• decrease​ in VB height over 40%

• instability in post. lig. complex

• ​neurological changes

• displaced​

​Unstable

• decrease in VB height from 20%-40%

• posterior lig. complex intact

• ​normal neurology

• undisplaced

​Stable

​Suggested ans

• failed conservative Rx

• ​symptoms produce unacceptable impairment to basic functional activities

  • severe constant pain

  • multi-direction & significant reduction in ROM​

• radiological importance​

  • articular cartilage degeneration

  • decrease sphericity of femoral head​

​Suggested ans

• DVT / bed sore

• ​dislocation

• fracture of bone / prosthesis

• scar pain

• infection

• LLD

• sciatic nerve injury / abductor weakness (depending on surgical approach)​

​Suggested ans

• previous injury to joint

• TB

• RA​

• overweight --> excessive loading

• ​deformity / malalignment --> uneven wear & tear

• occupational repetitive ​stress (e.g. manual worker)

​Suggested ans

• increase available ROM

• increase joint stability

• increase life span of prosthesis​

• decrease incidence of acetabulum cartilage erosion and protrusion

​Suggested ans