There is patchy mild cartilage thinning within the lateral compartment.does this suggest a tear? please help i am in a lot of pain.

Difficult to assess: based on limited info. I assume you are referring to the knee. That said, the description would suggest mild early degenerative arthritis rather than a meniscal tear.

Cartilage thin. : Thinning of the cartilage within a joint usually suggests some wearing down of the cartilage more than an actual tear of the cartilage. But a thinned can be torn.