Can Lasso Compression Socks Really Prevent Ankle Sprains?

In the US, there are roughly 628,000 ankle sprains per year [Waterman et al., 2010]. The median cost of a trip to the emergency room in the US for an ankle sprain is $1,008 [Shah et al., 2016]. In other words, roughly $630 million is spent on treating people with ankle sprains every year. The primary treatment for ankle injuries involves ankle tape or ankle bracing, but both solutions have a tendency of weakening supportive tissues within the ankle due to heavy movement restriction. This leaves the athlete dependent on these solutions for ankle health [Garrick et al., 1973].

When it comes to ankle injury prevention, the most commonly used solution is kinesio-taping which involves flexible tape that supports the joint without overly restricting motion [Pope et al., 1987]. The effectiveness of kinesio taping has been questioned by many, including studies that have shown kinesio taping to be no better than placebo or sham taping (e.g., https://www.sciencedirect.com/science/article/pii/S1836955314000095). There is also limited understanding of how kinesio taping works (http://www.running-physio.com/kinesio2/).

The Lasso Compression Sock is an ankle support solution developed by BWHealth to provide ankle support within a garment as an alternative to kinesio taping. The development of the sock was preceded by detailed analysis of how ankles twist and the force needed to prevent ankle sprains that results from the twist. Lasso Compression Socks utilize Lasso Compression Technology, which simulates the patterns and support of kinesio tape using targeted compression woven into the garment.

This study seeks to determine the effects of the Lasso Compression Technology on ankle inversion and eversion. Instead of relying on subjective assessments of pain by patients, which are susceptible to placebo effects, we applied real force on simulated ankles and compared the twist factor with Lasso socks and with regular athletic socks.

Methods

An ankle movement simulator was built to test the impact of Lasso Compression Socks on ankle inversion and eversion. The ankle was simulated using a ball in socket joint, which was built into a foot mannequin that was suspended in air.

This simulator was operated by several wires that controlled and measured motion of the foot. A hanging wire was set up to hold a weight which caused the ankle to invert or evert. A second wire was connected to an Arduino that was programmed to measure a change in inversion/eversion angle of the ankle. The ankle joint limited ankle inversion and eversion at 45 degrees (see Figure 1).

The process of collecting one sample is as follows:

1. Suspend ankle with attached sock (or no sock) depending on testing group
2. Pull sock taut and attach top of sock to hooks near top of the simulator
3. Level the foot and make sure there is no pulling force on the foot
4. Record the starting angle
5. Gently attach test weight to wire on pulley, and keep weight from swinging
6. Record final angle
7. Calculate the change in angle

This process was repeated for each condition - barefoot (no sock), a standard athletic sock, and a Lasso Compression Sock, and three samples were collected for each condition.

All three conditions were tested at 500g, 1000g, and 1500g of weight. These weights were selected based on the construction of the ankle joint in order to closely match the force applied during a natural ankle roll. The data recorded for the change in angle are reported below for each of the three test conditions, at each weight.

Figure 1 - The testing rig being adjusted to fit the Lasso compression sock

Data

Table 1- Results from the testing process

Figure 2 - A graph depicting the deflection of the ankle based on the weight applied in each testing condition

The mean change in angle in the Lasso sock condition was compared to the change in angle in the regular sock condition and a t-test was run.

The resulting p-values for each testing condition were all below 0.001, which fit within our 0.05 threshold. This successfully shows a statistically significant difference between Lasso socks and standard athletic socks.

Conclusion

In all weight conditions, the change in angle with Lasso sock was significantly less than the change in angle with a regular athletic sock. In fact, the average change in angle with Lasso sock (4.49) was less than 30% of the change in angle with conventional sock (16.84). Further, in the largest weight condition that mimicked the most severe sprain, the change in angle (and thus the preventive strength) of Lasso sock was more than 75% less than of the change in angle with a regular athletic sock.

We conclude that Lasso socks, with their compression technology, offer a significant reduction in ankle inversion and eversion over regular athletic socks, creating a highly preventative alternative to ankle taping that does not exist today. If the change in angle were interpreted to be equivalent to the potential for reducing the incidence of sprain, Lasso socks appear to reduce sprain probability by about 75% over regular socks.