Feheery/Cuboid pads

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Hi All,

I have been looking for evidence for the effectiveness of feheery/cuboid pads in the treatment of chronic lateral ankle instability and have had little success. I have found some studies describing them as useful for calcaneocuboid impingement but no references to lateral ankle.

Using them in clinical practice, they have a positive effect on generating improved lateral ankle stability but is this just due to generating STJ pronation moments?

I therefore thought i would pose a few questions

1. Where does the name "Feheery" originate from?
2. Is there any evidence feheery/cuboid pads have a positive impact in improving peroneal latency?


Best wishes

Simon

 

Hi Simon,

If memory serves there is a DPM called Raymond Feheery Jnr that is responsible for this particular eponym. At least that was I was once told.

I don't know of any published data which has looked at the mechanical effects of the cuboid/Feheery pad.

Ian

 

There are different causes of lateral ankle instability. One cause is peroneal latency, the time it takes for the peroneal muscles to contract in response to an inversion motion. My theory on this, is that peroneal latency is increased when increased pronation moment will increase pressure, and pain, in the sinus tarsi. Absence of peroneal activity has been seen in people with sinus tarsi syndrome. Increased peroneal latency has also been seen in sinus tarsi syndrome. My explanation for those findings is that sinus tarsi syndrome is caused when the STJ is forced to end of range of motion with a high pronation moment. At the end of range of motion of the STJ the lateral process of the talus is compressed into the floor of the sinus tarsi of the calcaneus. Additional pronation moment from the peroneal muscles will increase compression of the two bones in the sinus tarsi. The CNS inhibits peroneal activity. When this individual walks on uneven terrain, they can step so that there is an unexpectedly high supination moment from ground reaction force and they will start to supinate. The inhibited peroneal muscles will be late to fire and there will be a sprained ankle.

The other cause of ankle instability is a laterally deviated STJ axis. The ground is much more likely to cause a supination moment in these feet. When you assess STJ axis position, the exam is often made difficult by the fact the peroneals contract when you push medial to the STJ axis. This "reflex" occurs when they are not weight bearing and in comparison to people who have average or medial axes, who do not exhibit this peroneal contraction. This is the opposite of inhibited and I would certainly expect these individuals not to have a delayed peroneal activation.

Cuboid pad works by increasing force lateral to STJ axis that will tend to increase the pronation moment from the ground. This does have the potential for helping both causes of lateral ankle instability. However, it is unlikely to help the delayed peroneal activity and could increase sinus tarsi pain. I would prefer a full length valgus wedge, as opposed to a cuboid pad for the feet with a laterally deviated axis. (There are exceptions to that rule) The people with a medially deviated axis and sinus tarsi pain and lateral will paradoxically do better with a rearfoot varus wedge. (Reduced pain in sinus tarsi, more normal peroneal activity.)

Eric