Bond J R, Berquist T H
Department of Radiology, Mayo Clinic, Rochester, Minnesota.
Hand Clin. 1991 Feb;7(1):113-23.
Abnormal motion due to instability at the carpus and distal radioulnar joint can be difficult to diagnose clinically, and radiologic evaluation can be very helpful. The anatomy and kinematics are complex, and a directed approach is necessary to detect the findings that may be subtle and transient. Plain radiographic evaluation of the distal radioulnar joint is very sensitive to slight variations in patient position, and CT is more accurate when pain or cast immobilization make positioning difficult or when there is associated distal radial deformity. Static carpal instability patterns are present on routine radiographs where examination of the lateral view provides the key to diagnosis. The relations between the longitudinal axes of the radius, lunate, capitate, and scaphoid form the basis for classification of these instabilities. In dynamic carpal instability, routine radiographs are normal. The instability is demonstrated only with positional change or manipulation. Motion views can be very helpful, although direct observation of wrist motion on videotape fluoroscopy is the key to the diagnosis of dynamic instability. MR imaging motion studies provide better soft tissue definition and may show subtle changes in the triangular-fibrocartilage-associated distal radioulnar instability, as well as periarticular tendon subluxation about the wrist. The clinical role of MR imaging in the evaluation of wrist motion has yet to be clearly defined.
腕关节和桡尺远侧关节不稳定导致的异常运动在临床上可能难以诊断，而放射学评估可能非常有帮助。其解剖结构和运动学很复杂，需要采用有针对性的方法来检测可能细微且短暂的表现。桡尺远侧关节的X线平片评估对患者体位的轻微变化非常敏感，当疼痛或石膏固定使体位摆放困难或存在相关的桡骨远端畸形时，CT更为准确。静态腕关节不稳定模式在常规X线片上可见，其中侧位片检查是诊断的关键。桡骨、月骨、头状骨和舟状骨的纵轴之间的关系是这些不稳定分类的基础。在动态腕关节不稳定中，常规X线片正常。只有在体位改变或手法操作时才会显示出不稳定。动态观察片可能非常有帮助，尽管在录像透视下直接观察腕关节运动是诊断动态不稳定的关键。磁共振成像运动研究能提供更好的软组织清晰度，可能显示三角纤维软骨相关的桡尺远侧关节不稳定的细微变化，以及腕关节周围肌腱半脱位。磁共振成像在评估腕关节运动中的临床作用尚未明确界定。
