Background
Definition
Non-traumatic or traumatic condition of femoral head with bone death
Epidemiology
20 - 50 yo (average 38)
- M: F 4:1
NHx
70-80% with AVN will progress within 1 year
bone scan
ACJ Osteoarthritis
Aetiology
Post-traumatic (type III clavicle fractures)
Idiopathic
4 patterns
1. OA with osteophytes
- contribute to impingement
2. Osteolysis with resorption & gross osteoporosis
AVN
SONK vs Atraumatic AVN
>55 Often mid 30's
Painful THA
Aetiology
Intrinsic
Infection
Loosening
Thigh pain in uncemented
- micro motion at distal end of stem
- modulus mismatch
Stress fracture / insufficiency fracture
- pubic rami, sacral
Intra-operative fracture
Prosthesis failure
Subtle instability
Extrinsic
Infection
Risk factors
Patient
Advanced age
Immunosuppression - steroids / Rheumatoid / DM
Malnutrition - Lymphocyte count / Transferrin / Albumin
Vascular disease
Obesity
Poor skin i.e. psoriasis
Previous infection in joint
Infection elsewhere - i.e. UTi
Prolonged hospital admission
Revision surgery
Operative Factors
Preoperative
Multiple Myeloma
Definition
Uncontrolled proliferation of single clone of plasma cells
Epidemiology
Most common malignant tumour of bone
Age 50-60
2-3 / 100 000
Pathology
Highly differentiated B lymphocytes
- associated with abnormality of protein synthesis
Usually bone marrow of entire skeleton involved
Ewing Sarcoma
Principles
Treatment algorithm similar to OS
Overall prognosis similar to OS
- 70% long term survival
Definition
A malignant neoplasm composed of small round cells of uncertain histogenesis
Genetics
Recent data suggests it is of neuroepithelial derivation
- ? neuroectodermal cells
Aneurysmal Bone Cyst
Definition
Expansile pseudotumor of reactive hemorrhagic tissue arising in bone
- characterised by blood filled spaces separated by fibrous tissue
Types
Primary 50%
- arise de novo
Secondary 50%
- in association with other tumours
- probably secondary to haemorrhage into 1° tumour
- GCT / chondroblastoma / osteoblastoma / osteosarcoma
Acute
Definition
Infection of bone 2° blood-borne bacteria
Epidemiology
Most common children
- peak 10 years
True haematogenous OM rare in adults
- usually involves spine
M: F 2:1
Site
Most common femur & tibia