The first MTP joint is the most load-bearing small joint in the body, sustaining forces up to 120 percent of body weight during quiet standing and up to 800 percent during running. The sesamoids within the FHB insertion distribute this force and protect the underlying tendons. Hallux valgus, the most common foot deformity, involves progressive lateral deviation of the great toe and medial deviation of the first metatarsal at this joint. Gout preferentially affects this joint in its classic podagra presentation.
Gout characteristically presents as acute monarticular arthritis at the first MTP joint (podagra) from urate crystal deposition in the joint fluid. The sesamoid complex injury, turf toe, from hyperextension of the first MTP joint produces a plantar plate and sesamoid ligament injury that can cause significant functional impairment in athletes. Hallux rigidus from first MTP joint osteoarthritis produces progressive dorsiflexion limitation managed with joint debridement or arthrodesis.
Plantar plate and sesamoid ligament injury from first MTP hyperextension producing plantar pain and instability in field athletes on artificial turf, managed with rigid insole support and progressive rehabilitation.
First MTP osteoarthritis producing progressive dorsiflexion loss and pain during push-off, managed with joint debridement (cheilectomy) or arthrodesis for advanced degeneration.
