[Effectiveness evaluation of three-dimensional printed titanium-alloy prosthesis reconstruction after distal tibia tumor segment resection].

To evaluate the feasibility and short-term effectiveness of three-dimensional (3D) printed titanium-alloy prosthesis reconstruction after the distal tibia tumor segment resection.The clinical data of 6 patients with bone defect after distal tibia tumor segment resection treated with 3D printed titanium-alloy prosthesis reconstruction and tibiotalar joint fusion between January 2020 and December 2021 were retrospectively analyzed. There were 2 males and 4 females; the age ranged from 12 to 35 years, with an average of 18.5 years. Among them, 4 cases were osteosarcoma, 1 case was Ewing sarcoma, and 1 case was giant cell tumor of bone. The Enneking staging was stage ⅡA in 3 cases, stage ⅡB in 2 cases, and stage Ⅲ in 1 case. The disease duration was 2-5 months (mean, 3.2 months). All patients received preoperative neoadjuvant therapy, and patients with osteosarcoma and Ewing sarcoma started chemotherapy at3 weeks after operation. The systemic and local tumor conditions and prosthesis conditions were evaluated regularly after operation. The Musculoskeletal Tumor Society (MSTS) score and the American Orthopaedic Foot and Ankle Society (AOFAS) score were used to evaluate the lower extremity and ankle function.All patients were followed up 8-26 months, with an average of 15.6 months. There was no local recurrence and distant metastasis during the follow-up. The ankle joints of 5 cases were all in 90° functional position at last follow-up, and there was no complication such as prosthesis loosening and fracture; the ankle joint fusion was stable, the local bone ingrowth was good, and the daily activities could be completed, but the ankle range of motion was limited and the ankle joint was stiff. The MSTS score ranged from 22 to 26, with an average of 24, and 3 cases were evaluated as excellent and 2 cases were good; the AOFAS score ranged from 71 to 86, with an average of 80.6, and 4 cases were evaluated as good and 1 case was fair. One patient had severe periprosthetic infection at 2 months after operation, resulting in failure of prosthesis implantation, pain in limb movement, and poor ankle function; MSTS score was 12, AOFAS score was 50, and both were evaluated as poor; distraction osteogenesis was performed after removal of prosthesis and infection control, at present, it was still in the process of distraction osteogenesis, and local osteogenesis was acceptable.Using 3D printed titanium-alloy prosthesis and tibiotalar joint fusion to reconstruct the bone defect after distal tibia tumor segment resection has satisfactory mechanical stability and function, and is one of the effective distal tibial limb salvage methods.探讨使用3D打印钛合金假体重建胫骨远端瘤段骨切除术后骨缺损的可行性及近期疗效。.回顾分析2020年1月—2021年12月6例采用3D打印钛合金假体重建胫骨远端瘤段骨切除后骨缺损、同时融合部分胫距关节的患者临床资料。男2例，女4例；年龄12～35岁，平均18.5岁。其中骨肉瘤4例，尤文肉瘤1例，骨巨细胞瘤1例。Enneking分期：ⅡA期3例，ⅡB期2例，Ⅲ期1例。病程2～5个月，平均3.2个月。所有患者均行术前新辅助治疗，骨肉瘤及尤文肉瘤患者术后3周开始辅助化疗。术后定期复查评估全身及局部肿瘤情况、假体情况；采用骨骼肌肉系统肿瘤协会（MSTS）评分及美国矫形足踝协会（AOFAS）评分评价下肢及踝关节功能。.6例患者均获随访，随访时间8～26个月，平均15.6个月。随访期间均未出现局部复发和远处转移。其中5例末次随访时踝关节均位于90° 功能位，均未发生假体松动、断裂等并发症；踝关节融合稳定，局部骨长入良好，可完成日常活动，但踝关节活动度均受限、踝关节僵硬；MSTS评分为22～26分，平均24分，评价为优3例、良2例；AOFAS评分为71～86分，平均80.6分，评价为良4例、可1例。1例术后2个月出现严重假体周围感染造成假体植入失败，患肢活动疼痛、踝关节功能差；MSTS评分为12分、AOFAS评分为50分，评价均为差；去除假体、感染控制后予以牵拉成骨治疗，目前仍在牵拉成骨过程中，局部成骨可。.采用3D打印钛合金假体与胫距关节融合方式重建胫骨远端瘤段骨切除后骨缺损，可获得满意的机械稳定性及功能，是有效的胫骨远端保肢方式之一。.