Pursuant to §8-42-101(3.5)(a)(II), C.R.S., all permanent impairment ratings shall be based upon the American Medical Association Guides to the Evaluation of Permanent Impairment, Third Edition (Revised), in effect as of July 1, 1991, (AMA Guides). This rule implements the Division's permanent impairment rating guidelines on how to appropriately utilize and report permanent impairment ratings.
(A) Where the authorized treating physician has determined that the injured worker is at maximum medical improvement (MMI) and has not returned to his/her pre-injury state, physically and/or mentally, the treating physician shall determine or cause to be determined a permanent medical impairment rating in accordance with this Rule 12.
(B) Any Level II accredited physician determining permanent impairment shall rate in accordance with their administrative, legal and medical roles as established by Level II accreditation.
(A) For claims with a date of injury prior to July 1, 2008, a Level II accredited physician ('the Physician') shall apportion any preexisting medical impairment, whether work-related or non work-related, from a work-related injury or occupational disease using the AMA Guides, 3rd Edition, Revised, where medical records or other objective evidence substantiate a preexisting impairment to the same body part. Any such apportionment shall be made by subtracting from the injured worker's impairment the preexisting impairment as it existed at the time of the subsequent injury or occupational disease. The physician shall explain in their written report the basis of any apportionment. If there is insufficient information to measure the change accurately, the physician shall not apportion.
(B) For claims with a date of injury on or after July 1, 2008, the Physician may provide an opinion on apportionment for any preexisting work related or non work- related permanent impairment to the same body part using the AMA Guides, 3rd Edition, Revised, where medical records or other objective evidence substantiate a preexisting impairment. Any such apportionment shall be made by subtracting from the injured worker's impairment the preexisting impairment as it existed at the time of the subsequent injury or occupational disease. The Physician shall explain in their written report the basis of any apportionment. If there is insufficient information to measure the change accurately, the Physician shall not apportion. If the Physician apportions based on a prior non work-related impairment, the Physician must provide an opinion as to whether the previous medical impairment was identified, treated and independently disabling at the time of the work-related injury that is being rated. Identified and treated in this context requires facts reflecting that a medical provider previously noted and provided some level of treatment for the non work-related impairment.
(1) The effect of the Physician's apportionment determination is limited to the provisions in section 8-42-104. When filing an admission an insurer shall provide documentation reflecting compliance with section 8-42-104.
(2) If the Physician provides an opinion on the apportionment of medical and temporary disability benefits, the claimant's receipt of medical and temporary disability benefits shall not be reduced based upon any such opinion.
Any physician determining permanent physical impairment shall:
(A) Limit such rating to physical impairments not likely to remit despite medical treatment; and
(B) Use the instructions and forms contained in the AMA Guides and,
(C) Convert scheduled impairment rating to whole person impairments.
(D) Report final whole person and/or scheduled impairment rating percentages in whole numbers.
(A) Any physician determining permanent mental or behavioral disorder impairment shall:
(1) Limit such rating to mental or behavioral disorder impairments not likely to remit despite medical treatment; and
(2) Use the instructions contained in the AMA Guides giving specific attention to:
(a) Chapter 4, "Nervous System"; and
(b) Chapter 14, "Mental and Behavioral Disorders"; and
(3) Complete a full psychiatric assessment following the principles of the AMA Guides, including:
(a) A nationally accepted and validated psychiatric diagnosis made according to established standards of the American Psychiatric Association as contemplated by the AMA Guides; and
(b) Complete history of impairment, associated stressors, treatment, attempts at rehabilitation and premorbid history so that a discussion of causality and apportionment can occur.
(B) If the permanent impairment is due to organic deficits of the brain and results in disturbances of complex integrated cerebral function, emotional disturbance or consciousness disturbance, then Chapter 4, "Nervous System," shall be consulted and, may be used, when appropriate, with Chapter 14, "Mental and Behavioral Disorders." The same permanent impairment shall not be rated in both sections. The purpose is to rate the overall functioning, not each specific diagnosis. Determination of the appropriate chapter(s) is left to the professional judgment of the physician.
(C) The permanent impairment report shall include a written summary of the mental evaluation and the work sheet incorporated herein as part of this rule (Division form WC-M3-PSYCH). The impairment rating shall be established using the 'category definition guidelines' set forth in this rule, and which shall supplement the related instructions in the AMA guides. When appropriate, the physician shall address apportionment.
(D) Where other work-related permanent impairment exists, a combined whole-body permanent impairment rating may be determined by the authorized treating physician providing primary care if Level II accredited. Where the authorized treating physician providing primary care is not determining permanent impairment, it shall be determined by the Level II accredited rating physician designated by the authorized treating physician providing primary care.
(A) The AMA Guides do not provide for permanent impairment ratings specifically for the partial loss of use of the following:
(1) Forearm at the elbow;
(2) Joints at the wrist or ankle;
(3) Leg at the knee; or
(4) Toes at the metatarsal.
The AMA Guides define these as permanent impairments of the:
(1) Entire finger, whole hand, or whole upper extremity; or
(2) Entire toe, whole foot, or whole lower extremity.
(B) When an injury causes the partial loss of use of any member specified in the scheduled injuries, as set forth in §8-42-107(2), C.R.S., the physician shall use the most distal body part. The most distal body part is the body part farthest away from the central body.
(C) In calculating partial loss-of-use benefits, the most distal permanent impairment rating provided by the physician shall be multiplied by the number of weeks corresponding to the scheduled injury for the appropriate entire finger, whole hand, or whole upper extremity, or the appropriate entire toe, whole foot, or whole lower extremity, then multiplied by the amount pursuant to §8-42-107(6),C.R.S.
(A) The Cumulative Trauma Disorder (CTD) rating system is designed for disorders that primarily involve muscular, tendinous, ligamentous and bony structures. It follows the same general principles set forth in section 3.1j of the AMA Guides and has similar relative values for traumatic soft tissue conditions. Disorders that have vascular or neurologic involvement are rated by other sections of the AMA Guides.
(B) Impairments secondary to Cumulative Trauma Disorders may be accompanied by impairments that are ratable using existing portions of the AMA Guides. The Level II accredited physician shall first calculate any applicable impairment from range of motion, neurologic and/or vascular findings, or other disorders (section 3.1j) excluding grip strength. If no impairment exists under these sections of the AMA Guides and the physician has determined that the claimant has an impairment of daily living activities with anatomic and physiologic correlation, the physician shall proceed to rate the impairment as follows:
(1) Multiple joint and upper extremity sites can be involved in CTD. Limit the impairment determination to areas of primary pathology, with anatomic or physiologic correlation based on objective findings. Do not rate areas of reactive muscular spasm and radiating or referred pain.
(2) Determine the stage of cumulative trauma for each joint involved, Stage 1 is 0-10%, Stage 2 is 11-20%, Stage 3 is 21-30%, and Stage 4 is 31-40%. Refer to Rule 17, Exhibit 2.
(3) Identify the appropriate joint impairment found on Table 17 of Chapter 3 of the AMA Guides.
(4) Multiply the joint impairment from Table 17 by the CTD stage impairment from step B to yield an upper extremity impairment.
(5) If there is anatomic and physiologic basis to rate other joints in the same extremity, complete the rating in the manner described and combine the extremity ratings distal to proximal.
(6) If extremity impairment is bilateral, convert each upper extremity impairment to whole person rating and then combine whole person ratings for both right and left upper extremities as referenced in the AMA Guides. Complete the upper extremity worksheets, Figure 1 of Chapter 3 of the AMA Guides, for each extremity separately.
(C) The CTD rating system is preferred to impairment determined by decrease in grip strength. If grip strength is used, the CTD rating system shall not be used as it would be duplicative. Similarly, care must be taken to avoid duplicative ratings with other associated disorders where there is significant neurovascular involvement or where there is limitation in ranges of motion. For further reference to these cautions, refer to the AMA Guides, section 3.1j.