Final Ruling Made on Distal Clavicle Excision Shoulder Ratings: But is This Really the End?

In December, we reported on the Iowa Court of Appeals decision in Koeller v. Cardinal Logistics Mgmt. Corp., No. 25-0172, 2025 WL 3471237 (Iowa Ct. App., Dec. 3, 2025) regarding permanent impairment ratings for distal clavicle excision/resection (DCE) [1] procedures in workers’ compensation claims. The Iowa Supreme Court took the case on further review and has now provided a definitive answer on how DCEs are to be rated in shoulder cases.

The debate surrounding distal clavicle excision ratings rests on the interpretation of the AMA Guides, 5^th Ed. Table 16-27 (p. 506). The Guides provide an impairment rating of 10% of the upper extremity when a DCE procedure has been performed. However, Table 16-18 (p.499) of the Guides applies a 25% modifier to upper extremity impairments in the acromioclavicular joint, which, if applied, lowers the DCE rating to 3% of the upper extremity. The ongoing debate has been twofold: 1) whether the Table 16-18 modifier is properly applied to the 10% DCE rating; and 2) whether the Commissioner is in violation of Iowa Code section 85.34(2)(x) (prohibiting use of lay testimony or agency expertise in determining permanent impairments) by interpreting the Guides and making this decision.

The Iowa Supreme Court’s recent ruling in Koeller v. Cardinal Logistics Mgmt. Corp., No. 25-0172, 2026 WL 1354304 (Iowa 2026) provides a definitive answer to those questions. The Supreme Court reversed prior decisions made by the Commissioner, holding that the Table 16-18 modifier should not be applied to the 10% distal clavicle excision rating provided in Table 16-27 – meaning a DCE procedure results in a 10% upper extremity rating, not 3%. The Supreme Court also held the Commissioner does not use agency expertise when interpreting the meaning of the Guides. The Court found that interpretation of the Guides is a legal determination which is properly made by the Commissioner.

One question still remains: Is the need for a distal clavicle excision a work-related condition? In Koeller, the treating physician opined the DCE procedure was not caused by the work injury, but Claimant’s IME doctor disagreed, and the Commissioner accepted the IME opinion on the medical causation question. The Supreme Court affirmed, finding that substantial evidence supported the Commissioner’s acceptance of the IME opinion. However, if the Commissioner were to accept a medical expert’s opinion finding that a DCE procedure was not caused by the work injury, it would follow that no workers’ compensation benefits associated with an impairment could be awarded for the DCE.

[1] A distal clavicle excision, also known as a distal clavicle resection, is a surgical procedure that removes the outer end of the collarbone (clavicle) where it meets the shoulder blade addressing arthritis, and often done to create more space in the subacromial space, preventing bones from rubbing against the newly repaired tendon during shoulder movement.