Saudi Journal of Sports Medicine

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 18  |  Issue : 3  |  Page : 136--145

Screening of foot defects, deformities, and diseases among endurance runners: A cross-sectional study


Watson Arulsiingh DR1, Ganesh S Pai2,  
1 Department of Physiotherapy, Alva's Education Foundation, Dakshina Kannada, Karnataka, India
2 Department of Dermatology, Derma Care, Mangalore, Karnataka, India

Correspondence Address:
Watson Arulsiingh DR
Department of Physiotherapy, Alva's Education Foundation, Moodubidire, Dakshina Kannada, Karnataka
India

Abstract

Design: This is a cross-sectional study. Background: There was not a study in the past which exclusively defines and reports foot defects, deformities, and diseases among barefoot and shod endurance runners. Methods: Participants were added by snowball sampling method after fulfilling inclusion criteria as barefoot runners (n = 80), shod runners (n = 80), and healthy collegiate nonrunners (controls n = 80) from Dakshina Karnataka, India. Outcome Measures: Foot deformities, foot defects, and diseases were identified using valid tools. Results: All foot defects, deformities, and diseases for three groups were identified and analyzed by one-way ANOVA which revealed a significant difference in the foot defects, deformities, and diseases (P < 0.01). Type of running, duration of running, and foot type were associated with the foot defects, deformities, and diseases in each group at 95% confidence interval. Conclusion: This study concluded that there exists a significant difference in foot defects, deformities, and diseases between three groups and found a strong association between specific type of running, duration of running, and foot type with the foot defects, deformities, and diseases. Hence, this study alarms runners, coaches, and shoe manufacturers to work on strategies to prevent all foot problems reported among runners.



How to cite this article:
Arulsiingh DR W, Pai GS. Screening of foot defects, deformities, and diseases among endurance runners: A cross-sectional study.Saudi J Sports Med 2018;18:136-145


How to cite this URL:
Arulsiingh DR W, Pai GS. Screening of foot defects, deformities, and diseases among endurance runners: A cross-sectional study. Saudi J Sports Med [serial online] 2018 [cited 2020 Feb 23 ];18:136-145
Available from: http://www.sjosm.org/text.asp?2018/18/3/136/270321


Full Text



[INLINE:1]

 Introduction



Running is a popular form of exercise that people engage in to stay active and healthy. However, owing to a high incidence of runners' injuries, there arises a need to increase safety of running so as to derive the health benefits of running that overweigh the risk of injury.[1] Though researchers explore to understand the biomechanical variation of shod running from barefoot running, no evidences are available to state that barefoot running is better than shod running in preventing runner's injuries.

Moreover, it is clear that running shoe cannot completely bring about the working biomechanics of barefoot running. Foot problems are the most common injuries that are reported by long-distance runners. A previous study concluded that runner's shoes with arch supports and stiffened soles have negative impact on weakening foot muscles and arch and cause excessive pronation to place strain on the plantar fascia and lead to plantar fasciitis.[2]

Kouchi et al.[3],[4] reported significant morphological changes in feet of runners and nonathletes. Others [5],[6] claimed that bare footers do acquire very few foot defects. Researchers blamed that shoes do not always match the foot in regard to fit due to irregular fit of different lengths and widths, variations of the anatomical positioning of pedal soft tissue, and osseous structures that may alter the morphology and biomechanics of the foot.[7]

Blisters, jogger's toe, calluses and corns, subungual hematoma,[8],[9] macerated web spaces, plantar warts, and irritant dermatitis are fungal, bacterial foot infections, Talon noire or “black heel,” heel fissure,[9] tineapedis, onychomadesis, calcaneal petechiae, nail disorders [10] pitted keratolysis and folliculitis, athlete's nodules, jogger's itch, callosities, and talon noir were all common foot problems reported among marathon runners in European countries.[11] Other researchers [12],[13] from the USA reported unshod populations to have a lower percentage of pes planus and a lower frequency of foot abnormalities. Despite these foot problems among endurance runners, none threw insight into determining whether these foot disorders are more among barefoot runners or shod runners.

Barefoot running is an emerging trend, despite a subject of much controversy. Up-to-date, benefits of barefoot running appear to be more speculative and anecdotal than evidence based.[1] Additionally, associations of various factors causing runner's injuries were not well established.

Though little evidence of foot deformities, defects, and disease on healthy, elderly, diabetic populations are available, up-to-date, there is not a study in India which exclusively reports foot defects, deformities, and diseases among barefoot and shod endurance runners.

Research question 1

Are there any difference in the existence of foot defects, deformities, and diseases among barefoot and shod runners?

Research question 2

Are there any association between duration of running, type of running, and foot type to the development of foot defects, deformities, and diseases in shod runners and barefoot middle- and long-distance runners?

 Methods



Design

This is a cross-sectional study.

Participants

The study participants included barefoot runners (n = 80), shod runners (n = 80), and healthy collegiate nonrunners (controls, n = 80) from Dakshina Kannada, India.

This was carried out on middle- and long-distance shod and barefoot runners and nonathletic participants of Dakshina Kannada by snowball sampling method.

Adult long- and middle-distance shod and barefoot runners who run ≥30 km/week and also participated in running for a minimum of 3 years' duration with an age range of 18–55 years participated in this study. Both females and males were included. Healthy collegiate students had represented control group.

Runners were excluded if he or she had congenital deformities of foot, trauma in the feet other than sports related, athlete with auto-immune disorder, runner with metabolic diseases, smokers, runners with minimalist foot wear, had a history of or suspicious of diabetes, participant with suspected or known cardiac problem, gout patients, and any other neurologically affected foot.

Sample size fixation

A total sample of 255 was targeted at 5% dropout by conforming to the sample size of 240. For this purpose, 240 were elected out of 265 individuals who were screened in which 80 were barefoot runners and 80 were shod runners and other 80 were healthy nonrunner (controls) counterparts. Ethical committee approval was obtained before the start of the study. Purpose of the study was explained to each candidate. Informed consent was obtained for experimentation with human subjects. The privacy rights of human subjects must always be observed. Participant's each foot was evaluated to screen the deformities, defects, and diseases.

Materials used

Stadiometer, vernier caliper, weighing scale, goniometer ruler, custom-made Brannock ® style device, life size photographs of various foot disease and defects, color ink, graph sheet, pencil, 16.1 Mega pixel camera (Sony) with ×10 optical zoom, foot wear type picture chart, and shoe motion control property scale were used [Figure 1].{Figure 1}

Procedure for screening

Participant's each foot was evaluated to screen the deformities, defects, and diseases under the following methods and outcome measures.

To screen hallux valgus deformity,[14],[15] Life-size versions of the four photographs of grading of hallux valgus deformities were used. Students were asked to stand on an elevated platform and were instructed to walk in place for a few steps and then stand in a relaxed position. Validated Life size photographs [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d were kept alongside participants in standing position, and then hallux valgus deformity was identified.{Figure 2}

Screening Hallux rigidus [16] was based on range of motion of the first metatarsophalangeal (MTP) joint measured with goniometer with the foot in plantigrade position, Hallux rigidus was identified as directed by Coughlin and Shurnas and conformed by orthopedic surgeon [Figure 3].{Figure 3}

Forefoot and rear foot varus and valgus were screened as per the guidelines proposed by Buchanan et al.[17],[18],[19],[20] [Figure 4]. If positive degree was found, that was labeled as forefoot varus, labeled as neutral if it is 0°, and if negative degree was found, that was labeled as forefoot valgus.{Figure 4}

After the subtalar neutral position was determined, calcaneal tilt angle was measured. If calcaneal angle [Figure 5]a, [Figure 5]b, [Figure 5]c, [Figure 5]d, [Figure 5]e was more than 6° from neutral on either side, it was considered as rear foot varus and valgus deformity, respectively.{Figure 5}

Screening flat foot

According to Murley et al.[21] [Figure 6]a and [Figure 6]b, truncated foot length was measured as the perpendicular distance from the first MTP joint to the most posterior aspect of heel. Then, navicular height was divided by truncated foot length to derive truncated navicular height using foot prints. If values fall between 0.22 and 0.31, it was considered as normal arch of foot. If values were >0.18, it was documented as flat foot.{Figure 6}

Screening various foot defects, deformities, and disease

Standardized photographs of various diseases and defects of foot approved by the dermatologist [22],[23],[24] were used to screen foot disorder. Corns, calluses, and verrucas were screened as per the criteria.[25],[26] Evaluation of the shoe [27] was carried out with the validated tool developed by Barton et al. in 2009.

Data analysis

Sample size was fixed (95% significance) at 80% power with 30% risk of developing foot defects, deformities, and diseases in students only allowing 5% dropout through pilot study.

Descriptive data of demographic variables were generated. Mean foot defects, deformities, and diseases for three groups were analyzed using one-way ANOVA analysis.

 Results



Principal evaluator alone collected all the required samples from Alva's institution and Dakshina Kannada during the year 2009 to 2015 by visiting various colleges and attending all state, University level competitions.

Descriptive characteristics of participants in each group are provided in [Table 1]. The mean age of barefoot runner group was 20.68 ± 2.0, shod runners was 21.51 ± 8.2, and controls was 19.09 ± 3.1, who were screened in this study. The mean body mass index of barefoot runner group was 20.98 ± 2.5, shod runners was 19.86 ± 3.2, and controls was 18.74 ± 2.6. Mean distance run by barefoot runners per week was 81.87 ± 4.99 km and mean distance run by shod runners per week was 65.93 ± 24.14 km. Mean duration of shod runners was 5.35 ± 2.95 years. Mean duration of barefoot runners was 5.71 ± 2.46 years. [Figure 7], [Figure 8], [Figure 9], [Figure 10] illustrate the percentage of running type and foot type across groups. Descriptive data of mean foot defects, deformities, and diseases for three groups are summarized in [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12], [Table 13], [Table 14], [Table 15], [Table 16], [Table 17], [Table 18], [Table 19], [Table 20] with significance by one way anova analysis. Type of running, duration of participation, and type of foot were associated with the development of foot defects, deformities, and diseases in shod runners' group and barefoot runners' group.{Table 1}{Figure 7}{Figure 8}{Figure 9}{Figure 10}{Table 2}{Table 3}{Table 4}{Table 5}{Table 6}{Table 7}{Table 8}{Table 9}{Table 10}{Table 11}{Table 12}{Table 13}{Table 14}{Table 15}{Table 16}{Table 17}{Table 18}{Table 19}{Table 20}

Research question 1 (reporting of foot disorders across three groups)

Symptoms reported by runners

The current study reported equal existence of calcaneal pain, calf pain, and plantar fasciitis in both barefoot runners' and shod runners' groups.

Hallux valgus

The current study reported more number of hallux valgus in shod runners' group against barefoot runners and controls.

Ingrown toe nail, thick toe nail, and bunions

The current study reported more number of ingrown toe nail, thick toe nail, and bunion deformity in shod runners' group against barefoot runners and controls.

Callus

The current study reported more number of callus in shod runners' group against barefoot runners and controls.

Corn

The current study reported the shod runners to be affected with corn more than other groups.

Black toe, fore foot, calcaneal varus, valgus deformity, and calcaneal prominence

The current study reported more number of forefoot varus, valgus deformities and calcaneal varus, valgus deformities and black toe, and calcaneal prominence in shod runners compared to other groups.

Flatfoot

The current study reported more number of flatfoot found among shod runners compared to other groups.

Black heel

The current study reported more number of black heel among shod runners compared to other groups.

Fungal infection

The current study reported more number of fungal infections in foot among shod runners compared to other groups.

Hallux varus

The current study reported more number of hallux varus among barefoot runners against other groups.

Heel fissures

The current study reported more number of heel fissures among barefoot runners against other groups.

Plantar warts

The current study reported more number of plantar warts among barefoot runners compared to other groups.

Pitted keratolysis

The current study reported more number of pitted keratolysis among barefoot runners compared to other groups.

Blisters

The current study reported equal number of blisters among barefoot and shod runners which was not found in controls.

Research question 2

This current study found long-distance runners to have 1.46 times of developing hallux valgus, 4.69 times of developing corn, 2.25 times of odds risk in developing flatfoot over middle-distance runners in shod runner group, and exhibited a strong association with running distance to foot disorders.

Associating duration of running to foot problems

Shod runners' group

Participants with duration of running >5 years had shown 2.2 times of odds risk in developing black toe over who run <5 years' duration of running, and duration of running had shown a good association with these foot disorders.

Barefoot runners' group

Barefoot runners with <5 years' duration of running had 1.8 times of odds risk ratio over who have >5 years' duration of running in developing of blister in feet.

Association of foot type to foot problems

Shod runners' group

Runners with Egyptian foot had 2.1 times of odds risk in developing calcaneal deformity over Greek foot in shod runners' group, whereas square foot had 5.2 times of odds risk in developing callus in feet and 4.2 times of odds risk in developing calcaneal deformity over Egyptian foot in shod runners in the feet.

The current study found square foot to have 5.4 times of risk in developing callus and 8 times of odds risk in developing corn in feet over Greek foot in shod runners in shod runners' feet.

Barefoot runners' group

The current study reported Greek foot to have 2.1 times of odds risk over Egyptian foot in developing blister in barefoot runners' feet and square foot exhibited 3.3 times of odds risk over Greek foot in developing heel fissure in barefoot runners.

 Discussion



The results of this study demonstrated that shod long-distance runners had more number of foot defects, deformities, and diseases compared to barefoot runners in whom there were only few foot problems. Negligible foot disorders were reported among control group. This is the first cross-sectional study which classified long-distance runners into shod and barefoot running for the purpose of screening foot disorders existing among them. Though few surveys in the past reported the existence of foot disease among marathon runners from European countries, none have differentiated their frequency among shod and barefoot runners. Though ill-fitted shoes were blamed for the frequent occurrence of callus, corn, blisters, ingrown toe nail and black heel, toes and deformities among the shod runners, none have explored such existence of foot disorders among barefoot runners. This study finds equal number of foot symptoms reported among shod and unshod runners which is contrary to previous findings.[28-30]

Previous studies reported of existence of hallux valgus,[31],[32],[33],[34],[35] callus,[36],[37],[38],[39] corn,[36],[37],[38] collapsed foot arch [12],[40] and black heel,[29] and fungal infection [41],[42],[43] among shod runners yet not in the light of unshod runners and controls as of current study.

Joseph et al. reported hallux varus incidence among those who walk barefoot.[44] Another study reported pitted keratolysis among shod runners [9] and another reported occurrence of blisters in foot among marathon runners.[29],[45] Yet all these are not explored in the light of unshod runners and controls as of current study.

Previous study explained some association between running distance and foot infection.[45] Cowley and Marsden [46] reported that longdistance running has lowered foot arch immediately after marathon run on a shortterm basis. Few studies in the past reported no association between foot type to foot disorders.[47],[48] However, others explained some association between these variables.[49],[50],[51],[52],[53]

The current study shows foot problems of barefoot running against shod running. Foot problem present in barefoot running are quit fewer than shod running from the finding of present study. The endurance runners in Dakshina Kannada usually run on muddy ground as well as on road for their regular practice. Running barefoot cannot be completely recommended as broken glass or pieces of metal, animal excretes, and pebbles may be found on roadside, and until all the overall beneficial effects are proven. Hence, the emerging trend of minimalist running shoe can be an option until full light is shed on addressing foot problems that were reported with shod running and barefoot running.

One of the limiting factors that could not be controlled in this study was all runners in shod runner group had owned more than one shoes and used them alternatively for practice competition. Runner's shoe brand was not recorded. Hence, shoe characteristics could not be associated with the foot disorders.

Future study can associate foot defects, deformities, and diseases with across various types of minimalist running shoe and shod runner group with their brands as longitudinal design.

This study concluded that there exists a significant difference in foot defects, deformities, and diseases between three groups, of which shod runners had more foot defects, deformities, and diseases compared to barefoot runners and found a strong association between the type of running, duration of running, and foot type with the foot defects, deformities, and diseases. Hence, this study alarms runners, coaches, and shoe manufacturers to work on strategies to Prevent all foot problems reported among runners.

Declaration of patient consent

The authors certify that they have obtained all appropriate participants consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The participants understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgment

The authors express sincere thanks to Professor Radhakrishna, Physical education director, Alva's education foundation, for his contribution toward sample collection and all participants for their cooperation and referrals.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Jenkins DW, Cauthon DJ. Barefoot running claims and controversies: A review of the literature. J Am Podiatr Med Assoc 2011;101:231-46.
2Morio C, Lake MJ, Gueguen N, Rao G, Baly L. The influence of footwear on foot motion during walking and running. J Biomech 2009;42:2081-8.
3Kouchi M, Mochimaru M, Koto-Ku A. The feet of runners: Do they differ from the non-runners' feet? Tokyo, Japan: National Institute of Advanced Industrial Science and Technology; 2003.
4Shu Y, Mei Q, Fernandez J, Li Z, Feng N, Gu Y, et al. Foot morphological difference between habitually shod and unshod runners. PLoS One 2015;10:e0131385.
5Purim KS, Bordignon GP, Queiroz-Telles FD. Fungal infection of the feet in soccer players and non-athlete individuals. Rev Iberoam Micol 2005;22:34-8.
6Samuel B, Pod DS. Survey in China and India of feet that have never worn shoes. J Natl Assoc Chirop 1949;49:26-30.
7D'Aout K, Pataky TC, De Clercq D, Aerts P. The effects of habitual footwear use: Foot shape and function in native barefoot walkers. Footwear Sci 2009;1:81-94.
8Mailler-Savage EA, Adams BB. Skin manifestations of running. J Am Acad Dermatol 2006;55:290-301.
9Ramelet AA. Exercise-induced purpura. Dermatology 2004;208:293-6.
10Purim KS, Bordignon GP, Queiroz-Telles FD. Fungal infection of the feet in soccer players and non-athlete individuals. Rev Iberoam Micol 2005;22:34-8.
11De Luca JF, Adams BB, Yosipovitch G. Skin manifestations of athletes competing in the summer Olympics: What a sports medicine physician should know. Sports Med 2012;42:399-413.
12Lieberman DE. What we can learn about running from barefoot running: An evolutionary medical perspective. Exerc Sport Sci Rev 2012;40:63-72.
13Robbins SE, Hanna AM. Running-related injury prevention through barefoot adaptations. Med Sci Sports Exerc 1987;19:148-56.
14Adam P. The grading of hallux valgus the Manchester scale. J Am Podiatr Med Assoc 2001;91:74-8.
15Menz HB, Munteanu SE. Radiographic validation of the Manchester scale for the classification of hallux valgus deformity. Rheumatology (Oxford) 2005;44:1061-6.
16Coughlin MJ, Shurnas PS. Hallux rigidus: Demographics, etiology, and radiographic assessment. Foot Ankle Int 2003;24:731-43.
17Buchanan KR, Davis I. The relationship between forefoot, midfoot, and rearfoot static alignment in pain-free individuals. J Orthop Sports Phys Ther 2005;35:559-66.
18Gupta S. The relationship between forefoot, midfoot and rearfoot static alignment in pain free and painful heel in athletes. Serbia J 2008;2:67-74.
19Smith-Oricchio K, Harris BA. Interrater reliability of subtalar neutral, calcaneal inversion and eversion. J Orthop Sports Phys Ther 1990;12:10-5.
20Lattanza L, Gray GW, Kantner RM. Closed versus open kinematic chain measurements of subtalar joint eversion: Implications for clinical practice. J Orthop Sports Phys Ther 1988;9:310-4.
21Murley GS, Menz HB, Landorf KB. A protocol for classifying normal- and flat-arched foot posture for research studies using clinical and radiographic measurements. J Foot Ankle Res 2009;2:22.
22Kappes UP, Elsner P. Clinical and photographic scoring of skin aging. Skin Pharmacol Appl Skin Physiol 2003;16:100-7.
23Altman RD, Hochberg M, Murphy WA Jr., Wolfe F, Lequesne M. Atlas of individual radiographic features in osteoarthritis. Osteoarthritis Cartilage 1995;3 Suppl A: 3-70.
24Snider RK. Corns and calluses. In: Greene WB, editor. Essentials of Musculoskeletal Care. 2nd ed. Rosemont, Ill: American Academy of Orthopaedic Surgeons; 2001. p. 437-41.
25DeLauro TM, DeLauro NM. Corns and calluses. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, editors. Fitzpatrick's Dermatology in General Medicine. 7th ed. New York: McGraw-Hill; 2008. p. 97.
26Kennedy CT, Burd DA. Mechanical and thermal injury. In: Burns T, Breathnach SM, Cox N, Griffiths CE, editors. Rook's Textbook of Dermatology. 7th ed. London, England: Blackwell Science; 2004. p. 22.
27Barton CJ, Bonanno D, Menz HB. Development and evaluation of a tool for the assessment of footwear characteristics. J Foot Ankle Res 2009;2:10.
28Sinclair J, Cole T, Richards J. The influence of barefoot and shod running on triceps surae muscle strain characteristics. FAOJ 2016;9:4.
29Mailler EA, Adams BB. The wear and tear of 26.2: Dermatological injuries reported on marathon day. Br J Sports Med 2004;38:498-501.
30Altman AR, Davis IS. Prospective comparison of running injuries between shod and barefoot runners. Br J Sports Med 2016;50:476-80.
31Mafert B. Hallux valgus in a historical French population: Paleopathological study of 605 first metatarsal bones. Joint Bone Spine 2007;74:166-70.
32Hoffman P, St. Louis. Comparative study of the feet of barefooted and shoe-wearing peoples. J Bone Joint Surg 1905;iii:s2-3:105-136.
33Engle DJ. Notes on foot disorders among natives of the Belgian Congo. J Bone Joint Surg Br 1931;13:311-8.
34Sim-Fook L, Hodgson AR. A comparison of foot forms among the nonshoe and shoe-wearing Chinese population. J Bone Joint Surg Am 1958;40A: 1058-62.
35Shine IB. Incidence of hallux valgus in a partially shoe-wearing community. Br Med J 1965;1:1648-50.
36Paiva de Castro A, Rebelatto JR, Aurichio TR. The relationship between foot pain, anthropometric variables and footwear among older people. Appl Ergon 2010;41:93-7.
37Myerson M, Shereff M. The pathological anatomy of claw and hammer toes. J Bone Joint Surg 1989;71-A: 45-9.
38Zipfel B, Berger LR. Shod versus unshod: The emergence of forefoot pathology in modern humans? Foot 2007;17:205-13.
39Sanders JE, Goldsteine B, Leotta D. Skin response to mechanical stress: Adaptation rather than breakdown – A review of literature. J Rehabil Res Dev 1995;32:214-26.
40Yessis M. Explosive Running. Illinois, USA: Contemporary Books; 2000. p. 121.
41Shulman SB. Survey in China and India of feet that have never worn shoes. J Natl Assoc Chirop 1949;49:26-30.
42American Academy of Dermatology. Athlete's foot. Patient Information Pamphlet. Schaumburg, IL: American Academy of Dermatology; 1994.
43Lacroix C, Baspeyras M, de La Salmonière P, Benderdouche M, Couprie B, Accoceberry I, et al. Tinea pedis in European marathon runners. J Eur Acad Dermatol Venereol 2002;16:139-42.
44Joseph B, Jacob T, Chacko V. Hallux varus – A study of thirty cases. J Foot Surg 1984;23:392-7.
45Purim KS, Leite N. Sports related dermatosis among road runners in Southern Brazil. An Bras Dermatol 2014;89:587-92.
46Cowley E, Marsden J. The effects of prolonged running on foot posture: A repeated measures study of half marathon runners using the foot posture index and navicular height. J Foot Ankle Res 2013;6:20.
47Gottschalk FA, Sallis JG, Beighton PH, Solomon L. A comparison of the prevalence of hallux valgus in three South African populations. S Afr Med J 1980;57:355-7.
48Kurup HV, Clark CI, Dega RK. Footwear and orthopaedics. Foot Ankle Surg 2012;18:79-83.
49Orzechowski W, Wall A. Selected anatomical features of the foot with hallux valgus. Chir Narzadow Ruchu Ortop Pol 1999;64:311-7.
50Calvo A, Viladot R, Giné J, Alvarez F. The importance of the length of the first metatarsal and the proximal phalanx of hallux in the etiopathogeny of the hallux rigidus. Foot Ankle Surg 2009;15:69-74.
51Ogawa R, Hyakusoku H. Does Egyptian foot present an increased risk of ingrown toenail? Plast Reconstr Surg 2006;117:2111-2.
52Kagan B. Comparing Static Shod Soot Impressions with Barefoot Foot Impressions; International Educational Conference of the International Association for Identification. Providence, Rhode Island; August, 2013.
53Günal I, Koşay C, Veziroǧlu A, Balkan Y, Ilhan F. Relationship between onychocryptosis and foot type and treatment with toe spacer. A preliminary investigation. J Am Podiatr Med Assoc 2003;93:33-6.