S52.251 Displaced comminuted fracture of shaft of ulna, right arm

ICD-10-CM S52.251: Displaced comminuted fracture of shaft of ulna, right arm

ICD-10-CM code S52.251 identifies a displaced comminuted fracture of the shaft of the right ulna. Public coding sources list specific 7th character extensions for this diagnosis to denote the encounter type, fracture openness, and healing status. Clinical literature notes that ulnar shaft fractures can result from direct trauma and that comminuted fractures involve multiple bone fragments. 3 4 2

Plain-language overview

An isolated ulnar shaft fracture, sometimes called a nightstick fracture, is usually the result of a direct blow to the ulna while a person is attempting to shield themselves with their arms. 2

What this code represents

The ICD-10-CM code S52.251 represents a displaced comminuted fracture of the shaft of the ulna in the right arm, distinguishing this specific diagnosis from left arm or unspecified arm fractures. 3 4

Coding details

The CMS ICD-10-CM manual lists S52.251 with specific 7th character extensions, such as A for an initial encounter for a closed fracture and C for an initial encounter for an open fracture type IIIA, IIIB, or IIIC. 3 4

Additional 7th character extensions for S52.251 include D for a subsequent encounter for a closed fracture with routine healing, P for subsequent encounter for closed fracture with malunion, and M for subsequent encounter for open fracture type I or II with nonunion. 4

Documentation considerations

The CMS manual defines S52.251 variants by encounter status and fracture openness, including initial encounters for closed fractures, initial encounters for open fractures, and subsequent encounters for routine healing, malunion, or nonunion. 3 4

Clinical context

Clinical literature indicates that modern plate techniques for comminuted proximal ulna fractures can reduce implant failure and potential soft tissue irritation compared to tension-band wiring. 1

What the sources add

While the CMS manual provides the official code descriptions and 7th character extensions for S52.251, the Unbound Medicine source lists specific clinical extensions like routine healing and nonunion alongside their corresponding alphanumeric codes. 3 4

The clinical literature from NCBI Bookshelf discusses mechanisms and management for isolated ulnar shaft fractures, whereas the PMC article focuses on surgical management concepts for proximal ulna fractures and complex Monteggia lesions. 1 2

Sources

1. Fractures of the proximal ulna: current concepts in surgical management — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-25.
3. ICD-10-CM/PCS MS-DRG v35.0 Definitions Manual — cms.gov; accessed 2026-07-25.
4. ICD-10-CM 2024 | S52.251 - Displaced comminuted fracture of shaft of ulna, right arm — unboundmedicine.com; accessed 2026-07-25.