This case study focuses on scapula reconstruction using three-dimensional printing in a patient with low-grade osteosarcoma. Malignant tumors originating from the scapula often lead to destructive surgery, with poor functional status and quality of life for the patients. Using custom prosthetic technology through three-dimensional printing could be a possible solution for reconstruction with greater long-term functional outcomes. This study aims to assess the functional outcomes of the reconstruction. A 39-year-old patient with low-grade central osteosarcoma involving the lateral two-thirds of the scapula underwent a custom prosthetic reconstruction. The patient subsequently followed a rehabilitation protocol for 12 months. The results indicate that even though there was a slight decrease in the range of movement, and an increase in the disabilities of the arm, shoulder, and hand (DASH) score, no relevant increase in activities of daily living (ADL) disability was present at follow-up. The patient returned to carry out his daily activities without pain and with a minimal functional reduction in movement. In conclusion, three-dimensional prosthetic reconstruction is a valid alternative for scapula reconstruction, allowing excellent functional and aesthetic results in oncological cases.