Abstract
Background
Plantar calluses and corns are a common cause of foot pain, which can have a detrimental impact on the mobility and independence of older people. 1 In addition, ulcers can develop if calluses or corns are neglected or treated inappropriately. 2 Many calluses keratinize into plate shapes with accompanied by pain on pressure, whereas typical corns have a central plug that is 5-8 mm in diameter, yellow in color, often dome-shaped, and generally sensitive to pressure. The central plug is generally the most pressure sensitive and associated with pain from its initial appearance. Calluses are peeled hyperkeratinization using corn cutter or scalpel; corns are removed central plug using grinder. However, calluses and corns frequently develop at the same site after these mechanical debridement. Therefore, it is important to determine their cause to prevent occurrence and recurrence. Calluses and corns are the result of prolonged excessive mechanical friction and shearing forces to the skin, and there are no associated hematological, chemical, serological, or imunohistochemical abnormalities. 3 Calluses and corns are a common problem in people with diabetes because the tremendous pressure caused by them may result in ulceration. Calluses and corns often occur repeatedly at the same site on the foot, there is a possibility that some specific repetitive motions, such as walking, are associated with their occurrence. The consequence of certain manner of walking (gait), with different repeated plantar forces may cause calluses and corns. However, the relationship between calluses or corns and gait has rarely been investigated. The purpose of our study was to determine whether calluses or corns are related to gait features and to reveal what kind of gait features are related to callus or corns.
Method
A plate-shaped acanthosis was recognized as a callus by nurses with clinical foot care experience. Diagnosis of corns was also performed by the nurses; those with a central plug were recognized as a corn. A foot without calluses or corns was defined as a normal foot. To measure gait features, motion sensors were attached to the sacrum and dorsal portion of the foot in people with diabetes and people without diabetes. Gait features were defined as amplitude of acceleration, angular velocity, and angle. The 15- to 22-step mean value was calculated using the maximum value across steps per subject. These variables were compared between callus or corn feet group and normal feet group by t test and stepwise logistic regression analysis. The study was approved by the Ethical Committee of the Graduate School of Medicine, University of Tokyo (#3694).
Results
Gait features were measured in 107 subjects, 57 people with diabetes and 50 people without diabetes. Two hundred fourteen feet were divided into 3 groups of 32 callus feet (15.0%), 21 corn feet (9.8%), and 161 normal feet (75.2%). Comparison results of the gait variables between these groups are shown in Table 1. Finally, we observed that body yaw motion was related to the feet with calluses by logistic regression analysis (OR: 0.72 [0.56-0.91]). However, no gait features were related to the feet with corns.
Comparison of Gait Features Between the Feet With Calluses or Corns and Normal Feet.
Variables used in the logistic regression analysis. All data are represented as mean ± SD. T test, P < .05.
Conclusions
Although the cause of calluses and corns had not been clearly distinguished in previous studies and clinical settings, our new findings reveal that the feet with calluses are related to small yaw motion around body’s center of gravity, whereas the feet with corns are not related to any gait features. In the future, a more detailed relationship between gait and calluses should be studied to develop new callus prevention methods and prevent diabetic foot ulcers. To prevent corns, the relationship among the foot, shoe shape, and external force on corns will be investigated.
Footnotes
Acknowledgements
We thank the subjects of this study for their cooperation.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by JSPS KAKENHI No. 25540112.