82 Persistent Instability after Triangular Fibrocartilage Complex Tears
82.1 Patient History Leading to the Specific Problem
A healthy 26-year-old woman was referred for recurrent left ulnar-side wrist pain and distal radioulnar joint (DRUJ) instability. She had a left distal radius fracture 2 years ago while alpine skiing for which she was treated in a cast. Because of persistent wrist symptoms, she had an arthroscopic triangular fibrocartilage complex (TFCC) repair 6 months ago. The TFCC was sutured to the dorsal ulnar wrist capsule beneath the extensor carpi ulnaris (ECU) tendon. She claims the preoperative symptoms returned during rehabilitation while trying to recover motion and strength. She now has pain and weakness when lifting in supination and while performing tasks requiring torque using forearm rotation. She occasionally has painful clicking and rarely a clunk in the wrist when attempting power grip. These symptoms are consistent with DRUJ instability, which was likely caused by the combination of a TFCC tear and an ulnar styloid fracture in association with the distal radius fracture.
82.2 Anatomic Description of the Patient’s Current Status
There is slight prominence of the ulnar head, with overlying mild swelling surrounding the head. She has full wrist and forearm motion; however, she has obvious pain when at full supination, especially if done against resistance. Manipulation of the DRUJ shows increased translation (piano key sign), causes pain, and reproduces her usual symptoms (▶Fig. 82.1). The modified press test produces a typical dimple sign consistent with increased volar translation of the ulnar head (▶Fig. 82.2).
Radiographs show evidence of an old distal radius fracture, with mild loss of volar tilt (reduced to neutral tilt); however, there is no substantial shortening (~1 mm negative ulnar variance; ▶Fig. 82.3). There is also a moderately displaced ulnar styloid fracture and widening of the DRUJ space. The DRUJ is not subluxated on the lateral view. CT scan shows a flattened sigmoid notch, with substantial deficiency of its volar rim (▶Fig. 82.4). MRI shows a thick TFCC in its horizontal components (disk and radioulnar ligaments), a chronic avulsion of the TFCC from the fovea, and a moderately displaced ulnar styloid fracture (▶Fig. 82.5).
82.3 Recommended Solution to the Problem
The history, physical examination, and imaging studies are consistent with an avulsion of the TFCC from the fovea that resulted in DRUJ instability. Although an arthroscopic repair was performed, a repair to the wrist capsule does not reestablish the important site of attachment of the TFCC to the fovea. In addition, a flat sigmoid notch substantially reduces the inherent stability of the DRUJ and likely increases the risk of failure of an isolated soft-tissue repair.
Fig. 82.1 (a, b) Manipulation of the distal radioulnar joint shows increased translation (piano key sign), causes pain, and reproduces her usual symptoms.
Fig. 82.2 The modified press test produces a typical dimple sign consistent with increased volar translation of the ulnar head.
Fig. 82.3 (a, b) Radiographs show evidence of an old distal radius fracture, with mild loss of volar tilt (reduced to neutral tilt); however, there is no substantial shortening (~1 mm negative ulnar variance). There is also a moderately displaced ulnar styloid fracture and widening of the distal radioulnar joint (DRUJ) space. The lateral view does not show subluxation of the DRUJ.
Fig. 82.4 CT scan shows a flattened sigmoid notch, with substantial deficiency of its volar rim.
