Incidence of ligament lesions and associated degenerative changes in the elderly wrist

Evaluation of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments in cadavers with low-field-strength extremity-only magnet. Comparison of available imaging sequences and macroscopic findings

RATIONALE AND OBJECTIVES

The authors assessed the ability of a low-field-strength extremity-only magnet to provide visualization of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments.

METHODS

Twelve human wrists were examined with a 0.2 T extremity-only magnet. T1-weighted spin echo, proton density-weighted, and T2-weighted turbo spin echo, short-tau inversion recovery, and three-dimensional gradient recalled echo images were acquired, and sections of the specimens were then made that corresponded to the magnetic resonance images. Masked imaging analyses were correlated with macroscopic and limited histopathologic findings.

RESULTS

Low-field-strength extremity-only magnet allowed consistent visualization of the triangular fibrocartilage and accurate assessment of a small number of complete tears of the triangular fibrocartilage. The scapholunate ligaments in all cases were identified using a combination of imaging sequences. Consistent visualization of the lunotriquetral ligament with a low-field-strength extremity magnet was difficult.

CONCLUSIONS

Magnetic resonance imaging with a low-field-strength extremity-only magnet can be used to visualize the triangular fibrocartilage and the scapholunate ligament, but not the lunotriquetral ligament.

Ligamentous injuries of the wrist in the athlete

Wrist instability most commonly results from ligamentous disruption between bones of the proximal carpal row. Scapholunate and lunotriquetral dissociation are forms of this instability pattern. Carpal instability can also occur due to loss of the normal ligamentous restraints between the carpal rows. Ulnar midcarpal instability is an example of this pattern. The treatment of wrist instability depends on the specific type and degree of carpal disruption and the presence or absence of degenerative changes. Options include soft-tissue reconstruction, partial wrist fusion, limited carpal bone excision, or a combination of methods.

Wrist arthrography today

In recent years, wrist arthrography has been criticized for having low sensitivity and low specificity. This largely has been due to widely varying and less than rigorous technique and the reliance on criteria for abnormality that are now known to be invalid. Other criticisms have included the length of time needed to perform a three-compartment arthrogram with or without comparison to the contralateral side and the radiation dose to the patient. It is our belief, however, that with the use of the patient's history, symptoms and physical examination to develop a focused examination strategy, and with the use of digital equipment, the examination can be performed quickly and with minimal radiation dose to the patient. In order to improve the accuracy of arthrography, the radiologist must abandon the concept that simply identifying a communicating defect between the carpal compartments is a criterion for abnormality. He or she must utilize a meticulous approach to determine the site of communication to evaluate the features of the defects in order to determine the significance of the defect. As more is learned about the nature of traumatic and attritional defects and with further technologic advancements in cross-sectional imaging and three-dimensional rendering, it is quite possible that arthrographic imaging of the wrist will experience a resurgence of interest in the evaluation of posttraumatic wrist pain, avoiding the fate of such examinations as pneumoencephalography and oral cholecystography as many have predicted.

Intracarpal soft-tissue lesions associated with an intra-articular fracture of the distal end of the radius

Sixty patients who had a displaced intra-articular fracture of the distal end of the radius were managed with manipulative reduction and internal fixation performed under both fluoroscopic and arthroscopic guidance. According to the AO/ASIF classification system, seven fractures were type B1, two were type B2, three were type B3, thirteen were type C1, twelve were type C2, and twenty-three were type C3. Forty-one patients (68 per cent) had soft-tissue injuries of the wrist, including tears of the triangular fibrocartilage complex (twenty-six patients), the scapholunate interosseous ligament (nineteen), and the lunotriquetral interosseous ligament (nine). Thirteen patients had two soft-tissue injuries. Intracarpal soft-tissue injuries were identified most frequently in association with fractures involving the lunate facet of the distal articular surface or the radius.

Ulnar shortening osteotomy in posttraumatic ulnar impaction syndrome

Twenty-eight patients (average age 45 years) with posttraumatic ulnar impaction syndrome underwent ulnar shortening osteotomy of 3-15 mm. Contributing factors were malunited fractures of the distal radius in 20, diaphyseal fractures of the ulna and radius in 6, resection of the radial head and a traumatic tear of the triangular fibrocartilage in 1 patient each. Evaluation at an average follow-up of 20 months showed a high rate of satisfied patients (89%), but according to Chun's modification of the Gartland-Werley score there were 1 excellent (3.5%), 11 good (39.5%), 11 fair (39.5%) and 5 poor (17.5%) results. Degenerative changes of the distal radioulnar joint were associated with fair and poor results, and ulnar shortening osteotomy is only recommended in ulnocarpal impaction with an intact distal radioulnar joint. Osteotomy fixation with 3.5 mm dynamic compression plates enabled immediate postoperative mobilisation and resulted in a low complication rate. There was no advantage for the technically more demanding oblique as compared with a transverse osteotomy.