1/3 caucasian women > 64
Insufficient bone mass at time of skeletal maturity
- peak bone mass is achieved at age 25
Rapid loss of bone after menopause
Low body weight / weight loss / history of smoking / steroids
Type 1
- postmenopausal
- high turnover / osteoclast mediated
- F x 6
Clin Orthop 1989
- 38 patients treated with DXRT without surgery
- most breast cancer
- developed scoring system
- predicts post DXRT fracture risk in preDXRT long bones
- risk of fracture within 6 months
- irradiated without fixation
Four risk factors
Subtrochanteric
Lateral femoral shaft
Stress fractures
Associated with long term bisphonate use
Black et al. NEJM 2020
- reduction of hip fracture risk v risk of atypical femur fracture
- 10 year period
Stage 0
Natural history mixed
- depends on size of lesion and diagnosis
- treat if becomes asymptomatic
- may benefit from bisphosphonates
Stage 1 / Normal X-ray, abnormal MRI
Forage: 80% G/E
Bisphosphonates
Stage 2 / Abnormal X-ray with cysts and sclerosis
A: As for Stage I
Much less common than hip OA
- usually presents late
Similar causes as hip (AS IT GRIPS 3C)
Alcohol / Steroid / Trauma / Idiopathic
Gauchers
RA / RTx
Sickle Cell
Abnormality of type 1 collagen
- amino acid substitution of glycine with another amino acid
- prevents triple helix formation
Many many deformities described
- some 286 mutations of Type 1 collagen described
There are actually now 7
Type I
- mild
- AD
- blue sclera