Radiographic analysis of pisotriquetral joint and pisiform motion

We evaluated 45 wrists of normal volunteers fluoroscopically (15) and radiographically (30) to determine the optimal radiographic technique for profiling the pisotriquetral (PT) joint and to assess the pisiform motion. Real-time fluoroscopy showed that 4 views are necessary for optimal PT joint and pisiform visualization: wrist neutral/30 degrees forearm supination, wrist extension/30 degrees forearm supination, and active plus passive wrist flexion/45 degrees forearm supination with thumb abduction. Excursion percentage of the PT articular surface apposition on video imaging occurred 10% proximally in neutral, 20% distally in extension, and 40% proximally in flexion. Radiography showed pisiform excursion distally (2.5 mm) in extension and proximally with active (3 mm) and passive (2 mm) flexion. Pisotriquetral angle opened proximally (15 degrees ) in extension and distally with active (10 degrees ) and passive (5 degrees ) flexion. Pisotriquetral space averaged 1.5 mm in neutral, 1 mm in extension, 3.5 mm in active, and 3 mm in passive flexion. Pisohamate distance averaged 7.5 mm in neutral, increased to 8 mm in extension, and decreased to 2 mm with active and 0 mm with passive flexion. These views and parameters are useful for evaluating patients with PT joint injury and disease.