Clinical utility of a cluster of tests as a diagnostic support tool for clinical lumbar instability

Abstract Background Numerous clinical tests have been proposed for the diagnosis of clinical lumbar instability (CLI), but a cluster of clinical tests is still needed to increase the accuracy of CLI diagnosis. Objective To evaluate a diagnostic support tool intended to identify the presence of CLI using a cluster of clinical tests. Design Analytical cross-sectional study. Methods Two hundred participants with chronic low back pain (LBP) were diagnosed with or without CLI by an orthopedic surgeon. An orthopedic physical therapist used four clinical tests to identify CLI in each participant, including the apprehension sign (AS), the instability catch sign (ICS) with/without the abdominal drawing-in maneuver (ADIM), the painful catch sign (PCS) with/without the ADIM, and the prone instability test (PIT). Results For an individual test, the AS showed a high specificity (92.60%) and a positive likelihood ratio (LR+; 2.35) but a very low sensitivity of 17.40%. A cluster of three of the four examined tests provided the most diagnostic accuracy for CLI, with a high LR+ (5.76) and a high specificity (91.70%) but low sensitivity (47.80%) and a negative likelihood ratio (LR-; 0.57). Conclusions A cluster of three of the four examined tests was determined to comprise an inexpensive but powerful clinical support tool for the identification of CLI patients.