Orthopedic Coding Alert

The number of claims for hip replacement and bipolar hip conversion procedures is on the rise, according to statistics from the American Academy of Orthopaedic Surgeons (AAOS). As a result, payers are increasingly on the lookout for incorrect coding for these procedures.

The femoral head is the focus of bipolar hip conversion surgery, a category of partial hip replacement (hemiarthroplasty). In bipolar surgery, the structure of the prosthesis that replaces the natural femoral head is in two partstherefore, the label bipolar is applied.

Medical theory and patient experience both suggest that a femoral head with two parts enables a greater range of motion when the prosthesis moves across the acetabular socket, as the original ball of the joint once did. The bipolar head is also larger than the single, conventional (unipolar) prosthetic head, which means it takes more force to displace it from the acetabulum. Consequently, the use of a bipolar head helps to prevent a subsequent dislocation.

Recurrent dislocation of a total hip replacement (THR) is one of the reasons the bipolar prosthesis is selected for a conversioni.e. a procedure that follows a failed THR.

The most common reason for THR surgery is the deterioration of cartilage that occurs in osteoarthritis. An artificial joint can eliminate pain and restore movement.

Hip bone necrosis brought on by a wide range of conditions, including drugs, (e.g., corticosteroids, alcohol), disease (lupus), kidney transplants and fractures can also result in THR.

Often, a THR gives great relief from pain, restores mobility and all is well. At other times, a THR fails. When a THR fails, a surgeon must consider what to do next. A revisioni.e. another THRmight be in order. Or some sort of conversion, such as adding a brace or bipolar replacement, might be the better choice.

When a Revision Meets a Conversion

The May 1999 issue of Orthopedic Coding Alert, page 33, Plug Reimbursement Leaks by Coding Properly for Hip Conversions, considers in detail the distinction between a revision and a conversion of a THR. If a 27130 (arthroplasty, acetabular and proximal femoral prosthetic replacement [total hip replacement], with or without autograft or allograft) procedure is done and then fails, a subsequent THR would be a revision, coded according to its precise nature (range is 27134 to 27138).

But when something short of a total replacementsuch as placement of a supporting pin or other hardwareis followed later by a THR, it is a conversion, 27132 (conversion of previous hip surgery to total hip replacement, with or without autograft or allograft).

The value of the conversion code is the higher reimbursement level, one that pays as much as 9 percent more because it takes into account the cost of removing old hardware and scar tissue.

There is an important caveat to 27132, however. Removal procedures such as 20670 (removal of implant; superficial, [e.g., buried wire, pin or rod] [separate procedure]) are already bundled in the conversion code. Do not try to bill for them separately.

Bipolar Conversion

Because bipolar hip replacement often follows a dislocation of a THR, it can be thought of as a revision. But in this context, it is a new approach to the problem at the site of the hip, so it is a conversion.

A diagnosis code of 718.35 (recurrent dislocation of joint; pelvic region and thigh) is often tied to an intervention of bipolar hip replacement.

Coding might seem like a simple matter with a straightforward diagnosis. But Blair C. Filler, MD, FACS, director of medical education at Los Angeles Orthopedic Hospital, cautions, You have to be very careful.

The same device, a two-part femoral head, can be used for hemiarthroplasty (partial hip) and fracture repair, explains Filler. And there is a unique code for each situation.

CPT Code 27125 vs. 27236

Codes 27125 (hemiarthroplasty, hip, partial [e.g., femoral stem prosthesis, bipolar arthroplasty]) and 27236 (open treatment of femoral fracture, proximal end, neck, internal fixation or prosthetic replacement [direct fracture exposure]) are applied to hemiarthroplasty, but under different circumstances. Code 27236 is used when a fracture necessitates the surgery. There are many types of fractures, but an example of a diagnosis is 820.09 (transcervical fracture; subcapital).

The 27125 code should be used for a partial new hip that is [put in place] because of osteoarthritis, osteonecrosis brought on by cortisone treatment anything that would cause the hip to degenerate, says Filler. It should definitely not be used for a fracture.

If you are using an ICD fracture code, the CPT for the partial hip is 27236. Do not try to use 27125 with a fracture. You will be charged with fraud.

Why are there two codes for what is essentially the same resultthe placement of a bipolar hip? Filler explains, There is a greater reimbursement for 27125, an arthritic hip, because there is more work, such as removing the ball that is still attached to the femur. But in a fracture, the ball is already broken off.

Scrutiny Increases

Filler serves as a member of the American Medical Associations CPT advisory committee for the American Orthopaedic Association. He emphasizes coders must be clear about which procedure took place. He says, Payers look for the wrong code in bipolar conversion because 27125 pays more, and they dont want to pay it unless they must.

This does not mean that hip fractures and degenerative disease leading to hip surgery are separate events. For example, the American Academy of Orthopaedic Surgeons (AAOS) reports more than 350,000 Americans fracture a hip each year, at a current annual cost of
$9.8 billion.

More from the AAOS: 90 percent of the hip fractures occur in people over age 65 and 44 percent of all hospital stays caused by fractures fall into the category of hip fractures.

The AAOS expects the incidence of hip fracture to almost double by 2050 and is advocating an aggressive education program to dampen the projected number.

With the increase in hip fractures, coders can expect increasing scrutiny from payers over diagnosis and precise nature of surgery.