Table 1.

Grades of knee OA based on Kellgren and Lawrence score [9].

Grade	Description
Grade 1	Doubtful narrowing of the joint space with possible osteophyte formation.
Grade 2	Possible narrowing of the joint space with definite osteophyte formation.
Grade 3	Definite narrowing of joint space, moderate osteophyte formation, some sclerosis and possible deformity of bony ends.
Grade 4	Severe narrowing of the joint space, large osteophyte formation, with marked sclerosis and definite deformity of bone ends.