OBJECTIVE

To explore the feasibility of using biomechanical indicators as supplementary evaluation to the Musculoskeletal Tumor Society Scoring System (MSTS) for amputee patients.

METHODS

Twenty-four patients who underwent hemipelvectomy between September 2018 and January 2025 were enrolled. There were 15 males and 9 females with an average age of 61.4 years (range, 45-76 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 indicators of the intact limb exhibiting common characteristics were screened through correlation and sensitivity analyses. Test-retest reliability [interclass correlation coefficient (ICC)] of selected parameters was assessed to evaluate their potential as MSTS score supplements.

RESULTS

All biomechanical indicators showed significant positive correlations with MSTS scores across assistive devices ( <0.05). Seven indicators 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 levels ( <0.05), indicating high sensitivity, along with excellent test-retest reliability (ICC>0.74, <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.