Doctor performed a subacromial decompression, closed the portals then did a joint injection for post op pain. CPT Assistant Bonus Feature December 2007 states that you can't code the injection "when performed concurrent with another intra-articular procedure (eg. knee arthroscopy)". I can't find anything on this scenario in the AAOS guidelines and CCI doesn't preclude it. Does anyone else bill for this and can you refer me to the guidelines you are using. Thanks.