Introduction
In California workers' compensation cases, apportionment of permanent disability remains one of the most contested issues. Since the 2004 reforms and the landmark Escobedo v. Marshalls decision, physicians have been required to determine what percentage of permanent disability is directly caused by the industrial injury versus other factors. However, many Qualified Medical Evaluators (QMEs) continue to misapply the law, particularly when apportioning to asymptomatic degenerative conditions.
This blog post examines a recent case that highlights common errors in apportionment opinions and provides guidance on how to challenge legally vulnerable determinations.
The Case: Apportionment Based on MRI Findings Alone
In a recent case, a QME apportioned 20% of an injured worker's left knee disability to "preexisting asymptomatic degenerative changes" based solely on MRI findings. The QME's report contained several problematic statements:
- The QME claimed the apportionment "is not based merely on existence of an underlying asymptomatic degenerative condition, but rather its contribution to Ms. Scott's disability."
- However, the QME also acknowledged: "She denies preexisting functional limitations. The MRI findings represent preexisting asymptomatic degenerative changes which now contribute to her disability. There is no documentation prior to her 11/02/22 date of injury in regard to left knee medical treatment, functional restrictions, symptomatic complaints, or objective findings."
- When asked to explicitly confirm whether apportionment was based solely on asymptomatic MRI findings, the QME stated: "My understanding of California Labor Code 4663 is such that her apportionment based on her preexisting MRI findings of her left knee are justified given their contribution to her disability."
This opinion demonstrates a fundamental misunderstanding of apportionment law that we frequently encounter in our practice.
The Legal Framework: What Constitutes Valid Apportionment?
Labor Code 4663 and Substantial Medical Evidence
[Labor Code § 4663] requires physicians to make apportionment determinations based on causation of permanent disability. However, simply identifying a cause is insufficient. The physician must provide substantial medical evidence explaining:
- The specific nature of the disability
- How and why the disability is caused by the current industrial injury
- How and why the disability is caused by other factors
- The basis for the physician's opinion
Escobedo v. Marshalls: The "How and Why" Requirement
The WCAB in Escobedo established that a physician must explain the "how and why" of apportionment. The decision stated: "if a physician opines that 50% of an employee's back disability is caused by degenerative disk disease, the physician must explain the nature of the disease, how and why it is causing permanent disability at the time of the evaluation, and how and why it is responsible for approximately 50% of the disability."
Apportionment to Asymptomatic Conditions
While Escobedo and subsequent cases like E.L. Yeager Construction v. WCAB (Gatten) established that apportionment can include "pathology, asymptomatic prior conditions and retroactive prophylactic work preclusions," these cases still require the physician to explain the specific mechanism by which these asymptomatic conditions are actually contributing to the current disability.
In City of Petaluma v. WCAB (Lindh), the Court of Appeal emphasized that a medical opinion must "set forth the reasoning behind the physician's opinion, not merely his or her conclusions."
Common Errors in Apportionment Opinions
Based on our experience, we frequently see the following errors in QME reports:
- Circular Reasoning : The physician states that asymptomatic findings "contribute to disability" without explaining how they contribute.
- Mere Existence : Despite claiming otherwise, the physician effectively bases apportionment merely on the existence of a condition rather than its actual contribution to disability.
- Lack of Quantification Basis : The physician fails to explain why they chose a specific percentage (e.g., 20% rather than 10% or 30%).
- Failure to Differentiate : The physician fails to explain how they differentiated between disability caused by the industrial injury and disability caused by pre-existing conditions.
How to Challenge Legally Vulnerable Apportionment Opinions
When faced with a legally vulnerable apportionment opinion, consider the following strategies:
- Request Clarification from the Physician
Draft a detailed letter to the QME requesting clarification on:
- The specific mechanism by which the asymptomatic condition contributes to disability
- The basis for the specific percentage apportioned
- How the physician differentiated between industrial and non-industrial causes
- Any scientific literature supporting the opinion
- Depose the Physician
During deposition, ask pointed questions about:
- Whether the physician is aware of the legal requirements for apportionment
- The specific "how and why" of the asymptomatic condition's contribution
- Whether the patient had any pre-injury symptoms, treatment, or limitations
- The basis for the specific percentage apportioned
- File a Petition for Removal or Reconsideration
If the WCJ accepts an apportionment determination that lacks substantial medical evidence, consider filing a petition arguing that:
- The physician's opinion does not constitute substantial medical evidence
- The opinion fails to explain the "how and why" of apportionment
- The opinion effectively bases apportionment merely on the existence of a condition
- The opinion lacks a reasoned explanation for the percentage apportioned
Sample Letter Challenging Apportionment
Below is an excerpt from a letter we recently drafted challenging an apportionment determination:
Dear Dr. [Name]:
Your opinion that "these significant degenerative findings on her left knee MRI dated 12/07/22 contribute 20% to her disability" appears to lack the specific explanation required by law regarding "how and why" these asymptomatic degenerative findings are contributing to Ms. Scott's current disability.
While it is true that Escobedo and subsequent cases established that apportionment can include asymptomatic prior conditions, these cases still require the physician to explain the specific mechanism by which these asymptomatic conditions are actually contributing to the current disability.
To constitute substantial medical evidence supporting apportionment, please explain:
- The specific pathophysiological mechanism by which the asymptomatic degenerative changes are contributing to the current disability
- The medical reasoning behind your determination that precisely 20% of her disability is attributable to these pre-existing changes
- How you differentiated between disability caused by the industrial injury and disability caused by the pre-existing asymptomatic condition
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Conclusion
Challenging legally vulnerable apportionment opinions requires a thorough understanding of the law and careful analysis of medical reports. When a QME bases apportionment solely on asymptomatic findings without explaining how and why they contribute to disability, the opinion likely does not constitute substantial medical evidence.
By requesting clarification, deposing the physician, or filing a petition for removal or reconsideration, you can effectively challenge these opinions and ensure that your clients receive the full benefits they are entitled to under California workers' compensation law.
Remember, while apportionment to asymptomatic conditions is legally permissible, the physician must still provide substantial evidence explaining how and why the condition contributes to the current disability. A conclusory statement that MRI findings "contribute to disability" without explaining the mechanism of contribution does not meet the substantial evidence standard required by law.
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About the Author : Bruce J. Levitz, Esq. is a workers' compensation attorney specializing in complex workers' Compensation issues with the development of specific AI prompts. With over 40 years of experience representing injured workers, he has successfully challenged numerous legally vulnerable determinations.
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Disclaimer: This blog post is intended for informational purposes only and does not constitute legal advice. Each case is unique, and readers should consult with a qualified attorney regarding their specific circumstances.