Finger nail configuration is influenced by mechanical forces on finger pads

Risk Factors and Frequency of Ingrown Nails in Adult Diabetic Patients

The present study evaluated the properties of nails, frequency of ingrown nails in patients with type 2 diabetes mellitus (DM), risk factors for developing ingrown nails, and effect of diabetic polyneuropathy and vasculopathy on the development and outcome of ingrown nails. Our 6-month epidemiologic prospective study included 300 patients with type 2 DM attending a DM outpatient clinic for routine examinations. The general characteristics and foot changes of the study population were investigated. Diabetic polyneuropathy and vasculopathy were evaluated using a biothesiometer, monofilament tests, and arterial Doppler ultrasonography. The frequency of ingrown nails was 13.6%. Multivariate analysis with logistic regression showed that body mass index (odds ratio [OR] 1.077, 95% confidence interval [CI] 1.007 to 1.15; p = .03), previous trauma (OR 2.828, 95% CI 1.017 to 7,867, p = .042), a weak dorsalis pedis pulse (OR 2.72, 95% CI 1.17 to 6.30, p = .02), trimming type (OR 2.3, 95 CI 1.06 to 4.98), p = .35), onychogryphosis (OR 9.036, 95% CI 2.34 to 34.87, p = .001), and subungual hyperkeratosis (OR 4.3, 95% CI 1.99 to 9.3, p = .001) were predictive variables for ingrown nails in our population. The incidence of onychomycosis was significantly greater in patients with ingrown nails (p = .032) than in patients without ingrown nails. The nail curvature ratio was greater in the patients with ingrown nails than in the group with normal nails. Arterial Doppler ultrasound examinations showed peripheral arterial disease in 19 patients (46.9%) with ingrown nails. The prevalence of ingrown nails was greater in the patients with DM than in the healthy population. Our results indicate that nail type, nail morphology, and diabetic vasculopathy affect the formation and evolution of ingrown nails.

Foot loading is different in people with and without pincer nails: a case control study

Background

Recent studies suggest that pincer nails are caused by lack of upward mechanical forces on the toe pad. However, clinically significant pincer nails are also often observed among healthy walkers. It was hypothesized that in these cases, the affected toes do not receive adequate physical stimulation from walking and loading. To test this, the gait characteristics of pincer nail cases were assessed by measuring plantar pressure during walking.

Methods

In total, 12 bilateral pincer nail cases (24 affected feet) and 12 age- and sex-controlled healthy control subjects (24 ft) were enrolled in this prospective case–control study. Plantar pressure during free ambulation in both the barefoot and shod state was assessed using a digital pressure-plate system named S-Plate platform (Medicapteurs Co. France). First toe pressure and the frequencies of peak pressure in the first toe, metatarsal head, or other foot areas were calculated.

Results

In both the barefoot and shod state, the pincer nail group had significantly lower pressure on the first toe than the control group. In both the barefoot and shod state, the peak pressure area was mostly the metatarsal head area in the pincer nail group, whereas it was mostly the first toe area in the control group. Binomial logistic regression analysis revealed that peak pressure area was a significant risk factor for pincer nail development.

Conclusion

Walking behavior appears to contribute to pincer nail development. Pincer nails of walkers could be treated by correcting the walking behaviour so that more pressure is placed on the toe pad.