Generally, a worker must establish a causal connection between the work injury and the subsequent physical condition to receive benefits for a preexisting condition. Zavala v. Twin City Foods, 185 Wn. App. 838, 861, 343 P.3d 761 (2015). Causation must be proved through medical testimony establishing that it is more probable than not that the industrial injury caused the subsequent disability. Loushin v. ITT Rayonier, 84 Wn. App. 113, 122, 924 P.2d 953 (1996). Therefore, understanding the extent a preexisting condition is disabling before versus after an industrial injury often provides guidance as to whether the industrial injury caused an aggravation. Two recent Washington Court of Appeals cases offer guidance on applying this standard.

In Maria Molina v. Department of Labor & Industries, the claimant argued that her industrial injury aggravated her preexisting right knee osteoarthritis. Maria Molina v. Department of Labor & Industries, Wash. Ct. App. No. 40406-4-III (May 29, 2025). Claimant worked as a caregiver and injured her lower back, hip, and both knees while helping a patient off a bus on September 21, 2018. The testifying medical experts acknowledged that claimant had near end-stage tricompartmental osteoarthritis in her right knee in 2012. One of the testifying doctors stated that claimant would have been a candidate for a total knee replacement in 2012 if it were not for her age at the time. Another testifying doctor stated that her 2018 MRI findings would have existed irrespective of the industrial injury. The Court agreed that claimant’s condition would have continued to progressively worsen naturally and affirmed the previous ruling that the industrial injury did not aggravate the preexisting right knee arthritis.

In comparison, Seattle Children’s Healthcare v. Tonya Jilbert involves a similar case where the claimant argued that her industrial injury aggravated a preexisting condition. Seattle Children’s Healthcare v. Tonya Jilbert, Wash. Ct. App. No. 86753-9-I (June 9, 2025). In that case, the claimant worked as a medical assistant and injured her back in April 2018 when assisting a patient who was falling from an examination table. The industrial injury necessitated two surgeries in June 2018 which were authorized by the employer. Prior to the industrial injury, claimant had issues of incontinence which was symptomatic in 2017. The medical evidence showed that claimant’s symptoms were significantly exacerbated in frequency and severity after the 2018 surgery which was related to the claim. Since claimant’s condition became more disabling after the accepted surgery, the Court of Appeals found the industrial injury aggravated this preexisting condition.

When comparing the two above-noted cases, the decision came down to whether the medical evidence showed the industrial injury, or the authorized treatment, resulted in a new disability for the preexisting condition. In Molina, claimant’s preexisting right knee arthritis was already severe in 2012 to the point that it necessitated surgery. There was no medical evidence showing the industrial injury increased the level of disability in claimant’s right knee. Conversely, Jilbert had incontinence symptoms the year before the industrial injury, but the subsequent surgery authorized under the claim clearly increased the frequency and severity of this preexisting condition.

These two Court of Appeals cases demonstrate the importance of knowing the extent to which a preexisting condition was disabling before the industrial injury. In these types of cases, I highly recommend a medical canvass to obtain a comprehensive medical history. The medical records may help your IME provider or expert witness determine the extent a preexisting condition was symptomatic and disabling leading to the industrial injury.

If you have any questions regarding an aggravation issue, please feel free to contact me at (503) 412-3105 or [email protected].

Posted by Omeed Ghaffari.