Table 1 Experimental studies on the deformation as aetiological factor for DTI in transtibial prosthetic users
From: Exploring the role of transtibial prosthetic use in deep tissue injury development: a scoping review
Author and year | Objective | Loading scenario | Study Population | Quantitative Results | Qualitative results |
|---|---|---|---|---|---|
Portnoy et al. 2007 [29] | Test of feasibility of real-time FEa monitor to estimate internal tissue load | Dynamic load: Treadmill walking | - 5 unilateral TTAbs - 1 female, 4 male - Mean age 47.2 yrs. - Mean weight 68 kg | Max. principal compression stresses: - Fibular axis: 16.38 kPa (3.5 - 31 kPa) - Gastrocnemius axis: 8.19 kPa (1.75 - 13 kPa) | - Maximum compressive stress between midstance and push-off - High inter-patient variability in stress magnitude |
Portnoy et al. 2008 [34] | Estimation of internal tissue load during static load bearing | Static load: Weight bearing | - 1 unilateral TTA - Female - Age 29 - Weight 50 kg - Traumatic cause | - Compressive stress 240 kPa - Tensile stress 263 kPa - Shear stress 23 kPa - Compressive strain 85% - Tensile strain 129% - Shear strain 106% - SEDc 104 kJ/m3 - Von Mises stress 215 kPa | - Compression slightly above physiological levels in comparison to gluteal tolerance - High tensile and shear strains which may be risk for tissue viability - Stress and strain concentrations in flap under tibial end |
Portnoy et al. 2010 [31] | Determination of subject-specific dynamic stresses in soft tissues | Dynamic load: Walking on complex terrain | - 18 unilateral TTAs - 1 female, 17 male - Mean age 43 yrs. - Mean weight 79 kg - 11 traumatic, 7 vascular | Average peak von Mises stress: - Plane: 100 kPa - Grass: 80 kPa - Upstairs: 95.1 kPa - Up slope: 83 kPa - Downstairs: 115.4 kPa - Down slope: 141.9 kPa | - High inter-terrain and inter-subject variability - Higher stresses in vascular compared to traumatic patients - No immediate risk of DTI for 10 out of 18 subjects - Elevated peak stress when descending stairs or slope compared to plane gait |
Portnoy et al. 2011 [33] | Evaluation of risk of DTI development for during sitting with a donned prosthesis | Static loading: Sitting with 30° and 90° knee flexion | - 1 unilateral TTA - Male - Age 55 - Weight 73 kg Traumatic cause | At tibial end (90° flexion): - Principal stress: Compression 102.9 kPa Tension 66.6 kPa - Shear stress 67.2 kPa - Von Mises stress 129 kPa Volume of damaged area (after 75 min): - 30°: 13.5mm3 - 90°: 600mm3 | - Residuum at risk of DTI during sitting with 90° flexion - Risk of DTI posture dependent - Injury rate higher with increased knee flexion - Damage volume may be dependent on muscle thickness |