Table 1 Literature review with respect to the papers reporting on the functional evaluation of custom PD-AFOs. For each paper, when present, it is reported the AFO type(s), the customization criteria, the materials, the functional data/parameters, and the main outcome. Comfort assessment or other subjective scores are also reported
Authors/year | Population (size) | AFO type/ customization criteria | Material | Motor tasks | Functional parameters | Other scores | Main outcome |
|---|---|---|---|---|---|---|---|
Waterval et al. 2021 [56] | unilateral plantar flexor weakness (9) | dorsal leaf spring AFO Spring leaf Stiffness customizable energy cost optimized (Ankle7, OttoBock) | carbon fiber | walking | spatio-temporal parameters GRFs hip, knee, ankle kinematics and kinetics | Â | peak vertical GRF of the contralateral leg significantly reduced and symmetry improved (AFO vs. no AFO) |
Waterval et al. 2021 & 2020 | calf muscle weakness (34) | dorsal leaf spring AFO Spring leaf Stiffness customizable (Ankle7, OttoBock)e | carbon fiber | walking | spatio-temporal parameters hip, knee, ankle kinematics and kinetics energy cost | Â | reduction in energy cost (AFO optimized stiffness vs. non optimized) |
Kerkum et al. 2021 [35] | healthy subjects (12) | dorsal leaf spring AFO Spring leaf Stiffness customizable (Ankle7, OttoBock) | carbon fiber | walking | Ankle-foot kinematics work and power | Â | Total ankle-foot power increase with increasing footplate stiffness |
Lin et al. 2021 [57] | post-stroke drop-foot (12) | 1. energy-Storage 3D Printed AFO 2. anterior-support AFO | PLA + nylon+titanium thermoplastic | walking | spatio-temporal parameters pelvis, hip, knee, ankle kinematics (sagittal plane) | Evaluation of satisfaction (QUEST) | increased gait velocity and stride length (AFO1 vs. AFO2; AFO1 vs. barefoot) improved satisfaction (AFO1) |
Meng et al. 2021 [58] | post-stroke drop-foot (15) | morphology | PA2200 Somos NeXt PA12 | NA | NA | comfort weight feeling surface smoothness wearing issues cleaning issues | Somos NeXt scored better than one or more materials in comfort and surface smoothness |
Vasiliauskaite, et al. 2020 [51] | child with unilateral drop-foot (1) | 1. hinged AFO with adjustable ankle stiffness 2. posterior leaf spring stiffness tuned to achieve the orthotic goals | thermoplastic+metal polyamide-12 | walking | spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | Despite having the same ankle stiffness, AFO1 and AFO2 did not produce the same gait pattern |
Chae et al. 2020 [59] | unilateral drop-foot (1) | morphology | polyurethane | walking stairs ascent/descent up&go | NA | Modified Emory Functional Ambulation Profile | improved mEFAP (AFO vs. no-AFO) |
Esposito et al. 2020 [22] | unilateral lower limb reconstruction (12) | IDEO custom AFO (posterior leaf spring) Stiffness based body mass, load carriage requirements, and range of available pain-free motion | carbon fiber | walking | COP position COP velocity | NA | ±3 deg in strut flexion/extension strut alignment does not significantly affect the foot-ankle roll-over shape radius |
Liu et al. 2019 [11] | post-stroke drop-foot (12) | morphology | PA12 | walking | spatio-temporal parameters hip, knee, ankle kinematics | NA | improved velocity and stride length (AFO vs.no-AFO) |
Waterval et al. 2019 [50] | neuromuscular disorders and non-spastic calf muscle weakness (37) | dorsal leaf spring AFO (Carbon Ankle Seven, Ottobock, Duderstadt) adjustable stiffness | carbon fiber | walking | energy cost spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | energy cost −20% (optimal AFO vs. no-AFO) energy cost − 10.7% (optimal AFO vs. non-optimal AFO) |
Cha et al. 2017 [44] | unilateral drop-foot (1) | 1. sock-like design with anterior opening and malleoli holes 2. rigid AFO | thermoplastic polyurethane | walking | spatio-temporal parameters ankle kinematics | Evaluation of satisfaction (QUEST) | insufficient ankle dorsiflexion in swing (AFO1 vs AFO2) better wearing properties and comfort (AFO1 vs AFO2)) |
Esposito et al. 2017 [23] | unilateral lower limb reconstruction (24) | IDEO custom AFO (posterior leaf spring) Stiffness based body mass, load carriage requirements, and range of available pain-free motion | carbon fiber | walking | spatio-temporal parameters hip, knee, ankle kinematics (sagittal plane) | NA | limited power capabilities at the ankle, and reduced compensatory strategies at the knee with respect to amputees |
Arch & Reisman 2016 [34] | post-stroke (2) | custom AFOs Morphology-based, no shoe required | polycarbonate | walking | spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | increased net peak plantarflexion moment and natural ankle pseudo-stiffness. |
Whitehead et al. 2016 [60] | unilateral lower limb reconstruction (13) normal/healthy (13) | IDEO custom AFO (posterior leaf spring) | carbon fiber | stairs ascent/descent | spatio-temporal parameters hip, knee, ankle kinematics and kinetics (sagittal plane) | NA | stair ascent: greater bilateral hip power during pull-up and reduced ankle dorsiflexion and knee extensor moment (AFO vs. control) |
Ranz et al. 2016 [38] | unilateral ankle muscle weakness (13) | IDEO custom AFO (posterior leaf spring) 3 bending axis positions | carbon fiber nylon 11 (strut) | walking | sEMG: soleus, gastrocnemius, tibialis ant., rectus fem., biceps fem., vastus med. and gluteus med. spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | hip and knee moments were affected by bending axis position no difference in spatio-temporal parameters |
Arch & Stanhope 2015 [43] | normal/healthy (2) | passive dynamic AFO (posterior leaf spring) AFO stiffness according to natural ankle pseudo-stiffness | not reported | walking | Ankle kinematics and moments (sagittal plane) | NA | Â |
Haight at al. 2015 [25] | unilateral lower-limb reconstruction (12) | IDEO custom AFO (posterior leaf spring) variable stiffness based on ROM, activity level, types of activities, body mass, load carriage requirements | carbon fiber | treadmill uphill walking (10 deg slope) | spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | AFOs stiffer than nominal increased knee joint flexion |
Kerkum et al. 2015 & 2016, Meyns et al. 2020 | children with cerebral palsy (15; bilateral 14) | ventral shell spring-hinged AFO (vAFO) variable stiffness/ROM hinge | pre-preg carbon fiber | waking | energy cost spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | decreased net energy cost (vAFOs vs. no-AFO) no differences between vAFOs |
Harper et al. 2014 [42] | unilateral ankle muscle weakness (10) | IDEO custom AFO (posterior leaf spring) clinically prescribed stiffness | carbon fiber nylon 11 (strut) | walking | spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | no difference in kinematics/kinetics between the two materials (same AFO stiffness) |
Esposito et al. 2014 [24] | unilateral ankle muscle weakness (13) healthy controls (13) | IDEO custom AFO (posterior leaf spring) variable stiffness based on ROM, activity level, types of activities, body mass, load carriage requirements | carbon fiber nylon 11 (strut) | walking | spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | small differences in kinematics and kinetics (nominal stiffness vs. stiffer and more compliant) |
Dufek et al. 2014 [29] | Charcot–Marie–Tooth patients (bilateral 8) | posterior leaf spring AFO stiffness customization based on prior experience, visual observations of patient’s gait, weight and muscle strength, and amount of ankle deformity | carbon-fiber composite | walking | spatio-temporal parameters hip, knee, ankle kinematics and kinetics | NA | increased walking speed and stride length (custom AFO vs. no-AFO) AFO energy storage 9.6 ± 6.6 J/kg |
Creylman et al. 2013 [8] | unilateral drop foot (8) | morphology-based posterior leaf spring/shell | nylon 12 (AFO1) polypropylene (AFO2) | walking | spatio-temporal parameters hip, knee, ankle kinematics (sagittal plane) | NA | improved spatial temporal gait parameters and ankle kinematics (AFO1 & AF2 vs. no-AFO) |
Mavroidis et al. 2011 [7] | normal/healthy (1) | morphology-based posterior leaf spring/shell (based on Type C-90 Superior Posterior Leaf Spring, AliMed) | polypropylene (AFO1, standard) Accura SI 40 (AFO2) Somos 9121 (AFO3) | walking | spatio-temporal parameters ankle kinematics and kinetics (sagittal plane) | comfort | comparable functional outcome to standard AFO and better comfort (AFO2 and AFO3 vs AFO1) |
Lewallen et al. 2010 [62] | post-stroke drop-foot (13) | solid AFO vs. hinged vs. posterior leaf spring | thermoplastics | walking walking up/down 10 deg ramp | spatio-temporal parameters | NA | significantly reduced walking speed and stride length (solid AFO vs. all AFOs and no-AFO) only one subject preferred solid AFO over the other AFOs |
Bartonek et al. 2007 [31] | children with bilateral ankle muscle weakness (11 AFO; 6 KAFO) | morphology-based posterior leaf spring patient’s level of functional ambulation and body weight | pre-preg carbon-fiber | walking | spatio-temporal parameters hip, knee, ankle kinematics (sagittal plane) | frequency of use gait standing function changes walking velocity acceptance ease of putting on and removing | for most children, improved ankle plantarflexion moment (p < 0.001), ankle positive work (p < 0.001), and stride length (p < 0.001) (custom AFO vs. rigid shell thermoplastic AFO) |
Bartonek et al. 2007 [30] | children with bilateral ankle muscle weakness (2 AFO; 1 KAFO) | morphology-based posterior leaf spring patient’s level of functional ambulation and body weight | pre-preg carbon-fiber | walking | spatio-temporal parameters hip, knee, ankle kinematics (sagittal plane) | frequency of use gait standing function changes walking velocity acceptance ease of putting on and removing | increased stride length (2/2; custom AFO vs. rigid shell thermoplastic AFO) increased walking speed (1/2) perceived improved gait |
Desloovere et al. 2006 [63] | children with hemiplegia (15) | flexible posterior leaf-springs (PLS) Dual Carbon Fibre Spring AFO (CFO) clinical examination and gait analysis | thermoplastic thermoplastic & carbon and kevlar fibres pre-impregnated with epoxy (strut) | walking | spatio-temporal parameters hip, knee, ankle kinematics | NA | increased walking speed and stride length (PLS vs. no-AFO) larger ankle ROM and ankle velocity during push-off increased plantar flexion moment and power generation at pre-swing (CFO vs. PLS; p < 0.01). |
Gök et al. 2003 [64] | hemiparetic stroke patients (12) | 1. Seattle-type polypropylene AFO 2. metallic AFO | polypropylene metal | walking | spatio-temporal parameters hip, knee, ankle kinematics | NA | increased walking speed (AFO2 vs AFO1 vs. no-AFO) increased stride length (AFO1 vs. no-AFO; AFO2 vs. no-AFO) |
Sienko Thomas et al. 2002 [65] | children spastic hemi-plegia (19) | morphology-based 1. hinged AFO 2. posterior leaf spring (PLS) 3. solid AFO | thermoplastic | walking stairs ascent/descent | spatio-temporal parameters pelvis, hip, knee, ankle kinematics (sagittal plane) | Pediatric Evaluation of Disability Inventory (PEDI) | reduced ankle plantarflexion (AFOs vs. barefoot) |
Burtner et al. 1999 [66] | children with spastic diplegic cerebral palsy (4, and 4 healthy control) | 1. solid AFO 2. dynamic (spiral) AFO | Polypropylene graphite | static balance test | sEMG: gastrocnemius, tibialis ant., hamstrings, quadriceps, paraspinals, abdominals. hip, knee, ankle kinematics (sagittal plane) | NA | decreased activation of gastrocnemius, disorganized muscle-response patterns, decreased use of ankle strategies, increased knee joint angular velocity (AFO1 vs. AFO2 and AFO1 vs no-AFO) without AFOs or with dynamic AFOs. |