The abductory twist is an observation which is commonly seen when doing an observation of someones gait. Just as the heel begins to raise up the floor you often see a rapid sudden abduction or twist observed with the rearfoot. Even though it is a common observation during a gait evaluation, its clinical relevance is of some debate.
There are a variety of reasons for an abductory twist. One is that since the foot is pronating (moving medially at the rearfoot) this is trying to internally turn the leg. Simultaneously the other leg is in the swing phase going forward and is wanting to externally turn the lower limb. The lower limb is ‘battling’ with these two opposing forces. Friction between the floor and the rearfoot keeps the heel from moving. Immediately after load begins to come off the heel, the external rotation power from above can now abduct the rearfoot and it does so quickly. A second explanation is that there's a problem at the great toe joint in which it does not enable dorsiflexion correctly. This may be a hallux rigidus, a functional hallux limitus or a issue with the windlass mechanism which affects motion at the big toe joint. As that motion is difficult to start, the body abducts the rearfoot to maneuver sideways around that joint. A third explanation which is often only found in the physiotherapy literature is that the twist is as a result of control of movement around the hip joint. In that literature it is often described as a medial heel whip.
The primary reason for debate that goes on about the clinical relevance is that it is just an observation viewed during a gait assessment which is brought on by different things (ie, the loss of friction with the floor, an issue at the great toe or hallux joint or the hip joint). If it is a concern, then management is aimed at what is causing the abductory twist or medial heel whip and not aimed at the abductory twist per se. The treatment options to get rid of it is going to be very diverse contingent upon what is the best treatment choice for what's causing it. It is best to talk to a podiatrists about that and get some good advice.