These treatments cause bleeding and healing with fibrocartilage or scar cartilage which is not as resilient as normal hyaline cartilage. These treatments remain the first line of treatment for isolated lesions of articular cartilage in the knee.
The original Constitution required direct taxes to be apportioned among the states in accordance with population. An income tax is not so apportioned, so the amendment was needed to authorize such parts of the income tax as would constitute direct taxes.
The 24th amendment was important to the Civil Rights Movement as it ended mandatory poll taxes that prevented many African Americans. Poll taxes, combined with grandfather clauses and intimidation, effectively prevented African Americans from having any sort of political power, especially in the South.