the hallux is called the great toe due to its large size and importance in weight bearing. Comprising a distal and proximal phalanx, the hallux articulates with the first metatarsal (FIGURE 1) to form the first MTP joint. The joint is reinforced with collateral ligaments, a plantar plate, the plantar fascia, and 2 sesamoid bones.The sesamoids sit just proximal to the joint beneath the head of the first metatarsal. Encased within the flexor hallucis brevis tendons, the sesamoids distribute weight and provide leverage essential for increasing the torque production of the attached intrinsics.Additionally, the flexor hallucis longus tendon passes between the sesamoids and inserts on the distal phalanx of the hallux.Stiffness of the joint tissues combines with the tensile action of the plantar fascia to counter the external loading forces that dorsiflex the hallux during gait. Approximately 50° of first MTP joint motion is required for walking, whereby the hallux serves as the fulcrum of forward propulsion. The first MTP joint is condyloid in design, and allows the hallux freedom to rotate in the sagittal and transverse planes, while simultaneously constraining it from rotating independent of the first metatarsal in the frontal plane.As deformity progresses, overpronation culminates in rolling the first metatarsal off the sesamoids. The hallux follows, turning onto its side.This inclines the first MTP joint axis, which redirects motion away from the sagittal and toward the transverse plane.Weight now borne on the medial aspect of the hallux (FIG-URE 2) contributes a lateral push. The sequelae of events also lengthen or shorten the attached muscles, thus reducing their ability to produce or sustain force.Without adequate support from the muscles, the hallux and sesamoids may sublux or even dislocate. This releases tension from the plantar fascia. Should the plantar fascia fail and the arch collapse, surgery becomes the only viable option for treatment. Unfortunately, surgery does not always solve the problem, as the rate of recurrence is almost 15%
The first ray is the proximal member of the first MTP joint. Comprising the first metatarsal and first cuneiform, the first ray behaves as a single segment, because the metatarsocuneiform joint surfaces interlock and the first metatarsal moves independent of the second metatarsal and navicular about its own axis.The joint union is reinforced with a plantar ligament and by surrounding muscles (FIGURE 2). Irrespective of the anatomic design, the first ray may become unstable due to trauma, in arthritis disease states, with hallux valgus,or with generalized joint laxity
Stress testing is performed in clinical practice to screen for instability. However, subjectivity in the delivery of force and the assessment of motion may account for the wide range (10%-64%) of instability reported in patients with hallux valgus.Despite the discrepant range of reported cases, instability of the first ray is associated with and possibly precursory to the formation of deformity.Therefore, exercises that strengthen the muscles that support the first ray and hallux (FIGURE 3) may delay the onset and progression of hallux valgus deformity