T84.123A Displacement of internal fixation device of bone of left forearm, initial encounter

ICD-10-CM T84.123A: Displacement of internal fixation device of bone of left forearm, initial encounter

ICD-10-CM code T84.123A identifies the displacement of an internal fixation device within a left forearm bone during the initial encounter. This active diagnosis concept is classified under the semantic type of injury or poisoning. The forearm anatomy involves two parallel bones connecting the elbow and wrist, and fractures in this area are frequently managed via surgical internal fixation. 1 2 3

Plain-language overview

This diagnosis code describes a situation where an internal fixation device within a bone of the left forearm has undergone displacement, specifically captured during the initial encounter for this event. 1

The forearm contains two parallel bones connecting the elbow and wrist joints, and fractures in this anatomical region are frequently managed through surgical treatments involving open or closed reduction and internal fixation. 2

What this code represents

The official label for T84.123A is displacement of internal fixation device of bone of left forearm, initial encounter, and the terminology record classifies its semantic type as injury or poisoning. 1 3

Code T84.123A is an active terminology concept that holds a parent concept of T84.123, which denotes the displacement of an internal fixation device of bone of left forearm without the encounter specification. 1

Coding details

The code T84.123A provides specific laterality for the left forearm and uses a seventh character A to designate the initial encounter, distinguishing it from the subsequent encounter and sequela codes. 4

Within the coding hierarchy, T84.123A is distinct from T84.122A, which applies to the right forearm, and also differs from T84.123S, which represents the sequela of a left forearm fixation device displacement. 4

Documentation considerations

Accurate clinical documentation for this concept aligns with the code structure by identifying the left forearm, the displacement of the internal fixation device, and the initial encounter status. 1 4

What the sources add

Terminology records define the code's official label and hierarchical status, while clinical references establish that forearm fractures are managed with surgical fixation methods involving internal fixation devices. 1 2

A billing code lookup includes T84.123A among various mechanical complications of forearm fixation devices, differentiating displacement from breakdown and other mechanical complications during initial encounters. 5

Sources

1. ICD-10-CM T84.123A terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
4. ICD-10-CM 2024 | T84.1 - Mechanical complication of internal fixation device of bones of limb — unboundmedicine.com; accessed 2026-07-27.
5. Medical Billing Code Search — app.drchrono.com; accessed 2026-07-27.