S82.423M Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type I or II with nonunion

Billable ICD-10-CM code, FY2026.

Built from S82.423 with 7th character M (subsequent encounter for open fracture type I or II with nonunion).

Applies from S82 Fracture of lower leg, including ankle

Includes

• fracture of malleolus

Excludes1 (never code together)

• traumatic amputation of lower leg (S88.-)

Excludes2 (not included here)

• fracture of foot, except ankle (S92.-)
• periprosthetic fracture around internal prosthetic ankle joint (M97.2)
• periprosthetic fracture around internal prosthetic implant of knee joint (M97.1-)

7th character note

• The appropriate 7th character is to be added to all codes from category S82

Notes

• A fracture not indicated as displaced or nondisplaced should be coded to displaced
• A fracture not indicated as open or closed should be coded to closed
• The open fracture designations are based on the Gustilo open fracture classification

7th character required

• A — initial encounter for closed fracture
• B — initial encounter for open fracture type I or II
• C — initial encounter for open fracture type IIIA, IIIB, or IIIC
• D — subsequent encounter for closed fracture with routine healing
• E — subsequent encounter for open fracture type I or II with routine healing
• F — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with routine healing
• G — subsequent encounter for closed fracture with delayed healing
• H — subsequent encounter for open fracture type I or II with delayed healing
• J — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with delayed healing
• K — subsequent encounter for closed fracture with nonunion
• M — subsequent encounter for open fracture type I or II with nonunion
• N — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion
• P — subsequent encounter for closed fracture with malunion
• Q — subsequent encounter for open fracture type I or II with malunion
• R — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with malunion
• S — sequela

Applies from S82.4 Fracture of shaft of fibula

Excludes2 (not included here)

• fracture of lateral malleolus alone (S82.6-)

Medicare Code Edits (MCE v43.1 (April 2026))

• Unspecified code (laterality): Unspecified codes for which a more specific code identifying laterality (right, left, bilateral) exists within the same code family.

Code annotations containing back-references to S82.423M

Back-references to S82

• Type 2 Excludes: M23 Internal derangement of knee ("current injury - see injury of knee and lower leg (S80-S89)")
• Type 1 Excludes: M84.3 Stress fracture ("traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)")
• Type 1 Excludes: M84.4 Pathological fracture, not elsewhere classified ("traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)")
• Type 2 Excludes: S72 Fracture of femur ("fracture of lower leg and ankle (S82.-)")
• Type 1 Excludes: S81 Open wound of knee and lower leg ("open fracture of knee and lower leg (S82.-)")
• Type 2 Excludes: S92 Fracture of foot and toe, except ankle ("fracture of ankle (S82.-)")
• Type 2 Excludes: S92 Fracture of foot and toe, except ankle ("fracture of malleolus (S82.-)")

Nearby codes

• S82.423F Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with routine healing
• S82.423G Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for closed fracture with delayed healing
• S82.423H Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type I or II with delayed healing
• S82.423J Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with delayed healing
• S82.423K Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for closed fracture with nonunion
• S82.423M Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type I or II with nonunion (this code)
• S82.423N Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion
• S82.423P Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for closed fracture with malunion
• S82.423Q Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type I or II with malunion
• S82.423R Displaced transverse fracture of shaft of unspecified fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with malunion
• S82.423S Displaced transverse fracture of shaft of unspecified fibula, sequela