Background
Anthony DiJoseph worked as an HVAC technician for Jim’s Commercial Service from 1992 to 1997 and again from 2010 forward, spending his days gripping and grasping tools, lifting equipment, and using his hands continuously. By 2016 he noticed a lump in his hand. By 2019, three fingers on his right hand and two on his left had begun to curl involuntarily—Dupuytren’s contracture, a fibrotic condition that causes progressive digital flexion contractures. He also developed plantar fibromatosis, a related fibrous condition of the feet. He underwent bilateral hand surgeries in 2020 and returned to full duty—without filing a workers’ compensation claim at the time—but symptoms gradually recurred. On January 5, 2023, the pain in his hands and feet became intolerable and he stopped working. He filed a claim petition alleging that his work aggravated both conditions.
All four medical experts—including DiJoseph’s own physicians—agreed that neither Dupuytren’s nor plantar fibromatosis was caused by his work. The conditions have a genetic basis. DiJoseph’s treating physicians, however, testified that his HVAC work “exacerbated” and “aggravated” the pre-existing conditions, while the employer’s independent medical examiners testified there was no work-related aggravation at all. WCJ Joseph Hakun credited DiJoseph’s treating physicians and granted disability benefits, finding that the conditions were “impacted by Claimant’s work activities.” The Workers’ Compensation Appeal Board affirmed.
Employer appealed, arguing three points: (1) WCJ Hakun failed to make the essential causation finding that work was a “substantial contributing factor” to disability; (2) DiJoseph’s medical testimony was legally equivocal; and (3) WCJ Hakun capriciously disregarded the credited testimony of the employer’s experts.
The Court’s Holding
The Commonwealth Court (Judge Wolf, writing) affirmed. The court’s central holding addressed a recurring doctrinal issue in Pennsylvania workers’ compensation: the distinction between an aggravation injury and a case with “competing causes.”
Pennsylvania law recognizes that benefits may be awarded where a work-related aggravation of a pre-existing condition results in disability, even if the underlying disease was not itself work-caused. Where competing causes of disability are alleged, the employer is liable if the work-related cause was a “substantial contributing factor.” Employer argued that because DiJoseph’s own doctors conceded the conditions were genetically caused, the court should have required proof that work was a substantial contributing factor to the disability. The court rejected this framing. The substantial contributing factor test applies where multiple competing causes of disability are alleged; it does not apply where only one theory of disability is advanced. Here, no one alleged that work caused the Dupuytren’s. The sole theory was that work aggravated a pre-existing condition. The proper standard therefore was whether the aggravation “arose in the course of employment and was related to that employment.” The Board was correct to apply the aggravation framework, not the competing-causes framework.
On the equivocality challenge, the court held that Drs. Iannucci and Paiste provided legally sufficient unequivocal testimony. Dr. Iannucci stated there was “a direct relationship” between DiJoseph’s work duties and his disability and that work “exacerbated” his symptoms—a straightforward causation opinion. Dr. Paiste’s passive-voice statement that “bilateral hand conditions were aggravated” was offered in direct response to a question asking whether the conditions were “aggravated by Claimant’s work activity”; read in context, it was not equivocal. Finally, WCJ Hakun’s preference for treating physicians over IME physicians reflects a well-established credibility principle, not capricious disregard of uncontradicted evidence.
Key Takeaways
- The substantial contributing factor causation test applies only when competing causes for disability are alleged. Where a claimant advances only one theory of disability—aggravation of a pre-existing condition—the test is whether the aggravation arose in the course of employment and was related to employment. The two frameworks are not interchangeable.
- Medical testimony is not equivocal simply because the expert acknowledges that the underlying condition has a non-work origin. The relevant question is whether the expert unequivocally attributed the aggravation to work, and passive-voice constructions in expert testimony are read in their full context.
- A WCJ’s credibility preference for a claimant’s treating physician over an employer’s IME physician is not capricious disregard. Greater credence may properly be given to treating physicians, and the WCJ need not explain at length why IME testimony was rejected if the overall decision is comprehensible.
- Dupuytren’s contracture and plantar fibromatosis, while primarily genetic, can support a workers’ compensation aggravation claim when credible medical evidence ties the symptomatic progression to occupational physical demands.
Why It Matters
DiJoseph draws a clear line between two causation doctrines that are sometimes confused in briefing: the “aggravation” framework and the “substantial contributing factor” framework. Misapplying one for the other can be outcome-determinative. Employers who litigate workers’ compensation claims involving genetically predisposed conditions should be aware that conceding the genetic origin of a disease does not automatically shift the inquiry to the substantial contributing factor standard—if the claimant’s only theory is aggravation, the aggravation standard governs.
For claimants’ counsel, the case highlights the continuing value of treating physicians in WC proceedings. Their long-term familiarity with the claimant’s functional limitations is a recognized basis for credibility preferences. DiJoseph also provides a practical reminder that HVAC technicians, carpenters, machinists, and other tradespeople whose work involves sustained manual gripping may have viable aggravation claims even for conditions medicine has historically classified as purely hereditary.