1. Introduction

Parties and posture. Eckardt, a career aircraft mechanic with decades of physically demanding work, sought permanent total disability (“PTD”) benefits against the Treasurer of the State of Missouri as Custodian of the Second Injury Fund (“the Fund”). After an administrative law judge (“ALJ”) awarded PTD benefits, the Labor and Industrial Relations Commission (“the Commission”) reversed and denied benefits. Eckardt appealed to the Supreme Court of Missouri.

Background facts. Over a 40+ year career, Eckardt sustained multiple work-related injuries (including bilateral knees, left shoulder, wrists/carpal tunnel, and a right shoulder injury). His “primary injury” occurred in October 2015, when he was struck by a moving van’s open door, injuring his cervical spine, right shoulder, and right wrist. He underwent cervical fusion in July 2016, reached maximum medical improvement in January 2017, and retired in February 2017 because he could not physically perform his job.

Key issues. The appeal turned on two statutory gatekeeping questions under § 287.220.3:

• Whether Eckardt could treat a non-qualifying preexisting right-shoulder disability (46.4 weeks of permanent partial disability, “PPD”) as qualifying by applying a “synergistic effect”/“load factor” theory to push it over the statute’s 50-week minimum; and
• Whether Eckardt proved medical causation that his PTD resulted from the primary injury combined with only qualifying preexisting disabilities, where his sole medical expert expressly relied on non-qualifying conditions (including the under-50-week right shoulder impairment).

Cross-appeal noted but not reached. The Fund argued occupational diseases (e.g., carpal tunnel syndrome) do not qualify as preexisting injuries under category (ii). The Court affirmed denial of PTD without reaching that question because Eckardt failed the causation proof required even assuming carpal tunnel could be considered.

2. Summary of the Opinion

3. Analysis

3.1 Precedents Cited and Their Influence

• Treasurer of Mo. v. Parker (Mo. banc 2021). The Court relied on Parker for two foundational propositions:
  • The “subsequent compensable work-related injury” is often called the “primary injury,” framing the statutory architecture the Court applied.
  • More importantly, Parker supplies the controlling second-step causation rule: the claimant must show the primary injury results in PTD “when combined with all preexisting disabilities that qualify.” The Court also used Parker to stress that non-qualifying disabilities do not count “against (or for)” the claimant—meaning they must be excluded from the causation calculus, not treated as neutral add-ons that can remain embedded in an expert’s PTD opinion.
• Annayeva v. SAB of TSD of City of St. Louis (Mo. banc 2020). Cited for the claimant’s burden: Eckardt had to prove entitlement to PTD benefits. This burden allocation mattered because the evidentiary gap (no opinion excluding the non-qualifying right shoulder) was fatal to his claim.
• Klecka v. Treasurer of Mo. (Mo. banc 2022). Klecka supplied the Court’s two-condition framework under § 287.220.3 and a near fact-pattern match on proof failure:
  • The Court echoed Klecka’s insistence that PTD status and Fund entitlement are “entirely distinct questions.” Even if Eckardt seemed obviously unemployable, Fund liability requires the particular statutory combination proof.
  • The Court quoted Klecka’s evidentiary point: if the only expert opinion includes non-qualifying disabilities, the claimant must elicit testimony that PTD would persist absent those non-qualifying conditions. Eckardt did not.
• Glasco v. Treasurer of Mo. (Mo. App. 2017); Winingear v. Treasurer of Mo. (Mo. App. 2015); Pierson v. Treasurer of Mo. (Mo. banc 2004). These cases were used as historical context for the “load factor” concept:
  • Winingear and Pierson describe the pre-amendment Fund PPD scheme where the Fund paid only the incremental disability produced by the combination (the “synergistic effect”).
  • Glasco marks that the load-factor concept belonged to the older PPD framework. This history supported the Court’s conclusion that importing that concept into today’s PTD-only regime would contradict strict statutory construction.
• Ryan v. Second Injury Fund (Mo. App. E.D. 2024) and Walton v. Treasurer of Mo. (Mo. App. S.D. 2025). The Court highlighted an active split on whether an earlier “enhanced PPD” award can be used to get an otherwise non-qualifying disability over the 50-week threshold:
  • The Court adopted Walton’s reasoning that § 287.220.3 does not permit such enhancement for threshold qualification.
  • It rejected Ryan’s approach and directed that “Ryan and similar cases should no longer be followed on these grounds,” signaling a statewide resolution of that split in favor of a strict, non-enhanced threshold.
• Obermann v. Treasurer of Missouri (Mo. App. 2023). The Court distinguished Obermann to clarify an important evidentiary line:
  • Experts may consider non-qualifying disabilities in a general medical/vocational history review.
  • But experts may not include non-qualifying disabilities in the causation opinion that ties PTD to the statutory combination (primary + qualifying preexisting). In Obermann, repeated testimony established PTD irrespective of the non-qualifying condition; in Eckardt’s case, the doctor’s PTD opinion expressly relied on “bilateral shoulders,” and there was no alternative opinion excluding the non-qualifying right shoulder.
• Lynch v. Treasurer of Missouri (Mo. App. 2021) and Hazeltine v. Second Injury Fund (Mo. App. 2019). The Court rejected Eckardt’s reliance on these decisions because the Commission did not disbelieve or ignore the doctor; it concluded the opinion—accepted as stated—was legally insufficient to establish Fund liability under § 287.220.3.

3.2 Legal Reasoning

The Court’s reasoning follows the statute’s two-step structure and Missouri’s command to strictly construe workers’ compensation provisions (§ 287.800.1), reviewing legal issues de novo while deferring to the Commission on fact findings when supported by competent and substantial evidence.

A. Step One: Identifying “Qualifying” Preexisting Disabilities (the 50-week minimum)

Under § 287.220.3, at least one preexisting disability must be medically documented, fall within a listed category (here, category (ii): “direct result of a compensable injury as defined in section 287.020”), and equal at least 50 weeks of PPD.

Eckardt’s right shoulder was assigned 46.4 weeks PPD—below the minimum. Eckardt attempted to “enhance” that figure via a load/multiplicity factor by arguing “synergistic effects” of multiple disabilities should increase the PPD weeks for the right shoulder above 50.

The Court rejected this for two independent statutory-structure reasons:

• Doctrinal mismatch. The load factor existed as a way to compute the Fund’s liability for PPD under the prior statutory scheme—i.e., the Fund paid only the incremental disability above the simple sum. But the legislature eliminated Fund PPD claims effective January 1, 2014. The analytic machinery that generated “synergistic” weeks is therefore obsolete in the post-amendment PTD-only regime.
• Textual absence under strict construction. Nothing in § 287.220.3 authorizes increasing the PPD “weeks” assigned to a preexisting disability to clear the 50-week gate. Because the Court must strictly construe the statute, it refused to infer such an enhancement mechanism.

The Court further clarified that even when load-factor analysis existed, it did not function as Eckardt proposed: the synergistic increment was attributable to the combination, not a method to inflate an individual preexisting injury’s weeks for threshold purposes.

B. Step Two: Proving PTD Results from Primary Injury Combined with Only Qualifying Preexisting Disabilities

Even if a claimant has qualifying preexisting disabilities, Fund PTD liability requires proof that the primary injury, when combined with only qualifying preexisting disabilities, results in PTD.

The Court treated the evidentiary problem as straightforward:

• The doctor was the only medical causation witness.
• The doctor’s report expressly relied on “bilateral shoulders” as part of the “tipping point” explanation, which necessarily included the non-qualifying right shoulder condition.
• The record contained no testimony or report stating Eckardt would still be PTD if the non-qualifying right shoulder disability were excluded from the combination.

Thus, the Commission’s denial rested not on disbelief but on legal insufficiency: the sole causation opinion failed to isolate the statutory combination. The Court affirmed that approach as consistent with Parker and Klecka.

3.3 Impact

This decision meaningfully tightens and clarifies Missouri Fund PTD litigation under § 287.220.3 in three practical ways.

• 1) No “creative” path to the 50-week threshold. Claimants cannot use load-factor logic (or prior “enhanced PPD” concepts) to elevate an under-50-week preexisting condition into a qualifying disability. This makes the threshold more mechanical and predictable—and more unforgiving.
• 2) Expert-proof discipline: causation opinions must be “qualified-only.” The decision reinforces a litigation requirement that will affect case development:
  • Experts may take a full history, but
  • The final causation opinion must expressly link PTD to the primary injury combined with qualifying preexisting disabilities and must not rely on non-qualifying conditions.
  Where a claimant has both qualifying and non-qualifying conditions, the safer practice will be to obtain an explicit alternative/segregated causation opinion (“PTD even without X”).
• 3) Statewide resolution of the appellate split. By endorsing Walton v. Treasurer of Mo. and disapproving Ryan v. Second Injury Fund, the Court supplies uniform guidance on whether enhanced PPD can be used to meet the 50-week gate: it cannot. That reduces forum variability and shapes how past awards will (and will not) be leveraged in future Fund PTD claims.

4. Complex Concepts Simplified

• PPD vs. PTD. Permanent partial disability (PPD) compensates lasting impairment that is not totally disabling, often measured in “weeks.” Permanent total disability (PTD) means the claimant is unable to compete in the open labor market because of the disability.
• Second Injury Fund (the Fund). A statutory fund that can owe benefits in limited circumstances when a new work injury combines with qualifying preexisting disability to produce PTD, subject to strict statutory thresholds.
• “Primary injury.” The last (subsequent) compensable work injury that is combined with qualifying preexisting disabilities to assess PTD Fund liability.
• The “50-week threshold” in § 287.220.3. A preexisting disability generally must equal at least 50 weeks of PPD to be considered “qualifying” for Fund PTD purposes.
• “Load factor” / “synergistic effect” / “multiplicity factor.” A now-historical concept used to calculate extra disability attributable to the combination of injuries in pre-2014 Fund PPD cases. This case holds it has no place in today’s PTD-only Fund framework and cannot be used to inflate a preexisting injury’s PPD weeks to meet the 50-week gate.
• Why “including” a non-qualifying disability in a causation opinion is fatal. The statute requires PTD to result from the primary injury combined with qualifying preexisting disabilities. If the only expert opinion reaches PTD by factoring in a non-qualifying condition, the required statutory causal link is not proven.
• Maximum medical improvement (MMI). The point when a condition has stabilized and is not expected to improve substantially with further treatment—often a key marker for assessing permanent disability.

5. Conclusion

Eckardt v. Treasurer reinforces a strict, text-driven approach to Fund PTD claims under § 287.220.3. The Court (1) rejects any attempt to use load-factor/synergistic reasoning (or enhanced-PPD concepts) to push an otherwise under-50-week preexisting disability into “qualifying” status, and (2) demands precise causation proof that PTD results from the primary injury combined with only qualifying preexisting disabilities. The decision’s practical significance is evidentiary as much as doctrinal: claimants must build expert testimony that cleanly isolates the statutory combination, or the Fund claim fails even when overall disability appears obvious.