In rheumatoid arthritis of the foot, the first metatarsophalangeal (MTP) joint develops a characteristic deformity of:

• A Hallux rigidus with dorsal osteophyte formation
• B Claw toe with MTP hyperextension and IP flexion
• C Hallux valgus with lateral deviation of the great toe ✓
• D Hammer toe affecting the 2nd and 3rd toes only

Explanation

In rheumatoid arthritis, synovial pannus destroys the first MTP joint capsule and collateral ligaments, combined with forefoot valgus. The result is hallux valgus (lateral deviation of the great toe) — often severe — with subluxation of the MTP joint. Lesser toes develop hammer toe or claw toe deformities due to intrinsic muscle weakness and extensor mechanism imbalance. The sesamoids are displaced laterally. Metatarsal heads become exposed plantarly, creating painful callosities. This distinguishes RA foot from primary hallux valgus (biomechanical/genetic) and hallux rigidus (first MTP OA).

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.