Intraoperative checking of the first ray rotation and sesamoid position through sonographic assistance

Abstract

Introduction Hallux valgus (HV) deformity afects the orientation of the metatarsophalangeal (MTP) joint in three planes. Displacement in the coronal plane results in axial rotation of the frst metatarsal, with progressive subluxation of the frst MTP joint. Multiple techniques have been described to correct the malrotation itself. However, none of them have checked intraoperatively the fnal position of the frst metatarsal head and sesamoids previous to the fxation of the Lapidus procedure or frst metatarsal bone osteotomies. The aim of this article is to describe a novel technique to check the frst ray rotation and sesamoids position through sonographic assistance. Materials and methods Before fxation of the Lapidus procedure, with the ankle in maximal dorsifexion, the surgeon takes the linear ultrasound probe and places it on the sole to visualize the sesamoids, which should be viewed at the same level, with the fexor hallucis longus (FHL) centered between both. Once the ideal position of the head of the frst ray has been achieved, temporary fxation with K-wires is performed over the frst TMT joint and M1–M2 joint for further sonographic verifcation of the sesamoids beneath the frst metatarsal head. The height of the sesamoids relative to the second metatarsal head should be checked by sonographic control too. Results Four patients were included. Three females and one male. Their mean age was 76.4 years (R 61–72). Their mean BMI was 29 (R 27.5–32.24). The mean IMA (intermetatarsal angle) was 18.2 (R 17.2–19) degrees and the mean MPA (metatarsophalangeal angle) was 50 (R 36–63) degrees. Conclusions Sonographic assistance, is a widely available, inexpensive, and comparative imaging technique that can guide the frst ray rotation and sesamoids position in HV surgery, theoretically improving radiological outcomes