Knee Conditions

For limited flexion (bending): knee bends to at least 45 degrees but not more. For limited extension (straightening): leg extends to within 10 degrees of straight. For instability: slight recurrent subluxation or lateral instability. For arthritis: X-ray evidence with painful motion. Basically, your knee hurts and you have some limitation, but you can still get around.

For limited flexion: knee only bends to 30 degrees. For limited extension: can't straighten past 15 degrees. For instability: moderate recurrent subluxation or lateral instability (your knee gives out noticeably). More significant daily limitations.

For limited flexion: knee only bends to 15 degrees. For limited extension: can't straighten past 20 degrees. For instability: severe recurrent subluxation or lateral instability (your knee frequently gives out). Substantial difficulty with stairs, walking, standing.

For limited extension: can't straighten past 30 degrees. This level of limitation significantly affects daily activities.

For limited extension: can't straighten past 45 degrees. Your leg is basically stuck bent. Also the minimum rating for some prosthetic knee replacements.