Secondary Conditions from a Service-Connected Back: Radiculopathy, the Knees, and the Hip

The rule, in the regulation's own words

A secondary claim asks what your service-connected back has done to the rest of you. The regulation is 38 CFR 3.310. Part (a): a "disability which is proximately due to or the result of a service-connected disease or injury shall be service connected." Part (b) covers worsening: "Any increase in severity of a nonservice-connected disease or injury that is proximately due to or the result of a service-connected disease or injury, and not due to the natural progress of the nonservice-connected disease, will be service connected."

Part (b) has a catch. The VA "will not concede" aggravation unless the baseline severity of the second condition "is established by medical evidence created before the onset of aggravation" or by the earliest evidence after it. Allen v. Brown (1995) limits compensation to the disability "over and above the degree of disability existing prior to the aggravation." So the hip or knee records from before your back got bad are the baseline, and without them an aggravation claim has nothing to measure from.

In El-Amin v. Shinseki (2013), the VA examiner said the second condition was not caused by the service-connected one and stopped. The court held that opinion inadequate because it never reached aggravation. That is why my secondary letters answer causation and aggravation as two separate questions. The direct, secondary, and presumptive post explains the three kinds.

Radiculopathy is a separate condition, not a feature of the back rating

The VA rates the spine mostly on how far it bends. Pain, numbness, or weakness running down an arm or leg is rated separately, as a nerve condition, on top of the spine rating. Many veterans have never had the nerve involvement rated, because no one named it.

A neurosurgical review describes cervical radiculopathy as compression and inflammation of a nerve root at the foramen, "frequently caused by cervical disc herniation and cervical spondylosis" (Abbed and Coumans, 2007). A later review adds that most cases come from spondylosis, the ordinary degenerative change, not a soft disc (Iyer and Kim, 2016). The same anatomy applies in the low back. The condition the VA already service-connected is the usual cause of the one you are now claiming.

The letter has to show that chain in your records: an exam documenting pain or numbness in a nerve distribution, weakness, or a lost reflex, and which side; imaging showing narrowing or a herniation at the level and side that match; and an EMG or nerve conduction study if one was done. The EMG is not required, but when it names the root the argument is nearly finished.

The match matters more than the scan. Among 1,211 people with no neck symptoms, 87.6 percent had bulging discs on MRI; only 5.3 percent had cord compression (Nakashima and colleagues, 2015). "MRI shows degeneration" proves nothing on its own. Left-sided C6 symptoms, a missing left biceps reflex, and a left C6 foraminal narrowing on the same scan are a different thing.

The knees and the hip: where the evidence actually runs

The mechanism veterans describe is sensible: the back hurts, you limp or stiffen, load shifts to a hip or knee, you move less, you gain weight, the joint wears. But the published studies mostly run the other way, from the knee or hip toward the spine, and a letter that cites them backward will be caught.

The one study in my library that looked from the back toward the joints followed 983 Ontario adults, all 55 or older and already diagnosed with hip or knee arthritis, for about three years. Back pain at the start was strongly associated with worse hip pain and disability later. For the knee, the association was zero (Stupar and colleagues, 2010). For a hip that already has arthritis, there is some support that a painful back makes it worse: an aggravation theory, in older people, measured as pain and function, not new joint damage. For a back causing a knee condition, I have no study that shows it, and the one that tested it found nothing.

So a careful letter says the back-to-hip theory has limited support and is best argued as aggravation with a documented hip baseline. It says the back-to-knee theory rests on mechanism and this veteran's record, and names the gap. Then it does what the studies cannot: a physical therapy note documenting an antalgic gait from the back, a weight gain after the back took away the running, and the order the diagnoses appeared in. A template says "altered gait and biomechanical stress" and moves on. If the knee was itself injured in service, the stronger claim is usually direct, not secondary; the knee conditions post covers it.

In Walsh v. Wilkie (2020), a veteran with service-connected knee, hip, and back conditions claimed sleep apnea and hypertension through obesity, and the court held that aggravating obesity, not only causing it, can be the intermediate step. It remanded for a new opinion rather than granting the claim. The letter has to raise that theory in words and document the weight over time.

Knee to back: the same reasoning, in the direction the evidence supports

It helps to see the argument work where the studies run the right way: a service-connected knee and a later back condition. In 366 patients, a knee that would not extend the last 5 degrees was associated with a flattened lumbar curve, the "knee-spine syndrome" (Murata and colleagues, 2003). In 205 people with knee arthritis, the 22 percent with varus thrust, an outward lurch of the knee during walking, had a 3.6-fold risk of moderate to severe low back pain (Iijima and colleagues, 2020). In the only long-term study, 796 women imaged nine years apart, knee and hip arthritis on X-ray predicted progression of lumbar disc narrowing (Hassett and colleagues, 2003). The concept goes back to a 1983 paper defining a "secondary hip-spine syndrome," spine symptoms "aggravated by deformity of the hip" (Offierski and MacNab, 1983). Note the direction: hip to spine.

Even here there are limits. These are mostly cross-sectional studies in older civilians, and they support aggravation of a back condition better than the knee as its sole cause. The letter needs a measured extension deficit or a documented gait finding in this veteran, or the papers do not reach the case.

The examiner's counterargument is partly right

The examiner will say degenerative change is what spines and joints do with age, and genetics explains most of it. Concede both. Disc degeneration on imaging is present in 37 percent of symptom-free 20-year-olds and 96 percent of 80-year-olds (Brinjikji and colleagues, 2015a). One twin study put heritability of disc degeneration at 74 percent in the lumbar spine and 73 percent in the cervical spine (Sambrook and colleagues, 1999); a larger male twin study put it at 29 to 54 percent and called genetic and environmental influences "of similar importance" (Battie and colleagues, 2008). The back condition also progresses on its own: 62 percent of people who sought care for low back pain still had it a year later (Hestbaek and colleagues, 2003).

None of that decides a secondary claim, because the claim is not about why you have degeneration. It is about why this nerve, this hip, this side, at this time. Side: a left radiculopathy matching a left foraminal narrowing is not a story about aging in general, and in adults 50 and under, disc extrusion is four times more common with back pain than without (Brinjikji and colleagues, 2015b). Timing: a gait change documented by physical therapy, then hip symptoms, then the hip diagnosis, is a sequence the examiner has to explain away. Record: the baseline, so natural progress is subtracted honestly instead of used to deny the whole claim.

What I need from you

• The rating decision for the back or neck.
• Imaging reports for the spine, the hip, and the knees, with dates.
• EMG or nerve conduction studies, if any.
• Physical therapy, orthopedic, and primary care notes that describe a limp, a cane or brace, knee extension, or one-sided findings. These make the mechanism yours.
• Any record of the hip or knee from before the back got bad. This is the baseline for aggravation, and the item most veterans do not think to send.
• Every C&P exam and opinion on the secondary condition, especially a denial. If the examiner skipped aggravation, the letter says so by name.
• Weights over time, if the theory runs through weight gain.

The $395 records analysis tells you what is missing before you spend anything on a letter.

Who should write it

This is a musculoskeletal opinion, and it has to come from someone reviewing the whole musculoskeletal record at once, in date order. A spine-only reading misses the hip baseline. A joint-only reading misses the radiculopathy. I write these myself, and the letter says which theory has published support, which rests on your record, and which I will not argue because the evidence is not there. Your pain medication can cause its own secondary conditions; that is covered in the medication secondaries post. For the back or neck claim itself, see the back and spine nexus post.

Getting a nexus letter for a secondary condition from a service-connected back

Who writes it here. I am a board-certified emergency physician, and I write these opinions myself, from your records, with the literature above cited by name in the letter. I answer causation and aggravation separately, and I tell you on the screening call which conditions the record can support.

What it costs. The screening call is free, 15 minutes with me. A standard letter is $995 with the full records review included, or $395 for a records analysis first and $600 for the letter after it. If the VA has already denied this condition, you are rebutting an adverse C&P opinion, or the claim is at appeal, it is $1,495. Each additional condition on the same records is $500. No contingency, no percentage of back pay, and the price is confirmed in writing on the call before you pay anything.

How to start. Request the free screening call. You tell me what the VA has service-connected and what else hurts, and I tell you honestly whether a secondary opinion is likely to help. Records come later, through a secure link, never by email. No outcome is guaranteed. If the records do not support the claim, I will tell you that instead of writing the letter.

Studies and authorities referred to in this post

38 C.F.R. § 3.310, Disabilities that are proximately due to, or aggravated by, service-connected disease or injury (2025 edition).
Allen v. Brown, 7 Vet. App. 439 (1995) (en banc).
El-Amin v. Shinseki, 26 Vet. App. 136 (2013).
Walsh v. Wilkie, 32 Vet. App. 300 (2020).
Abbed KM, Coumans JV. Cervical radiculopathy: pathophysiology, presentation, and clinical evaluation. Neurosurgery. 2007;60(1 Suppl 1):S28-S34. PMID 17204882.
Iyer S, Kim HJ. Cervical radiculopathy. Curr Rev Musculoskelet Med. 2016;9(3):272-280. PMID 27250042.
Nakashima H, et al. Abnormal findings on magnetic resonance images of the cervical spines in 1211 asymptomatic subjects. Spine. 2015;40(6):392-398. PMID 25584950.
Brinjikji W, et al. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. AJNR Am J Neuroradiol. 2015;36(4):811-816. PMID 25430861. (2015a)
Brinjikji W, et al. MRI findings of disc degeneration are more prevalent in adults with low back pain than in asymptomatic controls: a systematic review and meta-analysis. AJNR Am J Neuroradiol. 2015;36(12):2394-2399. PMID 26359154. (2015b)
Stupar M, Côté P, French MR, Hawker GA. The association between low back pain and osteoarthritis of the hip and knee: a population-based cohort study. J Manipulative Physiol Ther. 2010;33(5):349-354. PMID 20605553.
Murata Y, et al. The knee-spine syndrome. Association between lumbar lordosis and extension of the knee. J Bone Joint Surg Br. 2003;85(1):95-99. PMID 12585585.
Iijima H, Suzuki Y, Aoyama T, Takahashi M. Relationship between varus thrust during gait and low back pain in individuals with knee osteoarthritis. Arthritis Care Res (Hoboken). 2020;72(9):1231-1238. PMID 31254449.
Hassett G, Hart DJ, Manek NJ, Doyle DV, Spector TD. Risk factors for progression of lumbar spine disc degeneration: the Chingford Study. Arthritis Rheum. 2003;48(11):3112-3117. PMID 14613273.
Offierski CM, MacNab I. Hip-spine syndrome. Spine. 1983;8(3):316-321. PMID 6623198.
Sambrook PN, MacGregor AJ, Spector TD. Genetic influences on cervical and lumbar disc degeneration: a magnetic resonance imaging study in twins. Arthritis Rheum. 1999;42(2):366-372. PMID 10025932.
Battié MC, et al. Genetic and environmental effects on disc degeneration by phenotype and spinal level: a multivariate twin study. Spine. 2008;33(25):2801-2808. PMID 19050586.
Hestbaek L, Leboeuf-Yde C, Manniche C. Low back pain: what is the long-term course? A review of studies of general patient populations. Eur Spine J. 2003;12(2):149-165. PMID 12709853.

This post is general information about VA claims, not medical advice about your condition or legal advice about your claim. Every opinion I write rests on the veteran's own records.

Related. Secondary conditions caused by your medications, The C&P examiner said no: what a rebuttal opinion has to do, Who can write a nexus letter?.