Three-Dimensional Printing and Navigation in Bone Tumor Resection

One of the most promising advances raised by the current computer age is performing research “in silico,” which means computer-assisted. The objective of this chapter is firstly to evaluate if a 3D in-silico model of an oncological patient could be used to make a 3D-printed prototype in real scale, discriminating precisely healthy tissues, tumoral tissues and oncological margins. Secondly, the objective is to evaluate if this prototype could be representative enough to allow testing osteotomies under navigated guidance based on images. A tumor resection for a patient with diagnosed metaphyseal osteosarcoma of the proximal tibia was transferred into a rapid prototyping model, fabricated using 3D printing and representing different structures in different colors. The planned osteotomy was executed using Stryker Navigator to guide the cutting saw and the prototype was opened to verify the precision of the performed osteotomy. Both osteotomy planes showed successful correspondence with the safe margin, with a maximum error of 1 mm. The application of these techniques in general orthopedics would help to reduce the incidence of unforeseen intraoperative failures, contributing to obtain predictable surgical procedures. This would implement a new way of performing development, research and training in orthopedics and traumatology by in-silico technology

Validity of an automatic measure protocol in distal femur for allograft selection from a three-dimensional virtual bone bank system

Osteoarticular allograft is one possible treatment in wide surgical resections with large defects. Performing best osteoarticular allograft selection is of great relevance for optimal exploitation of the bone databank, good surgery outcome and patient’s recovery. Current approaches are, however, very time consuming hindering these points in practice. We present a validation study of a software able to perform automatic bone measurements used to automatically assess the distal femur sizes across a databank. 170 distal femur surfaces were reconstructed from CT data and measured manually using a size measure protocol taking into account the transepicondyler distance (A), anterior-posterior distance in medial condyle (B) and anterior-posterior distance in lateral condyle (C). Intra- and inter-observer studies were conducted and regarded as ground truth measurements. Manual and automatic measures were compared. For the automatic measurements, the correlation coefficients between observer one and automatic method, were of 0.99 for A measure and 0.96 for B and C measures. The average time needed to perform the measurements was of 16 h for both manual measurements, and of 3 min for the automatic method. Results demonstrate the high reliability and, most importantly, high repeatability of the proposed approach, and considerable speed-up on the planning

Clinical Study Allograft Reconstruction for the Treatment of Musculoskeletal Tumors of the Upper Extremity

In comparison with the lower extremity, there is relatively paucity literature reporting survival and clinical results of allograft reconstructions after excision of a bone tumor of the upper extremity. We analyze the survival of allograft reconstructions in the upper extremity and analyze the final functional score according to anatomical site and type of reconstruction. A consecutive series of 70 allograft reconstruction in the upper limb with a mean followup of 5 years was analyzed, 38 osteoarticular allografts, 24 allograft-prosthetic composites, and 8 intercalary allografts. Kaplan-Meier survival analysis of the allografts was performed, with implant revision for any cause and amputation used as the end points. The function evaluation was performed using MSTS functional score. Sixteen patients (23%) had revision surgery for 5 factures, 2 infections, 5 allograft resorptions, and 2 local recurrences. Allograft survival at five years was 79% and 69% at ten years. In the group of patients treated with an osteoarticular allograft the articular surface survival was 90% at five years and 54% at ten years. The limb salvage rate was 98% at five and 10 years. We conclude that articular deterioration and fracture were the most frequent mode of failure in proximal humeral osteoarticular reconstructions and allograft resorption in elbow reconstructions. The best functional score was observed in the intercalary humeral allograft

Allograft Reconstruction for the Treatment of Musculoskeletal Tumors of the Upper Extremity

In comparison with the lower extremity, there is relatively paucity literature reporting survival and clinical results of allograft reconstructions after excision of a bone tumor of the upper extremity. We analyze the survival of allograft reconstructions in the upper extremity and analyze the final functional score according to anatomical site and type of reconstruction. A consecutive series of 70 allograft reconstruction in the upper limb with a mean followup of 5 years was analyzed, 38 osteoarticular allografts, 24 allograft-prosthetic composites, and 8 intercalary allografts. Kaplan-Meier survival analysis of the allografts was performed, with implant revision for any cause and amputation used as the end points. The function evaluation was performed using MSTS functional score. Sixteen patients (23%) had revision surgery for 5 factures, 2 infections, 5 allograft resorptions, and 2 local recurrences. Allograft survival at five years was 79% and 69% at ten years. In the group of patients treated with an osteoarticular allograft the articular surface survival was 90% at five years and 54% at ten years. The limb salvage rate was 98% at five and 10 years. We conclude that articular deterioration and fracture were the most frequent mode of failure in proximal humeral osteoarticular reconstructions and allograft resorption in elbow reconstructions. The best functional score was observed in the intercalary humeral allograft

Failure rates and functional results for intercalary femur reconstructions after tumour resection

Purpose To compare the results for patients treated with intercalary endoprosthetic replacement (EPR) or intercalary allograft reconstruction for diaphyseal tumours of the femur in terms of: (1) reconstruction failure rates; (2) cause of failure; (3) risk of amputation of the limb; and (4) functional result. Methods Patients with bone sarcomas of the femoral diaphysis, treated with en bloc resection and reconstructed with an intercalary EPR or allograft, were reviewed. A total of 107 patients were included in the study (36 EPR and 71 intercalary allograft reconstruction). No differences were found between the two groups in terms of follow-up, age, gender and the use of adjuvant chemotherapy. Results The probability of failure for intercalary EPR was 36% at 5 years and 22% for allograft at 5 years (p = 0.26). Mechanical failures were the most prevalent in both types of reconstruction. Aseptic loosening and implant fracture are the main cause in the EPR group. For intercalary allograft reconstructions, fracture followed by nonunion was the most common complication. Ten-year risk of amputation after failure for both reconstructions was 3%. There were no differences between the groups in terms of the mean Musculoskeletal Tumor Society score (27.4, range 16–30 vs. 27.6, range 17–30). Conclusions We have demonstrated similar failure rates for both reconstructions. In both techniques, mechanical failure was the most common complication with a low rate of limb amputation and good functional results. Level of evidence Level III, therapeutic study.Peer reviewe

Proximal Femur Allograft-prosthesis with Compression Plates and a Short Stem

Proximal femur allograft-prosthesis composites (APCs) performed with compression plates and a short stem theoretically could minimize the resorption or nonunion that reportedly occurs with long stems bypassing the diaphyseal osteotomy. To confirm this theoretical consideration, we retrospectively reviewed 34 patients with 38 proximal femoral APCs using a short-cemented femoral stem and compression plates for diaphyseal osteotomy fixation. In 26 patients, the plate fixation extended over at least half the femoral stem and in 12, it did not. We reinserted the abductor mechanism with two techniques: in 10 cases the host trochanter was reattached to the APC, and in 28 the host tendons were sutured to the tendinous insertion of the allograft. The overall survival of the entire series was 72% at 5 years and 69% at 10 years. Eleven of the 38 (29%) APCs were removed: three for infection, one for local recurrence of tumor, and seven for fractures. Trendelenburg gait occurred in four of 21 patients with direct tendon-to-tendon suture of the abductor mechanism and in three of six patients with trochanteric osteotomy. The overall APC survival rate was greater in patients in whom the allograft was adequately protected with internal fixation than in patients in whom it was not