Secondary Condition Claim · VASRD 5257
Knee, Other Impairment of Secondary to External Popliteal Nerve Paralysis
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 External Popliteal Nerve Paralysis.
Why Knee, Other Impairment of Is Linked to External Popliteal Nerve Paralysis
Often caused by knee trauma
Primary condition · VASRD 8521
External Popliteal Nerve Paralysis
The external popliteal (common peroneal) nerve runs behind the knee and controls the ability to lift the foot and toes upward. Damage to this nerve is a common cause of foot drop and is frequently linked to a knee injury, fracture, or nerve compression from the spine.
Secondary condition · VASRD 5257
Knee, Other Impairment of
This diagnostic code covers knee instability — the knee buckling, giving out, or shifting out of place — separately from pain or arthritis. Since the 2021 rewrite it rates two named things: recurrent subluxation or instability after a ligament sprain or tear, and instability of the kneecap (the patellofemoral complex) after surgical repair. The tier you land on depends less on how bad the instability feels than on what a medical provider has prescribed for it — a brace, a walking aid, both, or neither.
Knee, Other Impairment of VA Rating Tiers
The VA rates Knee, Other Impairment of the same way whether it's claimed directly or as secondary to External Popliteal Nerve Paralysis — severity of Knee, Other Impairment of itself determines the percentage.
| Rating | Criteria |
|---|---|
| 30% | The knee is unstable after a complete ligament tear that was not repaired or whose repair failed, and a provider has prescribed both a brace and a walking aid — or the kneecap is still unstable after surgery and needs both a brace and a cane or walker. |
| 20% | The knee is persistently unstable and a provider has prescribed a brace or a walking aid — one or the other, depending on whether the ligament tear was complete and whether it was repaired. |
| 10% | The knee is persistently unstable, but no provider has prescribed a brace or a walking aid for it. |
Example combined rating
20% External Popliteal Nerve Paralysis + 20% Knee, Other Impairment of = 36%
The VA combines ratings with Table I of 38 CFR 4.25, not simple addition — 20% and 20% combine to 36%, not 40%. These figures are illustrative; your actual rating for each condition depends on your own evaluation.
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Evidence for a Knee, Other Impairment of Secondary Claim
- •The prescription itself — the note or order from a medical provider prescribing a brace, cane, crutches, or a walker for walking. Since 2021 this is the single fact that separates the three tiers, and buying a brace over the counter is not the same thing.
- •An orthopedic evaluation documenting persistent instability with stability testing (Lachman, anterior drawer, pivot shift), and stating whether a ligament tear is complete or incomplete.
- •Operative reports where a ligament or the patellofemoral complex was repaired, plus follow-up notes on whether the repair held — a failed repair rates higher than a successful one on the same prescription.
Common questions about Knee, Other Impairment of secondary to External Popliteal Nerve Paralysis
- Can Knee, Other Impairment of be service-connected as secondary to External Popliteal Nerve Paralysis?
- Yes. Under 38 CFR § 3.310, a condition that is caused or aggravated by an already service-connected disability can be granted secondary service connection. Often caused by knee trauma You'll need a current Knee, Other Impairment of diagnosis and a medical nexus opinion linking it to your service-connected External Pop…
- What VA rating can I get for Knee, Other Impairment of as a secondary condition?
- Knee, Other Impairment of is rated under VASRD diagnostic code 5257 using the same criteria whether it's a direct or secondary claim: possible ratings are 30%, 20%, 10%. The rating depends on the severity of Knee, Other Impairment of itself, not on the severity of External Popliteal Nerve Paralysis.
- How does a secondary Knee, Other Impairment of claim affect my combined VA rating?
- The VA doesn't add ratings together. Using the official combined-ratings formula (38 CFR 4.25): a 20% rating for External Popliteal Nerve Paralysis combined with a 20% rating for Knee, Other Impairment of (example figures) produces a combined rating of 36%, not 40%. Approving Knee, Other Impairment of as secondary sti…
- What evidence do I need to service-connect Knee, Other Impairment of as secondary to External Popliteal Nerve Paralysis?
- Strong evidence for the underlying Knee, Other Impairment of diagnosis includes: The prescription itself — the note or order from a medical provider prescribing a brace, cane, crutches, or a walker for walking. Since 2021 this is the single fact that separates the three tiers, and buying a brace over the counter is no…
Primary condition
Full External Popliteal Nerve Paralysis guide
Secondary condition
Full Knee, Other Impairment of guide
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