Osteoarthritis

• Crepitus = crackling sound or sensation when joint is moved
• Characteristics on XR (LOSS):

  • L - Loss of joint space
  • O - Osteophytes (bone spurs)
  • S - Subarticular sclerosis (increased density of bone at the joint)
  • S - Subchondral cysts (fluid-filled holes in the bones)
• Osteoarthritis occurs in synovial joints and results from genetic factors factors, overuse and injury
• Osteoarthritis is thought to result from an imbalance between cartilage damage and the chondrocyte response, leading to structural issues in the joint.
• Chondrocytes are responsible for maintaining the homeostasis between synthesis and degradation of the extracellular matrix within articular cartilage.
• Over time, continuous ‘wear’ or trauma to the joint causes local inflammation and stimulation of chondrocytes to release degradative enzymes. These enzymes break down collagen and proteoglycan and ultimately destroy the articular cartilage.
• Over time, the cartilage thins leading to exposure of the underlying subchondral bone. This causes subchondral sclerosis and the continuous remodelling of subchondral bone forms subchondral cysts and osteophytes. This eventually leads to a progressive loss of joint space.
• There is no single cause for osteoarthritis, however, the following risk factors are associated with an increased likelihood of developing the condition:

  • Increasing age
  • Female sex
  • Obesity
  • Less commonly, articular congenital deformities or trauma to the joint
• Typical symptoms of osteoarthritis include:

  • Joint pain
  • Stiffness: typically, worse after activity and at the end of the day
  • Limitation in day-to-day activities
• In some cases, patients will experience referred pain. For example, in a patient complaining of pain in their lower spine or knee, the pain could be arising from the hip.
• The symptom of joint stiffness can be used to differentiate non-inflammatory arthropathies such as osteoarthritis from inflammatory arthropathies such as rheumatoid arthritis.
• In inflammatory arthropathies, joint stiffness improves with activity and stiffness typically lasts longer than 30 minutes in the morning.
• Typical clinical findings in osteoarthritis include:

  • Reduced active and passive range of movement (secondary to pain)
  • Tenderness over the joint lines
  • Crepitus on movement
• Typical clinical findings in the hands include:

  • Sparing of the metacarpophalangeal joints (knuckle)
  • Bouchard's nodes - PIP joint
  • Heberden's nodes - DIP joint
  • Squaring at the base of the thumb - CMC joint
  • Reduced functional movement (e.g. reduced grip strength)
• Diagnosis of OA can be made without the need for investigations if thepatient is over 45 years and has no morning stiffness (NICE)
• Relevant bedside investigations include:

  • Bodyweight and body mass index: obesity is a risk factor for lower limb osteoarthritis and may also aid the development of a management plan
• Relevant laboratory investigations include:

  • Serum CRP/ESR: if an inflammatory arthropathy is suspected, inflammatory markers should be requested. CRP and ESR are typically normal in osteoarthritis.
• Relevant imaging investigations include:

  • X-ray of affected joints: the most common imaging modality to assess the presence and severity of osteoarthritis
• Current NICE guidelines advise that osteoarthritis can be diagnosed clinically if a person meets the below criteria:

  • ≥ 45-year-old and
  • has activity-related joint pain and
  • has either no morning joint-related stiffness or morning stiffness that lasts no longer than 30 minutes
• Conservative management is the first-line treatment for osteoarthritis. NICE recommends the following:

  • Education and advice about their condition
  • Exercise: both muscle strengthening and general aerobic fitness
  • Weight loss (if overweight or obese)
• Medical management involves the prescription of analgesics in a stepwise approach and is commonly used alongside conservative management:

  • First-line: topical non-steroidal anti-inflammatory drugs (NSAIDs)
  • Second-line: paracetamol and topical analgesia
  • Third-line: NSAID, paracetamol and topical capsaicin
  • Fourth-line: opioid, NSAID, paracetamol and topical capsaicin
• Intra-articular corticosteroid injection can be offered for acute exacerbation of pain despite regular use of analgesia. Typically, these are performed in an outpatient clinic environment. The injection consists of both a steroid and local anaesthetic, pain relief lasts around 4-10 weeks
• Surgical management is pain persists or severe disability is present:

  • Arthroplasty (joint replacement)
  • Arthrodesis (fusion of joint)
• Commonly affected joints:

  • Hips
  • Knees
  • Distal interphalangeal (DIP) joints in the hands
  • Carpometacarpal (CMC) joint at the base of the thumb
  • Lumbar spine
  • Cervical spine
• General signs of osteoarthritis:

  • Bulky, bony enlargement of the joint
  • Restricted range of movement
  • Crepitus on movement
  • Effusions around the joint