Pre-existing Condition

Prior injuries do not bar a claim.

Start here, because carriers often imply otherwise. The statute is explicit: the fact that an employee has suffered a previous disability, impairment, anomaly, or disease—or received compensation for it—does not preclude benefits for a subsequent aggravation or acceleration of that condition.

Florida workers are not required to have been in perfect health. A degenerative spine, an old shoulder repair, or arthritis diagnosed years ago does not end a claim.

Apportionment: what actually gets reduced

The statute does allow apportionment. Where a compensable injury or need for medical care results from aggravation, acceleration, or merger with a preexisting condition, only the disabilities and treatment associated with the compensable injury are payable.

The mechanics:

• Impairment is apportioned based on the anatomical impairment rating attributable to the preexisting condition. If your overall rating is 15% and 5% is attributed to a prior condition, impairment benefits are paid on 10%.
• Medical benefits are apportioned by the percentage of the need for care attributable to the preexisting condition.

Critically, this applies regardless of whether the preexisting condition was disabling at the time of the accident or at the time of the rating — and without considering whether it would have become disabling without the accident at all.

Merger

The statute defines “merger” as the combining of a preexisting permanent impairment with a subsequent compensable one, where the effects considered together produce a rating greater than the sum of the two rated individually.

In plain terms: sometimes two injuries together are worse than the arithmetic suggests. The statute recognizes this, and it matters in serious cases.

The major contributing cause standard

Separately from apportionment, Florida requires that when a work injury combines with a preexisting condition to cause disability or a need for treatment, the work injury must be more than 50% responsible compared to all other causes combined—the major contributing cause. Medical evidence must establish that the work injury is the major contributing cause. This is the threshold question of compensability, and it is where most preexisting condition denials actually live.

Imaging alone is not enough.

This is the most useful thing on this page. Section 440.13(14)(a) provides that abnormal anatomical findings alone, in the absence of objective relevant medical findings, are not an indicator of injury or illness, not a justification for remedial care or the assignment of restrictions, and not a foundation for limitations.

Carriers cut both ways with this. They use it against workers to deny care. But it also cuts against carriers who point to an MRI showing degenerative changes — which nearly every adult spine shows — and argue the pain must be preexisting. Degenerative findings on imaging, without more, do not establish that your symptoms are attributable to a prior condition.

The false representation exception

One narrow circumstance does bar benefits entirely. If, at the time of entering employment, the employee falsely represented in writing that they had not previously been disabled or compensated for the condition, and the employer detrimentally relied on that misrepresentation, no benefits are payable.

All three elements are required: a false statement, in writing, at hiring, that the employer actually relied on to its detriment. Carriers occasionally assert this defense on much thinner facts.

Where preexisting condition disputes go wrong

• Apportionment assumed rather than proven—a percentage attributed to a prior condition with no preaccident records supporting it.
• Degenerative imaging treated as dispositive. See above — abnormal findings alone are not sufficient.
• Unrelated history dragged in. The privilege waiver covers conditions reasonably related to the claim. An old ankle injury is not relevant to a shoulder claim.
• Denial framed as disqualification. A denial that reads as though prior injury ends the claim, when the real issue is whether the accident is the major contributing cause.
• Workers concealing history. Understandable and counterproductive. Non disclosure at intake damages credibility, and the written misrepresentation defense exists for this reason.

What this means for your claim

Be straightforward about your medical history from the beginning. A prior injury is not fatal to a claim, but a discovered omission is very damaging to one.

Then hold the carrier to its proof. If it apportions, ask what preaccident anatomical impairment rating supports the percentage. If it relies on imaging, ask what objective relevant findings connect the degeneration to your current symptoms. Apportionment is a factual determination that has to be established, not an assumption a carrier gets to make.