If you had an old injury before your workplace accident, you may be wondering whether you still have a valid workers’ comp claim.
It’s a common worry, and insurance companies often lean on it to deny or reduce benefits. The short answer: yes, you may still be able to file — and recover — even if the affected body part wasn’t perfectly healthy before.
With 30+ years representing injured Missouri workers and more than $100,000,000 collected for clients, our firm focuses exclusively on Missouri workers’ compensation.
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What does “aggravating a pre-existing condition” mean?
A pre-existing condition is any injury, illness, or degenerative change that existed before your work accident — a prior back surgery, arthritis, an old knee injury, a previous shoulder tear, or age-related disc degeneration, for example.
“Aggravation” means a work event made that condition worse, accelerated it, or triggered new symptoms that weren’t limiting you before. You might have lived for years with a quiet, manageable condition until a lift, fall, or repetitive task at work pushed it into pain, restrictions, or the need for treatment.
In plain terms: you don’t have to be in perfect health to be covered. You have to show that work made things worse.
Can you still file a claim in Missouri?
In most cases, yes. Missouri workers’ compensation can cover a work injury even when a pre-existing condition is part of the picture — what often matters is whether the workplace incident was the prevailing factor in causing the new injury or the worsening of your condition.
Missouri law uses the “prevailing factor” standard, which generally asks whether the work event was the primary cause of the resulting medical condition and disability, compared to other causes. This is a fact-specific question, and it’s frequently where disputes arise. Every case is different; results depend on the facts.
This is also why these claims are so often denied or undervalued. The insurer may argue that your symptoms come from the old condition rather than the work event. Strong medical documentation connecting your current problem to a specific work incident or work activity is usually central to overcoming that argument.
Common situations we see
- A worker with prior back issues lifts something heavy and now needs injections or surgery.
- Someone with mild, symptom-free arthritis develops sudden pain and restrictions after a fall at work.
- A repetitive-motion job worsens an old shoulder or wrist injury over time.
- A new accident re-injures a body part that had healed years earlier.
In each of these, the key question is usually the same: did work make it meaningfully worse?
Why these claims get denied — and what helps
Insurers commonly deny aggravation claims by pointing to your medical history. Things that often help your position include:
- Prompt reporting of the work incident to your employer
- Consistent medical records describing how and when symptoms changed after the work event
- A clear before-and-after picture — what you could do before versus the limitations now
- Physician opinions addressing the prevailing factor question directly
If your claim has already been denied, you generally have the right to dispute it, and there are deadlines that apply. Acting sooner rather than later helps protect your options.
What to do next
If a workplace injury aggravated a condition you already had, don’t assume you’re out of options because of your medical history. These are some of the most disputed claims in Missouri workers’ comp — and also some of the most important to get right, because the medical and legal arguments can directly affect your benefits and any future medical care.
A consultation can help you understand whether the prevailing factor standard may apply to your situation, what documentation matters, and what steps come next.
Talk directly with Attorney James M. Hoffmann. At the Law Office of James M. Hoffmann, you work directly with James — not a call center or a junior associate. With 30+ years representing injured Missouri workers and more than $100,000,000 collected for clients, the firm focuses exclusively on Missouri workers’ compensation.