Table 3.

Radiographic characteristics of KOA and the symptoms of the patients.

Grade	Characteristics of KOA (Grade0-Grade4)	Symptoms of patients
Normal (Grade 0)	There are no radiographic abnormalities associated with KOA. There is no JSN or active change. Fig. 1(a) shows that the joint space between two bones is normal and equal on both sides.	Patients are able to move without any discomfort or difficulty.
Doubtful (Grade1)	There is doubtful JSN, and osteoporotic lipping could happen. Fig. 1(b) shows that there is a possible JSN, and the presence of osteophytes.	During this stage, most patients don't feel any pain or discomfort.
Minimal (Grade 2)	There are definite osteophytes and JSN may be found. This is a mild case of KOA, where the cartilage is probably still in reasonable shape. Fig. 1(c) depicts the probability of JSN and the presence of osteophytes.	In this stage, people will feel pain and stiffness in the knee joint after a long day of walking.
Moderate (Grade3)	At this stage, definite JSN, some sclerosis, and numerous osteophytes are evident. Fig. 1(d) depicts JSN with many osteophytes.	The patient frequently has pain when moving. Moreover, joint stiffness is prevalent after lengthy periods of sitting and in the morning.
Severe (Grade 4)	This is considered the most severe stage of KOA. This stage has large osteophytes, significant sclerosis, and bone abnormalities. Moreover, synovial fluid, cartilage, and knee joint space are diminished. Fig. 1 (e) shows that the joint space between the bones is completely eliminated, the cartilage is nearly gone, and massive osteophytes are present.	The patient usually feels a lot of pain and discomfort when walking or moving the joint.