Question: North Dakota Subscriber Answer: The best choice is ICD9 718.83 (Unspecified derangement of joint; forearm) to represent instability. The most common surgical options to treat ulnar impaction syndrome (after physical therapy or other modalities have failed) include an ulnar shortening osteotomy (25390, Osteoplasty, radius or ulna; shortening) and hemiresection arthroplasty (25442, Arthroplasty with prosthetic replacement; distal ulna). Depending on the situation, your surgeon might perform resection of the distal ulna (25240, Excision distal ulna partial or complete [e.g., Durrach type or matched resection]) or an arthroscopic wafer procedure (29999, Unlisted procedure, arthroscopy). Ulnar impaction syndrome is also known as ulnar abutment syndrome, and can be a common complication after distal radial fracture. The term means the distal ulna is no longer in line with the distal radius, resulting in the ulna being longer. The ulnar weight bearing load increases and causes chronic pain on that side of the wrist.