With the enaction of California Labor Code Sections 4663 and 4664 within SB 899 in 2004, the law regarding apportionment was radically changed.  The transition has not always been a smooth one and the Workers’ Compensation Appeals Board has been issuing decisions ever since in an attempt to define what apportionment is and to clarify when it may be applied.

Pertinent provisions of Labor Code Section 4663 state that:

(a) Apportionment of permanent disability shall be based on causation.

(b) Any physician who prepares a report addressing the issue of permanent disability due to a claimed industrial injury shall, in that report, address the issue of causation of the permanent disability.

(c) “…A physician shall make an apportionment determination by finding what approximate percentage of the permanent disability was caused by the direct result of injury arising out of and occurring in the course of employment and what approximate percentage of the permanent disability was caused by other factors both before and subsequent to the industrial injury, including prior industrial injuries.”

In seminal cases such as Brodie (Brodie v. WCAB (2007)) 40 Cal. 4th 1313, 72 Cal Comp. Cases 565) and Escobedo (Escobedo v. Marshalls (2005)) 70 Cal.Comp.Cases 604 (WCAB en banc)), the WCAB went on to underscore the fact that logic, common sense, and the basic principles of medicine dictate that there may be multiple causes contributing to any disability and an employer/insurance company is only liable for the portion of disability caused by the industrial injury pursuant to Labor Code Section 4664.

However, the WCAB has also issued decisions that tend to muddy the waters regarding apportionment.  The decision in Hikida (Hikida v. WCAB (2017)) is a prime example of this.  In this case, the WCAB upheld the opinion of the Agreed Medical Examiner that there could be no apportionment of disability to nonindustrial causes because the applicant had developed CRPS as a result of the treatment she received for her industrial injury. It was the new compensable consequential injury that, in turn, led entirely to the injured worker’s permanent disability.

Recently, I have received more than one medical-legal report from PQME’s and AME’s alike in which the physician attempts to apply the Hikida decision incorrectly, determining that the defendant is not entitled to any nonindustrial apportionment because the doctor believes the treatment, he/she received for the industrial injury worsened his/her disability.  In fact, it seems that these med-legal evaluators believe that Hikida kills off the possibility of non-industrial apportionment altogether.

Fortunately, the WCAB has provided us with a very clear and well-reasoned response to the problems raised by the Hikida decision: a recently published decision of the Sixth District Court of Appeals in County of Santa Clara v. WCAB (Justice), 2020 Cal. App. LEXIS 461.  In fact, the court in Justice clarified that it did not intend for the holding in Hikida to be applied so broadly in reference to apportionment.

In the Justice decision, the applicant had an industrial injury involving her knees and ultimately had a knee replacement surgery.  The med-legal evaluator disallowed all apportionment to non-industrial causes under Hikida.

In its holding, the Court of Appeals made a few key statements regarding the concept of apportionment.  First, “Where there is unrebutted substantial medical evidence that nonindustrial factors played a causal role in producing the permanent disability, the Labor Code demands that the permanent disability “shall” be apportioned.” (Id. at p. 16.) And second, “There is no case or statute that stands for the principle that permanent disability that follows medical treatment is not subject to the requirement of determining causation and thus apportionment, and in fact such a principle is flatly contradicted by sections 4663 and 4664.” (Id. at p. 18.)

The court in Justice goes on to distinguish that the reason for the decision to disallow apportionment in Hikida should be subject to a much narrower interpretation because the facts in that case were unique.  In Justice, the applicant developed an entirely new diagnosis as a result of a failed surgery that was, in fact, only the result of the failed surgery itself.  Obviously, this is not the case in the majority of workers’ compensation claims and, therefore, Hikida should be not applied.


Thus, thanks to the court’s recently published decision in the Justice case, a defendant’s right to apportionment to non-industrial factors under Labor Code Sections 4663 and 4664 remains alive and well.

At Yrulegui & Roberts, our workers’ compensation defense attorneys will continue to fight for your rights under the law to such apportionment to all non-industrial causes of disability, as well as all other affirmative defenses in each and every case.  If you have any questions regarding whether you are entitled to non-industrial apportionment in a case, contact our firm today.