M90.559

Billable

Osteonecrosis in diseases classified elsewhere, unspecified thigh

HCC Category Mapping

V28HCC 92 — Bone/Joint/Muscle Infections/Necrosis

0.209

V24HCC 39 — Bone/Joint/Muscle Infections/Necrosis

0.482

ESRDHCC 39 — Bone/Joint/Muscle Infections/Necrosis

0.000

RxHCCHCC 80 — Bone/Joint/Muscle Infections/Necrosis

0.000

What This Code Means

Bone death (osteonecrosis) in the thigh caused by another disease, side not specified. This occurs when bone tissue dies due to an underlying medical condition.

Coding Tips

•This is a secondary code - always code the underlying disease first (the condition causing the osteonecrosis)
•Use this code only when the specific side of the thigh is not documented; if laterality is known, use M90.551 (right) or M90.552 (left)

Clinical Significance

Secondary osteonecrosis of unspecified thigh represents bone death in the femur caused by an underlying classified disease, requiring complex medical management. This diagnosis significantly impacts risk adjustment due to the critical nature of femoral bone integrity and associated mobility limitations.

Documentation Requirements

✓Documentation of underlying classified disease causing the osteonecrosis
✓Clinical evidence of thigh bone involvement without laterality specification
✓Imaging confirmation of osteonecrotic changes (MRI, bone scan, or CT)
✓Provider documentation establishing causal relationship to primary disease
✓Treatment plan addressing both underlying condition and bone necrosis
✓Assessment of mobility status and weight-bearing capacity
✓Documentation excluding primary or traumatic causes
✓Monitoring for complications including pathological fracture risk

Commonly Confused Codes

M87.059 — Primary osteonecrosis of unspecified femur, not disease-related M90.551 — Same condition but specifically right thigh rather than unspecified M90.552 — Same condition but specifically left thigh rather than unspecified M86.159 — Chronic osteomyelitis of unspecified femur involving infection M79.3 — Panniculitis affecting thigh soft tissue rather than bone necrosis

Code Hierarchy

└M90Osteopathies in diseases classified elsewhere └M90.5Osteonecrosis in diseases classified elsewhere └M90.55Osteonecrosis in diseases classified elsewhere, thigh └M90.559Osteonecrosis in diseases classified elsewhere, unspecified thigh

└M90.559Osteonecrosis in diseases classified elsewhere, unspecified thigh