Overview
Rheumatoid arthritis commonly affects the foot and ankle. Disease is usually bilateral and symmetrical, with the forefoot frequently affected early.
Forefoot deformity
Chronic MTP synovitis produces:
- MTP instability and dorsal subluxation
- Hallux valgus
- Lateral deviation of lesser toes
- Clawing or hammering of toes
- Distal migration of the plantar fat pad
- Painful plantar callosities
Hindfoot and ankle
Possible deformities include:
- Planovalgus from posterior tibial tendon dysfunction and ligament attenuation
- Subtalar arthritis
- Ankle arthritis
- Progressive hindfoot valgus
Assessment
- Pain and functional limitation
- Skin integrity and plantar callosities
- Flexibility of deformity
- MTP instability
- Hindfoot alignment
- Ankle and subtalar motion
- Neurovascular status
Obtain weight-bearing radiographs.
Non-operative treatment
- Optimise systemic disease control with rheumatology
- Wide toe-box footwear
- Orthoses and accommodative insoles
- Callus care
- Analgesia
Operative treatment
Surgery is based on the site of pain, severity of deformity and whether deformity is flexible or fixed.
Forefoot
Options include first-MTP arthrodesis, lesser-toe procedures and metatarsal-head procedures where appropriate.
Hindfoot
Corrective fusion procedures may be required for painful fixed deformity or advanced arthritis.
Principles
- Treat the whole foot rather than a single deformity in isolation.
- Preserve soft-tissue envelope and vascularity.
- Coordinate perioperative management of immunosuppressive medication with the treating team.
References
- Orthobullets. Rheumatoid Arthritis – Foot & Toe Conditions.