Key References & Legislation
The aggravation rule matters
- • You can claim for the aggravation, acceleration, or exacerbation of a pre-existing condition.
- • Work does not need to be the only cause. It only needs to be a substantial contributing factor.
- • Insurers regularly point to “degenerative changes” on scans even when the worker was functioning normally before the work event.
- • Disputes about denied liability are commonly suitable for IRO-funded legal help.
What the law actually says
Under section 4 of the Workers Compensation Act 1987, an “injury” can include the aggravation, acceleration, exacerbation, or deterioration of a disease or prior condition. In plain English, that means the insurer cannot avoid liability just because your spine, knee, shoulder, or mental health was not perfect before the incident.
“...the aggravation, acceleration, exacerbation or deterioration of any disease...”
If you were doing your job, then after a work incident or period of work exposure you could no longer do it, the real question is usually what changed. That is why these claims often turn on pre-injury function, post-injury symptoms, and clear specialist evidence rather than on a single scan result.
How insurers usually frame the denial
- Degeneration argument: they point to wear-and-tear findings on MRI or CT and pretend those findings explain everything.
- Old records argument: they search GP notes for any prior pain complaint, even if you had kept working without restriction.
- Natural progression argument: they say your symptoms would have happened anyway, regardless of work.
- IME argument: they rely on a one-off insurer doctor instead of the clinicians who actually treated you.
When that happens, it helps to compare the denial against the broader guides onunfair IME reports,section 78 notices, anddenied claims generally.
Has the insurer blamed your injury on an old condition?
“Pre-existing condition” is one of the most common insurer excuses. It is not the end of the claim if work made the condition materially worse.
How to challenge the denial properly
The strongest aggravation disputes usually focus on a before-and-after story backed by objective records. It is rarely enough to argue in general terms that work was hard. You need evidence showing you were functioning, then a work event, workload, or series of duties produced a measurable decline.
Establish the baseline
Show you were working before the incident, doing normal duties, and not suffering the same level of restriction or incapacity.
Prove the change
Use certificates, specialist evidence, imaging context, and witness material to show a fresh worsening, new symptoms, or materially increased incapacity after work exposure.
Answer the insurer doctor
Where an IME blames natural degeneration, obtain a treating specialist or independent expert opinion that applies the legal test properly and explains why work was still a substantial contributing factor.
What usually goes wrong before the pre-existing-condition fight gets serious
The scan gets treated like the whole case
MRI and CT reports often mention degeneration, disc bulges, arthritis, or age-related changes. Insurers then act as if those words answer the legal question. They do not. The real issue is whether work caused a material aggravation, acceleration, or deterioration that changed function, symptoms, or capacity.
No one captures the worker's baseline properly
Many workers had old pain, old imaging, or even prior treatment but were still doing full duties before the work event. If that baseline is not written down clearly, the insurer can collapse the whole timeline into "this was always there".
The insurer doctor reframes aggravation as natural progression
A short insurer exam can be used to support aone-sided IME report, then hardened into aSection 78 denial. If treating doctors do not answer that reframing quickly, the file drifts toward a formal dispute.
Income and treatment issues start compounding
Once the insurer says the condition is pre-existing, it often starts affectingweekly payments, surgery approvals, and rehabilitation planning at the same time. The dispute stops being academic very quickly.
Evidence that often changes these cases
- Treating GP and specialist notes showing your function before and after the work event.
- Certificates of capacity that explain exactly which duties became impossible.
- Employment evidence describing lifting, repetition, awkward postures, pace, or the traumatic event itself.
- Old imaging interpreted in context, especially where degenerative findings existed without serious symptoms before work.
- Statements from supervisors, co-workers, family, or rehabilitation providers about the sudden functional change.
If the denial has also affected your income or treatment approvals, look at the connected guides onstopped weekly payments,treatment denials, andthe PIC dispute process.
Best next guide by insurer argument
If your denial letter leans heavily on one argument, go straight to the matching guide and build evidence in that sequence.
- "It is degeneration / pre-existing only" → stay on this page and build your before-and-after functional evidence first.
- "Our IME says no work causation" → review the unfair IME report guide and respond point-by-point.
- "Section 78 liability denied" → use the Section 78 notice guide for timeline and document order.
- "Weekly payments reduced or stopped" → triage with the weekly payments stopped guide in parallel.
Frequently asked questions
Do I have to disclose my old injuries?
Yes. Hiding an old injury usually backfires. The safer approach is to disclose it and explain clearly why work caused a new worsening, recurrence, or loss of function.
What if I had surgery on the same area before?
You can still have a valid claim. A previously operated body part can still be aggravated by work and may still justify weekly payments, treatment, and other benefits.
Is substantial contributing factor hard to prove?
It can be contested, but it is a common and winnable issue. The dispute usually turns on good factual and medical evidence, not on whether the worker had a perfectly healthy body before the incident.
Related dispute and evidence guides
Expert strategy for aggravation disputes
If the insurer says your symptoms are just degeneration or a pre-existing disease, get the denial reviewed before more benefits are lost.