Mastering The Technical Approach To The Scarf Bunionectomy
The European approach to the bunion commonly involves the scarf bunionectomy, much more so than here in the United States. Of the many bunion approaches, why should we bother adding another to the list? Those who utilize the scarf approach understand the stability, power of correction and utilitarian nature of this bunionectomy choice. I use the scarf as one of my go-to procedures for correcting mild to severe hallux abducto valgus.
During my foot and ankle surgical fellowship in Columbus, Ohio, I was fortunate to spend time with a “traveling” surgeon offering his European expertise regarding the scarf bunionectomy. His influence was borne out of his training, his own surgical practice and the second edition of Forefoot Reconstruction by Louis-Samuel Barouk, MD.1 This is a well-written basis for approaching the common first ray deformity with the scarf. I have referenced it multiple times in my attempt to master the scarf bunionectomy and it has served me well.
One should approach the scarf bunionectomy as a step-wise procedure.
The chronological steps include:
1) Lateral release of the metatarso-sesamoidal phalangeal complex
2) Scarf first metatarsal osteotomy
3) Medial soft tissue tightening
4) Akin phalangeal osteotomy
Releasing The Metatarso-Sesamoidal Phalangeal Complex
The first step of the bunionectomy is the metatarso-sesamoidal phalangeal complex lateral release. Even in more mild cases, one still does this step to ensure appropriate balancing and lasting correction. There are two goals with the lateral release.
1) Detaching the sesamoids from the first metatarsal head. The sesamoids are typically in the same relationship to the second metatarsal throughout the course of the deformity. By releasing the sesamoids from the first metatarsal head, the first metatarsal head, once cut, can shift back directly over the sesamoids.
2) Avoiding overcorrection. This occurs by leaving the metatarsophalangeal collateral ligament uncut. This will allow correction yet prohibit the hallux from varus.
Although one can perform the release from the medial aspect of the joint, I prefer the lateral intermetatarsal approach. This allows unmatched visualization of the anatomy. It also allows for access to the second metatarsal head, when necessary, through a shared incision.
One would make the incision longitudinally in the intermetatarsal region. Finger or blunt dissect to the metatarso-sesamoidal phalangeal complex. Palpate the sesamoid and transect the sesamoidal suspensory ligament. This allows visualization of the superior surface of the sesamoid. The next move is to release the proximal insertional band off the proximal phalanx. This allows the hallux to derotate and removes the lateral directed tension. In mild cases, one can skip this step but I recommend this step for moderate and severe cases. This is typically all that is necessary to release the sesamoids and hallux sufficiently. It is important to leave the lateral collateral ligament intact to prevent hallux varus. Lastly, if the sesamoid is arthritic and adherent, the surgeon should remove it.
Key Pearls On Performing The Scarf Osteotomy
The second step is the osteotomy itself. Making two interlocking chevron cuts increases the scarf’s stability. The shift can correct for the intermetatarsal angle and one can rotate in several directions, allowing versatility. The surgeon can also correct for shortening and lengthening with the osteotomy.