Causation Letters In Texas Workers’ Compensation Cases
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Causation Letters In Texas Workers’ Compensation Cases
When you’re hurt at work in Texas, one of the most important parts of your workers’ compensation case is causation — the medical explanation of what the accident actually caused inside your body. Insurance companies fight extent‑of‑injury disputes every day, and the only way to win those battles is with a strong, well‑reasoned causation letter from your treating doctor.
This post explains how doctors think about causation, what evidence they look for in your medical records and imaging, and what they must include in a causation letters in Texas workers’ compensation cases to help you win.
What Is Causation — And Why Does It Matter?
In Texas workers’ comp, causation means proving two things:
- You have an injury, and
- That injury was caused by your work accident.
Doctors must be able to say, within reasonable medical probability, that your injury would not exist but for the work accident. It’s not enough to show that you have pain or that an MRI shows a problem. The doctor must connect the dots between:
- the mechanism of injury
- timing of your symptoms
- objective findings on exam
- diagnostic imaging
- any pre‑existing conditions
This is the medical decision‑tree that determines whether your injury is accepted or denied.
How Doctors Actually Think About Causation
Doctors don’t guess. They follow a structured analysis — a step‑by‑step process that looks like this:
1. Mechanism of Injury (MOI)
Your doctor starts by asking: Could this accident realistically cause this type of injury?
Examples:
- Falling on an outstretched arm → possible rotator cuff tear
- Lifting a heavy object with twisting → possible lumbar disc injury
- Walking or standing → not a usual mechanism for meniscus tears
If the mechanism doesn’t match the injury, the claim is already in trouble.
2. Timing of Symptoms
Symptoms must start at the time of the accident or shortly after.
- Immediate pain = strong causal link
- Pain 1–3 days later = possible minor soft‑tissue injury
- Pain weeks later = usually not caused by the accident
3. Objective Physical Exam Findings
Subjective pain alone is not an injury. Doctors look for measurable signs:
- Swelling
- Loss of motion
- Weakness
- Reflex changes
- Sensory loss
- Positive orthopedic tests (McMurray, Drop Arm, Straight‑Leg Raise)
These must appear close in time to the accident.
4. Diagnostic Imaging
MRIs, CTs, X‑rays, and EMGs must match the symptoms and exam. A finding on MRI is not automatically a new injury. It must correlate with:
- The accident
- pain pattern
- physical exam findings
- The timing of symptoms
If it doesn’t match, it’s usually degenerative or incidental.
5. Pre Existing Conditions
Doctors must determine whether the accident:
- Caused a new injury,
- Aggravated a pre‑existing condition (new structural damage), or
- Simply exacerbated symptoms (no new damage).
Acute vs. Degenerative vs. Aggravation: What Imaging Really Shows
Your MRI or X‑ray contains clues that doctors use to decide whether your injury is new, old, or worsened by the accident.
Signs of an Acute (New) Injury
Doctors look for:
- Bone marrow edema (fresh trauma)
- Hemorrhage or fluid in muscle/tendon
- Large tendon tears without atrophy
- Annular tears with surrounding edema
- Acute fractures or joint disruption
- Acute denervation on EMG
These findings strongly support a new injury.
Signs of Degenerative (Pre‑Existing) Conditions
These are “diseases of life”:
- Tendon atrophy or fatty infiltration
- Retraction of the rotator cuff
- Horizontal or complex meniscus tears
- Meniscal extrusion
- Disc desiccation
- Osteophytes
- Facet arthropathy
- Joint space narrowing
These findings usually existed long before the accident.
Signs of Aggravation (Worsening of a Pre‑Existing Condition)
Aggravation requires new structural damage, not just more pain.
Doctors look for:
- New weakness
- New loss of motion
- Different neurologic deficits
- New swelling or instability
- Imaging changes compared to prior studies
- A biomechanically plausible accident that could worsen the structure
Even if the MRI looks the same, new objective deficits can still prove aggravation.
What Your Doctor MUST Include in a Causation Letter
A causation letter is not a formality — it’s the backbone of your extent‑of‑injury case. Here’s what treating doctors must include:
Biomechanics of the Accident: The Forces That Actually Caused the Injury
Before a doctor can say what was injured, they must explain how the injury happened inside the body.
Every accident generates specific forces, and those forces act on tissues in predictable ways. A strong causation letter must identify:
The Type of Forces Generated by the Accident
Examples include:
- Axial load (straight downward force through a joint or spine)
- Rotational force (twisting torque applied to a joint or limb)
- Shear force (sliding or shifting force across a joint surface)
- Traction force (pulling force through a tendon or nerve pathway)
- Compression force (impact or crushing force on bone or cartilage)
How Those Forces Acted on the Body
Doctors must explain how the accident’s forces interacted with your anatomy to produce the injury.
Examples:
- Rotational force applied to the knee stretched the meniscus beyond its tensile strength, causing a tear.
- Axial load through the spine compressed the disc, causing an annular tear or herniation.
- Traction force through the shoulder overloaded the rotator cuff, resulting in a full‑thickness tear.
- Shear force across the wrist joint disrupted the TFCC (triangular fibrocartilage complex).
This section is critical because it shows the judge or adjuster that the injury wasn’t random — it was the predictable result of the forces generated by the accident.
A Statement of Causation
The doctor must say: “Within reasonable medical probability, this injury was caused by the work accident.”
This is the legal standard in Texas workers’ comp.
Clinical Correlation
The letter must connect:
- Accident → Symptoms → Exam → Imaging
Acute vs. Aggravation vs. Exacerbation
The doctor must choose one and explain why.
Objective Evidence
The letter must cite measurable findings — not just pain.
Why Other Causes Are Less Likely
Insurance companies love alternative explanations. Your doctor must shut those down.
MMI and Treatment Needs
A brief explanation of why you are not at MMI and what treatment is still needed.
Why This Matters for Injured Workers
Insurance companies deny extent‑of‑injury claims because the causation letter is weak, vague, or missing key elements. When your doctor follows the medical decision‑tree above, your case becomes stronger, clearer, and harder for the insurance company to dispute.
Why This Matters for Injured Workers
The Texas workers’ compensation lawyers at MLF Legal help injured workers across Texas win extent‑of‑injury disputes by strengthening the medical evidence and guiding treating doctors on what must be included in their causation opinions.
If you need help with:
- A denied injury,
- A dispute over pre‑existing conditions,
- An aggravation claim, or
- A causation letter that needs improvement,
We’re here to support you.
Call The Texas Workers’ Compensation Lawyers at 214-357-1782 for immediate help.
FAQs: Causation Letters In Texas Workers’ Compensation Cases
A causation letter is a written medical opinion from your treating doctor explaining what injuries you actually sustained and how your work accident caused them. It connects the accident to the medical evidence using objective findings, imaging, and biomechanics.
Insurance companies often deny injuries by claiming they are pre‑existing, degenerative, or not related to the accident. A strong causation letter is the key to proving your injury is work‑related and should be covered.
It’s the legal standard in Texas workers’ comp. Your doctor must state that your injury more likely than not resulted from the work accident — not from aging, daily activities, or unrelated medical conditions.
Doctors rely on a structured analysis that includes:
- The mechanism of injury (how the accident happened)
- The forces generated by the accident (axial load, rotation, shear, traction, compression)
- The timing of your symptoms
- Objective physical exam findings
- Diagnostic imaging (MRI, CT, X‑ray, EMG)
- Any pre‑existing conditions
- Relevant medical literature
Biomechanics refers to how the forces from your accident acted on your body. Example: A twisting motion creates rotational force on the knee, which can stretch the meniscus beyond its tensile strength, causing a tear. Doctors must explain this cause‑and‑effect relationship in your causation letter.
- New injury: A completely new condition caused by the accident.
- Aggravation: The accident caused new structural damage to a pre‑existing condition.
- Exacerbation: The accident caused temporary increased symptoms without new structural damage.
Only new injuries and aggravations are compensable in Texas workers’ comp.
No. An MRI can show a tear, bulge, or abnormality — but it cannot prove when it happened or what caused it. Your doctor must correlate the MRI with:
- The accident
- Your symptoms
- Your physical exam
- The timing of onset
Doctors look for:
- Bone marrow edema
- Hemorrhage or fluid in muscle/tendon
- Large tendon tears without atrophy
- Annular tears with surrounding edema
- Acute fractures
- Acute nerve changes on EMG
Common degenerative signs include:
- Tendon atrophy or fatty infiltration
- Retraction of the rotator cuff
- Horizontal or complex meniscus tears
- Meniscal extrusion
- Disc desiccation
- Osteophytes
- Joint space narrowing
These usually existed long before the accident.
A strong causation letter must include:
- A detailed description of the accident
- The biomechanics and forces involved
- A specific diagnosis
- A statement of causation
- Clinical correlation (accident → symptoms → exam → imaging)
- Acute vs. aggravation vs. exacerbation
- Objective evidence
- Why other causes are less likely
- MMI status and treatment needs
Insurance companies will use any gaps to deny your injury. A vague or poorly written causation letter is one of the top reasons injured workers lose extent‑of‑injury disputes.
Yes. We regularly guide treating doctors on how to write strong, medically accurate causation letters that meet Texas workers’ comp standards. We can provide templates, examples, and case‑specific guidance.
Injured at work in Texas and your employer doesn’t have workers’ comp?
You may have the right to sue and recover full compensation.
Contact MLF Legal today for a free consultation. You pay nothing unless we win your case.
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