Other hypertrophic osteoarthropathy, left forearm

This code signifies a non-inflammatory enlargement of bone and soft tissue, specifically affecting the left forearm, that is not otherwise specified as primary or secondary hypertrophic osteoarthropathy. It often presents with clubbing of the digits, periostosis, and arthralgia. This condition is typically associated with an underlying systemic disease, though the specific etiology is not captured by this particular code.

Use this code when documentation clearly indicates hypertrophic osteoarthropathy affecting the left forearm, and the specific type (primary or secondary) is not identified or documented. This code is appropriate when the physician's diagnosis explicitly states "other hypertrophic osteoarthropathy" of the left forearm. Supporting documentation would include imaging reports showing periosteal new bone formation and clinical notes describing associated symptoms in the left forearm.

• Ensure laterality is accurately documented and coded; this code specifies the left forearm.
• Always look for documentation of an underlying cause, as secondary hypertrophic osteoarthropathy (M89.41-M89.42) would be more specific if identified.
• Do not confuse with osteomyelitis or other inflammatory bone conditions; hypertrophic osteoarthropathy is characterized by periosteal new bone formation without infection.