OAR 436-035-0040
Loss of Opposition in Thumb/Finger Amputations
(1)
Loss of opposition is rated as a proportionate loss of use of the digits which can no longer be effectively opposed.(a)
For amputations which are not exactly at the joints, adjust the ratings in steps of 5%, increasing as the amputation gets closer to the attachment to the hand, decreasing to zero as it gets closer to the tip.(b)
When the value for loss of opposition is less than 5%, no value is granted.(2)
The following ratings apply to thumb amputations for loss of opposition:(a)
For thumb amputations at the interphalangeal level: [Rating not included. See ED. NOTE.](b)
For thumb amputations at the metacarpophalangeal level: [Rating not included. See ED. NOTE.](3)
The following ratings apply to finger amputations for loss of opposition. In every case, the opposing digit is the thumb: For finger amputations at the distal interphalangeal joint: [Rating not included. See ED. NOTE.](4)
When determining loss of opposition due to loss of length in a digit, other than amputation or resection without reattachment, the value is established by comparing the remaining overall length of the digit to the applicable amputation chart under these rules and rated based on the overall length equivalency.(5)
If the injury is to one digit only and opposition loss is awarded for a second digit, do not convert the two digits to loss in the hand. Conversion to hand can take place only when more than one digit has impairment without considering opposition
Source:
Rule 436-035-0040 — Loss of Opposition in Thumb/Finger Amputations, https://secure.sos.state.or.us/oard/view.action?ruleNumber=436-035-0040.