What is an Abductory Twist?
An abductory twist is an observation made during gait in which there is a sudden abduction of the heel just as the heel comes off the ground. Some call this a medial heel whip.
There are two schools of thought as to what causes an abductory twist:
1) The one described in the video is the most commonly believed reason and is due to a foot that is overpronating as the leg is externally rotating. As soon as load comes of the heel, this causes the foot to suddenly abduct. The pathomechanics of this is discussed in detail here. Those who subscribe to this reason tend to call it an abduct0ry twist.
2) The other believed cause is that there is a weakness of the hip abductors. Those who subscribe to this view tend to call it a medial heel whip.
Forefoot Valgus
Forefoot valgus is a foot type in which the forefoot is in an everted position when the subtalar joint is in its neutral position and the midtarsal joint is maximally pronated. It is the opposite for the forefoot varus foot type.
Forefoot valgus is a difficult foot type to understand as it will function very differently depending on the range of motion at the midtarsal joint. A rigid midtarsal joint will mean that the rearfoot supinates. A flexible midtarsal joint means that the rearfoot will pronate more (more).
Overpronation
“Overpronation” – I wish that term will go away. It is really meaningless but is widely used by runners and running shoe shops, especially when they have no idea what they are talking about. See this video and you see what I mean:
Runners fall for this stuff all the time. They come in the clinic and think they know more about it than I do. They need to read blogs this like this for some common sense. There is still a lot to be learnt about the role that this plays in injury risk and so many pronation myths.
The Foot Posture Index
Most of the students that come to me during their training have no heard of this, but are more familiar with the rather esoteric ways of measuring ankle in the foot. They often loose site of what the purpose of it all is and make it much more complicated that it really is. The loose site of the big picture and focus on the minute numbers. I teach them about the Foot Posture Index, so they can better focus on what the foot is rather than attach something mystical to all the numbers that they seem to put too much faith in.
Forefoot Varus
Forefoot varus is an uncommon biomechanical dysfunction of the foot that causes the foot to pronate. It is due to a bony deviation that causes the foot to pronate or flatted to get to the ground. The only way to manage this type of flat foot is with foot orthotics. No amount of exercises or muscles strengthening will change anything, as the foot as to flatten to get to the floor.
Determining if forefoot varus is actually present or not is crucial, as there are potential problems if it is diagnosed as being present when its not (see this). The idea being is that if you use a forefoot varus post when there is no forefoot varus, then this will jam up the first pay to end range of motion and potentially be painful (more on this). Most cases of forefoot varus get confused with the soft tissue version of forefoot supinatis (link). There is a good collection resources here on this issue and its importance.
Autism
Podiatrists have an interest in autism or the autistic spectrum disorders for a number of reasons. First those who have autism have foot problems that need to be treated, so they need to be familiar with the behaviors of those with autism. Secondly, toe walking is common in those with autism, so if a child presents with toe walking, this needs to be considered in the differential diagnosis of the toe walking.
Thirdly, with the general interest of any health professional on the public health they need to be aware of the vaccination issues and the nonsense about this being the cause of autism!
The analysis of the gait in autism can give important clues and can even be used to identify autism. The are plenty of disussions on podiatry websites about autism.
The Windlass Mechanism
The windlass mechanism of the foot has been getting more attention over recent years and its role in normal foot function and pathological foot function.
There are plenty of discussions on the windlass mechansim on the web (for example) and videos about it. The windlass mechanism is the way the foot can support itself, so if it is not functioning properly, a range of different conditions can occur. For more, see this.