Strain of intrinsic musc/fasc/tend thmb at wrs/hnd lv, subs

This code signifies a strain injury to the intrinsic muscles, fascia, or tendons within the thumb, specifically at the wrist and hand level. It indicates that the patient is receiving follow-up care for this injury, such as during a cast change, medication adjustment, or physical therapy session. The "unspecified" nature means the laterality (left or right thumb) is not documented.

Apply this code for patients presenting for subsequent treatment of a thumb strain where the specific side of the thumb is not documented. This would include encounters for ongoing management of the injury after the initial diagnosis and treatment have been established. Examples include follow-up appointments for splint checks, wound care, or rehabilitation.

• Ensure the documentation clearly supports a "subsequent encounter" for the injury, not an initial visit.
• Verify that the injury is indeed a strain of the intrinsic thumb structures at the wrist/hand level.
• If laterality (left or right thumb) is documented, choose a more specific code from the S66.41- series.