Gilson Daub Attorney Patrick Mack Represents Client in Significant Iowa Supreme Court Appeal
Patrick Mack, partner and managing attorney of Gilson Daub’s Nebraska and Iowa offices, recently had the opportunity to represent a client in an appeal before the Iowa Supreme Court. The case, Koeller v. Cardinal Logistics, resulted in a decision issued on May 15, 2026.
Mack explains, “This was one of the more interesting appeals I have handled in my career. It required the Iowa Supreme Court to interpret a medical reference publication that is incorporated by reference in the Iowa Workers’ Compensation Act – the AMA Guides 5th Edition. Justice Mansfield accurately described this unique situation when he stated in the decision that the Supreme Court was tasked with resolving ‘an ambiguity created by a seeming contradiction in the AMA Guides.’”
The ambiguity centered on the use of a multiplier when calculating an impairment rating under Chapter 16 of the AMA Guides 5th Edition, which applies to upper extremity injuries. Contrary to what many might assume, using the multiplier actually reduces the overall percentage of disability assigned to the injured worker. In turn, this can reduce the injured worker’s entitlement to permanent partial disability compensation.
The appeal specifically focused on Section 16.7 and Table 16-27 of Chapter 16. Table 16-27 applies to total shoulder implant arthroplasties and resection arthroplasties. This commonly includes, but is not limited to, injuries requiring a shoulder surgery where the claimant’s distal clavicle is resected.
The multiplier is used in many the tables contained in Chapter 16 of the AMA Guides 5th Edition, but that chapter is completely silent on whether the multiplier should be used when calculating impairment ratings using Table 16-27. Nowhere in Chapter 16 does it state that the multiplier should be used when calculating an impairment rating using Table 16-27. However, it also does not state anywhere in Chapter 16 that the multiplier should not be used. Despite this, it has been our experience that the doctors in Iowa apply the multiplier when using Table 16-27.
In the Koeller decision, the Iowa Supreme Court determined that the multiplier should not be applied when using Table 16-27. The case is now being remanded back to the Commissioner to determine Claimant’s entitlement to permanent partial disability compensation.
Mack adds, “It will be interesting to see how the Commissioner decides this case on remand. Regardless of how it is decided, it may take another trip to the Iowa Supreme Court to fully resolve how impairment ratings should be calculated for upper extremity injuries in Iowa.”
If there are any questions about this case or Iowa workers’ compensation law generally, please don’t hesitate to reach out to Gilson Daub’s Iowa team.
