Objective To explore the feasibility of using biomechanical indicators as supplementary measures to the Musculoskeletal Tumor Society (MSTS) score for amputee patients. Methods Thirteen patients who underwent hemipelvectomy between June 2020 and April 2024 were enrolled. There were 9 males and 4 females with an average age of 59.2 years (range, 49-73 years). Participants performed gait tests at self-selected speeds using three assistive devices (prosthesis, single crutch, and double crutches). Motion data were analyzed using a customized OpenSim model. Biomechanical parameters of the intact limb exhibiting common characteristics were screened through correlation and sensitivity analyses. Test-retest reliability of selected parameters was assessed to evaluate their potential as MSTS score supplements. Results All biomechanical parameters showed significant positive correlations with MSTS scores across assistive devices (P<0.05). Seven parameters demonstrated Pearson correlation coefficients>0.8, including walking speed, maximum hip angle, maximum hip moment, peak hip flexion moment, peak hip extension moment, hip flexion impulse, and hip extension impulse. Among these, maximum hip moment, hip flexion impulse, and hip extension impulse exhibited significant between-group differences in adjacent MSTS score levels (P<0.05), indicating high sensitivity, along with excellent test-retest reliability (ICC>0.74, P<0.01). Conclusion Biomechanical indicators statistically qualify as potential supplements to MSTS scoring. Maximum hip moment, hip flexion impulse, and hip extension impulse demonstrate particularly high sensitivity to MSTS score variations.