DBEs are explained in Chapter 6. Table 7-1 (shown later in this chapter) is a quick reference chart for common lower extremity procedures or problems. All values are stand-alone; that is, they are not to be combined with any other values for the same joint, injury, or problem, with the exception of limb length discrepancy.

If Table 7-1 is not used, all other impairments for a given joint or body area can be combined, except as noted later in this chapter.

Use Table 7-2. (All tables and figures mentioned in the following subsections can be found in the section “Rating Specific Lower Extremity Impairments,” later in this chapter.)

Use Table 7-3.

Use Table 7-4.

Motion loss measurements should be active measurements (i.e., active on the part of the patient). Active versus passive range of motion measurements are not addressed in the AMA Guides. However, consultants on this issue unanimously agreed that active motion is the parameter of importance. An arc of ankle dorsiflexion motion is of no use to the patient if that individual can use the ankle only by reaching down and supplying the power to move it with his or her hands.

For loss of motion due to stiffness, musculotendinous malfunction, or skeletal problems, use Table 7-5 for the hip; Table 7-6 for the knee, Table 7-7 for the ankle, Table 7-8 for the hindfoot, and Table 7-9 for the toes.

The usual amount of weakness associated with a condition is assumed to exist and is built into the rating tables and therefore should not be routinely included as a separate element in the compensation scheme. That is, it is understood that individuals with loss of motion will have associated weakness. Likewise, it is not appropriate to include in the individual’s impairment rating a component for muscle weakness when that has already been compensated for by the values assigned for nerve injury or other measures of muscle weakness, or when the all-inclusive ratings of DBEs have been used. However, when the weakness is extreme, such as loss of an intact musculotendinous unit or irreversible atrophy for whatever reason, then it may be appropriate to include an impairment rating for muscle weakness. You should use only one of the following for a given area or condition:

The values in Table 7-1 are ratings for the usual results from a surgical procedure or fracture, and, as with all the guidelines in this manual, are to be extrapolated up or down depending on the outcome and based on the examiner’s experience. Usual loss of motion is the range typically encountered in patients who have had no complications and whose fracture was treated or whose surgery was performed by experienced surgeons. This value includes the usual amount of residual pain associated with the condition.

The values in Table 7-1 are stand-alone values, with the exception that limb length discrepancy may be taken into consideration if it is excessive (i.e., significantly more than that usually found associated with the condition or procedure). If significant limb length discrepancy is present, the impairment rating from Table 7-4 can be combined with the rating in Table 7-1 using the Combined Values Chart in Appendix B.

Table 7-2 is used for determining values for lower extremity amputations.

Table 7-3 indicates the ratings that are appropriate if there is no recovery of specific nerve function. For partial nerve function, interpolation is required to arrive at an appropriate value. For a detailed analysis of an individual case, refer to the AMA Guides.

Combine the impairment values for leg length discrepancy in Table 7-4 with other impairments in the lower extremity using the Combined Values Chart in Appendix B.