Distinguishing Osteoarthrosis Diagnoses
Question: What is the distinction in ICD-9-CM category 715 between “localized” and “generalized” osteoarthrosis, as well as between “primary” and “secondary?” What do these terms mean in this context?
Answer: Osteoarthritis is a common, chronic joint disorder that typically evolves (and worsens) as people age. The condition describes the degeneration and loss of articular cartilage, along with new bone formation (osteophytes) in and around the joints. Symptoms include limited range of motion and mechanical pain, which tend to worsen with movement. Joints most commonly affected include the knees, hips, cervical and lumbosacral spine, and the “knuckles” of the fingers and thumbs.
In ICD-9-CM, osteoarthritis of most sites—except the spine (see below)—is assigned to ICD-9-CM category 715. Within this category, the fourth digit specifies generalized or localized, while the fifth digit identifies primary vs. secondary.
- 715.0 Osteoarthrosis, generalized
- 715.10 Osteoarthrosis, localized, primary
- 715.30 Osteoarthrosis, localized, not specified whether primary or secondary
- 715.8 Osteoarthrosis involving, or with mention of more than one site, but not specified as generalized
- 715.9 Osteoarthrosis, unspecified whether generalized or localized
Localized osteoarthritis is osteoarthritis contained to a single site. It comes in two varieties:
- Primary, or idiopathic, osteoarthritis (715.1x) has no known cause. This is the most common form of osteoarthritis.
- Secondary osteoarthritis (715.2x) is due to an external or internal injury or disease (e.g., overuse, rheumatoid arthritis, obesity, etc.)
If localized osteoarthritis is not specified as primary or secondary, you should assign code 715.3x. Note that if bilateral joints are affected (e.g., both left and right knees), the osteoarthritis is still considered to be localized.
Generalized osteoarthritis (primary generalized osteoarthritis), in contrast to localized osteoarthritis, involves three or more joints or groups of joints, and is reported with 715.0.
If documentation does not specify whether the condition is generalized or localized, and it is not possible to query the treating provider to request an addendum to the documentation, assign 715.9x
Note that osteoarthritis of the spine is assigned to category 721. The specific code assignment depends on the site of the spine involved (i.e., cervical, thoracic, lumbar), and if myelopathy is present.