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018 Spraino® reduces the risk of lateral ankle sprain injury among indoor sport athletes: a pilot randomized controlled trial with 510 participants
  1. Filip Gertz Lysdal1,2,
  2. Thomas Bandholm3,
  3. Janne Tolstrup4,
  4. Mikkel Clausen5,6,
  5. Stephanie Mann3,
  6. Pelle Petersen7,
  7. Thor Grønlykke2,
  8. Uwe Kersting1,8,
  9. Eamonn Delahunt9,10,
  10. Kristian Thorborg3,6
  1. 1Sport Sciences, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
  2. 2Spraino ApS, Copenhagen, Denmark
  3. 3Physical Medicine and Rehabilitation Research—Copenhagen (PMR-C), Department of Physical and Occupational Therapy, Clinical Research Centre, and Department of Orthopedic Surgery, Amager-Hvidovre Hospital, Copenhagen University, Hvidovre, Denmark
  4. 4National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark
  5. 5School of Physiotherapy, Faculty of Health and Technology, University College Copenhagen, Copenhagen, Denmark
  6. 6Department of Orthopedic Surgery, Sports Orthopedic Research Center—Copenhagen (SORC-C), Amager-Hvidovre Hospital, Copenhagen University, Hvidovre, Denmark
  7. 7Section for Surgical Pathophysiology 7621, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  8. 8Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
  9. 9School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
  10. 10Institute for Sport and Health, University College Dublin, Dublin, Ireland


Background High shoe-surface friction is a proposed risk factor for ‘non-contact’ lateral ankle sprain (LAS) injuries. Spraino® is a novel product that minimizes friction at the lateral edge of the shoe, thereby potentially mitigating the risk.

Objective To determine preliminary effect and safety of Spraino® when used to prevent LAS injury among indoor sport athletes.

Design A double-blinded, prospective, two-arm pilot randomised controlled trial (RCT). Participants were allocated (1:1) to Spraino® or to a ‘do-as-usual’ control group. The random allocation was concealed for investigators and participants. Group allocations were outcome-assessor-blinded.

Setting Indoor sports clubs competing at divisional- or league level in handball, badminton and basketball in Denmark.

Participants 510 elite- and sub-elite indoor sport athletes with at least one previous LAS injury within the preceding 24 months were enrolled; 480 completed the trial.

Intervention Spraino®; a low-friction patch applied to the lateral side of the shoe.

Main Outcome Measurements The trial was explorative with evenly-valued outcome measures related to incidence and severity of self-reported LAS injuries, pain in the ankle, fear of injury and intervention-related adverse events.

Results A total of 151 LAS injuries were reported within the trial period, of which 96 were categorized as non-contact injuries. A total of 50 injuries were severe. All metrics favoured Spraino® with computed incidence rate ratios of 0.87 (95% CI, 0.62–1.23) for any LAS injury, 0.64 (95% CI, 0.42–0.97) for non-contact LAS injuries, and 0.41 (95% CI, 0.19–0.89) for severe non-contact LAS injuries. The relative time-loss for the total number of injuries was 0.65 (95% CI, 0.45–0.93). Fear-of-injury and ankle pain was also lower in the Spraino® group. Six participants reported minor harms due to slipping on the floor because of Spraino®.

Conclusions Spraino® was found to be effective and safe when used to prevent LAS injuries in indoor sports. Findings should be replicated in a confirmatory RCT.

Trial registration ClinicalTrials. gov: NCT03311490

Funding Innovation Fund Denmark (7038–00087A)

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