Third Edition of AMA Guides is “Starting Point” for Impairment Ratings in Colorado

The mandate provided in Colo. Rev. Stat. Ann. §§ 101(3)(a)(I) and 101(3.7), that impairment ratings must be “based on” the revised third edition of AMA Guides, does not prevent a physician from using a “normalization” process to make the impairment determination in spite of the fact that such a process is not mentioned in the revised third edition, held a Colorado appellate court in Fisher v. Indus. Claim Appeals Office, 2021 COA 27, 2021 Colo. App. LEXIS 337 (Mar 4, 2021). The term “based on” should be understood as meaning “the starting point, not the exclusive fount, of impairment rating methodology,” stressed the Court [Opinion, ¶19]. A physician should also base his or her impairment rating opinion on other “medical treatment guidelines and utilization standards” [Colo. Rev. Stat. Ann. § 101(3.7)]. Here, it appeared that the normalization process had been taught to—and used by—physicians for more than ten years.

Background

Claimant, a correctional officer for the Colorado Department of Corrections, suffered an injury to his left knee while walking up some stairs in December 2017. The department admitted that claimant injured his knee while he was on duty. Claimant’s treating physician determined that Claimant reached MMI as of early January 2019. The physician also decided that the injury to Claimant’s knee was permanent. Using a method known as “normalization,” described below, the physician calculated that Claimant’s net impairment was 13 percent of the lower leg. The department filed a final admission of liability based on the MMI date and the impairment rating.

The Normalization Process

The physician explained in a deposition that “normalization” is a process in which doctor compares the range of motion of a patient’s uninjured joint — in this case, claimant’s right knee — with the range of motion of the patient’s injured joint — in this case, claimant's left knee. The range of motion in the uninjured joint is considered to be the baseline. Once the range of motion in both joints is determined, the doctor then subtracts any impairment to the range of motion of the uninjured joint from the impairment to the injured joint to reach the final impairment figure.

The Desk Aid suggests, in relevant part, that using the uninjured joint for comparison purposes may be “a better representation of the patient's pre-injury state than … [the] population norms’ described in the revised third edition of the AMA Guides. During the physician’s deposition, he noted that while the third edition did not mention normalization, the topic was discussed in the fifth edition. Moreover, he indicated that the normalization process had been taught to doctors in workers' compensation accreditation courses for at least a decade.

At a hearing, Claimant challenged the physician’s methodology of “normalizing” the impairment to his left knee because it had not been based on the AMA Guides, third edition. While not mentioned in the third edition of the Guides, the practice is summarized in a Desk Aid published by the Department of Labor and Employment, Division of Workers' Compensation. In Claimant's case, normalization reduced his range of motion impairment by nine percentage points because he had pre-existing degenerative arthritis in his knees.

ALJ’s Decision

The ALJ rejected Claimant’s challenge to the Desk Aid, concluding that normalization was a legitimate process and that its use did not violate any mandate contained in Colo. Rev. Stat. Ann. § 101(3)(a)(I), which essentially states that impairment ratings must be based on the revised third edition of the AMA Guides in effect as of July 1, 1991. The judge awarded Claimant benefits based on the physician’s determination that the claimant’s left knee was thirteen percent impaired. The reviewing panel affirmed.

Appellate Court Opinion

As to Claimant’s position that the normalization process cannot be utilized by physicians since it is not contained in the revised third edition of the Guides, the appellate court first stressed that the plain language of subsections 101(3)(a)(I) and 101(3.7) did not bar the physician from employing the process of normalization. Both provides did provide that impairment rating “shall be based on” the revised third edition of the Guides.

Meaning of “Based”

The court concentrated on the meaning of “based.” The court said:

So, when the legislature stated that impairment ratings shall be "based on" the revised third edition of the Guides, it meant that the revised third edition is the starting point, not the exclusive fount, of impairment rating methodology. By employing "based on," instead of using a more limiting word such as "only," the legislature made clear that doctors should have some leeway and discretion when determining a patient's final impairment rating. When viewed from this perspective, we can see that the legislature intended the revised third edition to be the foundation upon which a doctor can begin to develop an impairment rating [Opinion, ¶ 19].

The court emphasized that, according to the physician, normalization had been taught to doctors for at least ten years — suggesting that normalization was a utilization standard. Moreover, it is discussed in the Desk Aid, which indicated to the court that normalization was found in medical treatment guidelines.

The term “based on” did not restrict doctors by requiring only the use of the revised third edition of the Guides, said the court. The court stressed that the Desk Aid stated that the determination of whether normalization was necessary rested squarely with the examining doctor, who “may” follow normalization procedures “when deemed appropriate.” In the court’s view, the Desk Aid did not reject the revised third edition of the Guides; rather, it expanded on the factors upon which doctors may, in their discretion, base impairment ratings. And, as the court had earlier pointed out, the legislature gave doctors that discretion by using the phrase “based on” in subsections 101(3)(a)(I) and 101(3.7).