The Return of “Major Cause” Under the Administrative Workers' Compensation Act (AWCA)

Since extensive amendments to the then-Workers’ Compensation Act were enacted in 2005, the term “major cause” has been used by the Oklahoma Legislature in its definition of a compensable injury. Generally speaking, in order for an on-the-job injury to be valid, greater than 50% of the resulting injury, disease or illness must be related directly to the work-related trauma, be it by way of a single event, or through cumulative trauma. However, this term was replaced by the usage of “sole cause” with enactment of the Administrative Workers’ Compensation Act (AWCA) in 2014. Per the AWCA, a compensable injury “means damage or harm to the physical structure of the body…caused solely as the result of either an accident, cumulative trauma or occupational disease arising out of the course and scope of employment.” This “sole cause” test caused some confusion, especially in claims involving cumulative trauma, in that it appeared to increase the burden of proof for a claimant who may have had some pre-existing arthritis or other non-job related pathology which made it more difficult to prove a compensable injury. The usage of sole cause was ultimately appealed, with the OK Court of Civil Appeals determining that literal application of the term sole cause would result in an “arbitrary and unreasonable denial of a remedy to a large class of injuries.” Sequel Youth & Family Services LLC v. Ayisi, 2018 OK CIV APP 7. Following the Ayisi decision, the AWCA was amended to resume the use of major cause in its definition of compensable injury. The sole cause language was deleted in place of the older major cause standard. So how does major cause apply from a practical standpoint - specifically, does major cause refer only to the need for medical treatment once a claim has been found compensable, or does it refer to the degree of evidence needed to prove a compensable claim to begin with?

The OK Court of Civil Appeals recently addressed this question in its opinion in Bryan Linn Farms v. Arthur Monsebais, Jr. In Monsebais, the claimant admittedly suffered from pre-existing, though non-symptomatic, arthritis in his injured knee. Both the treating doctor and Independent Medical Examiner (IME) determined that the claimant had aggravated his pre-existing condition at work, but also felt that the need for total knee replacement, recommended as treatment, resulted from the pre-existing arthritic condition rather than the trauma sustained on the job. In other words, the major cause of the need for knee replacement was the underlying arthritis. The claimant’s subsequent request for the total knee replacement was denied at the trial level based upon the major cause defense. This denial of treatment was subsequently overturned by the Commission En Banc.

Employer appealed to the OK Supreme Court, with the matter being assigned to Division 4 of the Court of Civil Appeals (COCA). The COCA unanimously upheld the need for a total knee replacement writing - ‘The “major cause” analysis is not involved in determining the need for or against a particular course of medical treatment for a compensable injury. Major cause is used in the analysis of determining a compensable on-the-job- injury…The employment must be the major cause of the injury, but employment does not need to be the major cause of the need for a particular course of treatment for a compensable injury. Claimant is not required to prove that the employment is the major cause of the need for a total knee replacement. The ALJ and Dr.s….erroneously imposed a burden on the claimant that is not required under the statutory scheme. An employer is required to provided medical treatment as may be reasonably necessary in connection with the compensable injury.’

So, as we analyze defenses going forward, we must be mindful that the term major cause applies to the underlying compensability of a claim, rather than reasonable and necessary medical treatment once a claim is determined to be compensable.

Please feel free contact our office should you have any questions regarding this significant appellate ruling, or with any other questions you may have.