Point-Counterpoint: Is A Lateral Release Necessary For Hallux Valgus Correction?
Surgeons have always considered release of the soft tissues about the lateral aspect of the first metatarsophalangeal joint (MPJ) to be an integral component in the correction of hallux valgus deformity.
There are many available techniques including an intracapsular release through a medial skin incision and a more traditional extracapsular release through either a separate lateral incision or the more standard dorsal incision. These approaches share a number of common components.
Typically, the surgeon frees the common adductor tendon (both transverse and oblique heads) from its insertion into the base of the proximal phalanx and fibular sesamoid, and severs the fibular sesamoidal ligament. One may or may not perform a lateral capsulotomy. On rare occasions, one may excise the fibular sesamoid. Additionally, transfer of the adductor tendon to the medial capsule or into the metatarsal neck is an option. Gaining surgical access to these structures from dorsal incisions also requires transection of the intermetatarsal ligaments.
Hallux valgus is a deformity in which the great toe laterally deviates or subluxes at the MPJ with the sesamoid visible in the interspace. Current concepts about the development of a bunion are predicated upon the unlocking of the MPJ in the pronated foot with the intrinsic lateral musculature, acting through the fibular sesamoid and pulling the toe into an abducted position. This creates a retrograde pressure that forces the metatarsal into adductus. It would appear to be intuitive to eliminate these lateral forces in order to correct a bunion and prevent its recurrence. Therefore, any effective lateral release should include the adductor tendons as well as the conjoined tendon of the fibular sesamoid. While logical, this remains a theory that has not been proven.
What You Should Know About The Sesamoids In Hallux Valgus
However, in the past decade or so, it has become accepted as fact that the sesamoids remain stationary in hallux valgus deformity. The prominence of the fibular sesamoid in the interspace and malalignment of the tibial sesamoid position are not the result of lateral drifting of the sesamoid complex, but of medial deviation of the first metatarsal. In fact, the sesamoids remain in their normal anatomic position throughout the development of hallux valgus deformity.
Coughlin and Mann as well as Jahss and Alvarez have commented on the fixed position of the sesamoids.1-3 Judge and co-workers published a multicenter review of hallux valgus surgery via Austin bunionectomy with an interspace release.4 One radiographic parameter they measured was the distance from the medial edge of the tibial sesamoid to the bisection of the second metatarsal shaft. They reported that this distance did not alter between pre-op and post-op X-rays. The authors concluded that the position of the sesamoids is fixed and the correction of hallux valgus should focus on moving the first metatarsal over the sesamoids.
Therefore, if we were to look for a baseline or normative structure to assess both the extent of deformity and degree of correction, it would be the relationship of the first metatarsal to the sesamoid complex. The sesamoid station is not affected by structure or mechanics, and this should be the standard by which we measure hallux valgus.
The hallux is intimately invested into the sesamoid apparatus via the plantar plate. This thick, dense fibrocartilaginous structure links the base of the proximal phalanx to the sesamoids. A study by Tanaka and colleagues looked at the relationship of the first metatarsal, second metatarsal and hallux in normal feet and those with hallux valgus, and confirmed this anatomic relationship.5 The authors demonstrated that with increasing degrees of metatarsus primus varus, the hallux did not drift medially with the first metatarsal but maintained its proximity to the second metatarsal and therefore the sesamoids as well.
“The base of the proximal phalanx in the hallux valgus foot was located on the same point as in the normal foot,” concluded Tanaka and colleagues.5 The authors concluded that hallux valgus is due to metatarsus primus varus and correction should include a lateral transfer of the metatarsal head.