Case control study, investigating what hand function and sensory function do patients perform 3-10 years following digital nerve injury and repair. The aim is to investigate if hand function is more limited following digital nerve injury in the thumb, index- and little finger, compared to less unburdened sensory surfaces in the fingers. Secondary aim is to investigate the long term sensory function following digital nerve injury.

Eligible patients are individuals treated at the Department of Hand surgery in Stockholm, Sweden during 2012-2018. Inclusion criteria include diagnostic codes (ICD-10) for a digital nerve injury in the thumb (S64.3) or finger (S64.4) in combination with the surgical code (KKÅ97) Nomesco classification of surgical procedures for nerve repair (ACB29). Exclusion criteria are concomitant flexor tendon injury and/or skeletal injury, amputations, and severe soft tissue injuries. Patients residing outside the Stockholm region and children below 18 years of age are also excluded. Initially a total number of 1330 patients have been identified. All medical records have been thoroughly scrutinized. After excluding concomitant tendon injury, a total of 606 patients remained with isolated digital nerve injury. A randomly selected sample of participants have been assigned to two groups: Patients with an injury to the digital nerve of the thumb, digit II radial side, digit V ulnar side were assigned to the "case" group and matched "controls" were randomly selected among patients with an injury to the digital nerves of either the ulnar side of digit II, either nerve of digit III and digit IV or the radial nerve of digit V. Cases and controls have been matched according to sex, year of injury and patient age.

For the purpose of this study, a clinical evaluation to investigate hand function, sensory function, strength, and ability to discriminate warm and cold and sharp and dull will be conducted. Questionnaires are used for Patient Reported Outcome Measures (PROM): Disability of the Arm Shoulder, and Hand (QuickDASH), Patient questionnaire HQ8 arm and hand (HQ8), The Hospital Anxiety and Depression Scale (HADS), Saltin-Grimby Physical Activity Level Scale (SGPALS), and in addition Douleur Neuropathique en 4 Questions (DN4) for assessment of neuropathic pain will be performed. All outcomes will be compared between groups defined as case (digital injury to the thumb, radial nerve of the index finger or ulnar nerve of the little finger) or control (all other digital nerve injuries).

Inclusion Criteria:

• diagnostic codes (ICD-10) for a digital nerve injury in the thumb (S64.3) or finger (S64.4) in combination with the surgical code (KKÅ97) Nomesco classification of surgical procedures for nerve repair (ACB29).
• treatment completed in Södersjukhuset hospital 2012 - 2018

Exclusion Criteria:

• concomitant skeletal injury,
• amputations
• severe soft tissue injuries
• microvascular reconstruction
• residence outside the Stockholm region
• patient age below 18 years of age

Participants with digital nerve injury were identified from a registry cohort consisting in 1330 patients. They were all treated due to a digital nerve injury at our hospital 2012 - 2018. A random sample of cases and controls were selected, matched for time from injury to evaluation, age and sex.