view.
case_images: OS-17-288-g007.jpg
case_images: PMC11735376_01_OS-17-288-g007.jpg
case_images: os14279-fig-0004
case_images: Ltd. (Tongzhou, Beijing, People's Republic of China), and fabricated by utilizing the electron beam melting technique (ARCAM Q10plus, Molndal, Sweden), with Ti6Al4V powder as the printing material (Figure 4).
case_images: (A) The intraoperative pictures after the removal of the affected talus and calcaneus through anterior approach; (B) the modular prosthesis was inserted and fixed to the talus and calcaneus; (C) the resected talus and part of calcaneus.
case_images: OS-17-288-g005.jpg
case_images: PMC11735376_01_OS-17-288-g005.jpg
case_images: os14279-fig-0005
case_images: Then, the UHMWPE component was pressed and assembled onto the metal component (Figure 5).
case_images: Postoperative 12 months ankle function, (A) dorsiflexion; (B) plantarflexion.
case_images: OS-17-288-g004.jpg
case_images: PMC11735376_01_OS-17-288-g004.jpg
case_images: os14279-fig-0006
case_images: The range of motion for dorsiflexion, plantarflexion, inversion, and eversion of the right ankle joint was measured as 10  and 35 , 15 , and 10  degrees, respectively (Figure 6).
case_images: Postoperative 12 months X-rays (A,B) and T-SMART (C,D) indicated the prosthesis was well positioned.
case_images: OS-17-288-g008.jpg
case_images: PMC11735376_01_OS-17-288-g008.jpg
case_images: os14279-fig-0007
case_images: Radiograph showed a good position of the prosthesis and T-SMART revealed an excellent integration of the prosthesis with the surrounding bone at the bone-prosthesis interface (Figure 7).