Review Question - QID 215737

Figure A demonstrates an isolated distal metatarsal osteotomy. A distal metatarsal osteotomy (Chevron) in isolation is indicated for patients with a mildly increased HVA (15°-25°) in the setting of an IMA <12° and a DMAA < 10° (Answer 1).

Hallux valgus, or lateral deviation of the great toe, is a complex multifactorial deformation of the first ray. Pronation of the great toe drives the abductor hallucis further plantar. This leaves the medial capsular ligament and its associated medial capsulosesamoid complex as the only remaining medial structures. The adductor hallucis is able to act unopposed, which drives the great toe further into valgus, thereby attenuating the medial capsular complex, and allowing for medial drift of the metatarsal head. Furthermore, the flexor hallucis brevis, flexor hallucis longus, adductor hallucis, and extensor hallucis longus increase the valgus moment at the first MTPJ, which aggravates the deformity (Illustration A). Surgical treatment of hallux valgus is based on a number of factors including the HVA, IMA, the distal metatarsal articular angle (DMAA), and the hallux valgus interphalangeus (HVI).

Park et al. performed a randomized controlled trial comparing two approaches for distal soft-tissue procedures in the surgical management of hallux valgus. 122 patients who underwent a distal chevron osteotomy were randomized to one of two groups. 60 patients underwent a dorsal first-web space approach and 62 underwent a medial transarticular approach. Final clinical and radiographic outcomes did not differ between the two groups, although the authors did postulate that a medial transarticular approach is an efficacious approach for a concomitant lateral soft tissue release.

Fakoor and co-authors performed a retrospective review of patients treated for moderate hallux valgus deformity. They reported on 44 patients who underwent either a chevron, scarf or McBride procedure. They reported that patients who underwent a scarf procedure had a significantly greater correction in both the HVA and IMA when compared to the chevron and/or McBride procedures. They conclude that the scarf osteotomy should be the first surgical option chosen for patients with moderate hallux valgus.

Pentikainen et al. performed a comparative study investigating the preoperative radiographic characteristics which correlated with recurrence following surgical treatment of hallux valgus. They reported on 100 consecutive patients: 50 had a chevron osteotomy fixed with a bioabsorbable pin, and 50 received a chevron osteotomy with no fixation. They concluded that 73% of feet had radiological recurrence of hallux valgus, and that recurrence was associated with preoperative congruence, DMAA, sesamoid position, HVA, and 1-2 IMA.

Figure A demonstrates an AP radiograph of a left foot demonstrating a distal metatarsal osteotomy.
Illustration A demonstrates the pathologic cascade behind the development of hallux valgus.

Incorrect Answers:
Answers 2 and 4: This patient with an increased IMA would require a combined proximal and distal osteotomy.
Answer 3: This patient with an increased IMA and DMAA would require a combined proximal and biplanar distal osteotomy.
Answer 5: It is unlikely that a patient would have an HVA this high with a normal IMA. Generally, as the first toe deviates laterally, it drives the lesser toes with it, increasing the 1-2 IMA. Regardless, the increased DMAA would necessitate a double osteotomy.