Secondary Condition Claim · VASRD 5257
A condition caused or aggravated by an already service-connected disability can be granted its own service connection as a secondary condition under 38 CFR § 3.310. Here's how that works for Knee, Other Impairment of when it develops after Muscle Group XV (Hip/Knee Flexors).
Weakened support muscles
Primary condition · VASRD 5315
Muscle Group XV (Hip/Knee Flexors)
Injury or weakness in muscles that flex the hip and knee.
Secondary condition · VASRD 5257
Knee, Other Impairment of
This diagnostic code covers knee instability - the knee buckling, giving out, or feeling loose during activity - separate from simple pain or arthritis. It's rated on how often and how severely the knee subluxates (partially dislocates) or shifts out of place, which is a different rating track than knee pain alone.
The VA rates Knee, Other Impairment of the same way whether it's claimed directly or as secondary to Muscle Group XV (Hip/Knee Flexors) — severity of Knee, Other Impairment of itself determines the percentage.
Example combined rating
10% Muscle Group XV (Hip/Knee Flexors) + 20% Knee, Other Impairment of = 28%
The VA combines ratings with Table I of 38 CFR 4.25, not simple addition — 10% and 20% combine to 28%, not 30%. These figures are illustrative; your actual rating for each condition depends on your own evaluation.
Primary condition
Full Muscle Group XV (Hip/Knee Flexors) guide
Secondary condition
Full Knee, Other Impairment of guide
See how Muscle Group XV (Hip/Knee Flexors) and Knee, Other Impairment of combine with the rest of your service-connected conditions using the official VA combined-ratings formula.
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