Elite Athletes With Chronic Ankle Instability Using Spraino®: A Cohort Study

Fear of re-injury and deficiencies in ankle joint function are common conditions amongst high performance (elite) athletes with chronic ankle instability (CAI), who participate in indoor sports. This fear of re-injury associates with the high recurrence rate of lateral ankle sprains, which is a primary characteristic feature of CAI. The Spraino® shoe patch is a new Danish invention, which is designed to reduce the risk of sustaining lateral ankle sprains in this population. This cohort study will investigate self-reported fear of re-injury and objectively measured ankle joint function in elite indoor sports athletes with CAI, both before and after a 10-week period during which they will use Spraino® during all training sessions and games.

Acute lateral ankle sprains are frequently incurred by athletes, who participate in indoor sports such as volleyball, handball, and badminton; accounting for up to 30% of all injuries sustained in these sports. Despite established injury prevention strategies, the prevalence of recurrent lateral ankle sprain injuries and the concomitant development of CAI is high for athletes participating in indoor sports. CAI is characterized by athlete self-reported feelings of ankle joint instability, episodes of ankle joint "giving-way", and recurrent lateral ankle sprains. Additionally, athletes with CAI, who participate in indoor sports, may develop a heightened fear of re-injury, which may deter them from performing optimally in their sport. This study is designed as a prospective cohort study. The objective is to investigate fear of re-injury and ankle function in elite athletes with CAI (n = 25), both before and after a 10-week period during which they will use Spraino® during all training sessions and games. This study seeks to answer the following research questions: Does fear of re-injury improve in elite indoor sports athletes with established CAI when using Spraino® for 10 weeks? Does the use of Spraino® improve their ankle function?

The intervention time is scheduled for 10 weeks with the primary time point of interest being at the completion of week 10. The combined number of training sessions and games for each participant over the 10-week time-period is anticipated to exceed 32 exposures to ensure adequate exposure of participants to the use of Spraino®. All participants will receive a weekly text message using a Short Message Services-system (SMS-Track) throughout the 10-week time-period. This will be used to quantify training and game exposure and to register occurrences of new ankle injuries.

Embedded in this study is a qualitative method (semi-structured interview after week 10) to assess the participants´ experiences of using Spraino®. The content analysis will be a descriptive analysis of the data with some degree of interpretive analysis. The qualitative study will be reported in a secondary paper with a clear reference to this primary study registration.

The study purpose and methodology were evaluated by four identified stakeholders from the highest sports level including a physiotherapist, a head coach, a team doctor and an athlete. Their feedback ensured that the research is relevant to real-life circumstances and adds value to existing injury prevention strategies in elite indoor team sport.

The enrollment process will start in October 2018 and conclude when 25 participants have been enrolled in the study.

Eligibility Criteria:
Inclusion Criteria:

* Participant is ≥ 18 years old at commencement of study.
* Participant can read, speak and understand English.
* Participant is playing in one of the two highest leagues in the following indoor sports: handball, volleyball and badminton with at least 32 training sessions during the study period.
* Participant is diagnosed with CAI using the definition endorsed by the International Ankle Consortium.:

  * Participant has previously incurred at least one significant lateral ankle sprain that resulted in swelling, pain, and temporary loss of function at least 12 months prior to study enrollment.
  * Participant has a history of multiple episodes of the ankle ''giving-way'', and/or recurrent sprain and/or "feelings of instability" in the past six months
  * Participant has a Cumberland Ankle Instability Tool (CAIT) score \<24
* Participant can fully participate in training sessions and is eligible for game selection before enrollment in the study.
* Participant can receive and reply to text messages on a cell phone using Short Message Services (SMS).

Exclusion Criteria:

* History of medial ankle sprain
* History of ankle surgery
* Participant who does not agree to sign the informed consent to participate in the study