Legal Update: Iowa Supreme Court Changes Impairment Ratings for Clavicle Excisions

        On 5/15/2026, the Supreme Court of Iowa issued a ruling in Koeller v. Cardinal Logistics Mgmt. Corp. that will have a significant impact on the way that claims involving clavicle excisions are compensated moving forward.

In this case, the claimant alleged that he injured his left shoulder while unloading his truck at work. The Agency had previously ruled that, in accordance with the prior decision in Jay v. Archer Skid Loader Service, rating physicians must apply a 25% multiplier to any rating for a distal clavicle resection. As a result, the 10% impairment rating assigned by the Claimant’s expert was reduced to 2.5%. On judicial review, the Supreme Court was tasked with determining the correct way to interpret the language of the AMA Guides (5^th Ed.) with respect to distal clavicle resections. In particular, the Court reconciled “an ambiguity created by a seeming contradiction” between Section 16.7 and Table 16-27. Koeller, 2026 WL 1354304 at *6 (Iowa 2026).

The opening of Section 16.7 of the AMA Guides states that the severity of impairments related to the “presence of resection or impact arthroplasty,” among other “impairments of the hand and upper extremity,” is rated in accordance with “Tables 16-19 through 16-30” before being “multiplied by the maximum value of the unit involved as specified in Table 16-18.” Id. The section of Chapter 16 that pertains to distal clavicle excisions is Section 16.7(b), and the table that pertains to 16.7(b) is Table 16-27. However, Table 16-27—unlike the other tables that are part of Section 16.7—does not include a footnote that states “[m]ultiply the relative value of the joint (Table 16-18) to determine the . . . impairment.” Id. As a result, this raises a question: should the 10% impairment rating assigned to shoulder resections under Table 16-27 be multiplied by the maximum impairment value of 25% for “disorders of the AC joint” listed in Table 16-18? Or does the absence of a footnote mean that the 10% impairment rating should stand as-is, with no multiplier?

In its decision, the Court concedes that “[s]tatutory interpretation isn't an exact science, and we need to acknowledge that both sides of this debate have some merit." Id. at *7. However, the court ultimately found that the situation was governed by Iowa Code section 4.7, which states that if a conflict between a general provision and a special provision is “irreconcilable, the special or local provision prevails as an exception to the general provision.” Iowa Code § 4.7. Based on this, the Court concluded that Table 16-27 was an exception to the general provisions of Section 16.7, and that “the values in Table 16-27 are not subject to a . . . multiplier.” Id.

What this means for parties in workers’ compensation cases, in plain English, is that clavicle excisions now receive higher impairment ratings and are worth more money. When clavicle excisions were subject to the 25% multiplier provided for by Table 16-18, the total impairment rating was capped at 2.5% or 3%. Now, however, the impairment rating for a clavicle excision is 10%. This equates to roughly 28-30 weeks more PPD than claimants received under the previous interpretation of Table 16-27.