Iowa Top Court Clears Up AMA Guides Question

Case File

The Iowa Supreme Court applied the AMA Guides to clarify that the impairment value for a distal clavicle excision didn't get the 25% multiplier from Table 16-18.

Case

Klein v. Whirlpool Corp., No. 25-0458 (Iowa 06/26/26, unpublished)

What Happened?

A worker injured his right shoulder while working for Whirlpool. The parties agreed that he sustained some permanent disability, but they disputed the extent of it.

Out of the three physicians who offered impairment ratings, the deputy commissioner found most persuasive the physician who assigned a 6% impairment for loss of range of motion and an additional 10% impairment for the distal clavicle excision under Table 16-27 of the AMA Guides. 

However, the deputy commissioner concluded that the 10% value for the distal clavicle excision had to be multiplied by 25% as instructed by Table 16-18, which reduced the distal clavicle excision impairment from 10% to 2.5%.

On intra-agency review, the commissioner affirmed. The district court denied the worker's petition for judicial review. The court of appeals affirmed the district court. The worker appealed to the Iowa Supreme Court.

Rule of Law

Under Koeller v. Cardinal Logistics Management Corp., 2026 WL 1354304 (Iowa 05/15/26), because the AMA Guides have been incorporated into Iowa workers' compensation law, their interpretation is properly within the domain of the agency and, ultimately, the courts. 

What the Iowa Supreme Court Said

The court found that the deputy commissioner erred in applying the 25% Table 16-18 multiplier and reducing that portion of the rating to 2.5%. Under the Koeller case, Table 16-27 provides the value of impairment of the upper extremity for a distal clavicle excision.

"Because Table 16-27 already gives an upper extremity impairment value, the additional conversion under Table 16-18 is not made," the court wrote. "'The specifics in section 16.7b of the AMA Guides prevail over the general statement in section 16.7.'"

Verdict: The Iowa Supreme Court vacated the Court of Appeals' decision, reversed the district court's judgment, and remanded the case.

Takeaway

In Iowa, the 10% impairment value for a distal clavicle excision under Table 16-27 is not subject to the 25% multiplier in Table 16-18 in the AMA Guides.

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