Erosive osteoarthritis (EOA)

• erosive osteoarthritis
  • believed to be a clinically uncommon subset of generalized osteoarthritis (OA)
    • characterized by a clinical course, which is frequently aggressive - erosive osteoarthritis is a distinct clinical entity from primary generalised nodal osteoarthritis
  • this condition is also known as inflammatory osteoarthritis
  • clinical features:
    • diagnosis based on the radiographic aspects of articular surface erosions
    • clinical features may lead to a suspicion of EOA. These include:
      • abrupt onset of pain, swelling, redness, warmth and limited function of IP joints of the hands are commonly found in most patients
      • throbbing paresthesias of the fingertips, which are often nocturnal
      • evolution in nodal deformities of distal IP (DIP) and proximal IP (PIP) may be seen to follow a variable course with no significant differences from non-EOA - with the exception of a more accelerated progression for EOA
  • radiological features:
    • classic radiological changes of EOA are characterized by a combination of bony proliferation and erosions
      • characteristic erosions are seen in DIPs and PIPs
        • most frequent lesions begin at the central portion of the joint in the form of a sharply marginated defect, usually preceded by joint narrowing
      • joint narrowing and erosions may be seen early in EOA, while only later are margins affected by bone proliferations leading to Heberden's and Bouchard's nodes
  • diagnosis:
    • diagnosis of EOA was accepted only for patients meeting American College of Rheumatology clinical criteria of OA of the hand and showing radiographic aspects of articular surface erosions - there is debate as to how many erosions need to occur for a diagnosis of EOA - some suggest that two erosions in two different IPs may be sufficient to be classified as EOA
  • conditions to be considered in the differential diagnosis include primarily nodal generalized OA, psoriatic arthritis and rheumatoid arthritis
    • possible to find erosive changes resembling EOA in endocrine diseases, microcrystal-induced diseases, chronic renal diseases, autoimmune diseases and others
  • laboratory features:
    • CRP levels are higher in erosive osteoarthritis than in non-erosive osteoarthritis patients. These levels probably reflect the disease activity of erosive osteoarthritis, as suggested by correlations between CRP and joint count at clinical observation and at bone scintigraphy (2)
    • EOA patients are rheumatoid factor negative and negative for anti-CCP antibodies
  • management
    • no definitive therapeutic approach to EOA has been reported
      • reasonable to assume that in the presence of a symptomatic EOA our therapeutic approach should differ from that used for common, nodal, non-EOA (1)
        • paracetamol is the drug of first choice in EOA - however this drug is frequently inadequate, and treatment must therefore be shifted toward non-steroidal anti-inflammatory drugs (NSAIDs)
        • intra-articular injections of corticosteroids may bring some symptomatic relief although there is no demonstration that such therapy may reduce the development of erosions or accelerate their healing
        • other possible therapeutic measures include:
          • hydroxychloroquine - there is study evidence for the efficacy of this therapeutic option in EOA
          • chondroitin sulfate

Reference:

1. Punzi L et al. Erosive osteoarthritis. Best Pract Res Clin Rheumatol. 2004 Oct;18(5):739-58
2. Punzi L et al. Value of C reactive protein in the assessment of erosive osteoarthritis of the hand. Ann Rheum Dis. 2005 Jun;64(6):955-7.
3. Punzi L et al.L. Value of synovial fluid interleukin-1 beta determination in predicting the outcome of psoriatic monoarthritis. Ann Rheum Dis. 1996 Sep;55(9):642-4.