Legal Definitions - aggravation rule

The aggravation rule is a principle applied in workers' compensation cases. It addresses situations where an employee has a pre-existing medical condition or injury that is then made significantly worse by a new injury or incident that occurs during the course of their employment.

Under this rule, if an on-the-job injury combines with a pre-existing condition, leading to a greater overall disability than what would have resulted from the work injury alone, the entire resulting disability is considered compensable under workers' compensation. This means the employer or their insurer is responsible for the full extent of the disability, even though a part of the underlying vulnerability existed before the work incident.

Here are some examples to illustrate the aggravation rule:

• Example 1: Worsening a Chronic Back Condition

  Imagine an administrative assistant who has a history of occasional, mild lower back pain, which they manage with stretching and over-the-counter medication. While lifting a box of files at work, they experience a sudden, sharp pain that leads to a herniated disc, requiring surgery and extensive physical therapy. Medical experts determine that while the assistant had a pre-existing susceptibility to back issues, the work-related lifting incident directly caused the severe herniation and the resulting prolonged disability. Under the aggravation rule, the entire disability, including the surgery, recovery time, and any long-term limitations, would be compensable through workers' compensation, as the work injury significantly aggravated their pre-existing condition.

• Example 2: Accelerating Degenerative Joint Disease

  Consider a construction worker who has early-stage osteoarthritis in their knee, which causes no pain or functional limitations. While working on a scaffold, they slip and fall, twisting their knee severely. This incident causes a meniscus tear and significantly accelerates the progression of their osteoarthritis, leading to immediate, debilitating pain and the need for a total knee replacement much sooner than would have otherwise been necessary. The aggravation rule would apply here, making the full cost of the knee replacement and the associated recovery period compensable, because the work injury substantially worsened and accelerated the impact of the pre-existing, asymptomatic arthritis.

• Example 3: Re-injuring a Previously Repaired Shoulder

  A warehouse employee previously underwent surgery to repair a torn rotator cuff in their shoulder from a sports injury, and had made a good recovery, regaining most of their strength and mobility. While attempting to move a heavy pallet at work, they feel a pop in the same shoulder. Subsequent medical evaluation reveals a new, more extensive rotator cuff tear and additional damage to the surrounding tissues, requiring a more complex and lengthy surgical repair and rehabilitation than the initial injury. Because the work incident directly aggravated the previously injured and repaired shoulder, leading to a more severe and disabling condition than if the shoulder had been completely healthy, the entire disability and treatment costs would be covered under the aggravation rule.