Most sarcomas arising in the lower extremity can be successfully treated with a limb salvage procedure.1 En bloc talectomy combined with tibiocalcaneal arthrodesis is an option for aggressive benign tumors of the talus.2 For sarcomas of the foot, below the knee amputation has been the standard for operative treatment.3 To the current authors' knowledge, no case of a limb salvage procedure has been reported for Ewing's sarcoma arising in the talus.
Recently, 3-dimensional (3D) printing technology has become the focus of attention in the field of orthopedic surgery.4 This technique has been used in the reconstruction of the calcaneus in a few case reports following total calcanectomy for chondrosarcoma,5 Ewing's sarcoma,6 and desmoplastic fibroma of the calcaneus.7 The current case is the first report of entire talus replacement using a 3D-printed talar prosthesis after total talus resection for Ewing's sarcoma.
A 30-year-old woman presented with a 1-year history of left ankle pain. Plain radiographs of the left ankle revealed an osteolytic lesion of the left talus (Figure 1). Magnetic resonance imaging of the left ankle joint revealed a hypointense lesion on T1 sequence. The rim of the lesion was enhanced following the intravenous administration of gadolinium (Figure 2). Bone scintigraphy showed increased radioisotope uptake only at the left midfoot (Figure 3). On core biopsy, the histological examination revealed a neoplasm with small blue round cell morphology. Immunohistochemical staining for CD99 and Fli-1 was strongly positive (Figure 4). Fluorescent in situ hybridization with the appropriate probe (ZytoLight SPEC EWSR1 Dual Color Break Apart Probe; ZytoVision GmbH, Bremerhaven, Germany) confirmed the presence of the 22q12.2 region translocation. At the time of diagnosis, staging workup showed no distant metastases.
Anteroposterior (A) and lateral (B) radiographs of the left ankle demonstrating the osteolytic lesion of the talus.
Preoperative T1-weighted coronal (A) and sagittal (B) magnetic resonance images depicting the hypointense lesion of the body of the talus. T2-weighted, fat-suppressed coronal (C) and sagittal (D) magnetic resonance images of the lesion.
Anterior (A) and posterior (B) view bone scintigraphy showing increased radioisotope uptake only at the left midfoot.
High-power photomicrographs of Ewing's sarcoma of the talus. Small blue round cell morphology on the biopsy fragment (hematoxylin and eosin, original magnification ×200) (A). Strong membranous and cytoplasmic immunopositivity for CD99 (brown diaminobenzidine, original magnification ×200) (B). Strong nuclear staining for Fli-1 (brown diaminobenzidine, original magnification ×200) (C).
The patient received 4 courses of neoadjuvant chemotherapy with a regimen of vincristine, cyclophosphamide, actinomycin D, and doxorubicin. Ten weeks later, there was a decrease in the extent of the talar lesion and improvement of the patient's symptoms. On the basis of consultation with the medical oncologist at their institution, the authors decided to perform a limb salvage procedure.
The patient was placed in the supine position. Under general anesthesia and pneumatic tourniquet, an anteromedial incision of the talus, 15 cm long, was performed to expose the ankle joint and the talus (Figure 5A). The medial malleolus was exposed by reflecting its periosteum but preserving the deltoid ligament. The medial malleolus was predrilled with a 2.5-mm drill (Figure 5B), and a transverse osteotomy at the level of the tibiotalar joint line was undertaken with a pneumatic saw blade (Figure 5C). The ligaments and capsules of the tibiotalar joint, the subtalar joint, the calcaneocuboid joint, and the talonavicular joint were divided (Figure 5D). Complete removal of the talus was performed (Figure 6). Total talectomy was followed by prosthetic reconstruction of the talus. Using preoperative computed tomography scans of the foot, preoperative planning of the procedure and the design of the talar prosthesis was performed (Figure 7). A stem was added to the anatomic design of the prosthesis to ensure subtalar fusion and stability. The prosthesis, which was a mirror image of the right talus, was printed by an Electron Beam Melting 3D printer (Implantcast GmbH, Buxtehude, Germany) based on computed tomography data. Titanium nitride coating was applied to the articulating surfaces of the prosthesis to prevent implant allergy and to reduce wear (Figure 8). An anatomic guide was fixed to the calcaneus with 2 pins, and a special rasp was used to prepare the insertion of the stem of the prosthesis to the calcaneus (Figure 9). The titanium porous stem of the talar prosthesis was then inserted into the calcaneus and the prosthesis was well seated on the calcaneus (Figures 10A–C). Two fins were configured for the primary fixation of the cementless tibial component of the total ankle system (TARIC Total Ankle System; Implant-cast GmbH). The tibia plafond was replaced with a press-fit commercially pure titanium and hydroxyapatite-coated metallic prosthesis (Figure 10D). A highly congruent polyethylene inlay (ultra high molecular weight polyethylene) was inserted, the ankle joint was reduced, and the medial malleolus was stabilized using a tension band technique with 2 partially threaded screws and wire (Figure 11). Pathologic examination of the talus specimen showed clear surgical margins and complete tumor necrosis.
An anteromedial incision, 15 cm long, is performed to expose the ankle joint (A). The medial malleolus is predrilled with a 2.5-mm drill, and a transverse osteotomy at the level of the tibiotalar joint line is undertaken with a saw blade (B). The ligaments and capsules of the tibiotalar joint, the subtalar joint, the calcaneocuboid joint, and the talonavicular joint are divided (C). The talus is exposed, free of surrounding ligaments (D).
Upper (A) and medial (B) views of the removed specimen of the talus.
Front (A), medial (B), and lateral (C) views of the design of the prosthesis based on the preoperative computed tomography scans of the left foot.
The 3-dimensional printed talar prosthesis with titanium nitride coating applied to the articulating surfaces. The stem and the surfaces that face the calcaneus are porous coated.
Intraoperative photographs. Complete talus resection (A). The anatomic guide is fixed to the calcaneus with 2 pins (B). A special rasp is used to prepare the insertion of the stem of the talar prosthesis into the calcaneus (C). The canal in the calcaneus is prepared to receive the stem of the prosthesis (D).
Intraoperative photographs. The titanium porous stem of the talar prosthesis is inserted (A) and fixed into the calcaneus (B). The prosthesis is well seated in place (C). The tibial plafond is replaced with a press-fit commercially pure titanium and hydroxyapatite-coated metallic prosthesis (D).
Intraoperative photograph. A polyethylene inlay is inserted and the medial malleolus is stabilized using a tension band technique with 2 partially threaded screws and a wire.
Following the procedure, the foot was placed in a cast and not bearing weight was advised for 3 weeks. Then, weight bearing was allowed in a boot, gradually increased to full weight bearing during the next 3 weeks (Figure 12). The patient was given adjuvant chemotherapy. At 1-year postoperatively, the medial malleolus tension band wire and screws were removed.
Postoperative anteroposterior (A) and lateral (B) radiographs of the ankle showing satisfactory alignment of the ankle joint and of the position of the talus prosthesis.
At the latest follow-up, 3.5 years after surgery, the patient had no pain and could walk unsupported barefoot. She also could continuously walk more than 6 blocks and hike to the mountains. The motion of the left ankle ranged from 5° of dorsiflexion to 40° of plan-tarflexion (Figure 13). The American Orthopaedic Foot & Ankle Society Ankle–Hind-foot Scale score for this patient was 86 of 100 points. Radiographic evaluation showed no loosening of the prosthesis (Figure 14).
Excellent range of ankle motion: 5° of dorsiflexion (A) and 40° of plantarflexion (B).
Anteroposterior (A) and lateral (B) radiographs of the left ankle at 3.5 years postoperatively demonstrating no signs of implant loosening.
Chemotherapy and below the knee amputation is indicated for most cases of Ewing's sarcoma of the foot.8 Attempts at limb salvage procedures have been reported for sarcomas of the calcaneus.9 Fresh-frozen allograft reconstructions have been the preferred modality in most of these cases. However, early collapse of the allograft and failure of the construction has been reported.9 Sakayama et al10 performed reconstruction of the talus using a frozen bone method, an autograft containing tumor treated by liquid nitrogen, resulting in successful salvage of the limb. Acrylic cement was used for mechanical support.10 One common problem among the cases of bone graft reconstruction was the long period of immobilization necessary to achieve bone union.
A custom-made prosthesis reconstruction for sarcomas of the calcaneus was first reported by Chou et al.11 This prosthesis was fixed to the talus via a posterior approach including plan-tar skin incision. At the 12-year follow-up, the patient could not walk more than 8 to 10 blocks and had persistent pain in the plantar heel pad. Walking barefoot was not possible, and the operated on foot required a different shoe.12 Imanishi and Choong5 recently reported the first use of a patient-matched 3D-printed titanium calcaneal prosthesis. At short-term follow-up of 5 months, the patient had satisfactory clinical results without any major complication or pain. Park et al7 and Papagelopoulos et al6 recently reported excellent clinical and radiographic results at 16- and 33-month follow-up, respectively, after calcaneus reconstruction using a 3D-printed calcaneus implant.
Custom-made prosthesis reconstruction for severe post-traumatic loss of the entire talus was first reported by Angthong.13 The prosthesis was made of stainless steel based on computed tomographic data of the normal contra-lateral talus. At short-term follow-up of 5 months, the patient had full function of the ankle and was able to participate in daily activities without any compromise. Taniguchi et al14 reported satisfying results with the use of an alumina ceramic total talar prosthesis for osteonecrosis of the talus. The prosthesis was produced based on computed tomographic data of the normal talus. The mean duration of follow-up was 52.8±22.0 months. At the time of final follow-up, osteosclerosis of the distal end of the tibia was identified in 44% of the patients. Tracey et al15 reported the restoration of radiographic alignment (talar height and tilt) for 14 patients receiving a 3D-printed total talar prosthesis for the treatment of talar avascular necrosis. However, no clinical results were reported.
In a cadaver model, Regauer et al16 reported on an internally braced custom-made prosthesis for total talus replacement. This prosthesis has a custom-made hemiprosthesis with 4 eyelets for fixation of artificial ligaments combined with the STAR prosthesis (Stryker, Mahwah, New Jersey). It has a high level of primary stability, but it has not yet been used clinically. In the reported case, 3D printing technology was applied to produce a stemmed titanium talar prosthesis. The stem inserted into the calcaneus offers additional hindfoot stability. The combination of a tibial plafond replacement with a 3D-printed talar prosthesis also can maximize postoperative ankle function and avoid the osteosclerosis of the distal end of the tibia. The use of a 3D-printed talar prosthesis following total talectomy can be an effective option for reconstruction with satisfactory ankle function. A limb salvage procedure for localized malignant or aggressive tumors of the talus is possible with the use of this technology. The paucity of clinical experience prevents clear recommendations over other treatment methods. Long-term follow-up studies are needed.
In this case, the entire talus was replaced with the use of a 3D-printed custom-made talar prosthesis for ankle reconstruction following total talectomy for Ewing's sarcoma. This emphasizes the use of a limb salvage procedure, based on 3D printing technology, as a functional alternative to below the knee amputation for sarcomas of the foot.
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- Park JW, Kang HG, Lim KM, Kim JH, Kim HS. Three-dimensionally printed personalized implant design and reconstructive surgery for a bone tumor of the calcaneus: a case report. JBJS Case Connect. 2018;8(2):e25.
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- Ottolenghi CE, Petracchi LJ. Chondromyxosarcoma of the calcaneus: report of a case of total replacement of involved bone with a homogenous refrigerated calcaneus. J Bone Joint Surg Am. 1953;35(1):211–214. doi:10.2106/00004623-195335010-00021 [CrossRef]
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- Chou LB, Malawer MM, Kollender Y, Wellborn CC. Prosthetic replacement for intramedullary calcaneal osteosarcoma: a case report. Foot Ankle Int. 1998;19(6):411–415. doi:10.1177/107110079801900612 [CrossRef]
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- Taniguchi A, Takakura Y, Tanaka Y, et al. An alumina ceramic total talar prosthesis for osteonecrosis of the talus. J Bone Joint Surg Am. 2015;97(16):1348–1353. doi:10.2106/JBJS.N.01272 [CrossRef]
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