november 2010

INTERPOSITIONAL ARTHROPLASTY

2010 CHANGES to CPT CODE 58661

One question that’s frequently asked is whether or not CPT code 58661 is considered a unilateral procedure or an inherently bilateral procedure? To answer that question, let’s look at CPT Assistant and CCI edit guidelines.

There is a CPT Assistant article from January 2002 that stated code 58661 was a unilateral procedure so modifier 50 should be appended when the procedure is performed bilaterally. This article was then superseded by a more recent article published in the May 2010 edition of CPT Assistant which now states that code 58661 describes a bilateral procedure so modifier -50 would not be appended to this CPT code nor would the coder append modifier 52 if the procedure is unilateral because the code descriptor states “partial or total” indicating that this code already takes into consideration a procedure that is only performed on one side of the body.

The guidelines differ for Medicare patients. When I need to determine the application of modifier -50 for Medicare patients I refer to the CCI edits. Each code that’s listed in the edits has a set of modifiers with “indicators” that specify payment policies for that particular modifier. For example, a CPT code with a payment indicator of “0” means that the 150% payment adjustment for bilateral procedures does not apply. Prior to January 1, 2010, CPT code 58661 had a payment indicator of “0” so CMS considered the procedure inherently bilateral. As of January 1, 2010, the payment indicator changed to “1” meaning that the 150% payment adjustment for a bilateral procedure DOES apply. For the facility this now means additional reimbursement when a bilateral procedure is performed.

Remember, for Commercial or Third Party Payors the coder should report 58661 without any modifiers regardless of whether the procedure was unilateral or bilateral (unless specific carrier policies apply) and for Medicare patients the coder would report 58661 with -RT or -LT for a unilateral procedure and for a bilateral procedure, report with the appropriate modifier(s) that are accepted by your MAC (RT/LT or modifier -50).