Back Pain Secondary to Flat Feet

If your flat feet (pes planus) are service connected and your lower back hurts, you can claim the back as secondary to the feet. VA service connects a diagnosed back condition, such as a lumbosacral strain or degenerative arthritis of the spine, not back pain by itself. The theory is a chain: flat feet roll inward, the legs and pelvis follow, and the lower back takes the strain. Some research supports parts of that chain, and some does not. Negative VA opinions lean on the second kind, so this page lays out both and explains what a winning opinion does with them.

Can flat feet cause back pain?

The research shows an association in some groups and a plausible mechanism, with real limits.

• In 97,279 Israeli military recruits examined at enlistment (Kosashvili and colleagues, Foot and Ankle International, 2008), 16% had flat feet. Intermittent low back pain was found in 10% of recruits with moderate or severe flat feet, against 5% of recruits with normal feet or mild flat feet. The study was a one-time record review of young people, and it counted back pain with no abnormal clinical or X-ray findings.
• In 1,930 adults in the Framingham Foot Study (Menz and colleagues, Rheumatology, 2013), the shape of the arch when standing was not linked to low back pain. How the foot moved when walking was: women whose feet rolled inward (pronated) had higher odds of low back pain (odds ratio 1.48 after adjusting for age, weight, smoking and depressive symptoms). The link was reported for women only.
• When 35 healthy people stood on wedges that rolled their feet inward (Khamis and Yizhar, Gait and Posture, 2007), the shins and hips rotated inward and the pelvis tilted forward. The authors concluded that forces acting on the foot can change alignment up to the pelvis.
• A similar study of 14 healthy young adults (Pinto and colleagues, Manual Therapy, 2008) used wedges to increase pronation, measured at the heel. With both feet on wedges, the pelvis tipped forward by an average of 1.57 degrees. With one foot on a wedge, it tipped forward and also tilted sideways. These were small, short-term changes in people without pain.
• Foot orthotics help some backs. In a trial of 225 adults with chronic low back pain (Cambron and colleagues, Archives of Physical Medicine and Rehabilitation, 2017), custom shoe orthotics improved pain and function at 6 weeks compared with no treatment, but the differences were no longer significant at 12 weeks and later. A 2020 review of 14 studies (Kong and colleagues, Research in Sports Medicine) found moderate evidence that custom orthotics help chronic low back pain. These trials were not limited to people with flat feet.
• A 2013 systematic review (O'Leary and colleagues, Journal of Back and Musculoskeletal Rehabilitation) found limited research on foot problems and low back pain overall.

In my read, the strongest support is for moderate or severe flat feet that roll inward when you walk, with back symptoms that followed years of foot problems. The research does not show that every flat foot causes back trouble, and a medical opinion has to explain why yours did.

How VA decides back pain secondary to flat feet

Secondary service connection is in 38 CFR § 3.310. VA grants it in two ways.

• Caused by. Your service-connected flat feet caused the back condition, at least as likely as not.
• Aggravated by. Your back condition is aggravated by your service-connected flat feet, meaning it would be less severe but for the flat feet (M21-1 V.ii.2.D). VA rates only the part above the baseline, so the opinion should describe the baseline, from the earliest medical evidence of the back's severity before the worsening. The text of § 3.310(b) still mentions natural progress, but VA's current manual no longer applies that part, and the worsening does not have to be permanent. An aggravation opinion that says only that the back is worsening through natural progression does not answer the question the manual now asks.

The claim needs three things in the file: a diagnosed back condition, service-connected flat feet, and a medical opinion linking the two with reasoning. A lumbosacral strain counts: it is DC 5237, rated under the same spine formula as arthritis and disc disease.

VA rating for back pain secondary to flat feet

The back is rated under the General Rating Formula for Diseases and Injuries of the Spine in 38 CFR § 4.71a, which applies "with or without symptoms such as pain (whether or not it radiates)." For the thoracolumbar spine, these are the levels.

• 100%: unfavorable ankylosis of the entire spine
• 50%: unfavorable ankylosis of the entire thoracolumbar spine
• 40%: forward flexion 30 degrees or less, or favorable ankylosis of the entire thoracolumbar spine
• 20%: forward flexion greater than 30 but not greater than 60 degrees; or combined range of motion not greater than 120 degrees; or "muscle spasm or guarding severe enough to result in an abnormal gait or abnormal spinal contour"
• 10%: forward flexion greater than 60 but not greater than 85 degrees; or combined range of motion greater than 120 but not greater than 235 degrees; or muscle spasm, guarding or localized tenderness without abnormal gait or contour; or a vertebral body fracture with loss of 50 percent or more of the height

Normal forward flexion is 90 degrees, and each measurement is rounded to the nearest five degrees. Nerve findings in the legs are rated separately under Note (1); see radiculopathy. The back VA rating page covers disc disease and the incapacitating episodes formula.

Pain and repeated use count. Section 4.40 says "a part which becomes painful on use must be regarded as seriously disabled," § 4.45 counts excess fatigability, incoordination and pain on movement, and § 4.59 treats "actually painful, unstable, or malaligned joints, due to healed injury, as entitled to at least the minimum compensable rating for the joint."

The back and flat feet ratings combine under 38 CFR § 4.25, larger rating first. Severe flat feet in both feet rate 30% under DC 5276. A 30% flat feet rating and a 20% back rating combine to 44, because the 20% takes its share of the remaining 70. VA rounds 44 to 40%.

The C&P exam for back pain secondary to flat feet

The examiner is asked whether your back condition is at least as likely as not caused by your flat feet and, separately, whether the flat feet aggravated it. An opinion that answers only the first question is inadequate under El-Amin v. Shinseki (2013).

A careful examiner looks at these things.

• How severe the flat feet are, and whether the feet roll inward when you walk, not just how the arch looks when you stand
• How long you have had foot pain, and when the back symptoms started
• Your gait, posture and pelvic position, and whether orthotics or shoes changed your back symptoms
• Other causes, such as age, a separate back injury, heavy work and weight

Watch for three lines in unfavorable VA opinions. In Board decision A25008106 (January 2025), the examiner said that flat feet in both feet put no uneven stress on the back and that flat feet are not a risk factor for back pain, and the Board relied on that opinion to deny the claim. In Board decision 25008512 (June 2025), a VA examiner wrote that no medical literature shows pes planus places extra mechanical stress on the back. The studies above speak to both points: wedge studies changed pelvic position when both feet rolled inward, and moderate or severe flat feet went with more back pain in military recruits. C&P exam prep can help you describe how your feet and back behave over a full day.

Why back pain secondary to flat feet claims get denied

The gaps that lead to a denial are predictable.

• The only medical opinion is a negative VA opinion, and nothing in the file answers it.
• A favorable opinion describes your treatment but not the link. In Board decision 25008512, a treating VA physician's favorable opinion got less weight because it listed the orthotics, therapy and lingering pain without explaining how the flat feet affected the back.
• No opinion addresses aggravation.
• The opinion does not deal with a separate back injury, an accident or age-related change in your file.
• The records show mild flat feet relieved by arch supports, which gives the theory little to stand on.

Nexus letter for back pain secondary to flat feet

A strong nexus letter for this claim does six things.

1. States that the doctor reviewed your records, including the flat feet history and rating, the back diagnosis and imaging, and any notes on gait, orthotics or posture.
2. Describes how severe your flat feet are and how they behave when you walk.
3. Gives an opinion on causation: your back condition is at least as likely as not caused by your service-connected flat feet.
4. Gives a separate opinion on aggravation: your back condition is aggravated by your service-connected flat feet, meaning it would be less severe but for the flat feet, and describes the baseline.
5. Explains the mechanism with the time course, such as feet that roll inward, a forward-tilted pelvis and years of strained posture, cites the research, and answers the argument that flat feet in both feet cannot cause uneven stress.
6. Deals with the other causes in your file directly.

Board decision A25021859 (March 2025) shows what works. A VA examiner reviewed the records, examined the veteran and explained that straining the back to compensate for flat feet throws off the body's alignment and leads to low back pain. The Board found that opinion had a sufficient explanation of why and how, and granted the back. Raven Nexus can organize your records and the research into a draft for your doctor to review. If your knees are also service connected, see back pain secondary to knee pain.

Questions veterans ask about back pain secondary to flat feet

Can flat feet cause back pain for a VA claim?

They can. VA can grant a diagnosed back condition secondary to service-connected flat feet under 38 CFR § 3.310 when a medical opinion explains how the feet caused it or made it worse.

What is the VA rating for back pain secondary to flat feet?

The same as any back condition under the General Rating Formula: 10, 20 or 40 percent based mostly on forward flexion, with 50 and 100 percent for ankylosis. It combines with your flat feet rating under 38 CFR § 4.25.

The examiner said both feet are flat, so there is no uneven stress. Is that right?

Not necessarily. In a lab study, rolling both feet inward on wedges tipped the pelvis forward, so flat feet on both sides can still change posture. An opinion should explain how that applies to you.

Do orthotics help my claim or hurt it?

Your records of orthotics and their effect on your back are evidence. If arch supports fully relieve your symptoms, that points to mild flat feet; if your back improved with them, that can support the link.

Does the bilateral factor apply to my back and flat feet?

No. Section 4.26 applies to disabilities of both arms, both legs or paired skeletal muscles. The spine is not a paired extremity, so the back rating combines in the ordinary way.

Sources

• 38 CFR § 3.310, secondary service connection; M21-1 V.ii.2.D, aggravation of a nonservice-connected disability by a service-connected one.
• 38 CFR § 4.71a, General Rating Formula for Diseases and Injuries of the Spine and its notes, DC 5237 and DC 5276; 38 CFR §§ 4.25, 4.26, 4.40, 4.45 and 4.59 (eCFR text as of October 1, 2026).
• El-Amin v. Shinseki, 26 Vet. App. 136 (2013), an opinion must address aggravation.
• Kosashvili Y, Fridman T, Backstein D, et al. The correlation between pes planus and anterior knee or intermittent low back pain. Foot and Ankle International. 2008;29(9):910-913. PMID 18778669.
• Menz HB, Dufour AB, Riskowski JL, et al. Foot posture, foot function and low back pain: the Framingham Foot Study. Rheumatology. 2013;52(12):2275-2282. PMID 24049103.
• Khamis S, Yizhar Z. Effect of feet hyperpronation on pelvic alignment in a standing position. Gait and Posture. 2007;25(1):127-134. PMID 16621569.
• Pinto RZ, Souza TR, Trede RG, et al. Bilateral and unilateral increases in calcaneal eversion affect pelvic alignment in standing position. Manual Therapy. 2008;13(6):513-519. PMID 17910932.
• Cambron JA, Dexheimer JM, Duarte M, Freels S. Shoe Orthotics for the Treatment of Chronic Low Back Pain: A Randomized Controlled Trial. Archives of Physical Medicine and Rehabilitation. 2017;98(9):1752-1762. PMID 28465224.
• Kong L, Zhou X, Huang Q, et al. The effects of shoes and insoles for low back pain: a systematic review and meta-analysis of randomized controlled trials. Research in Sports Medicine. 2020;28(4):572-587. PMID 32954802.
• O'Leary CB, Cahill CR, Robinson AW, et al. A systematic review: the effects of podiatrical deviations on nonspecific chronic low back pain. Journal of Back and Musculoskeletal Rehabilitation. 2013;26(2):117-123. PMID 23640312.
• Board of Veterans' Appeals citations A25008106 (January 29, 2025, denied), 25008512 (June 27, 2025, denied) and A25021859 (March 10, 2025, granted). Board decisions are not precedential.
• Board figures on this page: Claim Raven's read of every Board decision from 2021 to 2026 that it holds, and of every decision since 1992 for the longer view.