M90.579
BillableOsteonecrosis in diseases classified elsewhere, unspecified ankle and foot
HCC Category Mapping
V28HCC 92 — Bone/Joint/Muscle Infections/Necrosis
0.209V24HCC 39 — Bone/Joint/Muscle Infections/Necrosis
0.482ESRDHCC 39 — Bone/Joint/Muscle Infections/Necrosis
0.000RxHCCHCC 80 — Bone/Joint/Muscle Infections/Necrosis
0.000What This Code Means
Bone death (osteonecrosis) in the ankle and foot caused by another disease, side not specified. The bone tissue in the ankle and foot dies as a secondary effect of an underlying condition.
Coding Tips
- •Use only when the specific side of the ankle and foot is not documented or is bilateral
- •Always pair with a secondary diagnosis code for the underlying disease causing the osteonecrosis
Clinical Significance
Secondary osteonecrosis of unspecified ankle and foot represents bone death in these critical weight-bearing structures caused by an underlying classified disease. This diagnosis significantly impacts risk adjustment modeling due to mobility limitations and the complex care coordination required for management.
Documentation Requirements
- ✓Documentation of underlying classified disease causing the osteonecrosis
- ✓Clinical evidence of ankle and/or foot bone involvement
- ✓Imaging confirmation of osteonecrotic changes (MRI, bone scan, or CT)
- ✓Provider documentation establishing causal relationship to primary disease
- ✓Comprehensive management plan for both conditions
- ✓Assessment of mobility and weight-bearing capacity
- ✓Documentation excluding primary or traumatic causes
- ✓Treatment monitoring and complication assessment documentation
Commonly Confused Codes
M87.079 — Primary osteonecrosis of unspecified ankle and foot, not disease-relatedM90.571 — Same condition but specifically right ankle and foot rather than unspecifiedM90.572 — Same condition but specifically left ankle and foot rather than unspecifiedM86.179 — Chronic osteomyelitis of unspecified ankle and foot involving infectionM25.579 — Pain in unspecified ankle and foot, which is symptomatic rather than structural
Code Hierarchy
└M90Osteopathies in diseases classified elsewhere└M90.5Osteonecrosis in diseases classified elsewhere└M90.57Osteonecrosis in diseases classified elsewhere, ankle and foot└M90.579Osteonecrosis in diseases classified elsewhere, unspecified ankle and foot
└M90.579Osteonecrosis in diseases classified elsewhere, unspecified ankle and foot