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 [...]