Types of Osteoporosis
Cases of osteoporosis fall into two categories: primary and secondary. There are three types of primary osteoporosis:

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

• Senile osteoporosis (733.01) results from age-related calcium deficiency. It occurs in people older than 70 and is twice as common in women as in men. Women can have senile osteoporosis 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. The cause is unknown.

Secondary osteoporosis is usually caused by medical conditions (eg, chronic renal failure, rheumatoid arthritis, alcoholism) 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 the drug was taken correctly (adverse effect).

If the documentation in the medical record 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 (NOS) [733.00].

Pathological Fractures
Osteoporosis has no symptoms until a fracture occurs, which causes bone pain, loss of height, and abnormal curvature of the spine. If the fracture is determined to be a result of 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. Bones can break spontaneously or after a slight injury such as a strain, stumble, bump, or fall. Osteoporotic fractures often occur in the vertebra (733.13), hip (733.14), and wrist (distal radius or Colles’ fracture, 733.12). Vertebral fractures most often occur in weight-bearing vertebrae (T-8 or below) and are treated with back braces, analgesics, and physical therapy. Hip fractures are commonly treated by partial or total hip replacement (81.52 or 81.51, respectively) or by open reduction internal fixation of the hip (79.35).

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;

• nontraumatic fracture; and

• nontraumatic compression fracture.

When one of these terms is documented in the medical record, code 733.1x with the appropriate fifth digit may be assigned instead of a code from 800 to 820. If the physician documents stress fracture, assign code 733.93, 733.94, or 733.95, depending on the site of the stress fracture.

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 for treatment of osteoporosis, the fracture should be sequenced first, followed by the code for osteoporosis.

Compression Fracture
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.

Common treatments of compression fractures include the following:

• Vertebroplasty (81.65) is performed on patients for the treatment of vertebral compression fractures. It involves the injection into the vertebral body of a semiliquid material (polymethyl-methylacrylate or methyl-methacrylate), which hardens and, in turn, stabilizes and strengthens the compression fracture (AHA Coding Clinic for ICD-9-CM, 1999, fourth quarter, page 22).

• Kyphoplasty (81.66) is a technique that combines vertebroplasty with the insertion of an inflatable bone tamp that restores the vertebral body height while creating a cavity to be filled with bone cement.

Coding and sequencing for osteoporosis 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 Health Information Systems (800-367-2447), a supplier of coding and classification systems to nearly 4,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payors as the result of the misuse of this coding information.