Almost immediately after the Pennsylvania Supreme Court issued its game-changing workers' compensation ruling in Protz v. Workers' Compensation Appeal Board (Derry Area School District) last year, attorneys began gearing up to litigate the natural follow-up question: Should the decision be applied retroactively?

A much buzzed-about June 6 ruling by the Commonwealth Court en banc may have finally answered that question. “May have” is the operative phrase, however, because not everyone agrees on the potential significance of the decision. The confusion appears to boil down to competing definitions—or, perhaps more accurately, expectations—of “retroactive application.”

Here's what we know for sure: The Supreme Court's ruling in Protz a year ago partially reversed a Commonwealth Court decision by invalidating in its entirety Section 306(a.2) of the Workers' Compensation Act, which required doctors performing impairment rating evaluations of claimants to rely on “the most recent edition” of the American Medical Association Impairment Rating Guides. The justices found that portion of the statute unconstitutionally delegated the legislature's lawmaking authority to the AMA. Consequently, IREs performed pursuant to those guidelines were unconstitutional.