Iatrogenic second transfer metatarsalgia and the first metatarsal shortening and elevation after Scarf osteotomy.

BACKGROUND

Transfer metatarsalgia is a potential complication of hallux valgus surgery. This study aimed to investigate the shortened first metatarsal length and elevation and to compare groups with and without second transfer metatarsalgia after Scarf osteotomy.

METHODS

The first metatarsal length of 123 feet was measured via the Maestro's method using the metatarsal axial length and the relative second metatarsal protrusion to the first metatarsal. Metatarsal elevation was measured using the first metatarsal angle.

RESULTS

Second transfer metatarsalgia occurred after Scarf osteotomy in 11 (8.9%) feet. When baseline characteristics were considered in propensity score matching, the 11 feet were compared with the 33 feet in the control group. The group with transfer metatarsalgia showed a more shortened first metatarsal axial length (-4.1 ± 1.8 mm vs. -2.5 ± 2.2 mm, p = 0.032), a significantly longer relative second metatarsal protrusion (+5.8 ± 2.6 mm vs. +1.2 ± 2.6 mm, p < 0.001), and a significantly lower first metatarsal angle (18.1 ± 4.3° vs. 21.5 ± 4.0°, p = 0.012) than the control group postoperatively.

CONCLUSIONS

To avoid iatrogenic transfer metatarsalgia, first metatarsal length shortening should be minimized to at least less than 4.0 mm. Furthermore, the metatarsal parabola should be retained.