(See also Overview of Foot and Ankle Disorders.)
Contributing factors may include excessive foot pronation, wearing tight and pointed-toe shoes, and occasionally trauma. 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. In reaction to pressure from tight shoes, an adventitious bursa can develop medial to the joint prominence, which can become painful, swollen, and inflamed (see figure Bunion).
The initial symptom of bunion may be pain at the joint prominence when wearing certain shoes. The joint capsule may be tender at any stage. Later symptoms may include a painful, warm, red, cystic, movable, fluctuant swelling located medially (adventitial bursitis) and swellings and mild inflammation affecting the entire joint (osteoarthritic synovitis), which is more circumferential. With hallux limitus or rigidus, there is restriction of passive joint motion, tenderness at the dorsolateral aspect of the joint, and increased dorsiflexion of the distal phalanx.
Clinical findings are usually specific. Acute circumferential intense pain, warmth, swelling, and redness suggest gouty arthritis or infectious arthritis, sometimes mandating examination of synovial fluid. If multiple joints are affected, gout or another systemic rheumatic disease should be considered.
If clinical diagnosis of osteoarthritic synovitis is equivocal, x-rays are taken. Suggestive findings include joint space narrowing and bony spurs extending from the metatarsal head or sometimes from the base of the proximal phalanx. Periarticular erosions (Martel sign) seen on imaging studies suggest gout.
Mild discomfort may lessen by wearing a shoe with a wide toe box or with stretchable material. If not, bunion pads purchased in most pharmacies can shield the painful area. Orthotics can also be prescribed to redistribute and relieve pressure from the affected articulation. If conservative therapy fails, surgery aimed at correcting abnormal bony alignments and restoring joint mobility should be considered. If the patient is unwilling to wear large, wider shoes to accommodate the bunion because they are unattractive, surgery can be considered; however, patients should be told that orthotic devices should be worn after surgery to reduce the risk of recurrence.
For bursitis, bursal aspiration and injection of a corticosteroid are indicated.
For osteoarthritic synovitis, oral nonsteroidal anti-inflammatory drugs (NSAIDs) or an intra-articular injection of a corticosteroid/anesthetic solution reduces symptoms.
For hallux limitus or hallux rigidus, treatment aims to preserve joint mobility by using passive stretching exercises, which occasionally require injection of a local anesthetic to relieve muscle spasm. Sometimes surgical release of contractures is necessary.
Excessive turning in (supination) of the ankles, wearing tight and pointed-toe shoes, and occasionally trauma increase the risk of prominences at the medial 1st metatarsal joints (bunions).
Symptoms can include pain, synovial or cystic swelling, and limitation of passive joint motion.
Use clinical findings to confirm the diagnosis.
Treat initially with a wide or expansile toe box, bunion pads, orthotics, or a combination.