Technique of Tendon Interposition Arthroplasty for Chronic Volar Dislocation of the Distal Radioulnar Joint

Midsectional Magnetic Resonance Imaging Analysis of the Sigmoid Notch of the Distal Radioulnar Joint

Purpose  This study describes the anatomy and analyzes the variations of the midsectional morphology of the sigmoid notch. Methods  The wrists of 50 patients with suspected scaphoid fracture were evaluated by magnetic resonance imaging (MRI). Sigmoid notch length, volar and dorsal rim heights, insertion length of the volar radioulnar ligament, and Tolat morphology classification were measured on T1-weighted axial plane MRI. Ulnar variance and distal radioulnar joint (DRUJ) inclination were assessed on anteroposterior radiographs. Results  The most common sigmoid notch shapes were types C (C-shaped, 60%) and B (ski-slope, 30%), followed by types D (S-shaped, 6%) and A (flat, 4%). Types A and B had a flat dorsal rim (mean 0.77 ± 1.09 mm, range 0.0-1.54 mm, and mean 0.22 ± 0.3 mm, range 0.0-0.76 mm, respectively). Types C and D had more prominent dorsal rims (means 1.47 ± 0.59 mm, range 0.66-2.57 mm, and mean 1.6 ± 0.97 mm, range 0.8-2.68 mm, respectively). The average volar lip length was 1.60 ± 1.11 mm (range, 0.0-4.10). The dorsovolar length of the radius was 18.4 ± 2.01 mm; the length of the sigmoid notch was 14.3 ± 1.73 mm. The type of sigmoid notch according to Tolat was significantly associated with volar lip length ( p  = 0.005). The type of sigmoid notch was not associated with ulnar variance or DRUJ inclination. The length of the sigmoid notch was significantly associated with the type of sigmoid notch ( p  = 0.005). The analysis demonstrated a negative association between the sigmoid notch length and the volar insertion of the radioulnar ligament ( p  = 0.019). Conclusions  The transversal morphology of the sigmoid notch was either flat with the least congruence (similar to type A of Tolat), with volar congruence only (similar to type B), or with volar and dorsal congruence (similar to types C and D). A shorter sigmoid notch may be compensated by a broader insertion of the volar radioulnar ligament. Clinical Relevance  The measurements and correlations demonstrated in this study can be a guide when considering reconstructive procedures or dealing with the instability of the DRUJ.

Essex-Lopresti Lesions and Longitudinal Radioulnar Instability: A Narrative Review

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An Essex-Lopresti injury (ELI) is classically described as a radial head fracture with a concomitant interosseous ligament complex (IOC) injury. However, multiple injury patterns may be present, and an interosseous membrane (IOM) injury should be evaluated for in any axial load injury through the forearm. ELI may result in longitudinal radioulnar instability (LRUI).

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Diagnosis of an IOC injury can be difficult. Evaluation begins with standard wrist and elbow radiographs and is supplemented with radiographs and intraoperative maneuvers to assess for proximal radial migration. Magnetic resonance imaging and ultrasonography may be useful in the acute setting, although indications and the clinical importance of the findings remain unclear.

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Surgical management of an acute ELI is focused on restoration of radial length and temporary distal radioulnar joint (DRUJ) stabilization. Radial head excision in the acute setting should be approached with caution because proximal migration may not be present acutely but may develop over time. The indication for acute IOM repair and reconstruction remains unclear.

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Surgical management of a chronic ELI is focused on restoration of radial length, wrist leveling, and treatment of degenerative changes (either at the radiocapitellar joint or the DRUJ). Reconstruction of the central band can restore forearm load transfer and produce favorable functional outcomes, but its indications continue to be debated.

Irreducible Chronic Volar Dislocation of the Distal Radioulnar Joint After Surgery for Distal Radius Fracture: A Case Report

CASE

We report a case of irreducible chronic volar dislocation of the distal radioulnar joint (DRUJ) after surgery for distal radius fracture. The patient underwent volar locking plate fixation for distal radius fracture. Despite the satisfactory alignment of the distal radius, irreducible volar dislocation of the DRUJ was discovered at 5 weeks after the initial surgery. DRUJ reconstruction at 9 weeks after injury using the Adams-Berger procedure resulted in a stable and functional DRUJ and wrist.

CONCLUSION

To prevent postoperative DRUJ instability or dislocation, the DRUJ should be evaluated for stability immediately after fracture fixation.