S82.90XK Unspecified fracture of unspecified lower leg, subsequent encounter for closed fracture with nonunion

ICD-10-CM S82.90XK: Unspecified Fracture of Unspecified Lower Leg, Subsequent Encounter for Closed Fracture with Nonunion

ICD-10-CM code S82.90XK identifies an unspecified lower leg fracture during a subsequent encounter for a closed fracture with nonunion. The concept is active and classified as an injury or poisoning. Nonunion represents the body's inability to heal a fractured bone, which may involve complex orthopedic management. 1 2

Plain-language overview

Code S82.90XK is an active ICD-10-CM diagnosis representing an injury or poisoning, specifically addressing an unspecified lower leg fracture during a subsequent encounter for a closed fracture with nonunion. 1

What this code represents

The parent concept for S82.90XK is S82.90, which is the unspecified fracture of the unspecified lower leg, and the code has narrower concepts within the ICD-10-CM terminology. 1

Nonunion of bone is the body's inability to heal a fracture, and a widely accepted FDA definition is a fracture persisting for at least nine months without signs of healing for three months. 2

Coding details

The official terminology record lists the published abbreviation for S82.90XK as unsp fracture of unsp lower leg, subs for clos fx w nonunion, and the preferred name includes the subsequent encounter and nonunion details. 1

Documentation considerations

Fracture patterns contributing to nonunion include bone loss with fracture gaps greater than three millimeters, lack of cortical continuity, highly comminuted fragments, and butterfly fragments. 2

Coverage and utilization context

The code S82.90XK appears in Medicare coverage database records alongside S82.90XM for unspecified fracture of unspecified lower leg, and the official label is listed as subsequent encounter for closed fracture with nonunion. 3

What the sources add

The terminology record establishes the official code hierarchy and active status, while the clinical literature defines nonunion as the body's inability to heal a fracture and details complex orthopedic treatment protocols like two-staged surgical management. 1 2

The terminology record provides the exact code label and semantic type, whereas the clinical text explains the underlying physiological condition of nonunion that the code represents. 1 2

Questions to verify

The clinical text notes that nonunion is a complex orthopedic problem with a multifactorial etiology, and clinicians need to consider multiple therapeutic modalities for management. 2

Sources

1. ICD-10-CM S82.90XK terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. MCD Search — cms.gov; accessed 2026-07-27.