Interactive apps are not necessarily the better choice for the implementation of injury prevention programs

We are running a bit behind en sharing our work with the world, so this publication may not be that 'fresh' anymore ... yet still relevant (if you ask us). Implementation of an effective ankle injury prevention program through either an interactive App or a Booklet, showed similar outcomes on the short and the long run. Not only did both methods result in comparable compliance rates during the 8 weeks of the program, both methods also led to comparable ankle sprain recurrence rates and costs after one year of follow-up. Both the App and the Booklet can be used successfully and with the same cost efficiency. Apps are, as such, not necessarily always better.

Ankle sprains are the most common sports- and exercise-related injury. In addition to the direct burden of such injuries, there is an increased risk of incurring recurrent ankle sprain and the risk of chronic residual pain. Both the high incidence of ankle sprain, the high risk of recurrence, as well as the resulting societal costs justify preventive efforts.

To address the prevention of recurrent ankle injuries, numerous interventions have been developed. Examples of interventions are predominantly focused on using supportive material (e.g. tape and brace) and or the strengthening of the ankle by exercises. An intervention that has been shown repeatedly to reduce recurrent ankle injury risk is neuromuscular training. We have developed and tested such an intervention in the last decades. This 8-week program has now been shaped in the “Strengthen your Ankle” training program and has been implemented in The Netherlands both via a printed instructional Booklet and via a mobile application.

 Exercises of the 8-week Strengthen your Ankle Program.

Exercises of the 8-week Strengthen your Ankle Program.

 Exercise progression throughout the Strengthen your Ankle Program.

Exercise progression throughout the Strengthen your Ankle Program.

Previous studies have shown that both methods of implementing this neuromuscular training program are equally effective in enabling compliance with the program, as in reducing the number of self-reported recurrent injuries. Although equally effective on these outcomes, cost-effectiveness may still differ. As both methods require substantial development and implementation costs, it is important to evaluate whether the costs and the associated preventive effect of the App and the Booklet justify their widespread use. A number of studies have already addressed the importance of cost-effectiveness, and allow for comparisons of different methods. As a result, accurate analyses have been developed that determine the cost-effectiveness of the current intervention.

The present study followed the line of these studies, and evaluated the cost-effectiveness of the Booklet and the App in preventing recurrent ankle sprains over a 12-month follow-up.

In total, 220 athletes with a previous ankle sprain were recruited for this randomized controlled trial with a follow-up of 12 months. Half of the athletes used the freely available “Strengthen your ankle” App and the other half received a printed Booklet. After the 8-week program, athletes were questioned monthly on their recurrent injuries. Primary outcome measures were incidence density of ankle injury and incremental cost-effectiveness ratio (ICER). All comparisons were made with the Booklet group as the reference. 

During follow-up, 31 athletes suffered from a recurrent ankle sprain that led to costs resulting in a hazard ratio of 1.13 (95% CI: 0.56-2.27). The incremental cost-effectiveness ratio of the App group in comparison with the Booklet group was €361.52. The CE plane shows that there was neither a difference in effects nor in costs between both intervention methods.

 Cost-effectivenessplane presenting cost-effect pairs estimated using bootstrapping (1,000 samples) for the difference in ankle sprain recurrence risk between the App group and the Booklet group. Each dot represents one bootstrapped cost-effect pair and the difference in costs and effects of the App group compared to the Booklet group. The outcomes of the samples are spread over the four quadrants, with only 38% of the bootstrapped cost- effect pairs in the south-east “dominant” quadrant.

Cost-effectivenessplane presenting cost-effect pairs estimated using bootstrapping (1,000 samples) for the difference in ankle sprain recurrence risk between the App group and the Booklet group. Each dot represents one bootstrapped cost-effect pair and the difference in costs and effects of the App group compared to the Booklet group. The outcomes of the samples are spread over the four quadrants, with only 38% of the bootstrapped cost- effect pairs in the south-east “dominant” quadrant.

This study showed that the method of implementing the NMT program using an App or a Booklet led to similar cost-effectiveness ratios and the same occurrence of recurrent injuries leading to costs. Both the App and the Booklet can be used to prevent recurrent ankle injuries, showing no differences in (cost-)effectiveness at 12-month follow-up.

The full paper can be accessed here

van Reijen M, Vriend I, van Mechelen W, et al. Preventing recurrent ankle sprains: Is the use of an App more cost-effective than a printed Booklet? Results of a RCT. Scand J Med Sci Sports 2018;28:641–8