May 9, 2011

Coding for Bone Diseases
For The Record
Vol. 23 No. 9 P. 27

A bone disease is considered any condition that affects the skeletal system and can range from very serious, requiring prompt treatment, to chronic conditions that may cause limited range of motion, deformity, or pain. Some of the more common bone diseases are discussed here.

Osteoporosis
Osteoporosis, the most common bone disease, is an abnormal loss of bony tissue resulting in fragile or porous bones. Types of primary osteoporosis include the following:

• Postmenopausal osteoporosis (ICD-9-CM code 733.01) is caused by a lack of estrogen and affects women aged 51 to 75.

• Senile osteoporosis (733.01) results from age-related calcium deficiency and occurs in people older than 70; it’s twice as common in women as in men. Women can have senile and postmenopausal osteoporosis simultaneously.

• Idiopathic juvenile osteoporosis (733.02) occurs in children and young adults with normal hormone levels and function, normal vitamin levels, and no obvious reason to have weak bones.

Secondary osteoporosis is usually caused by medical conditions such as chronic renal failure or rheumatoid arthritis or hormonal disorders such as hyperthyroidism or hyperparathyroidism. Other causes of secondary osteoporosis include the following:

• Disuse osteoporosis (733.03) is due to immobilization or disuse of a bone (eg, hemiplegia).

• Drug-induced osteoporosis (733.09) can be caused by corticosteroids, heparin, barbiturates, and anticonvulsants. If the drug was taken correctly (adverse effect), sequence code 733.09 first followed by the therapeutic use E code identifying the drug. If the drug was taken incorrectly, sequence the poisoning code first followed by code 733.09 and the E code identifying the circumstances of the poisoning. When the documentation does not state whether the drug was taken correctly or incorrectly, it is assumed it was taken correctly.

If the documentation mentions curvature of the spine associated with the osteoporosis, assign one of the following codes in addition to the osteoporosis code, sequencing the osteoporosis code first:

• kyphosis (737.41), increased convexity of the thoracic spine;

• lordosis (737.42), increased concavity of the lumbar spine;

• scoliosis (737.43), lateral curvature of the spine; or

• unspecified curvature of the spine (737.40).

Other codes for osteoporosis include osteoporosis circumscripta (731.0); posttraumatic osteoporosis (733.7), which also includes disuse atrophy of bone; and wedging of vertebra, not otherwise specified (733.00).

Pathological Fractures
Osteoporosis has no symptoms until a fracture occurs. If the fracture is determined to be due to osteoporosis, it is considered a pathological fracture, which is a break of a diseased or weakened bone without any identifiable trauma or following a minor injury that would not ordinarily break a healthy bone. A pathological fracture is classified to code 733.1x, with a fifth digit identifying the fracture site. Osteoporotic fractures often occur in the vertebra (733.13), hip (733.14), and wrist (distal radius or Colles’ fracture, 733.12).

Other underlying causes of pathological fractures include metastatic tumor of the bone, osteomyelitis, Paget’s disease, disuse atrophy, hyperparathyroidism, and nutritional or congenital disorders. However, the fact that the patient has a bone-weakening condition such as osteoporosis does not mean the fracture is pathologic. Only the physician can determine whether the fracture is considered traumatic or pathologic, and physician documentation must be obtained to clarify the diagnosis.

The following terms are synonymous with pathological fracture: spontaneous fracture, insufficiency fracture, nontraumatic fracture, nontraumatic compression fracture, and chronic fracture.

When one of these terms is documented in the medical record, a code from subcategory 733.1 may be assigned instead of a code from 800 to 820. If the physician documents stress fracture, assign one of the following codes:

• 733.93, Stress fracture of tibia or fibula;

• 733.94, Stress fracture of the metatarsals;

• 733.95, Stress fracture of other bone;

• 733.96, Stress fracture of femoral neck;

• 733.97, Stress fracture of shaft of femur; or

• 733.98, Stress fracture of pelvis.

The sequencing of osteoporosis and pathological fracture depends on the circumstances of admission. If a patient is admitted for treatment of the pathological fracture rather than osteoporosis, the fracture should be sequenced first followed by the code for osteoporosis.

Compression fractures may be considered traumatic (work or sports related) or pathologic (due to disease process). Review the medical record to determine whether there was significant trauma to cause the compression fracture. If the documentation is unclear, ask the physician for clarification. Never assign a code for a traumatic fracture with a code for a pathologic fracture at the same site.

Osteogenesis Imperfecta
Osteogenesis imperfecta (756.51), also called brittle bone disease, is a congenital disorder characterized by fragile bones that break easily for no known reason. Symptoms associated with osteogenesis imperfecta include short stature, weak tissues, fragile skin, muscle weakness, loose joints, bleeding, easy bruising, early hearing loss, breathing problems, or curvature of the spine.

Paget’s Disease
Paget’s disease is a chronic disease that causes enlarged or deformed bones, leading to bone fractures, and occurs mostly in men. It is assigned to code 731.0, Osteitis deformans without mention of bone tumor. If the Paget’s disease occurs with bone cancer, then the appropriate code for the bone cancer is sequenced first followed by code 731.1, Osteitis deformans in diseases classified elsewhere.

Bone Cancer
Most of the time, bone cancer is considered metastatic, meaning the cancer originated somewhere else in the body and traveled to the bone. Metastasis to the bone is classified to code 198.5 and may come from cancer of the breast, prostate, or lung as well as many other sites. The main type of cancer that can actually start in the bone is sarcoma. Common types of malignant bone tumors include osteosarcoma (also called osteogenic sarcoma), chondrosarcoma, Ewing tumor (also called Ewing sarcoma), malignant fibrous histiocytoma, fibrosarcoma, giant cell tumor of bone, or chordoma.

Malignant bone tumors are classified to category 170, Malignant neoplasm of bone and articular cartilage. The fourth-digit subcategory identifies the location of the cancer.

Coding and sequencing for bone diseases are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to more than 5,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.

Coding for Pathological Fracture in ICD-10-CM
In ICD-10-CM, pathological fractures are classified to code M84.4, Pathological fracture, not elsewhere classified. Fifth and sixth characters are necessary to identify the location and the laterality of the fracture. In addition, a seventh character is required to identify whether the encounter is initial or subsequent.

If an underlying cause is related to the pathological fracture, then one of the following codes is assigned instead of a code from M84.4:

• Pathological fracture in neoplastic disease (M84.5-);

• Pathological fracture in age-related osteoporosis (M80.0-);

• Pathological fracture in other osteoporosis (M80.8-); or

• Pathological fracture in other disease (M84.6-).

ICD-10-CM Official Guidelines for Coding and Reporting from 2011 state that a pathological fracture code “should be used for any patient with known osteoporosis who suffers a fracture, even if the patient had a minor fall or trauma, if that fall or trauma would not normally break a normal, healthy bone.”

— Audrey Howard