Ligaments of the Scaphotrapeziotrapezoidal Joint: MR Anatomy in Asymptomatic and Symptomatic Patients

Presentation Format: Scientific poster presentation.

Purpose or Learning Objective: To evaluate the magnetic resonance imaging (MRI) anatomy of the scaphotrapeziotrapezoidal (STT) ligament complex in asymptomatic and symptomatic patients using a high-resolution three-dimensional (3D) proton-density (PD)-weighted sequence.

Methods or Background: In this retrospective study, the STT ligament complex of 42 asymptomatic and symptomatic patients (defined as radial-sided wrist pain) (male 69%; median age: 37.5 years) were examined undergoing MR arthrography of the wrist. Using a high-resolution 3D PD-weighted sequence (voxel size: 0.6 × 0.6 × 0.6 mm), two musculoskeletal radiologists independently assessed visibility, signal intensity (SI), and morphology of the radiopalmar scaphotrapezial ligament (rpSTL), palmar scaphocapitate capsular ligament (pSCCL), and palmar (pSTTC) and dorsal STT capsule (dSTTC). Thickness of each ligament was measured at the midportion. Extent of degeneration of the STT was also assessed. Qualitative and quantitative findings were compared between asymptomatic and symptomatic patients.

Results or Findings: The rpSTL was almost always visible (85.7%/80.1%; reader 1/reader 2). SI was rated as low in 63.9%/70.6% and increased in 36.1%/29.4%. Ligament morphology was rated as distinct in 63.9%/70.6% and indistinct in 36.1%/29.4%. The pSCCL was visible in all cases. SI was rated as low in 42.9%/42.9%, as increased in 38.1%/40.5%, and striated in 19.0%/16.6%. Ligament morphology was rated as distinct in 81.0%/73.8% and indistinct in 19.0%/26.2%. The pSTTC was visible in only 52.4%/42.9%, and dSTTC was detected in all cases by both readers. Mean thicknesses for the rpSTL, pSCCL, pSTTC, and dSTTC were 1.4 ± 5 mm/1.3 ± 0.5 mm, 2.8 ± 0.7 mm/2.7 ± 0.6 mm, 0.5 ± 0.5 mm/0.4 ± 0.4 mm, and 0.5 ± 0.3 mm/0.3 ± 0.3 mm for reader 1 and 2, respectively. In symptomatic patients, STT joint degeneration was significantly more common, and the rpSTL was rated significantly more often as increased SI and indistinct (all p values < 0.005). All other ligaments showed no significant differences in visibility, signal intensity, and morphology. No significant differences were found in ligament thickness.

Conclusion: High-resolution MRI can be used to visualize all components of the STT ligament complex. Morphological changes of rpSTL are significantly more often observed in patients with radial-sided wrist pain.