Amputation injuries of the fingertip are common in all ages. For decades it is known that conservatively treated fingertips can regenerate skin and soft tissues to form a functionally and cosmetically excellent new fingertip. Unfortunately, little is known about the mechanisms controlling this ability that, in humans, is confined to the fingertips. Even less is known about the bacteria that regularly colonize these wounds without noticeable negative impact on regeneration and healing. Medical evidence on fingertip regeneration in humans is largely limited to retrospective studies and case reports. This study will be the first randomized controlled trial on the conservative treatment of fingertip amputations in children and adults.

When managed without surgery, self-adhesive polyurethane film dressings are commonly used to establish a wet chamber around the injury. This provides the best conditions for tissue regeneration inhibiting the formation of scar tissue at the same time. Unfortunately these dressings do not offer mechanical protection, they do not stick to wet skin and leak malodorous wound fluid. The investigators therefore developed a silicone finger cap that deals with these problems offering a mechanically protected, wet chamber around the injury for optimal regeneration conditions. This finger cap also offers a puncturable reservoir for excess wound fluid, which by this route can be routinely analyzed for diagnostic and research purposes.

This randomized controlled trial will for the first time test acceptance, safety and efficacy of this novel medical device in comparison with conventional self-adhesive film dressings while gathering information on the clinical course and outcome of conservatively treated fingertip amputation injuries.

Based on sample size calculations for primary outcome, 22 patients older than 2 years will be enrolled within 24 hours after having suffered an injury distal to the distal interphalangeal joint comprising all layers of the skin with a substance defect that cannot be primarily adapted without further shortening of the finger or plastic surgery. Participants are randomly assigned to start their treatment for the first two weeks either with a conventional film dressing or with the novel silicone finger cap. They will be changed to the other modality for another two weeks before the patient or the guardian can decide, if they would want the film dressing or the finger cap for the rest of the treatment.

Inclusion Criteria:

• full skin substances defects distal to the distal interphalangeal joint (DIP-joint) unsuitable for primary surgical closure without further substance loss
• no more than five fingers per patient may be injured
• circumference of the proximal phalanx in between 3.0 cm and 9.0 cm
• signed informed consent

Exclusion Criteria:

• known hypersensitivity against medical silicone or self-adhesive films
• bony injuries requiring a surgical intervention
• bite injuries
• chronic dermatologic disorders of the hand
• intake of medications affecting wound healing, for instance/such as systemic (non-inhalative) glucocorticoids, immunosuppressive or blood-thinning medications
• known wound healing disorders
• ongoing or recently finished chemotherapy
• primary/congenital immunodeficiency
• diabetes mellitus
• pregnant or breastfeeding patients/women, as well as any women, when a pregnancy at the beginning or during the course of the study cannot be excluded (i.e. post-menopausal, oophorectomy or hysterectomy, contraceptive method with pearl index less than 1 %, sexual abstinence or partner with vasectomy)
• addiction or other diseases, which do not allow to assess the entity, scope and possible consequences of this clinical trial
• not cooperative patients
• participation in a clinical trial within the last four weeks