Hip Limitation Secondary to Knee Limitation of Flexion Claim Guide

The ICD-10 diagnosis codes most commonly used for DC 5252, Hip Limitation (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.

See the full diagnostic-code page →

Under 38 CFR 3.310 a secondary claim turns on three elements:

• A current diagnosis: a medical diagnosis of hip limitation (the secondary).
• A service-connected primary: Knee Limitation of Flexion, already service-connected (the primary). A 0% primary still counts.
• A medical nexus: a medical opinion linking the hip limitation to the knee limitation of flexion, 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.

Whether that medical link exists in any one case is a medical question decided on that case's own evidence (the nexus).

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 knee limitation of flexion caused the hip limitation (§ 3.310(a)), or it aggravated an existing hip limitation (§ 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: 90% of them found the knee limitation of flexion caused the hip limitation, 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 56 denied claims the Board looked at this pairing and found no link, meaning it decided the knee limitation of flexion neither caused nor worsened the hip limitation. 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.

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 hip limitation to your service-connected knee limitation of flexion and naming the mechanism.
• Flare-ups and additional functional loss addressed
• Hip range of motion measured in degrees
• Hip X-ray or MRI findings
• Antalgic gait or limp documented
• Hip replacement (arthroplasty) documented

The diagnostic code involved: DC 5252 (Hip Limitation). 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.

What veterans who win this pairing actually put in the file, and why each piece moves the claim.

• A current hip diagnosis: every case started from a diagnosed hip condition, such as degenerative changes, arthritis, synovitis, bursitis, or trochanteric pain syndrome.
• Proof the knee is service connected: the Board confirmed the knee was service connected, often from the rating code sheet, before it reached the link question.
• A nexus opinion with a rationale: the winning opinions said "at least as likely as not" and, in four cases, explained that the knee changed the gait and loaded the hip unevenly.
• An opinion from a doctor who examined you: a treating orthopedic surgeon outweighed a records-only VA opinion, and an examining DO's opinion carried the claim alone.
• Treatment records showing an antalgic gait: notes recording a limp or wobbling gait, plus a noted leg length difference, undercut a VA opinion that said there was no gait problem.
• An answer to other causes and to aggravation: the one denial came after VA blamed the back and found no aggravation, and no opinion in the file answered either point.
• Timely filing: two winning opinions counted because they arrived within 90 days after the Board hearing.

These five Board decisions from 2026 granted service connection for a hip condition as secondary to a service-connected knee. In every one, a private medical opinion linked the knee to the hip, and in four of them the opinion explained that the knee changed the way the veteran walked. Where VA had a negative opinion, the Board explained why it gave that opinion less weight. Each decision decided only that veteran's appeal. Published Board decisions are not binding precedent, so they show how the Board has reasoned, not how your claim will turn out.

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 criteria: 38 CFR § 4.71a

Every item below comes from a pattern in the decisions on this pairing, not from general claim advice.

For the mechanics of filing itself, see the Standard Claim Guide and the Fully Developed Claim Guide.

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.

1. You file the claim, naming Knee Limitation of Flexion as the service-connected primary and hip limitation as secondary. Directly with VA, through VA.gov, or with an accredited representative's help.
2. 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.
3. The C&P exam is conducted, usually with the examiner asked to address the specific secondary theory (causation and aggravation both).
4. 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.
5. VA issues the decision letter stating the outcome and the reasoning.
6. 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

For the full walkthrough, see Inside Your Claim and Claim Stages.

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 hip limitation symptoms relate to your knee limitation of flexion timeline, treatment, and any aggravation, that is the detail a nexus opinion relies on.

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.

Keep documentation of ongoing treatment, follow-up evaluations, and any updated diagnostic testing for your hip limitation 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 hip limitation worsens, see the Rating Increase Guide.