The abductory twist is an observation during gait analysis. It is a rapid medial movement or abduction of the heel as it unweights during walking.

It is sometimes confused with a medial heel whip but they are different entities. A medial heel whip occurs later in the foot cycle and could be due to problems around the hip.

Causes

There are several causes of abductory twist. One of the most common is that something blocks motion at the first metatarsophalangeal (big toe) joint as the heel comes off the ground. This can be due to hallux rigidus (+/- osteoarthrtis) or functional hallux limitus or it can be caused by a high force that needs to be applied to get the windlass mechanism established and then that forces the foot to do everything it can to get around that block of motion at the big toe joint and that often results in an abductor-adductor twist at the heel.

Another cause of abductory twist is that there is excessive pronation at the foot. This causes the internal rotation moment from below to win and keep the foot pronated past the point where it should be supinating. This causes the foot to rely on the abductor-adductor twist to do its job and that can lead to strain.

Finally, it could also be that there is a problem somewhere else in the gait cycle. Some people like to claim that this is caused by functional problems proximal to the foot in the hip and pelvis but they are usually confusing it with what I and others call the medial heel whip which happens later on in the swing phase of the gait cycle and could be related to either overpronation or functional hallux limitus.

Symptoms

An abductory twist is an observation made during a gait analysis and occurs when there is a rapid medial movement of the heel as it unweights. It can be a sign of many things but is generally seen as a proximal cause and the solution to it is usually dealing with the hip and pelvis.

It can also be a result of other things blocking motion at the first metatarsophalangeal joint (the big toe joint) such as hallux rigidus (+/- osteoarthrtis), functional hallux limitus or high windlass forces at that joint. If that is the case then you will probably see that other muscles have to work much harder during the gait cycle and this can put strain on those other muscles.

Another potential symptom is the need to ‘kneel’ or lean back to support the other leg during walking and running. This is a compensation pattern and is likely to be due to the weakness in that tib anterior muscle that makes up the abductor digitorum longus.

It can be caused by other factors too such as hip weakness or poor core strength. The best treatment is often the simplest – a short period of time off loading the foot and then doing some exercises that can improve the strength and function of the abductor hallucis muscle. A physical therapist is best placed to guide this. Exercises that promote rotation of the body can also be helpful such as Russian twist (but always consult your doctor or fitness expert before trying any new exercise).

Diagnosis

The abductory twist is a pretty common observation that happens in gait. It is that sudden medial movement or abduction that occurs with the heel (calcaneus) as it comes off the ground and unweights. It is actually quite an easy observation to spot if you know what to look for. Some clinicians tend to confuse this with a medial heel whip which is what you get when there is an external rotation of the heel after it has come off the ground. It is important to understand that this does not require treatment as it is not a problem on its own. It is simply an observation and a sign of something else that does need treating.

For example, it could be that there is a functional hallux limitus that is blocking motion at the first metatarsophalangeal joint in this guy and he needs to circumduct the foot as it comes off the ground to get around that block. There is a number of interventions that can help him with this, such as foot orthotics or interventions aimed at eliminating the underlying cause of the block in motion at that joint. Those treatments will vary depending on what is causing that block in the first place, such as a muscle weakness or a structural abnormality such as a hallux rigidus or osteoarthritis.

Treatment

There is no single treatment for abductory heel twist. The muscle strain may heal on its own if the problem is not caused by something else that needs treating, for example a block in motion at the big toe joint or overpronation of the foot. The treatment of the underlying cause should be the main priority as this will likely prevent other problems from developing, such as knee pain, IT band syndrome or trochanteric bursitis.

A medial heel whip sometimes gets confused with an abductory twist, but it occurs later in the gait cycle and more like a circumduction of the whole foot as it comes off the ground.

Wearing shoes with proper arch support and cushioning can help relieve strain on the abductor hallucis muscle. Ice application several times a day can reduce inflammation and help with pain. If pain persists, over-the-counter nonsteroidal anti-inflammatory medication may be prescribed. Physical therapy exercises that improve foot strength, stability and flexibility can also relieve strain on the abductor hallucis. The goal is to avoid activities that overstress the abductor hallucis, such as running or jumping for extended periods. In some cases, orthotics or other corrective devices may be recommended to help correct any biomechanical issues that contribute to the problem. Surgery is rarely needed unless the abductor hallucis tendon has become torn.