Видимо одна потому, что изучала этот вопрос более тщательно  А не полагалось на мнение ортопедов в наших поликлиниках http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7706341&dopt=AbstractJ Bone Joint Surg Br. 1995 Mar;77(2):254-7.The influence of footwear on the prevalence of flat foot. A survey of 1846 skeletally mature persons.Sachithanandam V, Joseph B.Department of Orthopaedics, Kasturba Medical College, Manipal, India.We analysed the static footprints of 1846 skeletally mature individuals to establish the influence of the age at which shoe-wearing began on the prevalence of flat foot. The incidence was 3.24% among those who started to wear shoes before the age of six years, 3.27% in those who began between the ages of 6 and 15 and 1.75% in those who first wore shoes at the age of 16 (p < 0.001). Flat foot was highest in those who, as children, wore footwear for over eight hours each day. Obese individuals and those with ligament laxity had a higher prevalence of flat foot (p < 0.01 and p < 0.0001, respectively). Even after adjusting for these two variables, significantly higher rates of prevalence were noted among those who began to wear shoes before the age of six years. Our findings suggest an association between the wearing of shoes in early childhood and flat foot.Вообще в базе данных ПабМеда немало обзоров исследований по поводу плоскостопия и обуви. Поищите, если понадобитсяhttp://pediatrics.aappublications.org/cgi/content/abstract/88/2/371?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=shoes&andorexactfulltext=and&searchid=1086366262077_6724&stored_search=&FIRSTINDEX=0&sortspec=relevance&resourcetype=1&journalcode=pediatricsShoes for Children: A ReviewLynn T. Staheli MD11 From the Department of Orthopedics, Children's Hospital and Medical Center, Seattle; and Department of Orthopaedics, University of Washington, Seattle1. Optimum foot development occurs in the barefoot environment.2. The primary role of shoes is to protect the foot from injury and infection.3. Stiff and compressive footwear may cause deformity, weakness, and loss of mobility.4. The term "corrective shoes" is a misnomer.5. Shock absorption, load distribution, and elevation are valid indications for shoe modifications.6. Shoe selection for children should be based on the barefoot model.7. Physicians should avoid and discourage the commercialization and "media"-ization of footwear. Merchandizing of the "corrective shoe" is harmful to the child, expensive for the family, and a discredit to the medical profession.Submitted on May 29, 1990Accepted on September 5, 1990