Assigning diagnosis codes for joint revision surgery is challenging in both ICD-9-CM and ICD-10-CM. Orthopaedic practices that carefully examine the instructions in both editions may find that they have been reporting staged revisions incorrectly for years. The following side-by-side comparison of ICD-9 and ICD-10 coding will help clean up diagnosis coding for staged revision surgeries.
Let’s start with the diagnosis coding for the initial surgery—a right total knee replacement for primary osteoarthritis. In ICD-9-CM, the diagnosis code is 715.16 (osteoarthrosis, localized, primary, lower leg). In ICD-10-CM, the code is M17.11 (unilateral primary osteoarthritis, right knee). Although both ICD-9 and ICD-10 require that the etiology of the osteoarthritis (primary) be documented, ICD-10 also requires that laterality (right knee) be specified.
Staged revision, part 1
One year later, the same patient returns, reporting pain, swelling, warmth, and a large effusion of 3 months duration. Radiographs show radiolucency beneath the femoral and tibial components, and a joint aspiration culture reveals the presence of Staphylococcus epidermidis. A staged revision of the implant is scheduled. The plan includes removal of the prosthesis and insertion of an antibiotic cement spacer, followed by 6 weeks of intravenous (IV) antibiotics and monitoring of serum C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) before a new prosthesis is implanted.
The diagnosis codes for the first of this two-stage procedure are as follows:
- 996.66 (Infection and inflammatory reaction due to internal joint prosthesis)
- 014.19 (Staphylococcus infection in conditions classified elsewhere and of unspecified site, other Staphylococcus)
- V43.65 (Organs or tissue replaced by other means: knee)
ICD-10-CM (required after Oct. 1, 2015)
- T84.53XA (Infection and inflammatory reaction due to internal right knee prosthesis; initial encounter)
- B95.7 (Other Staphylococcus as the cause of disease, classified elsewhere)
Although ICD-9 requires an additional code to identify the device involved, the ICD-10 code is specific to a knee prosthesis and includes laterality. Both ICD-9 and ICD-10 request that the infecting organism be identified with an instructional notation under the category: “Use additional code to identify infection.” Because no specific code exists for S epidermidis, the code for “other Staphylococcus” is used, indicating that the documentation in the record is more specific than the codes listed.
Note that the ICD-10 code (T84.83XA) includes an alpha 7th character to indicate the phase of treatment. Every code in Chapter 19 of ICD-10 that begins with the letters “S” or “T” requires a 7th character extension. The 7th character “A” is used during the “active treatment” of the injury or disease, and the surgery is considered “active treatment” for the infection and inflammatory reaction. In ICD-10, phase of treatment is always indicated by the 7th or last character, so an “X” placeholder is inserted as a placeholder in the 6th position because the “base code” has only 5 characters and the complete code requires a 7th character.
In ICD-10, the code remains the same for postoperative visits (dressing changes, staple removal, and management of the infection), but the final character is changed to “D” (T84.53XD) to indicate a subsequent encounter during follow-up for routine healing. ICD-10-CM uses the terms “initial” and “subsequent” to describe the active and routine healing phases of treatment. These descriptors have nothing to do with the Current Procedural Terminology (CPT) “new,” and “established” patient visit codes used for evaluation and management services.
In ICD-10-CM, the “A” (initial encounter) is assigned as long as the patient is receiving active treatment for the injury or disease. (For an in-depth discussion of the 7th character, see “When 7 Is Not a Lucky Number,” AAOS Now, November 2014.) The additional symptoms of pain, swelling, redness, and warmth are not reported separately because they are considered symptoms of the inflammatory and infectious process.
The conventions and general coding guidelines state that “the word ‘and’ should be interpreted to mean either ‘and’ or ‘or’ when it appears in a title.” Both primary codes above describe “infection and inflammatory reaction” and could be assigned even before the infection is confirmed, if an inflammatory reaction was evident and documented.
Staged revision, part 2
Nine weeks after the right knee prosthesis was removed, the patient returns to have the knee checked and to determine whether a new prosthesis can be implanted. The patient has completed 6 weeks of IV antibiotics, the knee aspirate was negative for infection, CRP and ESR are within normal limits. No redness or swelling is noted at the surgical site and incisions appeared clean and dry. The reimplantation or second stage of the knee revision is scheduled. The diagnosis codes for this visit and the reimplantation surgery are as follows:
- V54.82 (Aftercare following explantation of joint prosthesis)
ICD-10-CM (required after Oct. 1, 2015)
- Z47.33 (Aftercare following explantation of knee joint prosthesis)
In both ICD-9 and ICD-10, the code for “aftercare” following explantation (removal) of a joint prosthesis must be reported. However, ICD-10 also specifies this as a knee joint prosthesis. By this time, the infection has been eradicated and is not reported.
Many payers want the surgical diagnosis to be used during the 90-day postoperative global period, because no payment is issued for office visits related to the surgical diagnosis during this period. Table 1 shows all the ICD-10 codes that address aftercare following explantation of a joint prosthesis. Note that aftercare following the explantation of shoulder, hip, and knee joint prostheses have unique codes but laterality is not addressed.
The “Code Z47—Aftercare following explantation of joint ‘Excludes1’ note” indicates that codes from category Z89 (acquired absence of joint) should not be reported in addition to the codes for aftercare following explantation.
How payers will require staged revisions to be reported when ICD-10 is implemented on Oct. 1, 2015, is still unknown. Orthopaedic practices should focus on the coding guidelines and make sure these codes are loaded into their software systems to ensure the smoothest possible transition.
Margaret M. Maley, BSN, MS, is a senior consultant with KarenZupko & Associates, Inc., focusing on CPT and ICD-10 coding education for orthopaedic practices.
Information in this article has been reviewed by members of the AAOS Coding, Coverage, and Reimbursement Committee.