Miscellaneous Conditions

Melorheostosis

Epidemiology

  • Typically discovered around age 40.

Aetiology

  • Excessive periosteal bone formation.
  • Unknown cause; non-hereditary.

Clinical Features

  • Painful.
  • Skin changes: erythema, warmth, fibrosis, and induration.
  • Commonly affects the lower limb.

Imaging Features

  • “Dripping candle wax” appearance: periosteal bone extending along the outer bone surface and crossing joints.

Pathology

  • Normal bone features.

Management

  • Symptomatic treatment.
  • Surgical excision for prominent areas.
  • Release joint contractures.

Gorham Disease

Overview

  • Also known as Massive Spontaneous Osteolysis or Vanishing Bone Disease.
  • No curative treatment.

Gaucher Disease

Aetiology

  • Enzyme deficiency: Glucocerebrosidase.
  • Autosomal recessive disorder leading to:
    • Pancytopenia.
    • Thrombocytopenia.
    • Osteonecrosis and fractures.

Epidemiology

  • Most common in Ashkenazi Jews.

Imaging Features

  • Erlenmeyer flask deformity of long bones.
  • Subchondral and vertebral collapse.
  • Lucent metaphyseal areas.

Management

  • Enzyme replacement therapy.
  • Symptomatic management.

Neuropathic Arthropathy (Charcot Joint)

Definition

  • Joint destruction caused by trauma due to loss of protective sensation.

Aetiology

  • Chronic sensory nerve issues:
    • Diabetes (foot and ankle).
    • Alcoholism.
    • Spinal cord anomalies (malformation, tumor).
    • Syphilis (knee).
    • Syringomyelia (shoulder and elbow).

Clinical Features

  • Early stages mimic osteoarthritis.
  • Late stages resemble infection.

Imaging Features

  • Joint subluxations, collapse, and hypertrophic bone formation.

Management

  • Treat reversible causes.
  • Fusion or reconstruction of joints.
  • Total contact casting for ulcers.

Haemophilic Arthropathy

Aetiology

  • Haemophilia A: Factor VIII deficiency.
  • Haemophilia B: Factor IX deficiency (Christmas disease).
  • X-linked recessive inheritance.
  • Repeated haemarthroses leading to hypertrophied synovium and cartilage erosion.

Imaging Features

  • Squared distal pole of the patella.
  • Flattened distal femur.
  • Overgrowth of tibia and femur.

Management

  • Prevent haemarthrosis.

Pigmented Villonodular Synovitis (PVNS)

Epidemiology

  • Middle-aged adults; men = women.

Aetiology

  • Benign but locally aggressive synovial proliferation.
  • Often associated with prior trauma.

Clinical Features

  • Pain, restricted ROM, and swelling.
  • Diffuse or nodular form:
    • Nodular: Single nodule in the joint.
    • Diffuse: Recurrent haemarthroses.

Common Locations

  • Knee (80%) > hip > shoulder > ankle.

Diagnosis

  • X-ray: Bony erosions on both sides of the joint.
  • MRI: Dark nodule or nodular proliferation, sometimes with fat signals and haemarthrosis.

Pathology

  • Inflamed synovium with haemosiderin deposition.

Management

  • Nodular: Excision.
  • Diffuse: Total synovectomy (arthroscopic or open).
  • Arthroplasty for secondary arthrosis.
  • Recurrence rate: ~20% (usually due to incomplete excision).
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