M84.751KIncomplete atypical femoral fracture, right leg, subsequent encounter for fracture with nonunion

M84.751K is the ICD-10-CM diagnosis code for incomplete atypical femoral fracture, right leg, subsequent encounter for fracture with nonunion. It belongs to category M84 (disorder of continuity of bone), block M80-M85 (disorders of bone density and structure) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "K" means subsequent encounter for fracture with nonunion: use it for encounters after active treatment, while the patient is healing or recovering.

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 521 (Hip Replacement with Principal Diagnosis of Hip Fracture with MCC, relative weight 2.8515), DRG 522 (Hip Replacement with Principal Diagnosis of Hip Fracture without MCC, relative weight 2.1158), DRG 564 (Other Musculoskeletal System and Connective Tissue Diagnoses with MCC, relative weight 1.4908), DRG 565 (Other Musculoskeletal System and Connective Tissue Diagnoses with CC, relative weight 0.9783) and DRG 566 (Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC, relative weight 0.7378), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It was added in FY2017, effective October 1, 2016.

Before ICD-10, this condition was coded in ICD-9-CM as 733.82 (nonunion of fracture).