The causes are multiple:
-This condition affects the female sex in more than 90 % of cases, most often around the age of 50, an age when hormonal impregnation changes due to the menopause: this would lead to hyperlaxity favoring the deformation of the big toe.
-In 30 % of cases, a family factor is found.
- Excess weight also favors the formation of hallux valgus.
-The morphotype of the foot is a key element that can explain the deformity of the big toe. Indeed, in 75 % of cases, hallux valgus is associated with an Egyptian morphotype corresponding to the case where the big toe is longer than the second toe.
With this morphology, the big toe is too long to be able to position itself normally in the shoe, in particular when it has a pointed toe: it is thus forced to deform itself by taking in width the place that it cannot take in length, hence the deformation in hallux valgus.
Conversely, the square foot (big toe the same length as the second toe) and the Greek foot (big toe shorter than the second toe) are much less likely to cause hallux valgus.
Moreover, one of the objectives of the surgery will be to obtain one of these two morphotypes when the pre-operative morphotype is Egyptian. In this way, the operation will eliminate a cause of recurrence.
-Hyperlaxity is not the only cause of the predominance of hallux valgus in women, since it is also caused by wearing shoes with pointed toes and/or high heels.

To provide immediate relief, open-toed shoes are recommended, or alternatively, soft, flat shoes.
Painkillers may also be prescribed in some cases.
A podiatrist can also help to counteract the deformity of the toes with orthoplastics. This is only possible at the very beginning of the deformity, as this technique is not effective on a deformity that has already been fixed.
Moreover, wearing orthopedic insoles can be relevant when the toes are already clawed and the joints are already in a pronounced inflammatory state. This allows to reduce the pressure on these joints and thus to reduce this type of pain.
These treatments are symptomatic and will not prevent the long-term deterioration of the patient's foot. The only effective solution is surgery.

If the so-called symptomatic treatments do not succeed in stopping the evolution of the deformities and pain, only surgery can truly cure hallux valgus.
The choice of technique is made with the practitioner. There are minimally invasive techniques, with incisions of a maximum of 2 centimeters, and percutaneous techniques, which involve making very small incisions, of the order of a millimeter.
The procedure is performed under local anesthesia. Sedation can be offered to the patient if desired. The patient can leave the hospital the same day.

Hallux valgus always evolves spontaneously towards self-aggravation, accompanied by pain when walking and putting on shoes, which increases, sometimes associated with a sensation of numbness of the big toe.
At the beginning of the evolution, the deformity of the big toe is isolated: the main reason for consultation remains the pain located opposite the exostosis, where one finds most often an inflammatory bursitis which can ulcerate and lead to an infection. In addition to the classic deformity, there may be a rotation disorder: the toe turns on itself, so that the nail no longer looks towards the zenith.
The deformity continues to evolve on its own, so much so that the hallux valgus ends up deviating the other toes laterally. This is how the 2nd ray syndrome appears, corresponding to the appearance of a claw on the 2nd toe pushed by the big toe which takes its place.
This deformity, initially limited to the 2nd toe, progressively extends to the entire forefoot.
The lateral toes retracted in the form of claws will come into conflict with the shoe, resulting in painful dorsal corns.
At the same time, under the effect of the claw, the metatarsophalangeal joint will subluxate or even dislocate, giving rise to metatarsalgia (pain when pressing on the metatarsal head).
It is always preferable to correct deformities when they are limited to the big toe, which simplifies the surgical procedure but also the postoperative course and reduces the recurrence rate.

The goal is to realign the big toe to restore its anatomy, and consequently its function, while keeping the metatarsophalangeal joint intact, unlike many surgical techniques that have been abandoned (or should be), which have given hallux valgus surgery a bad reputation for recurrence and iatrogenic metatarsalgia. Today, there is a reliable surgical technique that was developed at the end of the 1990s: it is based on osteotomies in the 1st metatarsal and the 1st phalanx.
To reduce the deformity of the big toe, it will be necessary to reduce the excessive gap between the 1st and 2nd metatarsals (reduction of the metatarsus varus). To do this, a Scarf osteotomy is performed, allowing the translation of the 1st metatarsal towards the 2nd metatarsal.
The second bone procedure will be performed in the 1st phalanx by an osteotomy, allowing to achieve three objectives:
- reduction of the phalangeal valgus (= deviation of the 1st phalanx) by cutting a wedge-shaped segment of bone
- a shortening of the 1st phalanx allowing, in the case of an Egyptian foot, which could be a source of postoperative recurrence if not corrected, to transform it into a square or Greek foot.
- a correction of a possible rotation disorder in the big toe, in order to obtain a nail looking towards the zenith in post-operation.
To be successful, this surgical treatment must be accompanied by a rigorous postoperative protocol, both for the resumption of support and for the treatment of edema and pain.

The minimally invasive and percutaneous techniques mentioned above are interesting, but more difficult to implement for the practitioner.

-Percutaneous surgery
This technique is only 15 years old in Europe. It is not specific to the treatment of hallux valgus nor is it systematic. As its name indicates, it is performed through the skin, with miniature burs introduced after making very small incisions with mini scalpels. The surgeon cannot directly visualize the operation. He has of course several tools to do so:
The first is fluoroscopy. It consists of using a very low-powered X-ray machine in order to make the exposure of the patient and especially of the surgeon completely acceptable. Of course, this technique only allows the visualization of bones. It is mainly a means of control for an experienced surgeon who can thus see the operated areas.
Le deuxième est l'utilisation par le chirurgien son toucher et de son ressenti. La contrepartie est donc que seuls des chirurgiens très expérimentés peuvent utiliser la technique d’intervention percutanée.
Obviously, when properly performed, it has only advantages. It is minimally invasive and allows a quick recovery after the operation.

-Minimally invasive surgery
Cette technique ne demande que des incisions inférieures à 2 centimètres. En revanche, le reste de l’opération est comparable à une chirurgie « classique », avec quelques entrées percutanées. L’ostéotomie en mini-chevron est par exemple une technique développée récemment qui permet de minimiser fortement la taille du champ opératoire.

The essential criterion is the level of pain that the patient complains of. For a similar deformity, the feeling of pain can be completely different from one person to another. When walking and shoeing become painful, it is essential to put the option of surgery on the table.
A hallux valgus cannot resolve itself, it will necessarily deteriorate more or less quickly and progressively evolve towards a self-deformation.
The earlier the surgery is performed, the more likely it is to permanently prevent recurrence and the less invasive it will be.
Indeed, the new techniques of intervention can be used, they are much less cumbersome and have postoperative consequences in general limited.

This technique appeared a few years ago and is increasingly used for hallux valgus. When properly performed, it offers many advantages. It consists of operating through the skin, making mini incisions just sufficient to pass miniaturized instruments.
Il n’est pas possible pour le chirurgien de voir directement ce qu’il réalise. Son toucher et son expérience vont être primordiaux. Néanmoins il dispose d’une technique complémentaire qui lui permet malgré tout d’avoir une vision sur le déroulement de l’opération : l’amplificateur de brillance par fluoroscopie.
Elle consiste à s’aider d'un appareil à rayon X très peu puissant mais qui permet de visualiser un élément clé dans le traitement de l’hallux valgus : les os. L’appareil est bien sûr qualifié et stérilisé, et son taux de rayons est suffisamment faible pour que les chirurgiens puissent l’utiliser very regularly without risk. Note that this technique is only an aid and an extension of the surgeon's feeling. Nothing can replace his know-how and experience.

Les intérêts de cette technique sont évidents : les incisions sont très réduites, les douleurs sont moindres et la récupération est plus rapide. Elle permet d’éviter une hospitalisation.

The techniques used in the past have tarnished the image of this type of surgery to treat hallux valgus. Mini-invasive techniques and advances in local anesthesia allow for operations with very little pain in the overwhelming majority of cases.
La sensibilité à la douleur n’étant pas la même selon les personnes, il n’est pas possible de garantir une intervention avec « zéro douleur ». Toutefois la pratique de cette intervention uniquement en ambulatoire est un signe que la gestion de la douleur post opératoire ne pose en général aucun problème sérieux.
The management of pain is done very seriously in spite of everything. The quality of the local anesthesia will of course make it possible to feel no pain during the operation, but its effects will last at least 12 hours, limiting the pain that would immediately follow the operation. It is in fact in these hours following the operation that the pain can reappear, and the fact of having a prolonged analgesia in the operated area makes it possible to reduce post-operation stress and anxiety.
This device is complemented by a special device that will help the patient manage any pain once they leave the hospital. In the past, the patient had to stay in the clinic with an infusion to get an electric syringe.

Now the patient has a single-use analgesic diffuser which, with the help of home nurses, allows the patient to return home as soon as possible. This has several important advantages. The patient can indeed
- Eat at home and sleep outside the clinic
- To be quiet compared to the noisy environment of a clinic
- Be surrounded by your loved ones without restriction.

When symptomatic treatment options are exhausted, the only option left is surgery. It is the only way to eradicate the cause and the pain. The technique to be used must be shared between the patient and the practitioner. There are several approaches. The first is the percutaneous technique, which leaves only almost invisible incisions, and the second is called mini-invasive, and will be performed with incisions limited to 2 centimeters.
The procedures are performed with local anesthesia and sedation (optional). The patient does not need to stay at the clinic in the evening, and can leave immediately after the procedure.

La chirurgie est dite mini invasive quand les incisions pratiquées sont de l'ordre de 2 centimètres. Toutefois les techniques employées à l'intérieur du pied restent similaires à la chirurgie dite classique.
Once the incisions have been made, the surgeon will carry out the operation. By performing osteotomies with specific instruments, most of which are inspired by the percutaneous technique.

Les techniques employées permettent de reprendre appui sur son pied juste après l’opération, avec l’aide d’une chaussure spécifique que le patient devra garder environ une semaine. La reprise d’appui doit se faire avec l’ensemble de la plante du pied. En effet, il ne faut pas marcher en appuyant sur le côté du pied ou sur le talon. Cela n’est pas forcément évident et beaucoup de patients vont instinctivement ne pas respecter cette consigne. Il est normal d’appréhender la reprise de la marche après l’opération ; aussi on préconise un protocole progressif pour rassurer les patients.
During the first week, walking is allowed but must be limited to what is strictly necessary. It is recommended not to leave your home. Treading and prolonged standing without walking should be avoided. When the patient sits or lies down, it is recommended to elevate the foot and leg.
The following week, the patient can walk outside the home, gradually. Walking periods should be limited to about 15 minutes, but should not exceed a total of two hours per day.
Augmenter progressivement sa quantité de marche en fonction de son ressenti. Il est conseillé d'abandonner définitivement la chaussure spéciale et de mettre une chaussure souple et plate comme des « baskets ».
L’arrêt de travail dépend de l’activité. Le travail peut être repris au bout de deux semaines dans les cas favorables. Il ne faut bien sûr pas que l’activité nécessite de beaucoup marcher ou de « piétiner » de manière répétitive. Dans le cas contraire, la période de convalescence devra être prolongée. En cas de reprise précoce du travail, il faut que la surélévation du pied soit possible quand le patient sera assis.
In general, as a precaution, the prescribed time off work is about three weeks.