83 Arthroscopic Treatment of Ulnar Impaction
83.1 Patient History Leading to the Specific Problem
A 53-year-old woman presented with a 1-year history of right ulnar wrist pain. At times, she gets a very painful click. Torqueing with a key or other object increases the pain; opening a door is very painful. If she attempts to push off from a seated position, she gets severe pain. There is no history of trauma. She had been previously treated with a steroid injection into the wrist, which gave her 2 months of relief, but now the pain has returned to its previous level. Physical examination showed tenderness over the distal ulna. Lunotriquetral (LT) ballottement produces pain; compression of the distal radioulnar joint is painful.
83.2 Anatomic Description of the Patient’s Current Status
The carpus is separated and cushioned from the distal ulna by the triangular fibrocartilage complex (TFCC). The TFCC extends from the distal radius to the ulnar fovea and the styloid. The TFCC is the primary stabilizer of the distal radial ulnar joint. In the ulnar neutral wrist, the ulnar carpal joint bears 18% of the load of the wrist. Increasing the length of the ulna has been shown to increase the load on the ulnar carpal joint. Increasing the length of the ulnar by 2.5 mm can increase the load to 42% of the total load on the wrist. Forearm pronation and grip both result in increased ulnar length. Resection of the wafer of distal ulna has been shown to decrease the ulnar carpal load transmission. Ulnar impaction syndrome is a common source of ulnar-sided wrist pain secondary to excessive load across the ulnar carpal joint (▶Fig. 83.1). It is usually associated with a positive ulnar wrist, although it can occur in any ulnar variation. Ulnar impaction is commonly associated with a tear of the TFCC (▶Fig. 83.2).
83.3 Recommended Solution to the Problem
• Treatment of ulnar impaction syndrome is initially nonoperative with rest, splinting, NSAIDs (nonsteroidal anti-inflammatory drugs), and steroid injection.
• If conservative treatment options fail, surgery is recommended.
• Ulnar shortening osteotomy is considered the standard for surgical treatment.
• Complications of ulnar shortening osteotomy include nonunion, malunion, stiffness from prolonged immobilization, and long scars.
• Distal ulnar wafer resection is a less invasive procedure that has been shown to effectively reduce the load on the ulnar carpal joint.
• Distal ulnar wafer resections can be performed through an open or arthroscopic approach.
• Systematic reviews have shown that the arthroscopic procedure is a viable option to ulnar-shortening osteotomy.
83.4 Technique
Surgery is performed under general or regional anesthesia, using an upper arm tourniquet (▶Fig. 83.3). Standard 3–4 and 4–5 (or 6U) portals are utilized. A 2.7- to 2.9-mm arthroscope is used to visualize the radial carpal joint (▶Fig. 83.4, ▶Video 83.1); a complete arthroscopic examination including evaluation of the midcarpal joint is important to evaluate the integrity of the scapholunate (SL) and LT ligaments. A defect is found in the TFCC in the cases of ulnar impaction syndrome. The arthroscopic shaver and radiofrequency debrider is used to debride the frayed edges of the TFCC. Once the TFCC is debrided, the ulnar head can be visualized through the defect. A 3.0-mm burr is used to remove the distal ulna. The diameter of the burr is used to assess proper bone excision. Pronation and supination of the wrist in the traction tower ensure uniform circumferential bone excision. Interoperative C-arm fluoroscopy is utilized to ensure complete bone removal. The incisions are closed with fast-absorbing gut sutures and the wrist is immobilized in a splint.
