Effects of sitting postures on risks for deep tissue injury in the residuum of a transtibial prosthetic-user: a biomechanical case study.
Transtibial amputation prosthetic-users are at risk of developing deep tissue injury (DTI) while donning their prosthesis for prolonged periods; however, no study addresses the mechanical loading of the residuum during sitting with a prosthesis. We combined MRI-based 3D finite element modelling of a residuum with an injury threshold and a muscle damage law to study risks for DTI in one sitting subject in two postures: 30°-knee-flexion vs. 90°-knee-flexion. We recorded skin-socket pressures, used as model boundary conditions. During the 90°-knee-flexion simulations, major internal muscle injuries were predicted (>1000 mm(3)). In contrast, the 30°-knee-flexion simulations only produced minor injury ( < 14 mm(3)). Predicted injury rates at 90°-knee-flexion were over one order of magnitude higher than those at 30°-knee-flexion. We concluded that in this particular subject, prolonged 90°-knee-flexion sitting theoretically endangers muscle viability in the residuum. By expanding the studies to large subject groups, this research approach can support development of guidelines for DTI prevention in prosthetic-users.
Portnoy
S
S
Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Ramat Aviv, Israel.
Siev-Ner
I
I
Shabshin
N
N
Gefen
A
A
D000671:Amputation, Surgical / Q000534:rehabilitation; D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D003238:Connective Tissue / Q000293:injuries*; D020342:Finite Element Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging; D011187:Posture; D016059:Range of Motion, Articular; D018570:Risk Assessment; D013977:Tibia