Answer: You're in luck - you can report all three services without a hitch, unless your payer publishes guidelines to the contrary. Neither the National Correct Coding Initiative (NCCI) nor the American Academy of Orthopaedic Surgeons' Global Service Data bundles the following codes into one another:
29876 - Arthroscopy, knee, surgical; synovectomy, major, two or more compartments (e.g., medial or lateral)
29879 - ... abrasion arthroplasty (includes chondroplasty where necessary) or multiple drilling or microfracture
29880 - ... with meniscectomy (medial AND lateral, including any meniscal shaving).
If the surgeon's documentation supports the fact that he performed all of these services, you should report 29880, followed by 29879-51 (Multiple procedures) and 29876-51.
If you treat a Medicare patient, you should omit modifier -51, because Medicare's multiple endoscopy rule makes the modifier use unnecessary.