Lateral Ankle Treatment

This is a randomized control trial for pediatric patients who present to Scottish Rite for an acute lateral ankle avulsion fracture. Patients will be randomized into standard of care treatment or prolonged immobilization (test treatment). Standard of care treatment is booting with early range of motion or test treatment and gradually weaning from the boot. Test treatment (prolonged immobilization) is 6 weeks of immobilization in the form of a short-leg cast. The purpose is to see if prolonged immobilization will promote healing of the avulsion fracture and prevent the formation of a subfibular ossicle which occurs 100% of the time in standard of care treatment based upon our previous study. Patients will follow-up for a single visit between 6- and 12-months post enrollment for repeat imaging to assess for the formation/prevention of a subfibular ossicle. These visits will include an ultrasound and radiographs. Secondary outcomes include evaluation of function based upon PROs and biomechanical testing in the movement science lab at the follow-up visit. Enrolled patients may also be contacted for injury surveillance and PROs for up to 5 years following RTP.

Treatment Groups:

A) Standard of Care Treatment: Patients will receive brief immobilization (boot) as needed, followed by early range of motion exercises. Physical therapy and a return-to-activity plan will be implemented as symptoms allow.

B) Prolonged Immobilization (Casting): Patients will be treated with a non-weightbearing short leg cast for 6 weeks to promote avulsion fracture healing. This will be followed physical therapy, and a gradual return to activity.

Visits:

Visit 0:

This visit will occur at the time of the diagnosis and enrollment. All patients that have evidence of an avulsion fracture either on radiographs and/or ultrasound that meet inclusion criteria will be asked to enroll. Patients will undergo standard ankle radiographs as part of the standard of care.

Patients will also undergo a standard of care ultrasound including scanning of the lateral ankle to evaluate for radiographically-silent avulsion fracture. Treatment will be randomized. Patients or parent/LAR will be asked to fill out patient-reported outcomes (PROs) that include the HSS PediFABS, Oxford Ankle Foot Questionnaire for Children and PROMIS Physical Activity, Mobility, and Anxiety. Investigators will also collect demographics and injury related information from the medical record.

Visit 1 (Research Only Visit):

This will occur at 6-12 months post enrollment (4-16 months window). At this time, the patient and/or parent will fill out the same PROs as Visit 0. These patients will undergo repeat ankle ultrasound and radiographs to evaluate for continued avulsion healing verses early subfibular ossicle development. Radiographs are considered the standard of care for subfibular ossicle development. Ultrasound provides a non-radiating way to assess for and measure a subfibular ossicle in 3 dimensions. This will help see if one has developed and to see the size. Patients will also undergo biomechanical and pedobarography testing in the movement science lab to compare biomechanical differences between the two different test groups. During motion analysis testing, small reflective markers will be placed on the participants' feet, legs, arms, torso and head and electromyography sensors may be placed on the participant's legs. Markers and sensors will be held in place with tape to assure their placement during motion analysis. A subject calibration will be completed using the computer motion capture system while the participant stands quietly for approximately 1 minute. Following calibration, the participant will be asked to walk back and forth across the room along a 10m walkway until an appropriate number of clean data collections are completed (~10 walks). Participants may also be asked to walk at different speeds, jog, run, and perform other functional tasks including, but not limited to: accelerating/decelerating, cutting, drop landing, jumping, drop vertical jump, unilateral or bilateral limb squats, and/or sport specific movements. Participants will be given seated rest periods as necessary. Full body or lower extremity kinematics, kinetics, muscle activity and whole body center of mass will be determined for all activities. Subjects may be asked to complete these tasks barefoot or with shoes. Subjects may be asked to complete testing with or without ankle orthoses, as applicable. Participants will undergo motion analysis for research purposes only.

Bilateral strength testing of ankle (dorsiflexion/plantar flexion, inversion/eversion) muscle groups may be performed. The patient will perform two practice repetitions, followed by five recorded maximal effort repetitions, and may be conducted either isometrically or isokinetically. Maximal peak torque will be reported. Participants will undergo strength testing for research purposes only.

Plantar pressures may be collected one or two ways: 1) the participant may be asked to walk across a pressure plate (pedobarograph) embedded in the floor, or 2) foot pressures may be recorded via sensors placed within the participant's shoes. Both sensors (floor or in-shoe) provide a foot-print image of pressure under the foot, and it is collected dynamically at 50 to 240Hz.

Variables may include but are not limited to the peak pressure, maximal force, pressure-time integral, contact area and contact time of the entire foot, as well as within the different regions of the foot

Inclusion criteria

• Ages 5-12 at time of enrollment
• Diagnosis of first-time lateral ankle injury and an avulsion fracture visible on imaging who can be enrolled within 14 days of injury
• Patient and parent/legal guardian must speak English or Spanish

Exclusion criteria

• Previous ipsilateral ankle surgery
• Pre-existing musculoskeletal disease
• If patient has been casted prior to confirmation of avulsion fracture on imaging
• Developmental delay
• Does not meet inclusion criteria