Limb salvage surgery has become the treatment of choice for primary malignant bone tumors of the extremities, with 90% to 95% of patients being successfully treated with such procedures.1 However, the compact structure of the foot and its complex compartmentalization often lead to early tumor expansion to the adjacent tissues, which is not amenable to conservative surgical procedures.2 Belowknee amputation has been the most common treatment for many years. Recently, advances in imaging modalities, adjuvant therapies, and improved surgical techniques have made foot salvage surgery increasingly possible.3,4
The calcaneus is an unusual location for malignant lesions,5 and there are only a few reports of foot salvage after total calcaneus resection. Reconstruction options include bone allografts, vascularized or pedicled bone autografts, the combination of allografts with autografts, and custom-made calcaneus implants.4,6–17
Novel 3-dimensional (3D) technologies are revolutionizing clinical practice, making complex surgery more precise and easier to perform. Based on accurate imaging data, 3D printed implants may be tailored to patients' specific anatomic characteristics and may successfully address the significant reconstruction challenges after complex tumor resection.18
In this report, the authors present 2 patients with Ewing's sarcoma of the calcaneus who underwent foot salvage surgery. Both patients underwent total calcanectomy and reconstruction with a custom-made 3D printed implant. The preoperative planning, design of the endoprosthesis, and surgical technique are discussed.
Two patients with Ewing's sarcoma of the calcaneus were referred to the authors' department. The left calcaneus was involved in a 16-year-old boy (Figures 1–7), and the right calcaneus was involved in a 46-year-old woman (Figures 8–15). Plain radiographs of the foot showed a lytic lesion of the calcaneus (Figure 1A). Increased gadolinium uptake was evident on magnetic resonance imaging (Figure 8). Computed tomography showed no cortex involvement or penetration (Figure 1B). Bone scan showed increased radioisotope uptake at the calcaneus (Figure 1C). Core bone biopsy revealed Ewing's sarcoma in both patients. The diagnosis was confirmed with immunochemistry and genetic analysis studies. Staging showed no evidence of distant metastasis in either patient.
Lateral radiograph of the foot showing an osteolytic lesion of the left calcaneus (A). Transverse computed tomography scan showing no cortex destruction (B). Whole-body technetium-99m bone scan showing increased radioisotope uptake at the left calcaneus (C).
Lateral “L-shaped” incision including the previous biopsy tract (A). En bloc resection of the calcaneus (B). The resected calcaneus specimen (C). Magnetic resonance image showing the provisional bone cement spacer at the resection site (D).
Lateral view of the foot showing the proposed implant design (A). A hollow stem was added to the calcaneus implant to obtain subtalar fixation; in axis with the hollow stem a connection for an impactor was designed; and holes were designed in the circumference of the implant for attachment of soft tissue structures (B). Abbreviation: TiN, titanium.
Lateral (A) and medial (B) aspects of the 3-dimensional printed calcaneus implant.
Removal of the bone cement spacer through the previous incision (A); fixation of the 3-dimensional printed calcaneus implant to the talus using a special impactor (B); and reattachment of the Achilles tendon, enhanced with the flexor hallucis longus tendon, to the calcaneus implant (C, D).
Postoperative lateral radiograph of the foot showing the calcaneus implant in place with surface congruity to the cuboid (A). Computed tomography scans showing excellent fixation of the calcaneus implant to the talus and bone ingrowth into the hollow stem (B, C).
Photographs of the patient's foot showing asymptomatic ankle dorsiflexion (A) and plantarflexion (B).
T2 magnetic resonance image showing a high signal lesion of the right calcaneus.
En bloc resection of the calcaneus (A) and provisional bone cement placement at the resection site (B).
Postoperative plain radiograph (A) and computed tomography scan (B) showing the bone cement spacer.
Lateral view of the foot showing the calcaneus cement spacer (A). The calcaneus implant was designed smaller than the original to permit soft tissue coverage and wound closure (B).
Lateral (A), medial (B), superior (C), and inferior (D) aspects of the custom-made 3-dimensional printed calcaneus implant.
Removal of the bone cement spacer through the previous incision (A); fixation of the 3-dimensional printed calcaneus implant to the talus using a special impactor (B); and reattachment of the Achilles tendon to the calcaneus implant (C, D).
Postoperative lateral radiograph of the calcaneus (A). Computed tomography scans at last follow-up showing excellent fixation of the calcaneus implant to the talus and bone ingrowth into the hollow stem (B).
Lateral radiograph of the calcaneus at last follow-up (A). Photographs showing excellent clinical result with satisfactory ankle dorsiflexion (B) and plantarflexion (C).
Both patients were referred for neoadjuvant chemotherapy. After completion of neoadjuvant chemotherapy, because of the intraosseous location of the tumor, foot salvage was performed through a 2-stage surgery.
Initially, the patients underwent total calcanectomy for tumor resection. In a second stage, calcaneus reconstruction was conducted.
First Stage (Tumor Resection)
An extensile “L-shaped” lateral calcaneus approach was used. The horizontal part of the approach included a fusiform incision in line with the base of the fifth metatarsal. The skin islet with the biopsy tract was left behind to be resected en bloc with the tumor (Figure 2A). The posterior part of the incision was performed between the fibula and the Achilles tendon. Full-thickness flaps were created, while the sural nerve was identified and protected. Subsequently, the peroneal tendons were released and elevated toward the anterior flap. Dissection of the inferior flap continued until the calcaneal segment of the plantar fascia was adequately exposed. The superior part was also dissected until adequate exposure of the calcaneus was achieved. Then, the ligamentous structures around the calcaneus were dissected and the plantar fascia and Achilles tendon were detached. Avoiding the medial neurovascular structures, the medial ligaments were also dissected, and the calcaneus was removed (Figure 2B, Figure 2C, and Figure 9A). A handmade cement spacer was fashioned to fill the resection defect (Figure 2D, Figure 9B, and Figure 10). The stump of the Achilles tendon was temporarily attached on the spacer with sutures, and the surgical wound was closed. The ankle was immobilized using a leg cast. Partial weight bearing with a mid-calf protecting boot was allowed after 6 weeks. The postoperative course was uneventful, and both patients were referred for chemotherapy.
Histologic examination showed surgical margins that were free of tumor in both cases. There was complete tumor necrosis in the male patient and 98% tumor necrosis in the female patient.
Three-dimensional Printed Calcaneus Implant
For both patients, a computed tomography scan of the operated on foot was obtained and a digital projection was created. The articulation with the cuboid and talus and the resection defect were measured. The implants were designed to be smaller than the original bone to permit soft tissue coverage and to avoid wound closure complications (Figure 3 and Figure 11). Based on this planning, a custom-made titanium calcaneal endoprosthesis was manufactured using an Electron Beam Melting 3D printer (Q10, Arcam EBM, Molndal, Sweden). For better hindfoot stability, a porous-coated hollow stem was designed for subtalar fixation (Figure 3B, Figure 4, and Figure 12). The orientation of the stem was in line with the axis between the posterior facet of the talus and the posterior facet of the calcaneus implant. In the same axis, at the inferior aspect of the implant, a connector was also fabricated to receive an impactor (Figure 3B). The implant was polished for better articulation with the cuboid.9 In addition, special holes were designed in the circumference of the implant for reattachment of soft tissue structures.
Second Stage (Reconstruction)
After the completion of adjuvant chemotherapy and 9 months after the initial operation, the patients were scheduled for calcaneal reconstruction. The previous extensile lateral approach was used. After removing the cement spacer, the posterior facet of the talus was reamed to accept the stem of the custom-made calcaneus endoprosthesis. Then, the stem was introduced and fixed to the talus with the use of a customized impactor (Figure 5B and Figure 13B). The Achilles tendon was reattached to the posterior surface of the implant. Reattachment was achieved with nonabsorbable sutures (No. 5 Ethibond Excel; Ethicon, Inc, Somerville, New Jersey) (Figure 5D and Figure 13D). The flexor hallucis longus was used to enhance the Achilles reattachment in 1 case (Figure 5C). Plantar fascia, fibrofatty tissue of the plantar heel pad, and adjacent soft tissues were also reattached on the implant, and the surgical wound was closed.
The postoperative course was uneventful for both of the patients. At 6 weeks after surgery, partial weight bearing with a mid-calf protecting boot was allowed. Unrestricted weight bearing was allowed 6 weeks later.
At the last follow-up 2.5 years after treatment, there was no local recurrence or distant metastasis in either patient. Plain radiographs and computed tomography scans showed perfect fit of the endoprosthesis and no evidence of loosening (Figure 6 and Figure 14). The hindfoot was stable, and an acceptable ankle range of motion was recorded in both patients (dorsiflexion/plantarflexion: male, 10°/25°; female, 10°/40°) (Figure 7 and Figure 15, respectively). The male patient was pain free and could walk barefoot. The female patient occasionally experienced mild heel discomfort when walking barefoot and needed an extra heel cushion. Both patients could walk without support for 4 to 6 blocks. The American Orthopaedic Foot & Ankle Society Ankle–Hindfoot Scale score was 88 points for the male patient and 78 points for the female patient. The patients had returned to their previous activities and did not report restrictions in their daily living. No complication was documented and no additional surgery was necessary for either patient.
Calcanectomy without reconstruction has been reported; however, unfavorable cosmetic results, ulceration of the skin, and deformities frequently occur after such a procedure.19,20 Further, a 3-point gait is essential for physiologic locomotion, and the calcaneus forms the posterior part of this tripod.12
Different biological reconstruction techniques have been suggested after total calcanectomy for malignancies. In 1953, Ottolenghi and Petracchi14 were the first to describe a calcaneus fresh-frozen allograft in a patient with chondromyxosarcoma; however, their graft resulted in collapse. Similarly, Muscolo et al13 performed reconstruction with fresh-frozen calcaneus allograft in 2 patients (chondrosarcoma and giant cell tumor of the calcaneus). The graft incorporated in both patients, and good long-term functional outcomes were described (32 and 9 years of follow-up); however, collapse was documented for 1 of the grafts.13 Wozniak et al16 performed calcaneal replacement with a frozen femoral head-neck allograft in 3 young patients with primary bone tumors. A good result and restoration of walking without aids were reported in all patients; however, no additional information about functional outcome or follow-up was provided.
Microsurgical reconstruction techniques after total calcanectomy for tumors have also been reported.4,10–12,15 These studies describe mostly patients with soft tissue defects after wide tumor resection. The suggested reconstructive options in such cases include the use of vascularized (osteofasciocutaneous) iliac crest flap10,15 or pedicled (osteocutaneous) fibular flap, alone or combined with allograft.4,11,12 Most of the patients of these studies had good clinical outcomes; however, these flaps can be problematic. Vascularized iliac crest flaps are difficult to combine with sensory nerve reconstruction, while pedicled fibular grafts are not wide enough to reattach the Achilles tendon.9
The development of technology and the availability of custom-made endoprostheses, manufactured with 3D printing modalities, gave birth to more therapeutic options.18 Special software that analyzes data from computed tomography scans allows the accurate reproduction of implants, which was not previously possible.9 Chou et al7 described a patient with calcaneus osteosarcoma who underwent total calcanectomy and reconstruction with a custom-made calcaneus endoprosthesis. They used a 3D reconstruction model that reproduced identical dimensions of the affected calcaneus. The implant's surface was porous coated to allow soft tissue ingrowth, and screw holes were designed for fixation to the talus. Twelve years after surgery, the patient walked 8 to 10 blocks without support; however, she needed a shoe with adequate cushioning. She described some pain with weight-bearing activities as “discomfort.” Overall, she had a good functional outcome and mild degenerative changes of the talonavicular joint.6
Recently, Imanishi and Choong9 treated a 71-year-old man with osteosarcoma of the calcaneus with a custom-made implant. A calcaneal endoprosthesis, designed as the mirror image of the patient's healthy calcaneus, was manufactured with a 3D printer based on helical computed tomography measurements. The titanium implant was polished at the articulation areas, while the rest of its surface was porous coated with anchor points to allow reattachment of the soft tissues. Five months after surgery, the patient was pain free, his ankle was stable, and he could walk barefoot without support. He could walk continuously for more than 6 blocks with a protecting boot. The authors9 reported an overall satisfactory early clinical result.
In another study, a 23-year-old patient with a calcaneal desmoplastic fibroma was treated with a 3D printed titanium implant. Except from the solid structure, this calcaneal implant contained a 2-mm mesh with multiple suture holes for better soft tissue attachment. At 16 months of follow-up, the authors17 reported acceptable clinical and functional outcomes.
The current authors used a computed tomography scan obtained before the second operation to design a custom-made calcaneal endoprosthesis. This was done because changes at the hindfoot soft tissue envelope were expected after the index procedure. The talar and cuboidal aspects of the endoprosthesis were anatomically designed. However, the inferior part and the posterior part, as well as the volume of the implant, were adjusted to facilitate soft tissue coverage and unproblematic wound closure. The current authors preferred to fix the implant in the talus using a porous-coated stem for better subtalar stability. The authors avoided using screw fixation to the talus because screws have been reported to fail with time.6 In addition, their implant was polished for smooth articulation with the cuboid.
The authors decided to proceed with a staged surgical treatment in both patients with Ewing's sarcoma. The authors did not perform reconstruction in the index procedure. Histologic evaluation of the surgical margins after resection and extent of tumor necrosis after preoperative chemotherapy were important for limb salvage decision-making. In addition, the authors ensured that no complication after reconstruction would compromise adjuvant chemotherapy. Delayed calcaneus reconstructions have also been supported in the literature. Kurvin et al10 reported a late reconstruction (after 6 months) with vascularized iliac crest graft. Six years after calcanectomy, Degeorge et al8 performed calcaneal allograft reconstruction for a patient with low-grade chondrosarcoma. The restricted mobilization of the patient until final reconstruction may represent a drawback of this staged treatment; however, the current authors believe that this is a safer option.
For both calcaneus resection and reconstruction, the current authors used a lateral extensile calcaneus approach. There are different reports for lateral,8,10 medial,10,16 combined lateral with medial,4,15 and posterior (Cincinnati) approaches.6,7,9,17 In endoprosthetic reconstruction cases, the posterior approach is preferred.6,7,9,17 Imanishi and Choong9 thought that their good clinical results might have been partially due to the choice of this approach; however, they also stated that they had difficulties reaching the entire circumference of the talocalcaneal joint. In addition, the fixation of their implant was limited to the soft tissue structures (Achilles tendon, plantar fascia, spring ligament), so the direct visualization of the medial side was important for reconstruction.9 Chuo and Malawer6 and Chuo et al7 performed a posterior approach including an extra plantar skin incision. The current authors believe that the lateral approach is less traumatic to the hindfoot, providing adequate exposure of the calcaneus during resection. In addition, fixation of the endoprosthesis to the talus and soft tissue reconstruction were easily accomplished. The disadvantage of the lateral approach is the poor visualization of the medial neurovascular and ligamentous structures. However, the authors did not experience difficulties during resection or any complications at this site.
Excellent fit of the custom-made calcaneal endoprosthesis to the hindfoot was achieved during surgery for both of the current patients. Up to last follow-up, no instance of instability, infection, or other complication was documented. Both patients had a good clinical outcome and had successfully returned to their previous activities. Obviously, this is a small number of patients. Although the follow-up was longer than that of most reported cases, it was not long enough to draw safe conclusions regarding implant survival and patients' long-term clinical outcomes. Long-term follow-up is mandatory for these patients. However, the authors believe that this type of reconstruction should be considered an attractive alternative for patients with calcaneal malignancies who are candidates for limb salvage.
Limb salvage surgery is feasible for select patients with primary malignant bone tumors of the calcaneus. Total calcanectomy and reconstruction with a 3D printed endoprosthesis constitutes a promising therapeutic option with satisfactory functional outcome. A 2-stage technique allows a safe oncologic outcome.
- Henshaw R, Malawer MM. Review of endoprosthetic reconstruction in limb-sparing surgery. In: Malawer MM, Sugarbaker PH, eds. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases Dordrecht, the Netherlands: Springer; 2001:383–404.
- Choong PF, Qureshi AA, Sim FH, Unni KK. Osteosarcoma of the foot: a review of 52 patients at the Mayo Clinic. Acta Orthop Scand. 1999;70(4):361–364. doi:10.3109/17453679908997825 [CrossRef]
- Selch MT, Kopald KH, Ferreiro GA, Mirra JM, Parker RG, Eilber FR. Limb salvage therapy for soft tissue sarcomas of the foot. Int J Radiat Oncol Biol Phys. 1990;19(1):41–48. doi:10.1016/0360-3016(90)90132-4 [CrossRef]
- Li J, Wang Z, Guo Z, Yang M, Chen G, Pei G. Composite biological reconstruction following total calcanectomy of primary calcaneal tumors. J Surg Oncol. 2012;105(7):673–678. doi:10.1002/jso.23022 [CrossRef]
- Zeytoonjian T, Mankin HJ, Gebhardt MC, Hornicek FJ. Distal lower extremity sarcomas: frequency of occurrence and patient survival rate. Foot Ankle Int. 2004;25(5):325–330. doi:10.1177/107110070402500509 [CrossRef]
- Chou LB, Malawer MM. Osteosarcoma of the calcaneus treated with prosthetic replacement with twelve years of followup: a case report. Foot Ankle Int. 2007;28(7):841–844. doi:10.3113/FAI.2006.0841 [CrossRef]
- 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]
- Degeorge B, Dagneaux L, Forget D, Gaillard F, Canovas F. Delayed reconstruction by total calcaneal allograft following calcanectomy: is it an option?Case Rep Orthop. 2016;2016:4012180.
- Imanishi J, Choong PF. Three-dimensional printed calcaneal prosthesis following total calcanectomy. Int J Surg Case Rep. 2015;10:83–87. doi:10.1016/j.ijscr.2015.02.037 [CrossRef]
- Kurvin LA, Volkering C, Kessler SB. Calcaneus replacement after total calcanectomy via vascularized pelvis bone. Foot Ankle Surg. 2008;14(4):221–224. doi:10.1016/j.fas.2008.03.004 [CrossRef]
- Li J, Guo Z, Pei GX, Wang Z, Chen GJ, Wu ZG. Limb salvage surgery for calcaneal malignancy. J Surg Oncol. 2010;102(1):48–53. doi:10.1002/jso.21564 [CrossRef]
- Li J, Wang Z. Surgical treatment of malignant tumors of the calcaneus. Am Podiatr Med Assoc. 2014;104(1):71–76. doi:10.7547/0003-0538-104.1.71 [CrossRef]
- Muscolo DL, Ayerza MA, Aponte-Tinao LA. Long-term results of allograft replacement after total calcanectomy: a report of two cases. J Bone Joint Surg Am. 2000;82(1):109–112. doi:10.2106/00004623-200001000-00014 [CrossRef]
- 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]
- Scoccianti G, Campanacci DA, Innocenti M, Beltrami G, Capanna R. Total calcanectomy and reconstruction with vascularized iliac bone graft for osteoblastoma: a report of two cases. Foot Ankle Int. 2009;30(7):716–720. doi:10.3113/FAI.2009.0716 [CrossRef]
- Wozniak W, Raciborska A, Walenta T, Szafranski A, Szymborska A, Bajor M. New technique of surgical treatment of malignant calcaneal tumours: preliminary report. Ortop Traumatol Rehabil. 2007;9(3):273–276.
- 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.
- Papagelopoulos PJ, Savvidou OD, Koutsouradis P, et al. Three-dimensional technologies in orthopedics. Orthopedics. 2018;41(1):12–20. doi:10.3928/01477447-20180109-04 [CrossRef]
- Dhillon MS, Singh B, Gill SS, Walker R, Nagi ON. Management of giant cell tumor of the tarsal bones: a report of nine cases and a review of the literature. Foot Ankle. 1993;14(5):265–272. doi:10.1177/107110079301400506 [CrossRef]
- Smith DG, Stuck RM, Ketner L, Sage RM, Pinzur MS. Partial calcanectomy for the treatment of large ulcerations of the heel and calcaneal osteomyelitis: an amputation of the back of the foot. J Bone Joint Surg Am. 1992;74(4):571–576. doi:10.2106/00004623-199274040-00013 [CrossRef]