We found HGB (HR: 2.3, 95% CI: 1.1–5) and joint invasion (HR: 3.9, 95% CI: 1.8–8.7) to be useful for prediction of relapse risk in osteosarcoma patients (P = 0.025 and <0.001, respectively); thus, HGB and joint invasion were used to build the clinical nomogram and integrate them with the Rad-score to construct the radiomics nomogram. The gene discussed is CYGB; the disease is osteosarcoma.