The Rheumatoid Foot and Ankle

• Foot involvement is the initial RA presentation in 15-20 percent of patients
• Forefoot symptoms affect 70-80 percent of RA patients at 10-year follow-up
• Hindfoot valgus affects 30-50 percent of established RA patients
• Ankle arthritis is less common than forefoot/hindfoot but produces most disability
• Women are affected 2-3 times more often than men, with seropositive disease carrying the highest foot burden

• Forefoot pain is the leading cause of walking disability in RA
• Plantar callosities and ulceration occur over prominent MT heads in long-standing disease
• Footwear modification fails once fixed MTP dislocation is established
• Fall risk rises with hindfoot valgus and ankle arthritis
• Quality of life scores (HAQ, AOFAS) drop sharply with bilateral hindfoot disease

Synovitis is the upstream driver - pannus, cytokines (TNF-alpha, IL-6, IL-17), and erosive enzymes destroy cartilage and ligament

Plantar plate attenuation at the MTP is the single most important step in forefoot collapse

Tibialis posterior tenosynovitis is the driver of hindfoot valgus; it is present on ultrasound in 30-50 percent of RA feet

Tendon subluxation - FDL slips dorsally, becoming a dorsiflexor of the PIP and plantarflexor of the DIP (clawing)

Marginal erosions appear at the MT head and PIP joint first - they are the radiologic hallmark of RA

Moth-eaten subchondral bone in established disease (versus the sclerotic pattern of OA)

Juxta-articular osteopenia differentiates RA from the subchondral sclerosis of OA

Cyst formation in advanced disease, occasionally leading to pathological fracture of the MT head

• Pain location: Forefoot (most common) vs hindfoot vs ankle
• Duration of disease: Longer disease increases deformity and disability
• DMARD/biologic regimen: Methotrexate, anti-TNF, rituximab, JAK inhibitors
• Surgery history: Previous forefoot, hindfoot, hip or knee arthroplasty
• Footwear: Inability to tolerate off-the-shelf shoes signals severe deformity
• Ulceration: Current or recurrent plantar callosities

• Forefoot: MTP synovitis, dorsal subluxation, fixed vs flexible claw, hallux valgus angle
• Callosity pattern: Plantar MT heads (lesser toes) and medial first MT (hallux valgus)
• Hindfoot: Heel valgus, single-leg heel raise, too many toes sign, sinus tarsi tenderness
• Ankle: Tibiotalar line, ROM, tibiotalar vs subtalar pain on exam
• Skin and nails: Capillary refill, prior ulceration, onychomycosis
• Gait: Antalgic, externally rotated, vaulting over a stiff ankle

• RA prevalence is 0.5-1 percent worldwide, with seropositive disease carrying the highest foot burden
• Foot involvement occurs in 90 percent of patients at some point, with forefoot the most common site
• Racial variation is modest, but South Asian and African ancestry show more severe erosive disease
• Disease duration correlates strongly with foot deformity; deformity is rare in the first year but common after 5-10 years

• High-resource: combination biologic/DMARD therapy has reduced severe deformity; reconstruction is the dominant surgical workload
• Limited-resource: presentation with end-stage deformity is more common; off-the-shelf rocker-sole footwear and palliative Fowler-style surgery are the mainstay
• Universal principle: liaison with rheumatology to optimise DMARDs and biologics before surgery is the single biggest determinant of wound and infection outcomes

Modern third-generation TAA designs give 90 percent survivorship at 5-10 years in low-demand RA patients and preserve adjacent joint motion. Arthrodesis is more reliable in young, high-demand, heavy labourers and in severe deformity. There is no head-to-head randomised trial; choice is pragmatic and patient-led.

Continuation of methotrexate is supported by randomised evidence showing lower infection rates than withdrawal. Anti-TNF agents are typically held for one dosing cycle; the evidence for IL-6 inhibitors and JAK inhibitors is thinner. Always liaise with rheumatology rather than follow a single protocol.

Single-stage bilateral Fowler plus 1st MTP arthrodesis is described and accelerates recovery, but carries a higher wound and VTE risk. Most surgeons stage bilateral cases 3-6 months apart, particularly on biologics or in patients with poor soft tissues.

In RA, isolated talonavicular fusion is appealing because it preserves subtalar motion, but adjacent STJ arthritis is common and triple arthrodesis is more reliable long term. Decision is based on imaging, symptoms and the patient's age and demand.