Quantitative Evaluation of Vacuum-Induced Morphological Changes in Knee-Disarticulation: A Case Study for Personalized Prosthetic Socket Design

• Published in: Symmetry (Basel) Vol. 17; no. 10; p. 1719
• Main Authors: Darwich, Mhd Ayham, Nazha, Hasan Mhd, Ibrahim, Kaysse, Kamleh, Lourance, Shash, Maysaa, Ismaiel, Ebrahim
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 13.10.2025
• Subjects: Amputation; Asymmetry; Biomechanical engineering; Biomechanics; Computed tomography; Contact pressure; Customization; Deformation; Design; Finite element method; Geometry; In vivo methods and tests; Knee; Load; Load transfer; Morphology; Pressure distribution; Prostheses; Safety factors; Sockets; Soft tissues; Symmetry; Trauma; Al-Andalus; United States > US; Syria
• ISSN: 2073-8994; 2073-8994
• DOI: 10.3390/sym17101719

Achieving a best-fit prosthetic socket is essential to comfort, functional performance, and long-term residual limb health in lower-limb amputees. To our knowledge, no previous study has quantitatively compared in vivo residual limb geometry under vacuum versus non-vacuum conditions using high-resolution computed tomography (CT). In this patient-specific case study of a bilateral knee-disarticulation (KD) amputee, both residual limbs were scanned under standardized conditions: one enclosed in a vacuum-compressed sleeve and the contralateral limb untreated as a natural control, thereby minimizing inter-subject variability. CT-based 3D reconstructions enabled volumetric and cross-sectional quantification, including symmetry/asymmetry analysis of paired limbs, while finite element analysis (FEA) assessed the biomechanical consequences for socket performance. Vacuum application resulted in a 4.1% reduction in total limb volume and a 5.3% reduction in mid-thigh cross-sectional area, with regionally asymmetric displacement of soft tissues. FEA demonstrated that vacuum-induced geometry reduced peak Von Mises stresses (27.43 MPa to 15.83 MPa), minimized maximum displacement (1.72 mm to 0.88 mm), and improved minimum factor of safety (~2.0 to ~3.0), while homogenizing contact pressure distribution (peak fell from 2.42 to 1.28 N/mm2). These findings provide preliminary CT-based evidence that vacuum application induces measurable morphological adaptations with implications for socket conformity, comfort, and load transfer. While limited to a single patient, this study highlights the potential of vacuum-induced modeling to inform personalized prosthetic socket design.