The intervention (guidance recovery app) was malfunctioning and not storing data for efficacy outcomes.

Ankle sprains are the most common musculoskeletal complaint of children presenting to the emergency department (ED). Healing can often be protracted, leading to prolonged pain, missed school and work, and delayed return to a normal activity level. Smartphone apps have been shown to be associated with greater caregiver knowledge and improved outcomes in a number of conditions but have not been explored in ankle sprains. The investigators would like to know if using a smartphone app for children with ankle inversion injuries leads to improved functional outcomes such as pain, mobility, and return to activity. The investigators will be comparing a smartphone app that provides education and daily management reminders to a paper handout to see if the former leads to improved functional recovery.

Comprehensive discharge instructions are an integral part of care children discharged from the emergency department (ED). Unfortunately, providing consistent and thorough discharge instructions is highly limited by the workflow constraints of a busy ED. Currently, paper instructions are the standard for providing ED discharge information. Yet, there remains a great deal of variety in delivery of discharge instructions (1) and there is evidence that patients often do not fully comprehend (2, 3), recall (4), nor comply (5) with discharge instructions. Consequently, caregivers often commit errors related to knowledge and execution of ED discharge instructions (6). The use of a smartphone app following discharge from the ED offers a potential means to improve adherence to discharge instructions through consistent information, simplification of content, and reminders (2). Acute ankle sprains are one of the most common complaints presenting to primary care offices and EDs (7). In Canada and the United States, there are more than 2 million ED visits annually due to ankle trauma in children; 85% due to forced inversion (8). Adolescents and young adults have the highest incidence of ankle sprain (7.2 per 1,000 person-years). Although ankle sprains are often perceived as minor injuries, they can have a highly variable prognosis, with up to 64% of patients failing to achieve full recovery (9). Current guidelines are limited in determining prognostic factors associated with functional recovery (9). The resulting 'one-size fits all' approach (controlling acute inflammatory symptoms (9), using cryotherapy and anti-inflammatory medications, and early mobilization (7)) fails to consider the grade of injury, baseline level of functioning, and individual pain tolerance of the child. Educational guidance individualized to pain beyond the ED may improve functional outcomes. As of 2015, 82% of people age 18-49 years owned an app-enabled smartphone, and over half (58%) download health related smartphone apps (10). In adult medicine, many health-related smartphone apps have been shown to be associated with greater caregiver knowledge and improved outcomes in allergic rhinitis (10), post-operative monitoring (11), and musculoskeletal conditions (12). In children and adolescents, several studies have explored smartphone apps for asthma (13) and diabetes (14, 15). To date however, no smartphone apps have been developed for acute musculoskeletal injury management in children.

Inclusion Criteria:

(i) Age 12-21 years (ii) Presenting to the Emergency Department of the Children's Hospital, London Health Sciences Centre, London, Ontario, with a unilateral acute (<48 hours) ankle inversion injury.

(iii) Use a WiFi enabled smartphone with either an iOS or Android operating system with enough memory capability to host the App.

The diagnosis of an ankle inversion injury will be made on a clinical basis by the treating emergency physician after a fracture has been ruled out radiographically. We will include all grades of ankle injuries, including suspected Salter-Harris I of the distal tibia or fibula.

Exclusion Criteria:

• Children unable to read or understand English above at least a grade 8 literacy level
• Children who are not independently ambulatory (without the use of an assistive device)
• Children with a developmental disability precluding the full comprehension of study-related procedures,
• Children with multi-system or multi-limb injuries
• Children with a concomitant lower extremity fracture or dislocation (with the exception of a suspected Salter-Harris type I injury).