Croatian rotatory oblique three-dimensional osteotomy (CROTO) - a modified Wilson's osteotomy for adult hallux valgus intended to prevent dorsal displacement of the distal fragment and to reduce shortening of the first metatarsal bone.

Aim To evaluate biomechanical and clinical outcomes of a newly developed modification of the Wilson's osteotomy for hallux valgus: a three-dimensional subcaptial correction of the metatarsal head position with a simultaneous lateral and plantar shift with derotation intended to reduce displacement of the distal fragment and shortening of the first metatarsal bone. Methods Thirty four feet (28 female patients) underwent the new procedure and were evaluated before and 12 to 84 months (median=25.5) after the surgery. Results Plantar shift of the distal fragment was achieved in all feet. Shortening of the first metatarsal was moderate: ≤6 mm in 32/34 feet, 7 and 10 mm in the remaining two. Median difference in metatarsal index post- vs. pretreatment was -4.0. The hallux valgus angle, intermetatarsal and distal metatarsal articular angles were reduced in all feet. The American Orthopaedic Foot and Ankle Society score improved in all feet (median increase= 51.5). Conclusion The method allows for a lateral and plantar shift with derotation of the distal fragment and a mild/moderate shortening of the first metatarsal bone.