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Rheumatoid disorders of the foot and ankle

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In the midfoot RA weakens the ligaments that support the midfoot causing collapse of the arch. Bony prominences can appear on the arch. Rupture of the tibialis posterior tendon can occur, and if it does, the talonavicular joint and subtalar joints sublux and the hindfoot drifts into valgus, leading to midfoot hyperpronation.  



Objective evidence

Radiological evidence

Radiological evidence

Radiographs may show soft tissue swelling, subchondral bone erosions, osteopenia, joint space narrowing, bony destruction, and the classic finding of peri-articular erosions. Osteopenia starts in the metaphyseal region underlying collateral ligament attachments and becomes more generalized as the disease progresses. Cartilage destruction produces narrowing of the joint. Mal-alignment, displacement, and ankylosis of the joint mark end-stage rheumatoid disease.



Lab evidence:

Synovial fluid: Aspiration and analysis of the synovial fluid is important for distinguishing RA from non-inflammatory and infectious arthrosis. The fluid in patients with RA will be sterile, with increased neutrophils and increased protein but decreased viscosity.


RA is the most common of the inflammatory arthritides affecting about 1% of people, with female: male ratio of 3:1. The peak incidence is at age 50, and symptoms most commonly develop between age 40 to 60.   


RA can be systemic. Consider the diagnosis of RA as a red flag to prompt an evaluation of for problems elsewhere. RA is a systemic disease that affects blood vessels, nerves, and tendons throughout the body. Patients with extra-articular manifestation are more likely to have a high RF titer, more severe disability, and increased mortality rate.

  • Heart: pericarditis, cardiomyopathy, valvular incompetence from rheumatoid nodules and interstitial fibrosis
  • Eyes: rheumatoid scleritis is the most common ocular complication of RA and generally indicates a poor prognosis, nodular scleritis is a more advanced stage, keratoconjunctivitis also seen.
  • Nervous system: mononeuritis multiplex, and peripheral compression syndromes such as median neuropathy, vasculitic neuropathy occurs in 10% of these patients and in half of these patients (5%), neuropathies are predominantly sensory, whereas others (5%) present with a slowly progressive, distal symmetrical sensory or sensory-motor polyneuropathy--these neuropathies appear in severe and long-standing rheumatoid arthritis;
  • Kidneys: amyloid deposition
  • Felty's syndrome: anemia, splenomegaly, and leukopenia;
  • Vasculitis: a non necrotising arteritis of the small terminal arterials, but occassionally taking the form of a fulminating arteritis, presentin as skin lesions, leg ulcers, necrotizing arteritis of the viscera, digital infarctions, and fever;
  • Sjogren's syndrome: occurs in about 15% of RA patients, due to infiltration of exocrine glands w/ lymphocytes
  • Increased risk for developing lymphoid malignancies;


Treatment options and outcomes


Risk factors and prevention

Risk factors include:include HLA-DR4 haplotype


; female gender; smoking history; and periodontal disease. While alone it has not been associated with increased risk of developing RA, obesity has been linked to poorer prognosis and response to treatment modalities, as reported by Rodrigues et al (PMID: 24489135). Therefore, it is suggested that patient’s attempt weight loss to optimize treatment success. 


Synovium is partially derived from from the word ovum, Latin for egg, because of the yolk-like consistency of synovial fluid.


Synovitis, morning stiffness, rheumatoid factor, ACPA, HLA-DR4, symmetrical polyarthritis, hyperpronation, claw  claw toes


How to diagnose RA vs other arthritides (for example osteoarthritis)—noting the key signs and symptoms that distinguish one from other.  Earlier diagnosis and earlier treatment can greatly improve the prognosis for the patient.recognize RA and distinguish it from osteoarthritis 

How to analyze synovial fluid and distinguish inflammatory vs non-inflammatory, and infectious vs non-infectious arthritides.