Chapter 12 Distal Ulnar Resection

10.1055/b-0035-121122

Chapter 12 Distal Ulnar Resection

Introduction

Ulnar impaction syndrome is a common but often unrecognized cause of pain on the ulnar side of the wrist. Although it can be congenital (due to a long ulna), it is most often secondary to a distal radius fracture with axial subsidence, especially in older patients. This proximal shift in the radial epiphysis leads to the appearance of a “long ulna,” which translates to positive ulnar variance ( Fig. 12.1a–c ). Pain is often exacerbated during forced radial deviation, which causes the lunate to slide toward the ulnar head. The resulting injuries appear in succession over time: perforation of the radioulnar disk of the triangular fibrocartilage complex (TFCC) ligament, impingement between the distal ulna and medial aspect of the proximal lunate, and, eventually, lunotriquetral instability or even chondromalacia of the head of the hamate ( Fig. 12.2a, b ). Several treatments are possible, such as ulnar shortening, radial reconstruction osteotomy, and ulnar head resection. Arthroscopic distal resection of the ulnar head is a simple surgical technique that eliminates impingement without requiring wrist immobilization.

**Fig. 12.1a–c** a Drawing of the typically normal relationship between the ulnar head and distal radius (neutral ulnar variance). b Drawing of a positive ulnar variance where the ulna is longer than the radius. c Drawing of a negative ulnar variance where the ulna is shorter than the radius.

**Fig. 12.2a, b** a Drawing of the most common injuries resulting from ulnar impaction syndrome: central triangular fibrocartilage complex (TFCC) perforation; ulnar head chondromalacia; chondromalacia of the medial aspect of the lunate, often associated with triquetral chondromalacia; and lunotriquetral instability. b Drawing of these same injuries before TFCC perforation.

Operative Technique

Patient Preparation and Positioning

The procedure is performed under regional anesthesia with the patient supine and the arm abducted to 90° and resting on a hand table. A tourniquet is placed at the base of the arm and secured to the table. The elbow is flexed to 90°, and 5 to 7 kg of traction is applied using finger traps.

Exploration and Synovectomy of the Radiocarpal Joint

The arthroscope is introduced through the 3–4 radiocarpal portal; the 6R radiocarpal portal is used to pass instruments. The first exploratory step always consists of debridement of the inflamed synovial membrane with a shaver. This provides good exposure of the TFCC ligament and ensures that no synovial remains will be interposed in front of the scope or interfere with the resection step.

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