The hallux valgus interphalangeus is a deformity of the great toe. As for the hallux valgus, the great toe is deviated laterally towards the other toes. However, unlike hallux valgus, the cause of the deformity is located in the toe itself and not in the first metatarsal.
The hallux valgus interphalangeus is the direct consequence of an anatomical abnormality of the first phalanx (P1) of the great toe. Without deformity, the base and the head of P1 are parallel. In case of hallux valgus interphalangeus deformity, the base and the head aren’t parallel anymore.
This situation is purely of an anatomical nature. There is no other described cause of hallux valgus interphalangeus.
Nonetheless, it might be associated with other diseases like the usual hallux valgus. It is thus important to be diagnosed in order to treat it appropriately.
A hallux valgus interphalangeus is the most often without consequence. However, when it becomes pathologic, a deviation of the great toe’s last phalanx expresses on the great toe itself or on the 2nd toe.
On the great toe it sometimes comes with a callus on the interphanlangeal joint with the same mechanism that in claw toes, but in this case on the medial side of the joint.
The other consequence occurs on the 2nd toe, whose space is occupied by the deviated great toe. It causes a claw of the 2nd toe, particularly in case of greek forefoot.
As always it is best to avoid surgery. On this purpose, the choice of shoes is oriented towards spacious and flexible models in order to limit the conflict.
The podiatrist can also make a silicone orthoplasty. This small custom made mold is placed in the shoes around the toes. It aims to reduce conflicts between the toes and the shoe.
The surgical principles are very simple: restore the parallelism between the base and head of the great toe’s first phalanx. A bone cut (osteotomy) and removal is required to correct the phalanx’ axis. It’s called a closing wedge varisation osteotomy.
The correction has to to be fixed with hardware, usually a metallic screw, in order to allow an immediate secure full weight-bearing.
Percutaneous surgery is a particularly well-adapted procedure for this pathology. It requires two millimetric scars to cut the bone and insert the fixation screw under fluoroscopic control (peroperative X-ray solution). Thanks to the screw’s implantation, full weight-bearing is allowed immediately after surgery with non-medical usual shoes.