Testing the construct validity of a virtual reality hip arthroscopy simulator

Purpose: To test the construct validity of the hip diagnostics module of a virtual reality hip arthroscopy simulator. Methods: Nineteen orthopaedic surgeons performed a simulated arthroscopic examination of a healthy hip joint using a 70 degrees arthroscope in the supine position. Surgeons were categorized as either expert (those who had performed 250 hip arthroscopies or more) or novice (those who had performed fewer than this). Twenty-one specific targets were visualized within the central and peripheral compartments; 9 via the anterior portal, 9 via the anterolateral portal, and 3 via the posterolateral portal. This was immediately followed by a task testing basic probe examination of the joint in which a series of 8 targets were probed via the anterolateral portal. During the tasks, the surgeon's performance was evaluated by the simulator using a set of predefined metrics including task duration, number of soft tissue and bone collisions, and distance travelled by instruments. No repeat attempts at the tasks were permitted. Construct validity was then evaluated by comparing novice and expert group performance metrics over the 2 tasks using the Manne-Whitney test, with a P value of less than.05 considered significant. Results: On the visualization task, the expert group outperformed the novice group on time taken (P =.0003), number of collisions with soft tissue (P =.001), number of collisions with bone (P =.002), and distance travelled by the arthroscope (P =.02). On the probe examination, the 2 groups differed only in the time taken to complete the task (P =.025) with no significant difference in other metrics. Conclusions: Increased experience in hip arthroscopy was reflected by significantly better performance on the virtual reality simulator across 2 tasks, supporting its construct validity