Patients with longstanding gout may have masses of urate crystals deposited in soft tissue, cartilage and bone these are known as “tophi” (singular: tophus). The urate crystals also induce neutrophils to migrate to the joint, increasing the inflammatory process.
Once in the joint, these crystals induce synovial macrophages to produce inflammatory cytokines such as Interleukin-1 (IL-1). Gout occurs when uric acid (urate) crystallizes in the synovial lining of the involved joint. Gout is a painful arthritic condition that can affect any joint, but commonly involves the first MTP joint. In late stages, the extensor hallucis contracts, causing both extension and lateral deviation. In time, there is also lateral subluxation of the sesamoids. This subluxation of the abductor hallucis tendon pulls the hallux into pronation. and the proximal phalanx progressively moves laterally and the metatarsal medially the dorsomedial capsule attenuates and the abductor hallucis tendon slides under the metatarsal head. When there is a loss of congruence, the pull of muscles accentuates the deformity further. The MTP joint could remain congruent, but eventually can subluxate creating a non-congruent deformity. Beyond that, though, there is also a medial deviation of the first metatarsal along with soft-tissue enlargement of the first metatarsal head.
Thus, in hallux valgus there is a lateral deviation of the phalanx (towards the other 4 toes). A valgus deformity is one in which there is deviation at a joint such that the distal bone points away from the midline in the knee, for example, valgus produces a “knock-knee” configuration. Like hallus rigidus, which is named by one prominent feature, hallux valgus is also designated by one major finding (the valgus deformity of the MTP joint), though it actually comprises several. Of course, the signs and symptoms of the condition include all those of arthritis, not just the rigidity of the joint. This term is used to describe arthritis of the joint the name comes to mind because in the MTP joint the osteophytes growing from dorsal aspect of the first MT head impede motion (making the joint rigid) in a way that is not typically seen when osteophytes form near other joints around the body. In hallux rigidus, it is thought that overuse damages the joint surfaces and the nearby soft tissue surrounding the joint. Processes that can affect the first MTP joint include overuse wearing shoes that are too tight or ill-fitting trauma, autoimmune disease and deposition of uric acid crystals in the joint (gout). During athletic activities like jogging and running, these forces can approach two to three times body weight. The patella is probably the best-known sesamoid one of the carpal bones, the pisiform, is also a sesamoid, embedded within the tendon of flexor carpi ulnaris.)Īccording to Stokes et al., approximately 40% to 60% of body weight passes through the first MTP joint and great toe during normal gait (PMID:498650). By so doing, the sesamoid thereby increases the force the tendon applies, by lengthening its so-called 'lever arm'. (A sesamoid bone is one that lives within a tendon its function is to increase the distance between the tendon and the center of the joint. There are three joints of the great toe: the first metatarsophalangeal (MTP) joint, namely, the articulation between the metatarsal head and the proximal phalanx the interphalangeal (IP) joint between the proximal and distal phalanges and the articulation between the plantar aspect of the metatarsal head and the sesamoids, the two small bones embedded in the flexor hallucis brevis tendon. Disorders of the great toe (the hallux, in medical terminology) include degenerative arthritis ( hallux rigidus), bunions ( hallux valgus), gout and traumatic conditions (such as sesamoiditis or turf toe).
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