69 Distal Radioulnar Ligament Repair/Reconstruction
Distal radioulnar joint (DRUJ) instability can be acute, subacute or chronic, and the decision to proceed with repair versus reconstruction is multifactorial. The radioulnar ligaments (palmar and dorsal) are the primary stabilizers of the DRUJ. Ligament repair can be performed in the acute or subacute setting, while reconstruction is indicated in patients with subacute or chronic instability in the setting of congruous articular surfaces. Ligament reconstruction is typically achieved with tendon slips or free grafts.
Distal radioulnar joint (DRUJ) instability can be acute, subacute or chronic and the decision to proceed with repair versus reconstruction is multifactorial. Knowledge of the complex anatomy of the DRUJ is of key importance. The radial and ulnar articular surfaces have a different radius of curvature and the soft tissues surrounding the DRUJ are thus required to stabilize the joint. The triangular fibrocartilage complex (TFCC) is the name given to these soft tissues that span and support the distal radioulnar and ulnocarpal articulations. The radioulnar ligaments (palmar and dorsal) are the primary stabilizers of the DRUJ.
69.2 Key Principles
DRUJ instability may be associated with soft tissue injuries such as TFCC tears or with alterations in bony anatomy, particularly ulnar variance. The pathomechanism of instability is essential in determining the optimal treatment method, particularly in choosing between soft tissue repairs, reconstruction, osteotomies, and fusions.
Articular congruency at the DRUJ must be established. Integrity of the volar and dorsal radioulnar ligaments is essential. The goal is thus to restore stability and a painless arc of motion.
Gross instability should only be expected if the TFCC and interosseous ligaments are disrupted. Discontinuity of only a portion of the TFCC is less likely to lead to instability. Furthermore, in the acute setting such as with a distal radial fracture with DRUJ instability, direct repair is not always necessary. The DRUJ can be reduced and pinned in the most stable position, allowing the soft tissues to heal.
DRUJ ligament repair can be performed in the acute or subacute setting. It is also indicated in cases where a TFCC tear can be repaired.
DRUJ ligament reconstruction is indicated in patients with instability and irreparable TFCC tears in the setting of congruous articular surfaces.
Connective tissue disorders.
69.6 Special Considerations
As part of a detailed preoperative assessment plain films are obtained to assess ulnar variance. CT is helpful in defining the anatomy of the DRUJ and its instability. Using a “dynamic” scan, both wrists are evaluated in full forearm pronation, supination, and the neutral position. MRI is also useful in assessing the ligamentous structures, including all components of the TFCC, and looking for degenerative changes at the DRUJ. The assessment of static instability on advanced images is inadequate, and comparison with the uninvolved extremity is essential for diagnosis.
Soft tissue reconstruction is likely to fail and should be avoided if significant articular incongruity is present. Also, beware of patients with bilateral DRUJ hypermobility and a flat sigmoid notch, as the results are not predictable in cases of systemic hyperlaxity disorders.