Criteria: Thumb: Figure 16-12 Pie Chart of Thumb Impairments Due to Abnormal Motion at the IP joint (456), Figure 16-15 Pie Chart of Thumb Impairments Due to Abnormal Motion at the MP joint (457), Table 16-8a Thumb Impairments Due to Lack of Radial Abduction and to Ankylosis (459), Table 16-8b Thumb Impairments Due to Lack of Adduction and to Ankylosis (459), a Table 16-8b Thumb Impairments Due to Lack of Adduction and to Ankylosis (459); Fingers: Figure 16-21 Finger Impairment Due to Abnormal Motion at the DIP (461), Figure 16-23 Finger Impairment Due to Abnormal Motion at the PIP (463), Figure 16-25 Finger Impairment Due to Abnormal Motion at the MP (464)
Guidance: It is probable that impairment will be based primarily on range of motion deficits of the digits involved. The range of motion deficits would be combined with any loss due to digit nerve sensory deficits, amputation, and any other ratable disorders, as described in the Guides. Strength loss has a very limited role in impairment evaluation; the Guides state in Section 16.8 Strength Evaluation: “Decreased strength cannot be rated in the presence of decreased motion, painful conditions, deformities, or absence of parts (eg, thumb amputation) that prevent effective application of maximal force in the region being evaluated.” (508) Figure 16-1a Upper Extremity Impairment Evaluation Record (436) should be completed, which provides a mechanism for recording the data needed in impairment evaluation. Measurements are obtained bilaterally and the opposite hand may be used as a baseline, if normal for that individual. Impairment of thumb motion is determined as explained in Section 16.4d Thumb Ray Motion Impairment (454-460). The thumb ray has three articular units: interphalangeal (IP) joint, metacarpophalangeal (MP) joint, and carpometacarpal (CMC joint). There are five functional units of motion that are added. Impairments are based are the additive values obtained from Figure 16-12 Pie Chart of Thumb Impairments Due to Abnormal Motion at the IP joint (456), Figure 16-15 Pie Chart of Thumb Impairments Due to Abnormal Motion at the MP joint (457), Table 16-8a Thumb Impairments Due to Lack of Radial Abduction and to Ankylosis (459), Table 16-8b Thumb Impairments Due to Lack of Adduction and to Ankylosis (459), and Table 16-8b Thumb Impairments Due to Lack of Adduction and to Ankylosis (459). These values are added. Impairment of finger motion is determined using Section 16.4e Finger Motion Impairment (461-466) and the provided pie charts for the DIP, PIP and MP joints. Deficits of impairment for the DIP joint are assessed using Figure 16-21 Finger Impairment Due to Abnormal Motion at the DIP (461). These are combined with deficits of impairment for the PIP joint, as illustrated in Figure 16-23 Finger Impairment Due to Abnormal Motion at the PIP (463). The result is combined with deficits of impairment for the PIP joint, as illustrated in Figure 16-25 Finger Impairment Due to Abnormal Motion at the MP (464). Alternative approaches to assessing impairment should also be considered as explained in Section 16.7 Impairment of the Upper Extremity Due to Other Disorders (498-507). If there are multiple digits involved, each digit impairment is converted to hand impairment using Table 16-1 Conversion of Impairment of the Digits to Impairment of the Hand (438) and added. Hand impairment is converted to upper extremity impairment using Table 16-2 Conversion of Impairment of the Hand to Impairment of the Upper Extremity (439), and to whole person using Table 16-3 Conversion of Impairment of the Upper Extremity to Impairment of the Whole Person (439).
