Introduction
Methods
Search strategy
MEDLINE and Embase (Ovid) and CINAHL and SPORTDiscus (EBSCO) | |
---|---|
1. | exp foot orthosis/ |
2. | foot orthoses.mp |
3. | (orthotic* or orthos*s or insole* or heel insert* or ortho* material$ or shoe* or footwear or footwear material$ or sock* or hosier* or shod).mp |
4. | 1 OR 2 OR 3 |
5. | (kinetic* or plantar pressure* or peak pressure* or contact area or contact time or maximum force).mp |
6. | 4 AND 5 |
Inclusion and exclusion criteria
Inclusion criteria: | |
• studies that evaluated the effects of flat insoles constructed from different materials on plantar pressures; | |
• studies published in English; | |
• studies that compared to a control (shoe alone) condition; | |
• studies that used ‘in-shoe’ testing apparatus. | |
Exclusion criteria: | |
• studies conducted on animals (non-humans); | |
• studies that evaluated cadavers; | |
• studies conducted on children (aged under 18 years); | |
• studies that evaluated the effects of taping, padding, splinting, bracing, casting, contoured foot orthoses or insoles, or orthopaedic devices defined as other than flat foot orthoses or insoles; | |
• studies of activities other than walking; | |
• studies where participants had systemic, neurological or inflammatory arthritic pathologies such as diabetes mellitus, cerebrovascular accident, Parkinson’s disease, and rheumatoid arthritis; | |
• studies that were not peer-reviewed, scholarly publications of experimental or quasi-experimental research. |
Methodological quality assessment
Statistical analysis
Results
Quality assessment of included studies
Authors, date | Reporting | External validity | Internal validity – bias | Internal validity – confounding | Power | Total (max. 28) | Total % | ||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | |||
Healy et al., 2012 [6] | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 0 | 1 | 1 | U | 1 | U | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | U | 1 | U | 0 | 20 | 71 |
McCormick et al., 2013 [15] | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 1 | 1 | 1 | U | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 23 | 82 |
Rao et al., 2009 [16] | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 0 | 1 | 1 | U | 1 | U | U | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | U | 1 | U | 0 | 20 | 71 |
Rogers et al., 2006 [17] | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 1 | 1 | 1 | U | 1 | U | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 21 | 75 |
Tong & Ng, 2010 [18] | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 1 | 1 | 1 | U | 1 | U | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 21 | 75 |
The effect of orthotic materials on plantar pressures
Author, date | Study design/participants/ sample size | Equipment/protocol | Plantar pressure variables of interest | Type of foot orthosis/insole and materials tested | Main findings |
---|---|---|---|---|---|
Healy et al., 2012 [6] | Laboratory-based study with repeated measures design. ‘Healthy’ participants with mean (SD) age 30.9 (12.4) years, weight 69.3 (12.2) kg and height 172.0 (9.4) cm. N = 10 (4 males and 6 females). | F-Scan™ in-shoe system (Tekscan, Boston, USA) Sampling rate 100 Hz. Walking speed: “participants walked on a treadmill at a self-selected speed”, walking speed was then maintained across the subsequent testing conditions. Participants wore ‘standardised plimsoll shoes (a minimalist athletic shoe with a canvas upper and rubber sole).’ | Peak pressure (kPa), peak force (N/BW), pressure-time integral (kPa.s) and average contact area (cm2). | Conditions: (i) a shoe alone condition (i.e. control), (ii) 3 mm flat insole of low density polyurethane (Shore A hardness 20–25), (iii) 3 mm flat insole of medium density polyurethane (Shore A hardness 55 ± 3), (iv) 3 mm flat insole of low density EVA (Shore A hardness 25), and (v) 3 mm flat insole of medium density EVA (Shore A hardness 50). | Compared to a shoe alone condition, medium density polyurethane insole materials provided significant reductions in peak pressure (kPa) in the first metatarsal region (p < 0.05; 215.7 ± 69.8 kPa vs. 180.0 ± 67.2 kPa), as did both the medium and low density polyurethane as well as low density EVA at the lateral metatarsals (p < 0.05; 352.5 ± 77.4 kPa vs. 288.0 ± 62.9 kPa, 292.2 ± 51.6 kPa and 295.7 ± 54.8 kPa, respectively). Low and medium density polyurethane materials were most effective at increasing contact area (cm2) and reducing pressure time integral (kPa.s). |
McCormick et al., 2013 [15] | Laboratory-based study with repeated measures design. Participants with mean (SD) age 25.1 (9.63) years, weight 68.2 (13.8) kg and height 1.70 (0.11) m. N = 30 (7 males and 23 females). | Pedar® in-shoe system (Novel GmbH, Munich, Germany) Sampling rate 50 Hz. Walking speed controlled. Participants walked on a walkway in ‘standardised thin cotton socks’ and their most commonly used footwear.’ | Peak pressure (kPa), maximum force (%BW) and contact area (cm2). | Conditions: (i) a shoe alone condition (i.e. control), (ii) customised polypropylene foot orthosis, (iii) contoured polyethylene sham foot orthosis, (iv) contoured EVA sham foot orthosis, and (v) flat 3 mm EVA sham foot orthosis. | Compared to a shoe alone condition, a flat 3 mm EVA material with a vinyl top cover significantly reduced peak pressures (kPa) at both the medial and lateral heel, mean difference significant at the 0.05 level (Bonferroni adjusted). |
Rao et al., 2009 [16] | Laboratory-based study with repeated measures design. Participants with midfoot arthritis, mean (SD), range; age 63 (6), 55–78 years and body mass index 29.7 (5.1), 19.9–38.1 kg/m2. N = 20 (all participants were female). | Pedar® in-shoe system (Novel Inc., St Paul, MN) Sampling rate 90 Hz. Walking speed controlled. Participants walked over an undescribed surface in ‘subjects’ own footwear.’ | Average pressure (kPa), contact time (% stance) and contact area (cm2). | Conditions: (i) a shoe alone condition (i.e. control), (ii) shoe with custom moulded ¾ length shoe insert, and (iii) shoe with flat full length insert made of carbon graphite, semi rigid with an average thickness of 1.6 mm. | Compared to a shoe alone condition, a 1.6 mm flat carbon graphite insole provided reductions in average pressure (kPa), contact time (% stance) and contact area (cm2) in the medial midfoot and in contact time (% stance) and contact area (cm2) at the lateral midfoot. |
Rogers et al., 2006 [17] | Laboratory-based study with repeated measures design. Participants with mean age 25 years, mean weight 70.3 kg and mean height 1.73 m. N = 9 (2 males and 7 females). | F-Scan™ in-shoe system (Tekscan Inc., Boston, USA) Sampling rate not reported. Control of walking speed: not reported, so likely not controlled. Participants walked on a walkway in undescribed footwear other than it being ‘subjects’ shoes.’ | Peak pressure (kPa) and force-time integral (N.s). | Conditions: (i) a shoe alone condition (i.e. control), (ii) flat 6.4 mm thick PORON® insole, and (iii) combination flat 6.4 mm insole consisting of a 3.2 mm Plastazote® top-layer and a 3.2 mm PORON® bottom-layer. | Compared to a shoe alone condition, forefoot peak pressure (kPa) was significantly lower when using a 6.4 mm PORON® insole and a 6.4 mm PORON®/Plastazote® composite insole (p < 0.05). No significant differences were found in the force-time integral between the shoe alone condition and the PORON® (p = 0.64) and the shoe alone condition and PORON®/Plastazote® combination insoles (p = 0.42). |
Tong & Ng, 2010 [18] | Laboratory-based study with repeated measures design. ‘Healthy’ participants with mean (2SD*) age 29 (3) years, weight 75.0 (3.7) kg and height 1.75 (0.04) m. N = 5 (sex of participants not stated). | F-Scan™ in-shoe system (Tekscan Inc., Boston, USA) Sampling rate not reported. Control of walking speed: not reported other than “…subjects were instructed to walk at their usual walking speed…”, so possibly not controlled. Participants walked on a walkway in undescribed footwear other than it being ‘subjects’ sports shoes.’ | Minimum, maximum and peak pressures (kPa). | Conditions: (i) a shoe alone condition (i.e. control), (ii) 6.2 mm Slow Recovery PORON® (extra soft) flat insole, (iii) 6.2 mm PORON® (soft) flat insole, (iv) 6.2 mm PORON® (soft) and firm Plastazote® flat insole, and (v) 6.2 mm PORON® (soft) and soft Plastazote® flat insole. | Compared to a shoe alone condition, a 6.2 mm PORON® and firm Plastazote® combination insole provided significant difference for mean peak contact pressure (kPa) (p < 0.03; 60.7 ± 11.3 kPa vs. 47.9 ± 8.4 kPa) which accounted for an approximate 27% mean pressure reduction (whole foot). |