musculoskeletal and connective tissue disorders
Bunion
Introduction
Bunion is a prominence of the medial portion of the head of the first metatarsal bone. The cause is often variations in position of the first metatarsal bone or great toe, such as lateral angulation of the great toe (hallux valgus). Laxity at the first tarsometatarsal joint allows the metatarsal to rotate in the frontal plane, which causes the hallux to deform in the transverse plane and angulate laterally. Secondary osteoarthritis and spur formation are common. Symptoms may include pain and redness, bursitis medial to the joint, and mild synovitis. Diagnosis is usually clinical. Treatment is usually a shoe with a wide toe box, protective pads, and orthotics. For bursitis or synovitis, corticosteroid injection may be helpful. Surgical intervention may be considered for refractory pain and difficulty with ambulation. (See also Overview of Foot and Ankle Disorders .) Contributing factors may include excessive foot pronation, wearing tight and pointed-toe shoes, and occasionally trauma or a genetic predisposition. Joint misalignment causes osteoarthritis with cartilage erosion and exostosis formation, resulting in joint motion being limited (hallux limitus) or eliminated (hallux rigidus). In late stages, synovitis occurs, causing joint swelling. Tight footwear can exacerbate symptoms, and an adventitious bursa can develop medial to the joint prominence, which can become painful, swollen, and inflamed (see figure). A bunion (hallux valgus) is a lateral deviation of the hallux (first toe) on the first metatarsal. 