I. Bone and Joint Diseases: Clinical Principles

There are some key take home points to note of when approaching Bone and Joint diseases.

These are mostly clinical in nature, and require one to rely on the principles of thorough history taking and physical examination

1. Epidemiology is Important

- Age
  - - Neoplasms of the bone - children and adults get different bone tumours
  - - Older age group patients tend to get conditions such as osteoarthritis and osteoporosis

- Gender
  - - Certain inflammatory conditions, particular Rheumatoid arthritis or Systemic Lupus Erythematosus, tend to occur with greater frequency in females
  - - Osteoporosis tends to occur more frequently in postmenopausal women

2. Distribution of Disease is Important

This applies to BOTH bone and joint diseases

- Single or multiple site involvement
  - - Bones - Multiple bony lesions may raise the consideration for metastatic disease
  - - Joints - Some arthropathies are mono-articular whilst others are pauci- or polyarticular

- General size / structure of bone / joints
  - - Long bones (limb bones) vs Axial skeleton (spine, pelvis)
  - - Small bones or joints (eg. hands and feet)

- For bony neoplasms, specific location within long bones is important
  - - Diaphysis (Ewing sarcoma); Metaphysis (osteosarcoma); Epiphysis (giant cell tumour)

3. History of other conditions should be sought

4. Diagnostic Imaging is extremely Important

5. Joint Fluid Aspiration is a useful test for Arthropathies

This is a useful test in joint diseases

- Fluid can be sent to several labs for examination
  - - Microbiology - Gram stain, ZN stain, culture
  - - Pathology - for cytology examination and examination for crystals under the microscope
      - Gout - Negatively birefringent needle shaped crystals
      - Pseudogout - Weakly positively birefringent rhomboid shaped crystals

How do diseases of the MSK system manifest clinically?

Here are some main clinical manifestations of bone and joint disease (please note that this is not a detailed comprehensive list - for that you can refer to clinical texts):

1. Bones

Pain (night pain is worrying, eg. for neoplasm, or tuberculosis)

Swelling

Pathologic fracture - occurs in underlying abnormal bone, which can be due to infectious (eg. chronic osteomyelitis), metabolic (eg. osteoporosis) or neoplastic disease

Sinuses (associated with osteomyelitis)

Deformity (can be associated with metabolic conditions)

2. Joints

Pain, loss of function

Swelling
- Clinically, septic arthritis and crystal arthropathies can sometimes be difficult to distinguish from each other, and require examination of joint fluid aspirate - see point 5 above

Loss of function

Stiffness

Abnormal range of motion / locking (this may occur in traumatic conditions eg. ligamentous or meniscal injury in the knee, which will be covered during the clinical posting)