Quick and Easy Correction of a Symptomatic Pincer Nail Using a Shape Memory Alloy Device


  • The authors have indicated no significant interest with commercial supporters.

Address correspondence and reprint requests to: Hyun Sun Park, MD, Department of Dermatology, Seoul National University Boramae Hospital, 425, Shindaebang-2-dong, Dongjak-gu, Seoul 156–707 Korea, or e-mail: snudm@paran.com



Pincer nails are characterized by the transverse curvature increasing from the proximal to the distal aspect along the longitudinal axis. A novel treatment technique using a shape memory alloy device was recently introduced.


To determine the treatment outcomes and safety of a shape memory alloy device.

Methods and Materials

This was a retrospective analysis of 21 cases of pincer nail of the great toe in 14 patients. Subjective indices (pain, inconvenience, global assessment scores) and objective parameters (transverse angle, width index) on days 0 (D0) and 1 (D1) and weeks 2 (W2) and 12 (W12) were investigated.


All parameters started to show significant improvement on D1. From D0 to D1, pain score fell from 3.6 ± 1.0 to 1.5 ± 0.7, inconvenience score fell from 3.3 ± 1.0 to 1.5 ± 0.7, global assessment score increased from 1.5 ± 0.7 to 2.5 ± 0.7, transverse angle improved from 86.4 ± 27.7° to 114.7 ± 21.6°, and width index improved from 67.6 ± 13.1% to 89.0 ± 9.7%. These effects were consistent during 12 weeks of follow-up. Two cases (9.5%) recurred, but symptoms were less severe than before. No complication was identified.


A shape memory alloy device was an effective and safe way to rapidly correct symptomatic pincer nail deformity.