25310 vs 26480 Tendon transfer

When using tendon transfer codes, is the appropriate code where the tendon is harvested from or where it is transfered to? Specifically, our hand physicians do interpositional arthroplasties where a portion of the flexor carpi radialis tendon is harvested from the forearm and transfered to the base of the thumb metacarpal for stabilization of the MCP joint for arthritis. Should 25310, tendon transfer forearm, be used (area from where tendon is harvested) or 26480, tendon transfer MCP, (area to where tendon is transfered)? Thank you for your response.
E Guest

re: 25310 vs 26480 Tendon transfer

The transfer of the FCR to the base of the first metacarpal is not a part of the basic first CMC arthroplasty procedure and must be coded in addition to 25447 with either 26480, Transfer or transplant of tendon, carpometacarpal area or dorsum of hand; without free graft, each tendon, or 25310, Tendon transplantation or transfer, flexor or extensor, forearm and/or wrist, single; each tendon, as appropriate. Modifier 51 would be appended to the secondary procedure in either the 25447 + 26480 or 25310 code pairs.