The cause of<unk>  is still not fully understood. The disease can afflict patients of any age, but typically affects patients in their 30s. Though rare, it can also occur in children. Statistics show that generally more men are affected by<unk> 's than women in an estimated ratio of 3:2. The third (middle finger) metacarpal head has been reported to be the most common site of necrosis. Though osteonecrosis is a fairly common condition, many cases of avascular necrosis of the metacarpal head go without being diagnosed. This is because presentation of symptoms is variable depending on the patient. Sometimes, the patient may even choose to ignore their symptoms. Onset of<unk>  can possibly be attributed to steroid usage, trauma, systemic lupus erythematosus, renal transplant, or scleroderma. It can also afflict patients living with congenital short digits or atypical anatomical epiphyseal blood supply. In some cases, however,<unk>  can occur spontaneously.
Dieterich's disease
Milroy's disease
Mortimer's disease
Kimura's disease
Kienböck's disease
Tornwaldt's disease
Majocchi's disease
Hartnup disease