Application of three-dimensional printed endoprosthesis for reconstruction after metaphysis-involved intercalary tumor resection / 中华骨科杂志

ABSTRACT

Objective:To describe the design, manufacture and use of three-dimensional (3D)-printed endoprosthesis for reconstruction after metaphysis-involved intercalary tumor resection and to evaluate its outcome.Methods:Forty-three patients who received metaphysis-involved intercalary tumor resection followed by 3D-printed endoprosthetic reconstruction in Musculoskeletal Tumor Center, Peking University People's Hospital between January 2018 and December 2021 were retrospectively reviewed. There were 25 males and 18 males with an average age of 20.1±15.2 years (range, 4-58 years). The pathological diagnosis included 24 cases of osteosarcomas, 6 cases of Ewing sarcomas, 5 cases of chondrosarcomas, 2 cases of pleomorphic undifferentiated sarcomas, 3 cases of soft-tissue sarcomas (liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumor for each) and 3 others (adamantinoma, recurrent aneurysmal bone cyst and recurrent osteofibrous dysplasia for each). The tumors located at femur in 25 patients (58%), including 14 lesions involving distal femoral metaphysis and 11 lesions involving both proximal and distal metaphysis; the tumors located at tibia in 11 patients (26%), including 4 lesions involving distal tibial metaphysis, 5 lesions involving proximal tibial metaphysis and 2 lesions involving both proximal and distal tibial metaphysis; the tumors located at humerus in 7 patients (16%), including 1 lesion involving distal humeral metaphysis, 3 lesions involving proximal humeral metaphysis and 3 lesions involving both proximal and distal humeral metaphysis. The endoprosthesis was designed in a semi-modular fashion and consisted of three parts a diaphysis-fixing component, a semi-modular lap joint component, and a custom-made 3D-printed metaphysis-fixing component which was designed as two types with 3D-printed porous bone-contacting surfaces according to the osteotomy plane (Type I on meta-diaphyseal region, Type II on meta-epiphyseal region). The functional outcome was assessed using Musculoskeletal Tumor Society (MSTS) 93 system.Results:All surgeries were accomplished sucessfully. The median resection length and the distance from osteotomy plane to adjacent joint was 16.0 (13.0, 22.0) cm and 4.5 (3.5, 6.0) cm, respectively. 59 metaphysis-fixing components were installed in 43 patients. Type I components were used in single and dual ends of endoprosthesis in 12 and 6 cases respectively. Type II components were used in single and dual ends in 15 and 5 cases respectively. Hybrid endoprosthesis with Type I and II components were used in 5 cases. The mean follow-up time was 26.0 (17, 37) months (range, 12-54 months). The mean MSTS 93 score was 29.0 (28.0, 30.0) points (range, 21-30 points). Implant failures were found in 5 patients, including 2 cases of aseptic loosening (loosening was observed in the cementing diaphysis-fixing stems while no evidence of loosening in metaphysis-fixing components) and 3 cases of local tumor progression. The 2-year implant survival rate was 90.3% (95% CI 0.81, 0.99). Conclusion:Using 3D-printed intercalary endoprosthesis for reconstruction after intercalary resection of metaphysis-involved bone tumor shows satisfactory functional outcome and implant survival. Moreover, by assembling endoprosthetic components according to the different osteotomy plane, the semi-modularized endoprosthesis also provids a comprehensive and individualized reconstruction for patients with metaphysis-involved intercalary tumor.