The Indiana Worker’s Compensation Act (Indiana Act) does not designate the use of any particular rating guide for the assessment of a Permanent Partial Impairment (PPI) rating. Many medical providers are familiar with the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) and the Indiana Worker’s Compensation Board (Board) has long accepted references to the AMA Guides in support of PPI ratings. It is possible that in the future the Board will require that PPI ratings be based upon the AMA Guides so as to avoid a medical opinion report which assigns a PPI rating without any objective support. Even so, there are certain areas where the use of the AMA Guides may not be appropriate:
- Amputations: Indiana Law provides a specific benefit for a specific amputation. When an amputation has occurred, the only medical question is the level of the amputation. The level of the amputation should be established by the use of an amputation chart upon which a physician has drawn a line at the level of amputation. Once that level has been so designated, the benefit may be calculated and a PPI rating pursuant to the AMA Guides or otherwise is irrelevant. An exception would be where there is also impairment to a body part beyond the level of the amputation, in which case the PPI rating beyond the amputation must be considered.
- Conversions: The AMA Guides provide tables which allow a physician to convert a lesser body part PPI rating to a whole extremity or whole body PPI rating. But where the Indiana Act provides a specific benefit for the lesser body part (thumb, finger, arm below the elbow, arm above the elbow, toe, leg below the knee, leg above the knee, eye, ear or testicle), and the injury is limited to such lesser body part, a conversion beyond that lesser body part is irrelevant. An exception would be where there are impairments to multiple body parts. In such case, each lesser body part PPI rating should be established and then converted to a whole body PPI rating. The whole body PPI ratings would then be combined into one whole body PPI rating pursuant to the AMA Guides Combined Values Chart.
The Indiana Worker’s Compensation Board requires that a PPI rating to be submitted by a physician on the physician’s letterhead or other appropriate formal identifying medical document. It is not appropriate for a physician to write in the PPI rating on a “fill-in-the-blank” form provided by the employer or TPA.