Amputation of the middle finger at any level.
To support the higher 20 percent rating, medical records would need to show that more than one-half of the metacarpal bone was removed. Surgical operative reports and post-operative notes are the most direct source for this, because they typically describe exactly how much bone was resected. Imaging such as X-rays can also show the remaining length of the metacarpal and help confirm the extent of bone loss.
To support the 10 percent rating, records need to show that the amputation occurred at or proximal to the proximal interphalangeal joint, without significant metacarpal involvement. Again, surgical records and X-rays are the key sources.
If other fingers on the same hand are also affected, examination findings documenting the function of each finger matter, since VA may consider the combined picture across all affected digits. Statements from you or people who observe your daily activities can help show how limitations from the amputation affect tasks that require grip, pinch, or fine motor control.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.
