Home Health ICD-9/ICD-10 Alert

Question: Our patient had a total knee replacement (TKR) due to osteoarthritis, and went to rehab for therapy. While at rehab, she had acute cellulitis of the knee affecting the prosthesis and was placed on Vancomycin. She then experienced acute renal failure due to Vancomycin toxicity. She was transferred back to the hospital for dialysis and IV antibiotics. Then, once she had recovered, she was transferred back to the same rehab facility and is now going home. Our focus of care is the cellulitis. How should we code for this patient?

Vermont Subscriber

Answer: Your patient has been hospitalized twice and received treatment for a variety of conditions. But your focus of care for this patient is her cellulitis.

Important: Two coding rules to remember here are: Do not code conditions that no longer exist (unless they are relevant as a history code) and complications trump V codes.

So, for this patient, your principal diagnosis in M1020a will be 996.66 (Infection and inflammatory reaction due to internal joint prosthesis). Follow this with 682.6 (Other cellulitis and abscess; leg, except foot). Remember to also list V43.65 (Organ or tissue replaced by other means; knee joint).

This is an exception to the rule regarding using V codes when the condition is complicated. The tabular list instructions at 996.66 indicate that you should list the V43.6x code to identify the affected joint.

If your patient's infection is resolved, then V54.81 (Aftercare following joint replacement) would be the appropriate primary diagnosis, followed by V43.65.

Remember to include 996.66 for the infection at the joint prosthesis if the documentation indicates the joint is affected. If the cellulitis was limited to the skin around the incision without indication that the joint was affected, then you would list 998.59 (Other post-operative infection) along with the cellulitis code.

Tip: When an infection like this is being treated with Vancomycin, query the physician further. The bacteria involved is probably resistant -- for example with MRSA -- and you should indicate this in the coding.