3D-printed total humeral prosthesis with shoulder preservation in the treatment of humeral osteosarcoma: a case report

Background: For large malignant tumors of the humerus involving extensive portions of the diaphysis, total humeral replacement represents a critical option for limb salvage and functional reconstruction. However, maximizing preservation of shoulder and elbow joint function remains a significant challenge for surgeons. Case presentation: We report a case of a 24-year-old male with chondroblastic osteosarcoma of the humerus. Preoperative biopsy confirmed a high-grade sarcoma consistent with osteosarcoma, most likely the chondroblastic subtype. He received two cycles of neoadjuvant chemotherapy comprising cisplatin, adriamycin, and ifosfamide, along with the PD-1 inhibitor sintilimab. Subsequently, right humeral tumor resection was performed, followed by reconstruction with a 3D-printed prosthesis that preserved the shoulder joint and incorporated hemi-elbow arthroplasty. Postoperatively, an elbow brace was worn for four weeks, with the elbow maintained at 15° of flexion. After suture removal, chemotherapy and PD-1 inhibitor therapy were resumed. At the 9-month follow-up, the patient maintained functional use of the limb and performed activities of daily living independently. Physical examination revealed good shoulder and elbow motor function. Imaging confirmed proper prosthesis placement and robust osseointegration. Artifact-free CT scans of the shoulder and chest showed no evidence of local recurrence or distant metastasis. Conclusion: The semi-elbow prosthesis-designed using 3D printing technology while preserving the patient's humeral head-effectively maximizes preservation of shoulder and elbow joint function and enhances treatment satisfaction in young patients.