SUMMARY

March 4, 2021

2021COA27

No. 20CA0732, Fisher v. ICAO — Labor and Industry —

Workers’ Compensation — Benefits — Physical Impairment 

Ratings

Subsections (3)(a)(I) and (3.7) of section 8-42-101, C.R.S. 

2020, state that, in workers’ compensation cases, physical 

impairment ratings “shall be based on” the revised third edition of 

the American Medical Association’s Guides to the Evaluation of 

Permanent Impairment. In this opinion, a division of the court of 

appeals considers the question whether the phrase “shall be based 

on” the revised third edition of the Guides means that a doctor is 

barred from using an evaluative process to determine an 

impairment rating that is not described in the Guides. The division 

answers the question “no.”

The summaries of the Colorado Court of Appeals published opinions 

constitute no part of the opinion of the division but have been prepared by 

the division for the convenience of the reader. The summaries may not be 

cited or relied upon as they are not the official language of the division. 

Any discrepancy between the language in the summary and in the opinion 

should be resolved in favor of the language in the opinion.
COLORADO COURT OF APPEALS 2021COA27

Court of Appeals No. 20CA0732

Industrial Claim Appeals Office of the State of Colorado

WC No. 5-068-151

Kerry Fisher,

Petitioner,

v.

Industrial Claim Appeals Office of the State of Colorado and State of Colorado 

Department of Corrections,

Respondents.

ORDER AFFIRMED

Division I

Opinion by CHIEF JUDGE BERNARD

Rothenberg* and Taubman*, JJ., concur

Announced March 4, 2021

Hassler Law Firm, LLC, Stephen M. Johnston, Pueblo, Colorado, for Petitioner

No Appearance for Respondent Industrial Claim Appeals Office

Philip J. Weiser, Attorney General, D. Clay Thornton, Senior Assistant Attorney

General, Denver, Colorado, for Respondent State of Colorado Department of 

Corrections

*Sitting by assignment of the Chief Justice under provisions of Colo. Const. art. 

VI, § 5(3), and § 24-51-1105, C.R.S. 2020.
1

¶ 1 The American Medical Association publishes Guides to the 

Evaluation of Permanent Impairment that have been used over the 

years by doctors in workers’ compensation systems to evaluate and 

to describe patient impairments in terms of percentages of total 

disability. Ellen Smith Pryor, Compensation and a Consequential 

Model of Loss, 64 Tul. L. Rev. 783, 798 n.42 (1990). The Guides are 

focused on “specifying methods of measurement and the 

assignment of a single percentage for a given impairment.” Id. 

There are different editions of the Guides — the most recent edition 

is the sixth, see AMA, AMA Guides to the Evaluation of Permanent 

Impairment, Sixth Edition: Hardcover, https://perma.cc/6JZ6-6T7U

— and there are “significant differences among” them, “not only in 

emphasis of certain areas, but also as a reflection of the latest 

consensus in medical science within its subject matter.” Litchfield’s 

Case, 15 N.E.3d 252, 254 n.7 (Mass. App. Ct. 2014).

¶ 2 The revised third edition of the Guides is mentioned in section 

8-42-101, C.R.S. 2020, of Colorado’s workers’ compensation 

statutes, specifically in subsections (3)(a)(I) and (3.7). These 

subsections address one aspect of how a doctor should evaluate a 

work-related injury of a joint to determine the extent of the joint’s 
2

impairment, which, in turn, is used to determine the level of 

compensation that the worker will receive. 

¶ 3 As is pertinent to our analysis, subsection 101(3)(a)(I) states 

that “impairment rating guidelines . . . shall be based on the revised 

third edition of the [Guides] in effect as of July 1, 1991, and medical 

treatment guidelines and utilization standards.” Subsection 

101(3.7) is similar: “On or after July 1, 1991, all physical 

impairment ratings used under articles 40 to 47 of this title shall be 

based on the revised third edition of the [Guides], in effect as of July 

1, 1991.” 

¶ 4 In this appeal, we must address a question of statutory 

interpretation: Does the phrase “shall be based on the revised third 

edition” of the Guides mean that a doctor is barred from using an 

evaluative process to determine an impairment rating that is not 

described in the Guides’ revised third edition? For reasons that we 

set out below, we answer this question “no.” 

¶ 5 This statutory interpretation question is raised by claimant, 

Kerry Fisher, who seeks review of a final order of a panel of the 

Industrial Claim Appeals Office. The order upheld the decision of 

an administrative law judge, who assigned him a scheduled 
3

impairment rating of thirteen percent for his injured left knee. We 

affirm.

I. Background

¶ 6 The facts of this case are undisputed. Claimant worked as a 

correctional officer for the Colorado Department of Corrections. In 

December 2017, he suffered an injury to his left knee while walking 

up some stairs. The department admitted that claimant injured his 

knee while he was on duty.

¶ 7 Claimant’s authorized treating physician decided that he was 

at maximum medical improvement as of early January 2019. The 

physician also decided that the injury to his knee was permanent. 

Using a method known as “normalization,” which we will describe 

shortly, the physician calculated that the net impairment was 

thirteen percent of the lower leg. The department filed a final 

admission of liability based on the maximum medical improvement 

date and the impairment rating. 

¶ 8 Claimant thought that his impairment rating should have 

been higher. He challenged the physician’s methodology of 

“normalizing” the impairment to his left knee because it had not 

been based on the Guides’ third edition. 
4

¶ 9 When describing this methodology, the physician explained in 

a deposition that “normalization” is a process in which doctors

compare 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.

¶ 10 The practice of normalization is summarized in a Desk Aid

published by the Department of Labor and Employment, Division of 

Workers’ Compensation. Dep’t of Lab. & Emp., Div. of Workers’ 

Comp., Desk Aid #11, Impairment Rating Tips (July 2020), 

https://perma.cc/G9KX-Q2ZH. As is pertinent to our analysis, in 

addition to describing the normalization process, the Desk Aid’s

discussion of “Rating of Extremities Using Contralateral Joint/

‘Normalization’” makes several other points. 

 Using the uninjured joint for comparison purposes may be 

“a better representation of the patient’s pre-injury state 
5

than . . . [the] population norms” described in the revised 

third edition of the Guides. Id. 

 The revised third edition of the Guides “has little 

commentary on” normalization, while the fifth edition and 

the Division of Labor “consider it reasonable to compare 

both extremities [ — i.e., normalization — ] when there are 

specific conditions which would make the opposite, 

non-injured extremity serve as a better individual baseline.” 

Id.

 An evaluating doctor should not use normalization if the 

opposite joint “has a known previous injury because that 

joint may not reflect the ‘normal’ [range of motion] for 

that individual.” Id.

¶ 11 The revised third edition of the Guides — the edition 

mentioned in subsections 101(3)(a)(I) and 101(3.7) — does not 

address normalization. But, as we mentioned above, the fifth 

edition discusses it, and, according to the physician, the 

normalization process, as outlined in the Desk Aid, has been taught 

to doctors in workers’ compensation accreditation courses for at 

least the last decade.
6

¶ 12 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.

¶ 13 When considering this case, the administrative law judge 

noted that panels of the Industrial Claim Appeals Office had already 

rejected numerous challenges to normalization and to the Desk Aid, 

as had a division of this court in Kurtz v. Industrial Claim Appeals 

Office, (Colo. App. No. 11CA2561, Oct. 18, 2012)(not published 

pursuant to C.A.R. 35(f)). The judge then rejected claimant’s 

challenge to the validity of the Desk Aid, concluding that 

normalization was a legitimate process and that its use did not 

violate any mandate in subsections 101(3)(a)(I) and 101(3.7). The 

judge therefore awarded claimant benefits based on the physician’s 

determination that the claimant’s left knee was thirteen percent 

impaired. The reviewing panel affirmed the judge’s order. 

II. General Legal Principles

¶ 14 We uphold a judge’s factual findings in a workers’ 

compensation case if they are supported by substantial evidence in 

the record. § 8-43-308, C.R.S. 2020; Kieckhafer v. Indus. Claim 

Appeals Off., 2012 COA 124, ¶ 12. “However, we review de novo 
7

questions of law and of the application of law to undisputed facts.” 

Winter v. Indus. Claim Appeals Off., 2013 COA 126, ¶ 7. 

Consequently, if a panel’s decision misconstrues or misapplies the 

law, it does not bind us. Paint Connection Plus v. Indus. Claim 

Appeals Off., 240 P.3d 429, 431 (Colo. App. 2010). Because the

underlying facts are undisputed in this case, we review the panel’s 

application of the law to the facts de novo.

¶ 15 We also review the panel’s interpretation of the statutes at 

issue in this case de novo. Lobato v. Indus. Claim Appeals Off., 105 

P.3d 220, 223 (Colo. 2005). When interpreting a statute, we must 

determine and give effect to the legislature’s intent. Davison v. 

Indus. Claim Appeals Off., 84 P.3d 1023, 1029 (Colo. 2004). If the 

statutory language is clear, we interpret the statute according to its 

plain and ordinary meaning. Specialty Rests. Corp. v. Nelson, 231 

P.3d 393, 397 (Colo. 2010).

III. Analysis

¶ 16 Claimant contends, as he did at the previous stages of his 

case, that (1) subsections 101(3)(a)(I) and 101(3.7) state that 

impairment ratings “shall be based” on the revised third edition of 

the Guides; therefore (2) doctors cannot employ the process of 
8

normalization because it is not mentioned in the revised third 

edition; (3) even though normalization is discussed in the Desk Aid, 

doctors nonetheless cannot use the process because the Desk Aid

“is not law”; and, as a result, (4) the Division of Workers’ 

Compensation “has overstepped its authority and changed the 

calculation of extremity ratings inconsistently with the law.” We 

disagree for the following three reasons, and we therefore conclude 

that the panel did not err when it affirmed the judge’s order. 

¶ 17 First, the plain language of subsections 101(3)(a)(I) and 

101(3.7) did not bar the physician from employing the process of 

normalization. To remind the reader, both subsections provide that 

impairment ratings “shall be based on” the revised third edition of 

the Guides. § 8-42-101 (emphasis added). 

¶ 18 The use of the word “based” is critical to interpreting 

subsections 101(3)(a)(I) and 101(3.7). As a verb, it means “to find a 

foundation or basis for: to find a base for” and “to make, form, or 

serve as a base for.” Merriam-Webster Dictionary,

https://perma.cc/5SP2-LPZ5. Among the many definitions of the 

noun “base,” the most relevant to this case are: “a main ingredient”; 

“a first or bottom layer of something on which other elements are 
9

added”; “the fundamental part of something”; and “the starting 

point or line for an action or undertaking.” Id. 

¶ 19 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.

¶ 20 The Kansas Supreme Court reached the same conclusion in 

Johnson v. U.S. Food Service, 478 P.3d 776, 779 (Kan. 2021). 

Johnson involved Kansas’s version of subsections 101(3)(a)(I) and 

101(3.7), which reads that “[t]he extent of permanent partial general 

disability shall be . . . based on [the Guides].” Id. (quoting 2013

Kan. Sess. Laws 539). The court reasoned that “[u]sing the phrase 

‘based on’ typically signifies a guideline rather than a mandate.” Id.

at 780. In other words, “[t]he use of the phrase ‘based on’ indicates 
10

the [l]egislature intended the [Guides] to serve as a standard 

starting point . . . .” Id.; cf. Hughes v. United States, 584 U.S. ___, 

___, 138 S. Ct. 1765, 1775 (2018)(A court “imposes a sentence that 

is ‘based on’ a [federal Sentencing] Guidelines range [in a criminal 

case] if the range was a basis for the court’s exercise of discretion in 

imposing a sentence.”).

¶ 21 Second, in addition to referring to the revised third edition of 

the Guides, subsection 101(3)(a)(I) states that “impairment rating

guidelines . . . shall [also] be based on . . . medical treatment 

guidelines and utilization standards.” According to the physician, 

normalization has been taught to doctors for at least ten years —

which suggests that normalization is a utilization standard — and it 

is discussed in the Desk Aid — which indicates that normalization 

is found in medical treatment guidelines. The Desk Aid therefore 

supplies guidance for doctors who are determining permanent 

impairment ratings. 

¶ 22 But, claimant asserts, by promulgating the Desk Aid, the 

Division of Workers’ Compensation adopted a “law[] that [was] 

contrary to” subsections 101(3)(a)(I) and 101(3.7). See Suetrack 

USA v. Indus. Claim Appeals Off., 902 P.2d 854, 855 (Colo. App. 
11

1995)(“Any regulation that is contrary to or inconsistent with the 

regulatory authorizing statute is void.”). 

¶ 23 The Division might have set up such a conflict (1) if it had 

required doctors to follow the normalization process, as described in 

the Desk Aid; or (2) if it had issued a rule under the rule-making 

process of the Administrative Procedure Act, see § 24-4-103(1), 

C.R.S. 2020, that incorporated the contents of the Desk Aid, and 

this rule “establishe[d] a norm that commands a particular result in 

all applicable proceedings,” Hammond v. Pub. Emps.’ Retirement 

Ass’n, 219 P.3d 426, 428 (Colo. App. 2009).

¶ 24 But it did not set up such a conflict. Rather, using the same 

reasoning that supports our conclusion that the phrase “based on” 

does not restrict doctors to using the revised third edition of the 

Guides, we further conclude that the phrase “based on” does not 

require doctors to use “medical treatment guidelines and utilization 

standards” such as the Desk Aid instead of the revised third 

edition. See § 8-42-101(3)(a)(I).

¶ 25 The Desk Aid was not issued pursuant to the rule-making 

process, and there is no indication that the Division intended it to 

serve as a rule that would mandate a particular result in all cases. 
12

Rather, the Desk Aid simply “establishes guidelines that do not 

bind the agency to a particular result.” Hammond, 219 P.3d at 428. 

For example, when discussing normalization, the Desk Aid states 

that “the Division consider[s] it reasonable to compare both 

extremities when there are specific conditions which would make the 

opposite, non-injured extremity serve as a better individual 

baseline.” (Emphasis added.) In this way, the Desk Aid serves as 

an “interpretive rule” as described by section 24-4-103(1), which is 

not subject to the formal rule-making process, including notice and 

an opportunity for comments, and which is “not meant to be 

binding . . . .” See Hammond, 219 P.3d at 428. Indeed, the panel 

concluded that the Desk Aid was an interpretive rule, and we agree. 

¶ 26 Third, it has long been the law that the two inquiries into 

whether, in the course of conducting a division-sponsored 

independent medical examination, a doctor properly applied the 

Guides, and whether the subsequent rating was overcome by clear 

and convincing evidence, “are questions of fact.” Wackenhut Corp. 

v. Indus. Claim Appeals Off., 17 P.3d 202, 204 (Colo. App. 2000); 

see also McLane W. Inc. v. Indus. Claim Appeals Off., 996 P.2d 263, 

265 (Colo. App. 1999)(“Whether the . . . physician has properly 
13

applied the . . . Guides in ascertaining the impairment rating and 

whether that rating has been overcome by clear and convincing 

evidence are questions of fact to be determined by” the judge.). 

And, because the appropriate application of the Guides is a 

question of fact, a panel will not set aside a judge’s decision if it is 

supported by substantial evidence in the record. See Wackenhut, 

17 P.3d at 204; see also Leewaye v. Indus. Claim Appeals Off., 178 

P.3d 1254, 1256 (Colo. App. 2007)(“We are bound by the [judge’s] 

factual determinations . . . if they are supported by substantial 

evidence in the record.”).

¶ 27 Yet, in the twenty years since Wackenhut and McLane were 

issued, the legislature has not amended subsection 101(3)(a)(I) or 

subsection 101(3.7) to change this law by limiting doctors’

discretion or by requiring them to comply strictly with the revised 

third edition of the Guides. Indeed, despite amendments to one or 

both of these subsections in 2004 and 2009, the statutory 

statement that impairment ratings are to be “based on” the revised 

third edition remains unchanged. Because the legislature is 

presumed to be aware of judicial statutory interpretations, “where, 

as here, there is no express intent to repeal or abrogate existing law 
14

. . . we presume that the legislature ‘accepted and ratified [our] 

prior judicial construction’ of the statute.” Sullivan v. People, 2020 

CO 58, ¶ 17 (quoting People v. Swain, 959 P.2d 426, 430-31 (Colo. 

1998)).

¶ 28 To summarize, the Desk Aid states that the determination of 

whether normalization is necessary rests squarely with the 

examining doctor, who “may” follow normalization procedures 

“when deemed appropriate.” In our view, the Desk Aid does not 

reject the revised third edition of the Guides; rather, it expands on 

the factors upon which doctors may, in their discretion, base 

impairment ratings. And, as we have pointed out above, the 

legislature gave doctors that discretion by using the phrase “based

on” in subsections 101(3)(a)(I) and 101(3.7). Given the legislature’s 

acceptance of this medical discretion, and its long-term acceptance 

of Wackenhut and McLane, we conclude that the panel’s 

interpretation of subsections 101(3)(a)(I) and 101(3.7) is consistent 

with the legislature’s intent. We therefore will not set it aside. See 

Zerba v. Dillon Cos., 2012 COA 78, ¶ 37 (“The [p]anel’s 

interpretation [of the Workers’ Compensation Act] will . . . be set 

aside only ‘if it is inconsistent with the clear language of the statute 
15

or with the legislative intent.’” (quoting Support, Inc. v. Indus. Claim 

Appeals Off., 968 P.2d 174, 175 (Colo. App. 1998))).

¶ 29 Claimant’s two remaining contentions do not persuade us to 

reach a different conclusion. 

¶ 30 Initially, claimant asserts, without citing any legal authority, 

that, by recommending normalization, “the Desk Aid specifically 

discriminates against individuals based on age and body habitus

[physical build],” ostensibly because older workers are more prone 

to arthritis and cannot “remember every injury that they have 

suffer[ed] to the nonindustrial injured limb.” But he does not 

articulate how the panel’s interpretation of subsections 101(3)(a)(I) 

and 101(3.7) discriminates against him and other similarly situated

workers. And he does not offer any examples illustrating how the 

physician, the Division, the judge, or the panel treated him 

differently or how his individual circumstances produced an 

unequal application of subsections 101(3)(a)(I) and 101(3.7). We 

decline to address this contention because he has not developed it. 

See Sanchez v. Indus. Claim Appeals Off., 2017 COA 71, ¶ 41

(declining to address “underdeveloped arguments” (quoting 

Antolovich v. Brown Grp. Retail, Inc., 183 P.3d 582, 604 (Colo. App. 
16

2007))); Meza v. Indus. Claim Appeals Off., 2013 COA 71, ¶ 38

(same).

¶ 31 Finally, claimant theorizes that the physician wrongly thought 

that he was required to follow the normalization procedure 

described in the Desk Aid even though its use is discretionary. But 

he does not develop this assertion either. Rather, he simply raises 

it, without offering legal authority or citations to the record to 

support it. We therefore will not address it. See Mauldin v. Lowery, 

127 Colo. 234, 236, 255 P.2d 976, 977 (1953)(“It is the task of 

counsel to inform us, as required by our rules, both as to the 

specific errors relied on and the grounds and supporting facts and 

authorities therefor.”); see also Sanchez, ¶ 62 (“‘Given the dearth of 

legal grounds offered,’ we decline to address claimant’s remaining 

arguments.” (quoting Meza, ¶ 38)).

¶ 32 The order is affirmed.

JUDGE ROTHENBERG and JUDGE TAUBMAN concur.