How Pre-Existing Injuries Affect Personal Injury Claims

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January 30, 2026 | By The Calderon Law Firm
How Pre-Existing Injuries Affect Personal Injury Claims

Having a pre-existing injury does not prevent you from recovering money in a Texas personal injury claim. The law is clear that an at-fault party is responsible for any aggravation or worsening of a prior medical condition their negligence causes. 

However, despite these legal protections, you must still be weary. An insurance adjuster will likely review your medical history, looking for any reason to argue that your current pain is from old age or a previous injury, not from the recent accident. 

If you are concerned that your medical history is being used to deny your fair recovery, a personal injury lawyer in Houston, TX at the Calderon Law Firm is here to help. We have deep experience handling these difficult situations. Call us today to discuss your legal options at no cost.

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Key Takeaways for Claims Involving Pre-Existing Injuries

  1. A pre-existing condition does not bar your claim. Texas law, specifically the Eggshell Plaintiff Rule, holds a negligent party responsible for aggravating or worsening a prior injury.
  2. The focus is on the change in your condition. Your case will center on proving the difference in your health, pain, and abilities before and after the accident.
  3. Full disclosure and consistent medical treatment are essential. Hiding your medical history destroys credibility, while prompt and consistent care creates the evidence needed to prove your claim.

The Eggshell Plaintiff Doctrine: Why You Are Still Protected

The eggshell plaintiff rule (sometimes called the thin skull rule) comes from a core principle in Texas law stating that a defendant must take the victim as they find them. If a minor crash causes a major injury because of a pre-existing vulnerability, the defendant is responsible for the full scope of that new or worsened injury. Their carelessness doesn't get a discount because you were already dealing with a health issue.

Plaintiff Doctrine


The Texas Pattern Jury Charges (the instructions given to juries) specifically tell jurors they must determine the damages that resulted from the aggravation of a pre-existing condition. The focus is on what changed for the worse after the accident, and the person who caused that change is held responsible for it.

Distinguishing Between Degeneration and Aggravation

One of the most common hurdles in these cases is the post-accident MRI. For example, an adjuster might point to your imaging results and say, "See? The report mentions degenerative disc disease. This isn't from the crash, it's just arthritis." This argument feels defeating, but it misrepresents both medicine and the law.

The fact is, many imaging findings of conditions like spinal degeneration are a normal part of aging. A systematic review of studies published in the American Journal of Neuroradiology showed that disc degeneration has a prevalence ranging from 37% in asymptomatic 20-year-olds to 96% in 80-year-olds. Another study found that by age 60, nearly 90% of people show signs of disc degeneration on an MRI, even if they have no pain at all. 

Asymptomatic vs. Symptomatic: The Key Difference

The key question is not what your MRI shows, but how you felt and functioned before the accident. There is a huge difference between a condition that exists on a scan without causing problems (asymptomatic) and one that actively produces pain and limits your life (symptomatic). 

So, if you were living without pain before the crash, the collision remains the clear cause of your new symptoms, regardless of what an older MRI happens to show.

The Crumbling Skull Defense

In response, the defense might use an argument known in legal theory as the crumbling skull. They will suggest that your condition was naturally worsening and would have required surgery or caused you pain eventually, even without the accident. Their goal is to convince a jury that the accident didn't change the outcome, it just slightly sped up the inevitable.

How We Prove the Change

Our job is to defeat that narrative. At Calderon Law Firm, we build a case to demonstrate the clear before and after picture of your life. We use a legal standard called the but-for test: we work to prove that but for (i.e., if it weren’t for) the defendant's negligence, you would still be working, enjoying your hobbies, and living your life without this new or worsened pain.

We do this by:

  • Analyzing Medical Imaging: We work with medical professionals to identify acute findings on an MRI, like swelling or edema, which point to a recent trauma, as opposed to chronic findings like bone spurs that may have been there for years.
  • Documenting Your Prior Activity Level: Evidence of your physical capabilities before the accident is powerful. This could include gym membership records, photos of you on vacation, work attendance records, or testimony from friends and family about your active lifestyle.

The Role of Medical Records in Texas Personal Injury Cases

Think of your medical history as a map. It shows where you've been. An insurance company will try to use that map to argue you were already at your current destination of pain and limitation. Our job is to show that their insured's negligence sent you down a completely different and more difficult road.

The Gap in Treatment Problem

Sometimes, after an injury, people try to tough it out for a few weeks before seeing a doctor, hoping the pain will subside. Insurance companies view this gap in treatment as evidence. 

They will argue that if you were truly hurt, you would have sought medical care immediately. Any delay, in their eyes, suggests the injury either wasn't serious or that something else must have happened during that gap to cause the pain.

Consistency Is Key

Your reporting must be consistent. If you tell your lawyer that your pain is a 9 out of 10 but you tell your doctor you're "doing fine," that inconsistency will be used against you. 

Texas juries value credibility, so be completely honest and thorough with your medical providers at every visit. If a part of your body hurts now when it didn't before, or if it hurts in a different way, that specific change must be in your doctor's notes.

Affidavits and Medical Expenses

In Texas, we use a tool under the Texas Civil Practice and Remedies Code § 18.001 to prove that your medical bills are reasonable and necessary. We file affidavits from your medical providers attesting to their bills. The defense may then file counter-affidavits, typically from a hired expert, claiming the treatment wasn't for the new injury but for your old, pre-existing condition. 

Calculating Damages: The Delta Principle

Remember that in Texas, a defendant is only liable for the harm they caused. This means we must calculate the delta, which is the difference between your life and physical condition before the accident and your condition after. The value of your claim is found in that difference.

The formula looks like this:

Your Total Current Disability — Your Pre-Accident Disability = Your Recoverable Damages

Economic Realities in Texas

This calculation is especially significant for many Texans. Our state is home to industries that demand physical labor, such as oil and gas, construction, and agriculture. A bad back that was a manageable annoyance for an office worker is a career-ending injury for a welder or construction foreman after it has been aggravated in a collision. In these cases, the delta includes a substantial claim for loss of earning capacity if the new injury forces early retirement or a change to a lower-paying field.

Pain, Suffering, and the Loss of Enjoyment of Life

Damages extend beyond medical bills and lost wages to include the things you no longer do. If you had mild arthritis in your knees but could still play golf twice a week, and now you cannot walk the course at all, that loss has value. If you could lift your grandchildren before the crash but cannot now, that loss is real and compensable. 

The Policy Limits Problem

Aggravated injuries frequently require more extensive and expensive medical care, like spinal surgery or joint replacements. This treatment often exceeds the Texas minimum auto liability limits of $30,000. 

When this happens, pursuing a claim against your own Underinsured Motorist (UIM) coverage becomes necessary, making the case more difficult. A lawyer helps you identify all possible sources of recovery.

Common Pitfalls to Avoid When You Have a History of Injury

Mistake 1: Hiding Your Medical History. 

Credibility is everything. You must assume the insurance company will find out about your prior injuries, as they have access to claims databases and will request your records. If you deny a previous back injury in a deposition and they produce records showing years of treatment, your credibility is destroyed. 

  • Strategy: Be upfront about your history from the beginning. Acknowledge the old injury, but be prepared to explain exactly how the new injury is different and worse.

Mistake 2: Working Through the Pain.

Many Texans have a strong work ethic and a tendency to downplay pain. While admirable, failing to seek prompt medical attention sends a signal to the insurer that your injury wasn't severe. Following your doctor's orders and attending all appointments is a legal requirement known as mitigating your damages.

  • Strategy: Always get evaluated by a doctor immediately after an accident. Consistent medical compliance shows that you are taking the injury seriously and creates a clear record of your symptoms and treatment.

Mistake 3: Signing Blank Medical Authorizations.

An insurance adjuster may send you a form that gives them blanket permission to access your entire medical history, from birth until now. They are fishing for anything they might use to blame your pain on something else.

  • Strategy: Never sign a blanket authorization. Let your attorney handle the retrieval of medical records. We will ensure that only the relevant history (typically the few years prior to the accident) is provided, protecting your privacy and preventing the defense from muddying the waters with irrelevant information.

FAQ: Pre-Existing Conditions in Texas Injury Claims

What if I was already on disability for my back before the car accident?

Even if you were not working, you may still be compensated for the ways the accident made your life worse. The focus shifts from lost wages to non-economic damages, like increased pain, loss of quality of life, and the need for more medical care (for example, requiring in-home assistance you didn't need before).

Can the insurance company blame my obesity for my knee injury?

While the defense may argue that weight complicates recovery, the Eggshell Plaintiff rule still applies. A defendant cannot escape liability just because a lighter person might have withstood the impact with less damage. They are responsible for the injuries they actually caused to you.

Does a prior Workers' Comp claim affect my current car accident case?

It creates complexities. If the workers' compensation carrier paid for treatment to the same body part, they may have a right to be reimbursed from your settlement (a subrogation lien). Clear medical expert testimony is necessary to separate the harm caused by the work incident from the new aggravation caused by the car accident.

What if I re-injured a body part that I had surgery on 10 years ago?

These cases are highly complicated but have significant value. An accident that damages surgical hardware (like screws or plates) or causes a previously successful surgery to fail may require a difficult and expensive revision surgery. The defendant is responsible for the cost of fixing the new damage.

Your History Does Not Define Your Current Rights

Do not let an insurance adjuster dictate the value of your health and well-being. Their job is to protect their company's bottom line. The law, however, is designed to protect people, with all their unique histories and vulnerabilities.

Define Your Current Rights


Proving an aggravation claim requires a detailed presentation of medical evidence, a firm grasp of Texas legal precedent, and a willingness to push back against the insurance company's narrative. At Calderon Law Firm, we understand how to build a case that clearly distinguishes who you were before the accident from who you are now.

If you are ready to move forward with a team that knows how to protect your full recovery, contact us today for a free consultation.

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