If you've ever taken piano lessons, you know that the thumb is considered the first finger of the hand. Anatomically, it is also referred to as the first phalanx (finger). However, when you are coding an x-ray of the thumb, images are captured of the thumb, hand, wrist, and all of the joints in between. How you code a radiograph that includes the thumb depends on what is being looked at, as well as any NCCI edits that may exist between the imaging codes being reported.

Let's do a quick review of the anatomy associated with the thumb: 

• Thumb
  • distal phalanx (bone tip)
  • proximal phalanx (nearest the joint)
• Hand
  • first metacarpal bone
• Wrist
  • Carpal bones (usually trapezium or scaphoid as related to thumb injuries)
• Joints
  • Interphalangeal (IP): Where the distal phalanx and proximal phalanx connect
  • Metacarpophalangeal (MP): Where the proximal phalanx and first metacarpal bone connect
  • Carpometacarpal (CMC): Where the base of the first metacarpal and the trapezium connect 

Most fractures of the thumb, approximately 80% of them, are actually fractures of the first metacarpal bone, which is a hand bone and not the bones of the thumb (distal/proximal phalanx). Two common fractures of the first metacarpal (hand) include: 

1. Bennett’s type: Single fracture at the base of the first metacarpal
2. Rolando type: Multiple fractures at the base of the first metacarpal

When the documentation refers to the first metacarpal as a “fracture of the thumb,” it can cause confusion for coders, which is why understanding the anatomy makes all the difference. Codes for reporting imaging of the bones of the thumb, hand, and wrist include: 

• 73140 – Finger(s) (min 2 views) (e.g., distal and/or proximal phalanx)
• 73120 – Hand (min 2 views) (e.g., first metacarpal)
• 73130 – Hand (min 3 views) (e.g., first metacarpal)
• 73110 – Wrist, complete (min 3 views) (e.g., trapezium, scaphoid)

An image of just the hand almost always includes some view(s) of the fingers, thumb, or wrist – it is just inevitable since we are talking about imaging such a compact and small area. However, attention should be paid to the imaging order from the physician (what was ordered and why) and what was actually produced. If there isn't enough detail to clarify the order, a provider query identifying the issue should be submitted and waited upon for a response before the final code assignment is made.

Additionally, the final diagnosis code assigned to the encounter must support the imaging performed, either with an injury code or a condition, symptoms, or disease code. If imaging is done "in-house," the documentation must identify a reason for the order, that the provider requested the imaging and why, along with documentation of the findings, which could shed further light on the situation as well. 

When imaging is focused on a potential problem with the CMC joint, or the carpals nearest the thumb (trapezium or scaphoid), report code 73110 (see CPT Assistant 2018; Diagnostic Radiology (Diagnostic Imaging) for imaging of the wrist.

If imaging is focused on the first metacarpal or metacarpophalangeal (MP) joint, report the appropriate 73120-52 (single view), 73120 (2 views), or 73130 (3 views) of the hand.

If imaging is focused on the injury located at the interphalangeal (IP) joint, report 73140.

However, in those instances when the provider isn't exactly sure where the injury may be located or the extent of the damage and as such, orders multiple images of the fingers, hand, and wrist, the National Correct Coding Initiative (NCCI) edits provide guidance important for proper reporting of the images. 

Example:

A 14-year old male presents with swelling, pain, and immobility of the right thumb following a wrestling match, with pain extending into the wrist. Following examination, the provider orders a 3-view x-ray of the hand and thumb and a 3-view x-ray of the wrist. The final diagnosis is a closed Bennett’s fracture of the right hand, initial care (S62.211A). Surgery is scheduled for ORIF of the right first metacarpal base fracture.

A review of the actual images produced included more views than originally ordered, including: 

• 3 views of hand (73130)
• 2 views of the thumb, which also captured the index and middle fingers (73140)
• 3 views of the wrist, with attention to the MP and CMC joints and trapezius (73110)

Plugging these codes into the Find-A-Code NCCI Edit Validation tool reveals an edit between 73140 and 73130, with an NCCI indicator of “1.” The "1" indicates that under the appropriate circumstances, an NCCI modifier, such as modifier 59, or RT and LT, could be appended to code 73140 to override the edit. But, how do you know when it is appropriate to override this NCCI edit?

There are two main reasons for overriding an NCCI edit:

1. The service was performed at a different encounter (on the same day and same patient)
2. The service was performed on a different (non-contiguous) anatomic site

Since both 73140 and 73130 were performed during the same encounter and anatomic site (thumb and hand being contiguous sites), it is appropriately bundled for the circumstances and not eligible for modifier 59.

The following is an example of a circumstance in which an NCCI modifier would be appropriate to override the NCCI edit:

Example 2:

A 32-year old female suffered a traumatic injury to her left thumb and right hand after falling down the stairs about an hour ago. She admits to stretching out her hands to try and break her fall. She complains of left thumb pain that radiates into the wrist and pain in her right index and middle fingers. Radiographs, including 3 views of the hand including the thumb and 2 views of the fingers of the right hand (with particular attention to the index and middle fingers) were ordered and done in the office. Imaging revealed no evidence of fractures in either the thumb, hand, or fingers. 

In this case, it would be appropriate to report 73130-LT (hand with thumb) and 73140-RT (fingers). Modifier 59 would not be required, as HCPCS modifier RT and modifier LT accomplish the same thing (identifying different anatomic sites). Additionally, the correct ICD-10-CM code for supporting medical necessity would need to be reported, which would include the symptoms the patient was feeling and the injury sustained.

Global or Split?

Don't forget the global components of TC and 26 when coding for radiology services. If the provider organization owns the equipment but contracts with an outside radiology group to review and interpret the findings with a report, only TC is reported for the technical component.

If the provider is contracted to review, interpret, and write a report on the image taken by another entity, then onlymodifier 26 is reported.

However, if the provider organization both owns the equipment and the physicians interpret and write the report, then the service is reported globally (without any modifiers).