Pre-Existing Conditions and Florida Workers’ Comp

Reviewed by Scott J. Sternberg, a Florida workers’ compensation attorney with decades of experience representing injured workers in Florida. Last legally reviewed October 2026.

A pre-existing condition does not automatically bar a Florida workers’ compensation claim. If a workplace accident aggravates an old injury or a degenerative condition, benefits are generally available as long as medical evidence shows the work accident is more than 50 percent responsible for the need for treatment or the disability. The catch is that the carrier will closely review your medical history, and benefits can be reduced or stopped if the pre-existing condition later becomes the main cause.

Most adults have some wear and tear by the time they get hurt at work. A bad back from years of lifting, arthritis in a knee, an old shoulder injury from high school sports, or early carpal tunnel symptoms are all common. Insurance carriers know this, which is why “pre-existing condition” is one of the most frequent reasons they dispute causation. Understanding how Florida workers’ compensation laws actually treat prior conditions can keep a valid claim from being denied.

Does a Pre-Existing Condition Disqualify You?

No. Florida workers’ compensation is a no-fault system, and the law does not require a worker to be in perfect health on the day of the accident. Employers take employees as they find them. What the law requires is proof that the work accident, and not the earlier condition, is the major contributing cause of the injury, the disability, or the treatment you are asking the carrier to pay for.

That distinction matters. A worker with mild, manageable arthritis in a knee who tears a meniscus after slipping on a wet warehouse floor has a new injury layered on top of an old condition. The question is not whether the arthritis existed. The question is which one is driving the need for surgery, time off work, and ongoing care.

The 50 Percent Rule: Major Contributing Cause

Section 440.09(1), Florida Statutes, requires that a compensable injury be the major contributing cause of any resulting injuries. The statute defines major contributing cause as the cause that is more than 50 percent responsible for the injury compared to all other causes combined, and it must be established by medical evidence only. Your testimony about how much better you felt before the accident helps tell the story, but a doctor must put the causation opinion on the record.

When an injury combines with a pre-existing condition, section 440.09(1)(b) adds a second layer. The employer must pay benefits only to the extent the work injury is and remains more than 50 percent responsible for the injury compared to all other causes combined, and thereafter remains the major contributing cause of the disability or need for treatment. The words “and remains” are where many disputes start. A claim that is accepted at the beginning can be challenged months later if a doctor says the underlying condition has taken over.

The chart above is an illustration only, not data from a real case. It shows how a carrier may argue that the work injury has dropped below the 50 percent threshold as a degenerative condition progresses. Whether that argument holds up depends on the medical evidence.

Aggravation vs. Natural Progression

Most pre-existing condition disputes come down to one question: did the accident make the condition worse, or would it have reached the same point on its own? Carriers frequently argue natural progression, especially with degenerative conditions that show up on almost every adult MRI. Common examples include:

• Degenerative disc disease: a lifting injury that turns a stable, symptom-free spine into one that needs injections or surgery. See our discussion of back injuries on the job.
• Knee and shoulder arthritis: a fall or strain that causes a tear or sudden loss of function in a joint that had been working. Our article on work-related knee injuries covers the medical side.
• Carpal tunnel and nerve conditions: symptoms that existed before but worsened with job duties. Insurers often deny these as pre-existing, as explained in our guide to carpal tunnel syndrome and Florida workers’ comp.
• Heart conditions: cardiac events at work, where the carrier will compare job exertion against prior heart disease. We cover this in heart attacks and workers’ comp.

Gradual injuries follow their own rules. A repetitive motion injury can be compensable when prolonged exposure to a work hazard, greater than what the general public faces, causes a new injury or aggravates a pre-existing one.

How Carriers Argue It and How Claims Are Supported

Apportionment: When Benefits Can Be Reduced

Even when a claim is accepted, a pre-existing condition can affect how much is paid. Under section 440.15(5)(b), when a compensable injury aggravates or accelerates a pre-existing condition, the permanent impairment attributable to the accident is compensated while the portion of the impairment rating attributable to the pre-existing condition is apportioned out. The statute applies a similar approach to medical benefits.

Apportionment matters most once you reach maximum medical improvement and a doctor assigns an impairment rating, because that rating drives impairment income benefits. Apportionment requires medical support. A carrier cannot simply decide that half of your problem came from an old injury.

This example is hypothetical. Actual ratings and apportionment percentages depend on the physician’s findings and can be challenged.

Why Honesty About Prior Injuries Matters

It can be tempting to leave an old injury off an intake form or downplay it to the adjuster. That is a serious mistake. Florida law makes benefits unavailable to a worker who knowingly makes a false, fraudulent, or misleading statement to obtain benefits, and carriers routinely pull prior medical records, pharmacy history, and earlier claim files. A prior condition that is disclosed can be explained. A prior condition that was hidden can sink an otherwise strong claim.

The same goes for testimony. Questions about prior injuries come up in nearly every case, and inconsistent answers are among the common deposition mistakes that carriers use to attack credibility.

Evidence That Strengthens an Aggravation Claim

• Medical records from before the accident showing the condition was stable, mild, or not being treated
• Work history showing you performed full duties without restrictions until the accident
• A clear account of the specific incident or exposure, reported to your employer promptly
• Imaging taken after the accident that shows new findings compared with older studies
• A treating physician’s written opinion that the accident is the major contributing cause

Scott J. Sternberg on Pre-Existing Condition Denials

“Almost every client we meet has some prior history, and the insurance company will find it. A denial based on a pre-existing condition is not the end of the case. The real question is what changed on the day of the accident. When we can show that someone was working full duty, without treatment or restrictions, and then could not after a specific incident, that before-and-after picture often carries more weight than an MRI showing normal wear and tear.”  Scott J. Sternberg, Sternberg | Forsythe, P.A.

Told your injury is “pre-existing”? That label is often where the fight begins, not where it ends. “Scott Sternberg got me all of my workers’ compensation benefits quickly. He negotiated a fair lump sum settlement for me.” John D. Call (561) 687-5660 or contact us online for a free consultation.

When the Carrier’s Doctor Blames Your Old Condition

In Florida, the carrier generally selects the authorized treating physician, and that doctor’s causation opinion carries significant weight. If the doctor attributes your symptoms to a pre-existing condition, you are not stuck with that opinion. Florida law allows an injured worker a one-time change of physician and an independent medical examination, and a second opinion can be critical when causation is the main issue in the case.

Deadlines still apply while a causation dispute plays out. You generally must report a work injury to your employer within 30 days, and a petition for benefits must usually be filed within two years of the accident or within one year of the last payment of benefits, whichever is later. Our overview of time limits in Florida workers’ comp cases explains the exceptions.

Frequently Asked Questions

Can I get workers’ comp in Florida if I had a pre-existing condition?

Yes. A pre-existing condition does not bar a claim. Benefits are available when medical evidence shows the work accident is more than 50 percent responsible for the injury, disability, or need for treatment compared to all other causes combined.

What does major contributing cause mean in Florida workers’ comp?

Major contributing cause means the cause that is more than 50 percent responsible for the injury compared to all other causes combined. Florida law requires it to be shown through medical evidence, usually a physician’s opinion.

Can the insurance company stop my benefits because of an old injury?

It can try. Florida law requires the work injury to remain the major contributing cause of the disability or need for treatment. If a doctor later says the pre-existing condition has become the main cause, the carrier may seek to stop benefits, and that opinion can be challenged.

What is apportionment in a Florida workers’ comp claim?

Apportionment is a reduction that removes the portion of a permanent impairment rating, and in some cases medical care, that a physician attributes to a pre-existing condition rather than the work accident. It must be supported by medical evidence.

Should I tell the insurance company about my prior injuries?

Yes. Florida law bars benefits for workers who knowingly make false or misleading statements to obtain them, and carriers routinely review prior medical records. Honest disclosure lets your attorney explain how the work accident changed your condition.

What if the authorized doctor says my condition is pre-existing?

You have options. Florida law allows a one-time change of physician and an independent medical examination, and an attorney can help obtain medical evidence that addresses causation.

Common Concerns About Claims With a Prior Injury

“I already had back problems, so I probably do not have a case.” Many successful claims involve prior back problems. The question is whether the work accident is the major contributing cause of your current need for treatment, which is a medical question that deserves a real answer.

“If I tell them about my old injury, they will deny me.” Carriers usually find prior records anyway. Disclosing your history and explaining how your condition changed is far safer than having it discovered later.

“My claim was accepted, so I do not need to worry.” Under the major contributing cause rule, a carrier can revisit causation later in the claim. Watch for letters about benefits being suspended or a new doctor’s opinion on causation.

What Happens When You Call

When you call Sternberg | Forsythe, P.A., a member of our team will ask how and when you were hurt, what prior injuries or treatment you have had, and where your claim stands with the carrier. If you have a denial letter or medical records, we will ask you to share them. The consultation is free, and you will leave with a clear understanding of whether the pre-existing condition issue can be challenged and what to do next. Learn more about how a Florida workers’ compensation lawyer handles these disputes and what to expect in the Florida workers’ compensation claims process.

Talk to a Florida Workers’ Compensation Attorney

A prior injury should not cost you benefits for a new one. Sternberg | Forsythe, P.A. represents injured workers throughout Florida, with offices in West Palm Beach, Boca Raton, and Orlando. “I came to them after dealing with my own case for almost 2 years. The only regret I have is not getting a work comp lawyer sooner.” Dewey Doyle. Call (561) 687-5660 or request a free consultation. Hablamos Español.