Pincer Nails: Definition and Surgical Treatment - Huidziekten.nl

Pincer Nails: Definition and Surgical Treatment 

R. Baran, MD*, E. Haneke, MD† 

, and B. Richert, MD‡ 

* Nail Disease Center, Cannes, France, † Klinikk Bunaes, Oslo, Norway, and 

‡ Department of Dermatology, University Hospital, Liege, Belgium 

background. There are four main types of ingrown nail. 

These are distal nail embedding, juvenile (subcutaneous) ingrown 

nail, hypertrophy of the lateral nail fold (lip), and pincer 

nail. 

objective. The etiology of pincer nail may be hereditary or acquired. 

The mechanism of the most common form, an enlarged 

base of the distal bony phalanx, is discussed. 

TRANSVERSE OVERCURVATURE, progressively 

pinching the nail bed distally, is usually called pincer 

nail. The curvature commonly increases from proximal 

to distal, giving it a trumpet-like appearance. The 

condition is quite frequent on toes, but rare on fingers. 

Other names for this condition include incurved nail, 

unguis constringens, transverse overcurvature, trumpet 

nail, convoluted nail, omega nail. 

Etiology 

There are several different variants of pincer nails, 

both hereditary and acquired. 1 The hereditary pincer 

nail is almost always symmetrical2 

(Figure 1). Similar 

nail changes may be seen in other family members. 

The great toes are usually affected but the smaller toes 

may also be involved. The great toe commonly shows 

a lateral deviation of the long axis of the distal phalanx, 

but the overcurved nails are deviated even more 

laterally. When the lesser toes are involved they exhibit 

a medial deviation. This anomaly is already seen 

in adolescents and young adults. Of interest, epidermolysis 

bullosa simplex (Dowling–Meara type) 3 may 

be associated with pincer nail abnormality, with slight 

thickening in both finger and toenails. 

Acquired pincer nails are not symmetrical, though 

fingernail involvement may be extensive and appear to 

be fairly symmetrical. Acquired pincer nails may be 

due to a number of different dermatoses, of which 

psoriasis is the most frequent. Tumors of the nail apparatus 

such as exostosis, implantation cyst, or myx- 

R. Baran, MD, E. Haneke, MD, and B. Richert, MD have indicated 

no significant interest with commercial supporters. 

Address correspondence and reprint requests to: R. Baran, MD, Nail 

Disease Centre, 42 rue des Serbes, 06400 Cannes, France, or e-mail 

baranrmd@cote-dazur.com. 

© 2001 by the American Society for Dermatologic Surgery, Inc. • Published by Blackwell Science, Inc. 

ISSN: 1076-0512/01/$15.00/0 • Dermatol Surg 2001;27:261–266 

methods. Use of roentgenogram and magnetic resonance imaging 

highlights exophytes of the base and dorsal hyperostosis 

of the distal phalanx. 

results. Global assessment may lead in mild cases to medical 

therapy. Usually, however, the lateral matrix horn must be surgically 

removed or cauterized by phenol. Dermal grafting under 

the nail matrix provides excellent long-term results. 

oid pseudocyst4 

may lead to pincer nails, a condition 

reversible after treatment of the cause. 

Tinea ungium due to Trichophyton rubrum, 

affecting 

equally the great toenail and thumb nail, has been shown 

to be responsible for pincer nails. 5 The nails gradually 

return to normal after systemic antifungal treatment. 

Pincer nail deformity may occur after placement of 

an arteriovenous fistula (AVF) 

6 

in the forearm. The 

nail changes are then restricted to the index and little 

fingers. This potential and long-lasting adverse effect 

of circulatory disturbance and/or venous hypertension 

from AVF for hemodialysis is relatively common and 

should be recognized as a specific sign of circulatory 

disturbance caused by the AVF. 

Pincer nails have been reported after some �-block 

ers such as practolol 

7 

and acebutolol. 

8 

Transverse 

overcurvature of the nails is reversible after discontinuation 

of the drug. 

Pronounced pincer nails have developed in association 

with a metastasing adenocarcinoma of the sigmoid 

colon. They are considered as a marker of gas- 

trointestinal malignancy. 

9 

Acquired pincer nail deformity in an infant with 

Kawasaki’s disease affected all digits of the hands and 

to a lesser extent, the toes. Given the absence of pain, 

the nails were left undisturbed and the overcurvature 

spontaneously resolved as the nails grew out. 10 

The most frequent cause of acquired pincer nails is 

deformity in the foot with deviation of the phalanges, 

probably as a result of ill-fitting shoes. 

11 

Acquired pin- 

cer nails of the fingers are commonly seen in degenerative 

osteoarthritis of the distal interphalangeal joints. 

Pathophysiology 

The overcurvature is most probably due to an enlarged 

base of the distal phalanx to which the matrix

262 

baran et al.: pincer nails: definition and surgical treatment 

Figure 1. Hereditary pincer nails: A) front view, B) symmetrical 

dorsal view. 

is firmly bound by ligament-like collagen fibers (Figure 

2). Since toenails are markedly curved, the curvature 

of the proximal (matricial) nail plate portion will 

decrease and consequently the curvature will increase 

distally (Figure 3). 

Radiographs and magnetic resonance imaging (MRI) 

of big toes with pincer nails invariably show an enlargement 

of the base of the distal phalanx and often 

hooklike lateral osteophytes pointing distally (Figure 

4A). This is virtually always more pronounced on the 

medial aspect, explaining why the nail’s longitudinal 

axis is deviated more laterally than that of the distal 

phalanx. The distally more pronounced overcurvature 

exerts traction on the nail bed which is transduced to 

the bone by the ligament-like fibers fixing the solehorn 

to the tip of the terminal phalanx. This eventually results 

in a traction osteophyte which is also often seen 

on radiographs1,12 

and MRI (Figure 4B). 

Signs and Symptoms 

The toenails present a physiologically transverse convexity 

that is more pronounced than in the fingernails. 

When this transverse curvature becomes exaggerated, 

Dermatol Surg 27:3:March 2001 

Figure 2. Enlarged base of the distal phalanx in pincer nail. 

the lateral nail plate edges dig into the lateral grooves 

and upon further incurving start to pinch the nail bed 

(Figure 5). After a while, the soft tissue may actually 

disappear and may even be accompanied by resorp- 

tion of the underlying bone. 

Morphologically there are three clinical types: the 

“common” pincer nail (trumpet nail deformity), the 

tile-shaped nail, and the plicated nail. The most frequently 

seen type is the trumpet nail deformity with 

the overcurvature increasing along the axis from prox- 

imal to distal. 

14 

13 

The lateral plate margins virtually roll 

in, sometimes even forming a tube (Figure 6). The nail 

bed becomes pinched, shrinks in its transverse diameter, 

and is lifted up distally by the continuous traction 

exerted on the distal dorsal tuft. The lateral plate margins 

may eventually break through the epidermis and 

produce granulation tissue mimicking an ingrown toenail. 

Cutting the nail may become more and more difficult 

and painful with increasing overcurvature; furthermore 

this is frequently associated with thickening 

of the nail plate. To enhance the cosmetic appearance, 

patients and podiatrists tend to round the distal margin 

of the overcurved nail plate; this reduces pressure 

on the most distal portion of the lateral nail grooves, 

Figure 3. The curvature of the proximal nail plate segment decreases 

and consequently increases distally.


Figure 4. MRI showing A) lateral osteophyte at the base of the 

phalanx and B) distal traction osteophyte. 

however, there is a great risk of leaving a nail spike 

which inevitably will pierce into the soft tissue. 

Pachyonychia congenita may mimick pincer nails, but 

it is usually not painful and involves both finger and toenails. 

Pain is not a consistent symptom of pincer nails. 

Some extreme cases are completely painless, whereas 

sometimes even mild cases may cause excruciating pain, 

provoked by no more than the weight of a bed sheet. 14 

Figure 5. Pincer nail, a moderate case. 


Figure 6. Trumpet nail. 

263 

Tile-shaped nails are characterized by an even, 

transverse overcurvature with the lateral nail edges remaining 

parallel. This type is usually less severe, does 

not cause serious symptoms, and is frequently seen in 

tall young people with the “unguis incarnatus syn- 

drome” 

15 

or in fingernail overcurvature. 

The plicated nail presents a moderate convexity 

with one (Figure 7) or both lateral plate edges being 

sharply bent to form a vertical sheet pressing into the 

lateral nail groove. Bilateral symmetrical involvement 

of the nails is mainly seen on fingers, but unilateral angling 

of a nail is common in foot deformities. 

Indications for Treatment 

The major indications for treatment are pain and inflammation. 

Other indications are interference with 

wearing shoes and cosmetic embarrassment. Therapeutic 

approaches vary according to the severity and 

Figure 7. A) Unilateral nail plication. B) After surgical excision of 

the lateral matrix horn.

264 


type of overcurvature, possible risk factors, previous 

unsuccessful treatment, and a multitude of personal 

and psychological preferences of both the treating 

physician and patient. 

Conservative Treatment 

Most patients consulting a physician have already 

tried some conservative treatment. Usually they try to 

clip down the lateral edge of the incurved nail as far as 

possible proximally and they only stop when they cut 

into the skin of the lateral nail groove. Since the nail is 

frequently thick and hard, it should first be softened 

using an emollient under occlusion for some days or a 

10-minute hot foot bath prior to nail clipping. 

In early overcurvature, thinning of the central portion 

of the nail plate from the lunula to the free margin 

may alleviate the pain, since this technique increases 

the nail plate’s pliability. A single groove or a 

series of grooves may be cut into the nail plate surface 

using a burr, or the entire nail plate is ground to thin 

it. Recently the use of 40% urea paste and subsequent 

removal of the softened nail material, performed regularly 

over a period of 1 year, was shown to normalize 

hereditary pincer nails in a 38-year-old woman. 16 

There are several alternative methods for mechanical 

correction of malformed nails, called orthonyx. 

17–19 

The principle is to exert tension on the transverse nail 

curvature in order to gradually flatten the plate. After 

cleaning the lateral nail grooves, a stainless steel brace 

is inserted on the nail plate and fixed under the lateral 

edges. An adjustment is made to the brace in order to 

exert countertension on the plate, and with a series of 

adjustments the nail plate gradually flattens over a period 

of 6 or more months. We have obtained good responses 

in treating fingernail overcurvature associated 

with osteoarthritis; however, immediate relapse was 

observed after orthonyx treatment. More recently, 

elastic plastic braces glued to the abraded nail surface 

were successfully used by Effendy et al. 

Conservative treatment always appears to be tempting 

to patients. However, no publication recommending 

clipping, grooving, thinning, and orthonyx with 

steel or plastic braces has mentioned the bone alterations 

seen in nearly all patients on X-ray films. The 

patients we saw all experienced recurrences, usually in 

only about half the time needed to correct the pincer 

nail. We therefore believe that conservative treatment 

of pincer nails gives only some temporary relief. 

Surgical Treatment 

Repeated nail avulsions21 

were thought to permit the 

pinched nail bed tissue to flatten spontaneously during 

the period of nail plate regrowth. However, many pa- 

20 


tients experience a dramatic worsening of their condition 

after nail avulsion, and it has been found that 

there is rarely any benefit from this procedure. Furthermore, 

nail avulsion is known to increase the phys- 

iological transverse curvature of normal hallux nails. 

22,23 

There is a technique aimed at correcting the firm 

swelling of the distal nail bed. The nail bed is cut by a 

median longitudinal incision and the soft tissues are 

dissected from the terminal phalanx. Reversed tie-over 

sutures are put in the lateral nail folds and tied over a 

pad on the plantar aspect of the toe in order to spread 

the nail bed. The resulting triangular defect is covered 

with a free skin graft. The stitches are removed after 

about 3 weeks. An onycholytic area will develop cor- 

responding to the size of the free graft. 

24 

This tech- 

nique was slightly modified by primarily suturing the 

nail bed and inserting a small plastic plate between the 

curved nail plate and the flattened resutured nail 

bed, 12 however, the result was not permanent. 

In fact, these surgical techniques do not take into 

account the underlying bone alterations which cause 

the overcurvature. Except for permanent nail eradication 

by surgical nail ablation or phenolization, relapses are frequent. 

Judged from the presumed pathogenesis of pincer 

nails, it was felt that either the lateral osteophytes or 

the matrix horns which are pushed outward and forward 

by these bony excrescences would have to be removed. 

Removal of the lateral osteophytes is the procedure 

thought to offer the best chance of flattering 

the nail bed, but it would result in damage to the lateral 

ligaments of the distal interphalangeal joint. Therefore 

the permanent removal of the lateral matrix horns 

was considered to be the simplest, least painful, but 

nevertheless a sufficiently effective treatment modality. 

(Figure 8). In some cases it may be supplemented 

by laterally expanding the pinched nail bed and cutting 

the distal dorsal bony tuft, if this abnormality is 

prominent and associated with pain in the tissue, just 

beneath the midportion of the distal nail plate. 

14 

1,12,25–27 

Under regional block anesthesia, lateral nail strips 

of the entire nail plate are avulsed. The digit is exsanguinated 

and the matrix horns are dried and either 

carefully dissected and removed, or phenolized by vigorously 

rubbing in liquefied (90%) phenol for 3 minutes. 

Small antibiotic tablets are inserted into the 

wound cavities. In Haneke’s technique (Figure 9) this 

treatment is followed by a median incision of the nail 

bed from the lunula border to 2 mm beyond the hyponychium 

and carried down to the bone. During this 

incision, the traction osteophyte is felt with the scalpel 

even when it was not obvious on the roentgenogram. 

The pinched nail bed is then dissected from the terminal 

phalanx, the distal dosal tuft with the osteophyte 

is rongeured off, and the nail bed is expanded and su-


Figure 9. Haneke’s procedure. A) The nail plate (1) is shortened, 

showing the pinched nail bed (2). Bilateral cautery of the lateral matrix 

horns (3) will narrow the nail plate. A longitudinal median incision 

in the nail bed is carried down to the bone. B) The dorsal tuft of 

the phalanx is removed with a bone rongeur. The nail bed is sutured 

and then expanded using reversed tie-over sutures placed in the 

folds and tied over the plantar aspect of the toe. A frontal view C) 

before and D) after treatment. Replacing the original nail with a donor 

“nail bank transplant” will avoid keratinization of the nail bed. 


265 

tured using 6-0 monofil absorbable sutures (PDS II). 

Reverse tie-over sutures are placed in the lateral nail 

folds, with small rubber tubes being used as a cushion 

to prevent the sutures from cutting through the nail 

folds. These sutures keep the nail bed stretched over 

the bone and are removed after about 3 weeks. In more 

than 50 patients, a success rate of more than 80% was 

achieved with this technique. 

Zook’s team 

28,29 

has suggested another effective pro- 

cedure which may offer the best chance of flattening the 

nail bed. It is important not only to flatten the sterile 

matrix (nail bed) but also to flatten the lateral portions 

of the germinal matrix. Uniformly good results 

were obtained with this in relief of pain and improvement 

of appearance. 

In his technique, successful treatment of pincer nail 

involves removing the tubed nail to visualize the nail 

bed. The paronychium is freed from the periosteum of 

the distal phalanx through an incision on the tip at the 

distal end of the paronychium. Fine scissors are used to 

free the paronychium from the periosteum proximally 

to beyond the nail fold, allowing the nail bed to flatten. 

A strip of dermis of adequate volume (at least 1 cm in 

width) is then pulled beneath the paronychium. 

In conclusion, mild cases of pincer nail may sometimes 

benefit from conservative treatment, but usually 

chemical or surgical removal of the lateral matrix 

horns, or dermal grafting under the nail matrix provide 

excellent long-term treatment. 

References 

Figure 8. A) Pincer nail of a thumb before 

treatment. B) The same digit after phenol cautery 

of the lateral matrix horns. 

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