Current issues of ACP Journal Club are published in Annals of Internal Medicine


Review: Avulsion with phenol prevents recurrence of ingrown toenails


ACP J Club. 2000 Jan-Feb;132:30. doi:10.7326/ACPJC-2000-132-1-030

Source Citation

Rounding C, Hulm S. Surgical treatments for ingrowing toenails. Cochrane Review, latest version 13 Mar 1999. In: The Cochrane Library. Oxford: Update Software. [PubMed ID: 20257889]



In patients with ingrown toenails, how do various methods of surgical treatment compare with each other and with chemical treatments?

Data sources

Studies were identified by searching the Cochrane Controlled Trials Register, MEDLINE, EMBASE/Excerpta Medica, and CINAHL; schools of podiatry and manufacturers of cryotherapy, radiowave, and electrosurgical equipment were contacted; and reference lists of relevant studies were reviewed.

Study selection

Studies were selected if they were randomized or quasi-randomized trials that compared 1 form of surgery with another or with other treatments that aimed to permanently remove all or part of an ingrown toenail and had ≥ 6 months of follow-up.

Data extraction

Data were extracted on study quality (allocation concealment, intention-to-treat analysis, baseline comparability, and follow-up). Outcomes considered were regrowth, relief of symptoms, healing time, infection, postoperative pain, and patient satisfaction.

Main results

9 studies were included. 1 study that compared nail avulsion and phenol with nail avulsion alone showed that the addition of phenol reduced symptomatic recurrence {P < 0.001}* but increased the rate of postoperative infection {P = 0.002}*; fewer patients receiving phenolization, however, were dissatisfied {P < 0.001}* (Table). Avulsion with phenol reduced symptomatic recurrence (5 trials) {P = 0.008}* more than did surgical excision, and treatments did not differ for postoperative infection (2 trials) {P = 0.28}* (Table). Insufficient data were available to quantify other outcomes.


In patients with ingrown toenails, nail avulsion with phenol is more effective in preventing recurrence than avulsion alone or surgical excision. 1 study shows avulsion with phenol increases postoperative infection.

*P values calculated from data in article.

Source of funding: No external funding.

For correspondence: Ms. C. Rounding, UK Cochrane Centre, Summertown Pavilion, Middle Way, Oxford OX2 7LG, England, UK. FAX 44-1865-516311.

Table. Avulsion with phenol (AvP) vs avulsion (Av) or surgical excision (SE) for ingrown toenails†

Outcomes at ≥ 6 mo AvP Av RRR (95% CI) NNT (CI)
Symptomatic recurrence 11% 77% 85% (74 to 91) 2 (2 to 2)
Patient dissatisfaction 16% 53% 70% (52 to 81) 3 (3 to 4)
Postoperative infection 11% 0.9% 722% (59 to 4154) 10 (6 to 25)
Weighted event rates RRR (CI) NNT (CI)
Symptomatic recurrence 5% 11% 54% (17 to 75) 17 (10 to 59)
Postoperative infection 11.6% 18% 35% (-42 to 70) Not significant

†Abbreviations defined in Glossary; RRR, RRI, NNT, and CI calculated from data in article.


The meta-analysis by Rounding and Hulm evaluates surgical methods for the treatment of ingrown toenails. The authors conclude that phenol with avulsion was superior to surgical excision for prevention of symptomatic recurrence but at the cost of increased rates of postoperative infection.

Surgical and carbolic acid (phenol) have been used concurrently as a treatment for ingrown toenails since at least 1901 (1). Both have been reported successful at permanently eradicating symptomatic ingrown toenails. Basic surgical principles deem it reasonable to hypothesize that surgical excision of the matrix by any of a number of techniques will consistently result in less postoperative inflammation than phenolization, which, because of its caustic nature, has the potential to cause soft-tissue or bony infection (2). At least 1 author, however, maintains that the overall potential for complications with phenol or surgical treatment is similar (3).

Rounding and Hulm have done a good job of synthesizing their conclusions in this review of a wide range of studies with different design criteria, inclusion parameters, and secondary outcome measures (i.e., differences in healing times and degree of pain).

Because of the caustic nature of phenol, a priori use in medically immunocompromised or ischemic patients should be contraindicated. However, Felton and Weaver (4) state that phenol can be used in patients with diabetes mellitus.

Rounding and Hulm’s conclusions appear reasonable. The following 3 study parameters, however, should also be considered: the experience and professions of a representative sample of surgeons, the degree of infection in the ingrown toenail before treatment, and the age and medical history of the study patients.

If this review were expanded to include such treatments as negative galvanism, trephine, osteotrypsy, laser ablation (3), or sodium hydroxide or silver nitrate chemical cautery, different conclusions might be reached.

Allan S. Goldberg, DPM
St. John’s Episcopal Hospital, Smithtown
Far Rockaway, New York, USA


1. Dagnall JC. The Foot. 1991;1:51-5.

2. Caprioli R, Bilotti MA. Surgical nail procedures. Clin Podiatr Med Surg. 1989;6:431-51. [PubMed ID: 2650852]

3. Kuwada GT. Long-term evaluation of partial and total surgical and phenol matrixectomies. J Am Podiatr Med Assoc. 1991;81:33-6. [PubMed ID: 1993975]

4. Felton PM, Weaver TD. Phenol and alcohol chemical matrixectomy in diabetic versus nondiabetic patients. A retrospective study. J Am Podiatr Med Assoc. 1999;89:410-2. [PubMed ID: 10466294]