Incorrectly fitted footwear, foot pain and foot disorders: a systematic search and narrative review of the literature

The search strategy yielded 1681 citations. Following title and abstract review, 18 articles were included and a narrative summary of the findings is provided. A summary of all included studies including participant characteristics, method of analysis and main findings are presented in Table 1.

For all included studies, sample sizes ranged from 50 to 440 participants, with the median number of participants being 138. Mean or average age was reported in all but one study [15]. One study recruited only children [16] and four studies recruited only older participants [17‐20]. Three studies recruited only female participants [21‐23], while two other studies recruited predominantly male populations, including underground coal miners [24] and war veterans [25]. Participants with specific medical conditions were recruited in seven studies [15, 16, 25‐29], including diabetes [25, 28, 29], diabetic peripheral neuropathy [15], Down’s syndrome [16], Alzheimer’s disease [27] and inflammatory arthritis [26]. Specific ethnic groups were examined in three studies including participants of Japanese [21], Thai [19] or Singaporean [26] ethnicity. Finally, four studies recruited specific populations [24, 25, 30, 31], including war veterans [25], underground coal miners [24], rock climbers [30] and three different population groups from New York City (a foot specialist private practice, an academic diabetic foot and ankle clinic, and a charity centre serving homeless people) [31].

The majority of included studies were cross-sectional in design [16‐30] and three studies were case-control in design [15, 31, 32]. All except one study reported the method for measuring the foot [32]. The dimensions of the foot were measured during relaxed bipedal stance in all except two studies that measured the foot while the participant was in a seated position [18, 19]. It has been suggested that feet should be measured during standing to account for changes in dimensions due to splaying of the foot after the acceptance of bodyweight [33]. The studies that measured the foot while sitting did not provide a justification for doing so.

All except three studies measured the length of the foot, with most using a manual device, including a measurement stick [18, 25, 29‐31], Brannock® device [15, 17, 26, 27] or callipers [19, 21, 28]. Two other studies analysed the area of a foot tracing [16, 20], while another measured the dimensions of a 3-dimensional scan taken from a foot mould [24].

Two studies only measured foot width [22, 23] while 10 studies measured foot width in addition to foot length [16‐20, 24, 26‐29], using a variety of manual devices such as a tape measure [19], Brannock® device [17, 26, 27] or callipers [18, 28, 29]. Four studies measured foot width using measurements from foot tracings [16, 20, 22, 23] while one analysed a 3-dimensional scan of a foot mould [24].

All except one study measured the shoes brought by participants to the testing session. The only study that did not measure the participants’ shoes asked participants to report their usual shoe size [28]. For all studies, footwear dimensions were measured using the same method as the measurement of the foot. Most studies used a manual device to measure footwear dimensions [15, 17‐19, 21‐23, 25‐31]; two used measurements from a tracing of footwear [16, 20], and one study analysed a 3-dimensional mould of the internal dimensions of the shoe [24].

There were differences in the way that foot and shoe dimensions were compared and footwear fitting assessed. Several studies used a pragmatic approach guided by shoe sizing [15, 18, 19, 25‐29, 31, 32]. For example, one study considered a shoe to be incorrectly fitted if it was at least half a British shoe size larger or smaller than the foot [31]. In contrast, other studies considered shoe fitting to be incorrect if measurements such as overall area, length or width differed between footwear and the foot [16, 20‐24, 30]. In these cases, even though footwear and the foot may be different dimensions, footwear size may be correct. This is particularly relevant for length, as it has been suggested that appropriately sized footwear should have a space of at least 10–20 mm between the end of the foot and the shoe [33, 34]. In presenting results related to particular participant groups in this review, a distinction will be made between studies that deemed shoes to be incorrectly fitted based on shoe sizing, and studies that measured differences between the dimensions of the foot and the shoe.

Most studies explicitly reported fitting variables such as length or width, or commented on overall footwear fit by reporting only one variable, usually length. However, there were five studies that reported the number of participants that were wearing incorrectly fitted shoes based on more than one variable [15, 18, 26, 27, 29]. Four studies reported that between 63 and 72% of participants were wearing incorrectly fitted shoes based on length and width [18, 29], while one study reported that 68% of participants wore incorrectly fitted shoes based on three measures (length, width and depth) [26]. One study compared total foot and shoe area to determine footwear fit, finding that the total area of the footwear was smaller than total area of the foot in 47% of participants [20].

Among the studies that provided specific fitting details, the percentage of participants wearing footwear too long for the foot ranged between 14 [32] and 73% [21] (median 38% [27]) and too short between 0.6 [28] and 98% [30] (median 10% [20]). In terms of width, between 30 [32] and 88% [23] (median 58% [27]) of participants wore footwear that were too narrow and one study found that only 1% of participants wore footwear that was too wide [28]. One study examined depth, finding that 31% of participants wore footwear that was too shallow [26].

The association between incorrectly fitted footwear and foot pain or foot disorders was investigated in eight studies [17, 18, 20, 23, 25, 28, 30, 31], with all but one study [31] reporting significant associations between incorrectly fitted footwear and some form of foot pain or foot disorder.

There were five studies that reported an association between incorrectly fitted footwear and foot pain or impaired quality of life [17, 18, 23, 28, 30]. These studies reported a strong association between tight footwear and foot pain, with between 84 [23] and 91% [30] of participants reporting generalised foot pain while shod. However, the characteristics of recruited participants influenced findings. For example, the study that found that 91% of participants described foot pain was conducted on rock climbers, who wear tightly fitted footwear to optimise contact with the climbing wall. There was also evidence that loose footwear was associated with foot pain, with 64% of participants reporting generalised foot pain while shod [23]. Regarding quality of life measures, one study that recruited 65 older people in Spain found those with ill-fitting shoes displayed significantly poorer overall foot health using the Foot Health Status Questionnaire [17]. In terms of specific regions of the lower extremity, one study reported that incorrectly fitted footwear was significantly associated with the presence of pain in the ankle in women [28].

There were three studies that investigated the association between incorrectly fitted footwear and foot disorders [18, 20, 25]. Among these there was evidence that incorrectly fitted footwear was associated lesser toe deformity in older people [20] and the presence of corns in older people [18]. Importantly, there was also evidence of a strong association between current foot ulceration and incorrectly fitted shoes in older people with diabetes [18, 25] with participants with current foot ulceration up to 5 times more likely to be wearing incorrectly fitted shoes compared to individuals without foot ulceration [25].