The optimal duration for the wrinkle test in a clinical setting

To determine the time needed or the development of a positive result on the wrinkle test among patients with complete laceration of a digital nerve in a clinical setting. We prospectively recruited 20 patients who had undergone surgery for digital nerve laceration. The wrinkle test was conducted at a follow-up session up to 2 months after surgery, and the time to a positive wrinkling result was recorded. The wrinkle test was compared between the patient’s injured versus uninjured contralateral finger. The average time required for a positive result on the wrinkle test was 24.5 min (± 11), with 25% patients requiring 40 min to obtain a positive result. When evaluating a patient with digital nerve injury in a "non-laboratory" environment, the wrinkle test may require up to 40 min to obtain a positive result. Our study suggests that if tests are completed following the generally accepted time limit reported in the literature (30 min), up to 25% of tests may produce false negative results.