Table 1.

Risk factors for OA [2], [14], [15], [16].

Forms of OA	Risk factors for OA
Primary OA	Constitutional risk factors	Hereditary and genetic factors	Age, sex, genetic inheritance
		Idiopathic
Secondary OA	Congenital	Congenital and developmental disorders
	Acquired	Activity-related risk factors	Occupational/repetitive activities, sports activity, traumatic
		Local mechanical factors	High body mass index, obesity, muscle weakness, alignment, mechanical instability
		Behavioural and hormonal factors	Smoking, oestrogen
		Local osseous factor	Bone marrow lesion, bone mineral density
		Inflammatory
		Infection
		Vascular	Avascular necrosis, haemarthrosis
		Connective tissue disorder	Ehlers–Danlos syndrome, Marfan syndrome
		Neuropathic	Diabetes mellitus, Charcot syndrome

OA = osteoarthritis.