Since the 2005 Escobedo v. Marshall’s decision, the California Workers’ Compensation community had considered the issue of apportionment to pre-existing pathology pretty well solidified. Then came the 2017 decision in Hikida v. WCAB (2017) 12 Cal.App.5th 1249. Hikida had the profound effect of limiting a defendant’s ability to establish apportionment to pre-existing factors when permanent disability was solely caused by reasonable medical treatment of the industrial injury.

Hikida v. WCAB. In Hikida, the applicant developed carpal tunnel syndrome [CTS] as an industrial injury. An AME determined that the CTS was 10% due to non-industrial factors. As a result of an industrially provided carpal tunnel release, she developed Complex Regional Pain Disorder [CRPS]. The CRPS condition rendered her permanently totally disabled. A WCJ allowed apportionment of 10% based on the AME original assessment of the carpal tunnel syndrome. However, the Court of Appeals reversed and disallowed the apportionment since the medical evidence supported that the total disability was directly and entirely related to the CPRS, not the underlying carpal tunnel.

The holding in Hikida evolved through WCAB decisions to the point that it was used as support for the position that an employee would be entitled to unapportioned compensation when permanent disability was caused by reasonable industrial medical treatment. (See Sutter Solano Medical Center v. WCAB (Go) (2018) 83 CCC 381 (writ denied).) In essence, employees began to assert that ANY disability due to industrial medical treatment was not subject to apportionment.

Fast forward to May 2020.

County of Santa Clara v. WCAB (Justice). The 6th District Court of Appeal issued its decision in County of Santa Clara v. WCAB (Justice) that significantly limited the developing interpretation of the Hikida holding. 

In Justice, the employee fell at work causing a meniscal tear in the left knee. In time, her right knee became symptomatic as a consequence of the left. The employee underwent a total right knee replacement. She later underwent a total left knee replacement. The parties referred the case to an AME who noted osteoarthritis, a tear and other pathology in both knees all of which pre-dated the fall at work.

Despite the clear evidence of pre-existing pathology, the employee was awarded 48% permanent disability without apportionment. In disallowing apportionment, the trial judge stated, “Hikida holds that where medical treatment results in an increase in permanent disability, permanent disability should be awarded without apportionment.”

The defendant appealed and the 6^th DCA saw a factual distinction between the Hikida and Justice cases. The appellate decision clarified the case scenarios: “The Hikida court’s conclusion that there should be no apportionment makes sense only because the medical treatment in Hikida resulted in a new compensable consequential injury, namely CPRS, which was entirely the result of the industrial medical treatment. It was this new compensable consequential injury that, in turn, led entirely to the injured worker’s permanent disability. …Although parts of the Hikida opinion can be read to announce a broader rule that there should be no apportionment when medical treatment increases or precedes permanent disability, it is clear that the rule is actually much narrower. Put differently, Hikida precludes apportionment only where industrial medical treatment is the sole cause of the permanent disability [emphasis added].

Take away. The Justice case provides significant clarification to the law of apportionment and severely limits the progressive evolution of Hikida’s holding. The Justice decision references the “requirement” to apportion where there are multiple causes. The case notes the employer shall be required to pay for permanent disability only related to the effects of the industrial injury and not to disability attributed to other factors consistent with the Escobedo decision.

However, defendants should be reminded that while the Justice holding allows for apportionment non-industrial factors contributing to impairment after industrial medical care, it is still the defendant’s burden to establish the existence of those non-industrial factors by substantial medical evidence. A defendant should develop medical evidence of pre-existing pathologies and comorbidities (diabetes, heart conditions, smoking use of certain medications etc.) that can contribute to residual impairments and disabilities.