Knee Limitation of Flexion Secondary to Flatfoot Claim Guide
Knee Limitation of Flexion (VA diagnostic code 5260) is sometimes claimed as secondary to service-connected Flatfoot (code 5276) under 38 CFR 3.310. We analyzed published Board of Veterans' Appeals decisions on that pairing; here is what they show. It is an encyclopedic reference, not a forecast.
The Numbers, from 1.9M Appeals
We analyzed the Board's published decisions and found knee limitation of flexion (DC 5260) claimed as secondary to flatfoot (DC 5276) is a real, mid-sized claim pool that loses more often than it wins once it reaches a merits decision.
How those 859 issues came out
Start with the essentials
- 01Service Connection
The ways a secondary connection can be established for this pairing.
- 02Diagnosis and Evidence
Common symptoms and the evidence cited in published Board appeals.
- 03Your History
What you experienced, what others observed, and what treatment changed.
Understand the claim
ICD-10 Diagnosis Codes for Knee Limitation of Flexion
The ICD-10 diagnosis codes most commonly used for DC 5260, Knee Limitation of Flexion (the kind on your medical records, decision letter, or C&P exam report). VA rates the disability and its residuals, not the diagnosis itself, so coding can vary.
What a secondary claim on this pairing needs
Under 38 CFR 3.310 a secondary claim turns on three elements:
- A current diagnosis: a medical diagnosis of knee limitation of flexion (the secondary).
- A service-connected primary: Flatfoot, already service-connected (the primary). A 0% primary still counts.
- A medical nexus: a medical opinion linking the knee limitation of flexion to the flatfoot, showing the primary caused or aggravated it.
See the Secondary Claim guide for the caused-versus-aggravated split, and the Nexus Letter guide for what makes the medical opinion strong.
Why knee limitation of flexion is claimed secondary to flatfoot
Whether that medical link exists in any one case is a medical question decided on that case's own evidence (the nexus).
Pairing research and evidence
Symptoms Recorded in Granted Knee and lower-leg conditions Decisions
We analyzed 9,720 granted Board decisions involving knee and lower-leg conditions for symptoms named in sentences about the condition (rating-criteria recitations excluded). Descriptive of the published record, what the Board wrote down, not a checklist of what to report.
Bar length shows decisions. Percentages remain context.
Detected by phrase-reading the decision text with condition-specific vocabularies. Source: Board of Veterans' Appeals decisions, RateMyVSO analysis.
Caused By vs Aggravated By: What the Board Found
The outcome split above counts whole issues. This section goes one layer deeper. Under 38 CFR § 3.310 a secondary claim can be won two ways: the flatfoot caused the knee limitation of flexion (§ 3.310(a)), or it aggravated an existing knee limitation of flexion (§ 3.310(b)). Every grant rests on one or the other, so the numbers below divide up the granted claims only.
Direct causation is the route that carries most grants here: 77% of them found the flatfoot caused the knee limitation of flexion, the rest found aggravation. A practical consequence for the nexus opinion: it should address both routes, because a medical opinion that only argues causation leaves the aggravation theory, a separate legal basis, on the table. See the caused-vs-aggravated guide for how the two theories differ.
On the other side: in 64 denied claims the Board looked at this pairing and found no link, meaning it decided the flatfoot neither caused nor worsened the knee limitation of flexion. That is a separate group from the grants above, counted here so the picture is not one-sided.
We analyzed published Board decisions on this pairing to build this split. The grant split covers granted claims only; denied, remanded, and dismissed claims are not in it. Descriptive of the published record, not a prediction.
What VA Looks For: Tests, Records, and Diagnostic Codes
We analyzed published Board decisions on these claims and ranked the records that appeared most often:
- A medical nexus opinion: the one record VA weighs most on a secondary claim, a doctor's statement linking your knee limitation of flexion to your service-connected flatfoot and naming the mechanism.
- Range of motion measured in degrees
- Meniscal pathology documented
- Knee MRI or X-ray findings
- Instability testing
- Giving way, buckling, or locking reported
- Knee replacement (arthroplasty) documented
The diagnostic code involved: DC 5260 (Knee Limitation of Flexion). The rating levels for this code are in the rating section below.
Records ranked by how often published Board decisions cited them. The exam that captures most of this is covered in the C&P Exam section below. Source: Board of Veterans' Appeals decisions, RateMyVSO analysis.
The Evidence That Wins Knee Limitation of Flexion Secondary Claims
What veterans who win this pairing actually put in the file, and why each piece moves the claim.
- A current knee diagnosis: The granted cases had diagnoses such as a meniscal tear, an ACL tear, degenerative arthritis, or osteoarthritis on a VA or private exam (A26036582, A26016600, A26006466).
- Proof your flat feet are service connected: Every grant started from service-connected pes planus. In one case the rating decision had already found it, and the Board did not disturb that finding (A26016600).
- A nexus opinion that explains how: The winning opinions described altered gait, pronation, or a change in how weight-bearing forces reach the knee (A26036582, A25082881, A26006466). Denials had no such opinion (A24006016).
- Medical literature behind the opinion: The Board gave more weight to opinions that cited studies or literature (A26024725, A26016600) and less to one that cited none (A22015566).
- An opinion on aggravation, not just cause: The Board noted when a VA exam failed to address aggravation, and private opinions on aggravation supported one grant (A26036582, A26006466).
- Treatment records showing a gait problem: A VA note of weak gait years earlier and a provider letter on altered gait both helped (A26016600, A26036582).
- A full record review with accurate history: Opinions lost weight when they rested only on the veteran's statements or missed a post-service knee injury (A26039074, A22015566).
Evidence Cited in Published Knee and lower-leg conditions Decisions
We analyzed 190,664 published Board decisions involving knee and lower-leg conditions for condition-specific evidence, counting only case-specific mentions (boilerplate recitations excluded). "Favorable" is the share of decisions citing that evidence where every issue was granted or the outcome was mixed; the baseline across all these decisions is 45.6%, combining every diagnostic code below. Evidence appearing in a decision does not mean it decided the case. Descriptive of the published record, not a prediction.
Bar length shows decisions citing the evidence.
By diagnostic code
These codes are grouped together above. They do not perform the same, so find your own code here rather than reading the combined figure. A code retired in the schedule rewrites appears without a link, because its decisions were judged under criteria that no longer apply.
Bar length shows published decisions reviewed.
Detected by phrase-reading the decision text with condition-specific vocabularies. Source: Board of Veterans' Appeals decisions, RateMyVSO analysis.
Board Grants on This Pairing, Dissected
These five published Board decisions granted a knee condition as secondary to service-connected flat feet (pes planus). In every one, a medical opinion tied the knee to the feet, and most of those opinions said the flat feet changed how the veteran walked. In three, the Board weighed a positive opinion against a negative VA opinion and found the evidence at least evenly balanced, so the benefit of the doubt went to the veteran. Board decisions are not binding precedent. Each one decides only that veteran's appeal, on that veteran's record.
Private letters on altered gait beat a VA exam that skipped aggravation Citation A26036582 (April 20, 2026), Hearing docket
The record: A September 2020 VA contract exam diagnosed a right knee meniscal tear and anterior cruciate ligament tear. The examiner said the knee was less likely than not due to the flat feet. The examiner reasoned that medical literature did not show an injury to one joint affects another, unless there was major muscle or nerve damage or a leg length difference of more than 5 centimeters with an obvious Trendelenburg gait. The examiner did not address aggravation. The veteran's private provider (no credential stated) wrote two March 2020 letters. One said the flat feet severely altered his biomechanical gait. The other said the veteran's "pain in his feet has led to an alteration of his gait and a change in how the forces of weight-bearing are accommodated by his foot, ankle and knee complex", and found the knee condition more likely than not related to that altered gait.
Why it won: The Board found the evidence at least evenly balanced. Taken together, the private evidence showed the flat feet altered the veteran's gait, which in turn led to the right knee disability. The Board resolved the doubt in the veteran's favor under 38 CFR 3.102 and granted secondary service connection under 38 CFR 3.310.
An orthopedic surgeon's opinion backed by medical literature Citation A26024725 (March 19, 2026), Hearing docket
The record: A May 2024 private opinion from an orthopedic surgeon said the service-connected pes planus contributed to the left knee and left ankle injuries. The surgeon submitted medical literature to support that conclusion. VA examination reports in the file reached the opposite conclusion, but they did not include any medical literature.
Why it won: The Board found the surgeon's opinion highly probative because it had a more thorough rationale and was supported by literature. It called that opinion the most probative evidence on the issue and granted the left knee as secondary to pes planus under 38 CFR 3.310.
A positive VA exam that cited studies, plus years of gait notes Citation A26016600 (February 24, 2026), Hearing docket
The record: The rating decision on appeal had already found a diagnosis of left knee degenerative arthritis and that the pes planus was service connected. A July 2020 VA examiner found the knee at least as likely as not due to the pes planus, based on how severe the pes planus was, and said the knee problem began after the pes planus. That examiner cited medical studies. An August 2020 VA addendum disagreed, saying there was no credible medical evidence of a link and no prolonged alteration of gait from the pes planus. VA treatment records noted a weak gait as early as November 2011.
Why it won: The Board pointed to the November 2011 gait note and found the positive and negative opinions at least in approximate balance. It gave great weight to the July 2020 opinion because it rested on a thorough record review, cited medical literature, and gave a detailed rationale. The Board resolved reasonable doubt for the veteran and granted the left knee as secondary to pes planus.
VA's own examiner tied both knees to a change in gait Citation A26006466 (January 23, 2026), Hearing docket
The record: October 2020 VA exams diagnosed bilateral knee osteoarthritis. October 2020 VA opinions said the knee conditions were caused by the bilateral pes planus because of the veteran's change in gait. Private medical opinions said his severe foot conditions aggravated his knee, ankle, and hip conditions. Earlier April 2019 VA opinions said the knee conditions were related to age and normal wear and tear.
Why it won: The Board acknowledged the negative April 2019 opinions but found the evidence in equipoise. It resolved reasonable doubt in the veteran's favor and granted both knees as secondary to the service-connected pes planus.
One private exam explained the strain chain from feet to knees Citation A25082881 (September 26, 2025), Hearing docket
The record: The veteran reported left and right knee pain, and the Board found this indicative of disabilities in those joints. A July 2025 private examiner gave positive opinions that the knee, hip, and ankle problems were the result of biomechanical strain caused by pes planus. The examiner pointed to excessive pronation, pelvic misalignment, and altered gait placing repetitive stress on these joints over time. The decision describes no negative VA opinion on the knees.
Why it won: The Board found the evidence persuasively in favor of the knees being related to the service-connected pes planus. Resolving any reasonable doubt for the veteran, it granted both knees on a secondary basis, along with the hips and right ankle.
Why VA Denies, and How the Board Answered
The rationales below are the ones VA examiners actually used against this pairing in the published record, each paired with the Board's response.
- Read the left column first: if a VA opinion in your file uses one of these arguments, that is the reasoning your own evidence has to meet.
- The right column is the counter: it shows how the Board actually answered that argument, with the decision cited.
- A rationale appearing here is not a verdict: the same argument won some cases and lost others, on different records.
| VA examiner's rationale | How the Board answered it |
|---|---|
| Medical literature does not show an injury to one joint affects another, unless there is major muscle or nerve damage or a leg length difference of more than 5 centimeters with an obvious Trendelenburg gait. | The Board noted the examiner never addressed aggravation. It weighed that opinion against private letters describing an altered gait, found the evidence evenly balanced, and granted the knee. (A26036582) |
| The flat feet do not alter the veteran's gait, and the knee strain is more likely from obesity and natural aging. The October 2024 examiner also said the feet did not aggravate the knees. | The Board gave three VA opinions great weight because they reviewed the record and gave a complete rationale. It gave the private opinion little weight because it rested solely on the veteran's statements without a record review. Denied. (A26039074) |
| No credible medical evidence links the knee to pes planus, and there was no prolonged alteration of gait. | The Board pointed to VA treatment records noting a weak gait as early as November 2011, and to a positive VA opinion that cited medical studies. It found the evidence balanced and granted. (A26016600) |
| No scientific literature discusses knee and hip problems in association with the foot, and the knee surgeries followed injuries after service. | The Board sided with VA. The private chiropractor cited no literature, did not review the service records, and relied on inaccurate facts, since the veteran himself reported a knee injury on the stairs in 1995. Denied. (A22015566) |
| Pes planus may be a contributor to the knee arthritis, but how much cannot be said without resort to speculation. An earlier VA examiner did not think the pes planus was the source. | The Board called the "may be a contributor" comment speculative and equivocal, gave it little probative value, and found no other medical evidence for the link. Denied. (9915616) |
| No VA exam was given, and no medical opinion in the file linked the knee to the flat feet. | In one case the secondary theory was first raised at the Board hearing; in the other, the gait and balance evidence first came in at the hearing. Both came after the rating decision, so under the current appeals system the Board could not send the claims back for an exam. The veterans' own accounts of how they walk were not competent medical evidence of a link. Denied. (A24006016, A26038001) |
If granted: rating and daily function
If Granted: How Knee Limitation of Flexion Is Rated
The VA assigns one of these percentages based on what your medical record documents. Plain-language summary of the rating criteria at 38 CFR; the controlling text is the regulation itself.
| Rating | What the record has to show for DC 5260, Knee Limitation of Flexion |
|---|---|
| 30% | Your knee bends only 15 degrees from a straight leg (flexion means bending the joint). A healthy knee bends to about 140 degrees, so at this level the knee barely bends at all. |
| 20% | Your knee bends only 30 degrees from a straight leg (flexion means bending the joint). A healthy knee bends to about 140 degrees, so this is a severe loss of bending. |
| 10% | Your knee bends only 45 degrees from a straight leg (flexion means bending the joint). That is about one-third of the roughly 140 degrees a healthy knee bends. |
| 0% | You can only bend your leg forward to 60 degrees (flexion means bending a joint forward). A normal leg can bend about 120-135 degrees at the knee, so this rating applies when your leg movement is significantly restricted and you can only achieve less than half of normal bending range. |
Do's and Don'ts
Every item below comes from a pattern in the decisions on this pairing, not from general claim advice.
- Get a medical opinion that explains how your flat feet changed the way you walk and how that strained your knee. The winning opinions all described a mechanism, most often an altered gait.
- Ask the doctor to cite medical literature. The Board favored opinions with literature over VA reports without it (A26024725, A26016600).
- Ask that the opinion address both causation and aggravation. The Board noted when a VA exam skipped aggravation (A26036582).
- Point to treatment notes that record a limp or weak gait. A 2011 gait note helped tip one case (A26016600).
- Put your secondary theory and your evidence in before the rating decision. Two denials turned on a theory or evidence first offered at the Board hearing (A24006016, A26038001).
- Don't rely on your own statement about how you walk as the medical link. The Board rejected that, even from a veteran with medical training (A24006016).
- Don't submit an opinion built only on what you told the doctor. The Board gave such an opinion little weight (A26039074).
- Don't leave out a knee injury after service. An opinion that missed a 1995 fall on the stairs lost its weight (A22015566).
- Don't settle for a hedged opinion like "may be a contributor." The Board called that speculative (9915616).
- Don't assume the gait link is obvious. Several VA examiners found no gait change, and the Board followed them when nothing explained otherwise (A26039074, A22015566).
Prepare and take the next step
Prepare: your own working pages
Optional. These are your own notes, in your own words. They are not a VA form, they are not sent to the VA, and nothing here is a medical finding or a prediction about your claim.
Three reminders while you prepare
- Keep the two conditions separate
Record the history, diagnosis, symptoms, and treatment for Flatfoot and Knee Limitation of Flexion separately before describing the possible relationship. Go to this part
- Ask about causing and worsening separately
A clinician may need to address whether Flatfoot caused Knee Limitation of Flexion, whether it worsened it, and what other explanations the record shows. Go to this part
- Build the timeline from records you have
Mark missing or unverified records honestly. Research from published Board decisions describes the record reviewed; it does not predict an individual claim. Go to this part
Sign in or create an account to save your answers and come back to them later. You can fill these in and print them without an account.
Two-condition timeline
Knee Limitation of Flexion: symptoms and daily function
Provider questions about the relationship
Records and unanswered questions
Decision-letter reading sheet
Quick Checklist Before You File
- Service connection already in place for Flatfoot, and a current medical diagnosis of knee limitation of flexion.
- Diagnostic testing, imaging, or clinical records documenting the knee limitation of flexion, whatever your provider used to diagnose and track it.
- A nexus opinion, whenever possible from a doctor familiar with knee limitation of flexion, stating it is at least as likely as not caused or aggravated by the flatfoot, and naming the mechanism rather than just the conclusion.
- Lay statements: spouse, family, friends, or battle buddies describing what they've witnessed or noticed.
- Your STRs and any VA opinions already in the file on either condition. If a VA opinion already went against you, your submitted opinion or statement should address its specific reasoning.
For the mechanics of filing itself, see the Standard Claim Guide and the Fully Developed Claim Guide.
The Claims Process, Step by Step
A secondary claim moves through the same pipeline as any other. Understanding who does what helps you know who to contact and what to expect.
- You file the claim, naming Flatfoot as the service-connected primary and knee limitation of flexion as secondary. Directly with VA, through VA.gov, or with an accredited representative's help.
- VA assigns a Veteran Service Representative (VSR) to develop the claim: gather your service treatment records, VA and private medical records, and order a C&P exam if needed.
- The C&P exam is conducted, usually with the examiner asked to address the specific secondary theory (causation and aggravation both).
- The file goes to a Rating Veteran Service Representative (RVSR), the "rater," who weighs the medical evidence and decides service connection and, if granted, the rating percentage.
- VA issues the decision letter stating the outcome and the reasoning.
- If denied or under-rated, you choose an appeal lane, Supplemental Claim, Higher-Level Review, or a Board appeal, covered below.
Who's who: VSO vs. VSR vs. Rater vs. C&P Examiner
Your VSO
An accredited representative, agent, or attorney. Not a VA employee. Helps prepare and file, and can represent you on appeal. Has no authority to decide your claim.
VSR
VA staff who develops the claim: gathers records and schedules the exam. Does not decide the rating.
Rater (RVSR)
VA staff who reviews the complete file and makes the actual decision on service connection and percentage.
C&P Examiner
Conducts the exam and, where asked, gives a nexus opinion. Does not decide the claim, but the opinion's reasoning and legal framing carry real weight.
For the full walkthrough, see Inside Your Claim and Claim Stages.
DBQs and Your C&P Exam
A Disability Benefits Questionnaire (DBQ) is the standardized form the examiner completes for your condition. See the DBQ Guide for how these forms work and whether a private DBQ from your own doctor can be submitted instead of relying solely on a VA exam. For what to expect and how to prepare, see the C&P Exam Prep Guide, and be specific about how your knee limitation of flexion symptoms relate to your flatfoot timeline, treatment, and any aggravation, that is the detail a nexus opinion relies on.
Reading Your Decision Letter, and What to Do If Denied
Your decision letter has a narrative "reasons and bases" section and a codesheet with the rating and effective date. See the Reading Your Decision Letter Guide or use the Letter Interpreter tool to decode your own letter. If denied, you have three main lanes:
- Supplemental Claim: refile with new and relevant evidence, such as a nexus opinion that addresses the mechanism and the specific VA rationale you're rebutting. See Supplemental Claim Guide.
- Higher-Level Review (HLR): a senior reviewer looks at the same evidence again, useful if the denial rested on a legal error. See HLR Guide.
- Board Appeal: your case goes to a Veterans Law Judge, with a direct review, evidence, or hearing docket. See Board Appeal Guide.
Not sure which lane fits? See the Appeals decision guide for a side-by-side comparison.
After You Win: Maintaining Your Rating
Keep documentation of ongoing treatment, follow-up evaluations, and any updated diagnostic testing for your knee limitation of flexion on file, this protects you if VA schedules a future reexamination. See Protect Your Rating for when a rating becomes protected and Future Reexaminations for what triggers one. If your knee limitation of flexion worsens, see the Rating Increase Guide.
References and related resources
Frequently Asked Questions
Does Flatfoot have to be highly rated to support a knee limitation of flexion secondary claim?
No. 38 CFR 3.310 looks at whether the service-connected Flatfoot caused or aggravated the knee limitation of flexion, not at how severe the Flatfoot rating is. Even a 0% service-connected primary can anchor a secondary claim.
What do the percentages on this page mean?
They are the historical outcomes of 859 published Board decisions on this exact pairing: 14% granted, 23% denied, 63% remanded. They describe decided appeals already on record. They do not predict what would happen in any individual case.
RateMyVSO. Educational resource. Not affiliated with the U.S. Department of Veterans Affairs. Not legal advice. All RateMyVSO tools are free. Find a VSO representative for personalized guidance.