Ky. Top Court Upholds Impairment Rating Despite Minor Deviation from AMA Guides

Case File

Although a doctor's 10% impairment rating of an injured Kentucky coal worker fell between Category II and Category III in the AMA Guides, the doctor's slight deviation of between 2% and 5% wasn't enough to show that the doctor's opinion was not grounded in the Guides. In the Kentucky Supreme Court's view, a minor deviation from the AMA Guides was not enough to defeat an impairment rating when the opinion remained grounded in the Guides and no competing medical evidence showed the rating was unsound.

Case

O'Bannon v. Muhlenberg County Coal Co., LLC, No. 2025-SC-0508-WC (Ky. 10/22/26)

What Happened?

A coal worker filed a workers' compensation claim due to pain and physical limitations in his neck, hands, lower back, shoulders, and knees. An administrative law judge found that the worker suffered cumulative trauma to his neck and awarded permanent partial disability and medical benefits.

The ALJ ultimately relied on a doctor who diagnosed the worker with cervical radiculopathy (10% whole person impairment), lumbar radiculopathy (10% whole person impairment), bilateral shoulder weakness (4% whole person impairment), knee weakness (10% whole person impairment in each knee), and bilateral median neuropathy (i.e., carpal tunnel syndrome; 4% whole person impairment) secondary to 10 years of underground coal mining. This doctor assigned a combined whole person impairment of 40% pursuant to the AMA Guides.

The company requested an independent medical examination, and the doctor who performed it diagnosed the worker with diffuse, widespread subjective complaints of non-radicular neck and back pain, shoulder pain, knee pain, and hand pain. The IME doctor opined that the worker's work in the coal industry did not cause cumulative trauma or repetitive stress injuries and assigned a 0% whole person impairment.

The ALJ ultimately concluded that the worker had a 40% combined whole person impairment rating for his work-related cumulative trauma injuries and also concluded that the worker could not return to underground mining work and awarded PPD benefits enhanced by the 3-multiplier pursuant to KRS 342.730(1)(c)(1).

The company filed a petition for reconsideration, which the ALJ denied. The company then appealed to the Board, which affirmed. The Court of Appeals held that the ALJ relied on a medical opinion that was not supported by the AMA Guides. The worker appealed to the Kentucky Supreme Court.

Rule of Law

Under Kentucky law, the AMA Guides are an integral tool for assessing a claimant's disability rating. To be grounded in the Guides is not to require a strict adherence to the Guides but rather a general conformity with them. Impairment ratings need not strictly adhere to every provision of the AMA Guides. Rather, a physician's opinion must be sufficiently grounded in and generally conform to the Guides to constitute substantial evidence.

What the Kentucky Supreme Court Said

According to the court, there was "no reason based in law, fact, or interpretation of the AMA Guides" that the decision of the ALJ and the Board should not stand with regard to the doctor's 10% impairment rating of the worker's cervical spine.

Although the AMA Guides did not specifically list 10% as an option for rating impairment due to cervical disorders, the court found that this fact did not require reversal of the ALJ's decision because:

(1) Not only did the doctor explain that the worker had a positive left Spurling's test and positive left straight leg test, but he also explained the methodology behind the tests.

(2) The doctor also referred to x-rays of the worker's cervical and lumbar spine and testified that he is board-certified in neuroimaging.

(3) The company did not question the doctor specifically regarding the 10% rating assigned to O'Bannon's cervical spine during his deposition. 

(4) The two physicians who examined the worker on behalf of the company offered no criticism of the doctor's diagnoses, methods, or impairment ratings in their reports, and neither testified.

"In other words, [the doctor's] 10% impairment rating assigned to the cervical spine went wholly uncontested by any other medical expert," the court wrote. "There was simply no medical evidence presented to question, let alone contradict, his assessment or to point to a conclusion that his deviation from the AMA Guides was not medically sound or grounded in the AMA Guides with regard to the cervical impairment rating, even though it did not strictly adhere to them."

The court emphasized that no physician testified that the doctor's methodology was inconsistent with the AMA Guides or medically unsound. In the absence of competing medical testimony challenging the cervical impairment rating, the court concluded that the ALJ was entitled to rely on the physician's opinion despite the slight deviation from a specific Guides category.

Verdict: The Kentucky Supreme Court reinstated the Board's decision and the ALJ's award, concluding that the physician's impairment rating was sufficiently grounded in the AMA Guides despite a slight deviation from a listed percentage category.

Takeaway

Kentucky courts do not require mechanical adherence to the AMA Guides when assigning impairment ratings. A physician's impairment opinion may remain valid if it is generally grounded in the Guides and supported by sound medical reasoning. Employers challenging an impairment rating should present specific medical evidence identifying why the physician's methodology departs from the Guides, as an unchallenged medical opinion is likely to be accepted by the ALJ.

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