Feasibility of First Metatarsophalangeal Joint Injections for Sesamoid Disorders: A Cadaveric Investigation

ObjectiveTo determine whether accurately placed first metatarsophalangeal joint (MTPJ) injections consistently deliver injectate to the metatarsosesamoid articulations.DesignProspective anatomic cadaver study.SettingProcedural skills laboratory at a tertiary care academic institution.ParticipantsFive unembalmed cadaveric lower limb specimens, free from trauma, surgery, or major deformity of the medial forefoot.MethodsUltrasound guidance was used to accurately inject the first MTPJs of each cadaveric specimen with diluted, blue-colored latex. At a minimum of 24 hours after injection, each specimen was dissected to determine whether the latex was present between the metatarsal head and sesamoid bones (metatarsosesamoid articulations).Main Outcome MeasuresThe presence or absence of latex within the first MTPJ and both the tibial and fibular metatarsosesamoid articulations.ResultsIn all 5 cadaveric specimens, ultrasound-guided first MTPJ injection accurately delivered latex into the first MTPJ. In addition, in each specimen, latex was seen between the metatarsal head and both the fibular and tibial sesamoid bones.ConclusionsAccurate first MTPJ injections reliably deliver latex to the articular surfaces of the metatarsosesamoid articulations. Clinicians administering diagnostic or therapeutic injections for patients with sesamoid disorders should consider injecting the first MTPJ as an alternative to direct metatarsosesamoid articulation injections.