Labor code 4664(a) states that the employer "shall only be liable for the percentage of permanent disability directly caused by the injury arising out of and occurring in the course of employment".
Section 4664(b) states that "if the applicant has received a prior award of permanent disability, it shall be conclusively presumed that the prior permanent disability exists at the time of any subsequent industrial injury. This presumption is a presumption affecting the burden of proof".
Does Labor Code section 4664 mean that if a claimant sustained an injury in 1999 that settled by way of stipulations with request for award for 15%, thereafter sustaining another injury to the same body parts in 2006 warranting the residual disability of 25%, that the residual disability after apportionment will be 10%?
The answer is not as straightforward as you would think. A conclusive presumption is not necessarily something that is conclusively presumed, at least for purposes of this labor code section and how it has been interpreted thus far. We know from the Kopping case that in order to obtain apportionment under labor code section 4664 the defendant has the burden of proving the prior award and how the prior disability overlaps with the current disability. It is insufficient to simply point out that a prior award to the same body part exists.
Unfortunately the concept of overlap (whether successive injuries to the same body part or to separate parts of the body) gets somewhat complicated when prior awards are calculated using different standards.
In one case, the AME was also the same AME for an older PDRS case. He attempted to retroactively rate the prior injury under the AMA guides. However the AME used the DRE method to do the retrospective rating yet, for the current injury, he used the ROM method. This resulted in the WCAB remanding the case back to determine whether it is possible to rate the injury under the same (ROM) standard.
In another case the AME report successfully translated two prior awards issued under the PDRS with the injury in question by examining the prior AME reports from the old injury, rating the new injury under the AMA guides, describing what restrictions would be applicable if the 1997 schedule applied and then comparing what the old versus the new restrictions would be.
The lower courts have placed importance on the criteria used to determine the percentage of disability for a prior award or disability. This has so far required an "apples to apples" comparison. Whether this will hold up in higher courts is somewhat unclear.
It is of critical important that the evaluator be instructed on what is needed to ensure that LC 4664 apportionment holds up. A mere statement that the claimant sustained an injury to the same body parts which resulted in the stipulations with request for award and therefore apportionment is appropriate is likely insufficient. The reviewing attorney and/or claims examiner needs to be cognizant of this potential pitfall.
Please do not forget that if apportionment fails under 4664 there is always labor code section 4663 – but that is the subject of a different article.
© Copyright 2009 Grancell, Lebovitz, Stander, Reubens and Thomas. This article originally appeared in the firm's Quarterly Review (Second Quarter 2009). Reprinted with permission.