Here's what I was able to find....hopefully it will help.
Subject Ask Margie: Aspiration and injection in same joint
Source Coder Pink Sheets: Orthopedic
Publication Orthopedic: Orthopedic Coder's Pink Sheet, May 2010, Vol. 11, No. 5
Effective Date May 3, 2010
Publish Date May 3, 2010
Question: Can I report 20610 twice in the same joint - once for aspiration and once for injection?
Answer: No, you can't. I am starting to see this error coming up in audits more and more for some reason. The CPT descriptor for 20610 reads: "Arthrocentesis, aspiration and/or injection; major joint or bursa (e.g., shoulder, hip, knee joint, subacromial bursa)." The term "and/or" in the description tells you the code "includes the performance of one or all of the procedures described in the same major joint or bursa," CPT explains. "Therefore, code 20610 should only be reported one time when both aspiration and injection are performed in the same major joint or bursa" (CPT Assistant, March 2001).
Similarly, for knee or hip injections, at least, you also may not report multiple units of 20610 for multiple injections into the same joint.
A few years ago, I asked members of the American Academy of Orthopaedic Surgeons' (AAOS) Coding Committee about separate reporting of injection codes to the shoulder during the same treatment session (e.g., 20610 to the glenohumeral joint and 20605 to the acromioclavicular joint). In general, they agreed that separate billing could be warranted if separate needles were used. In the shoulder, the AC and GH joints are separated by the joint capsule. By contrast, in the knee, once the solution is injected it will cover the medial, lateral and patellofemoral compartments.