Prone Instability Test

Execution:

  1. Patient lies in prone position with the legs hanging off the table and the feet on the ground
  2. The examiner applies PA pressure on the processus spinosi of L1-L5
  3. If pain is provoked on a vertebrae from L1-L5, the patient is asked to lift the feet off the floor
  4. The examiner then applies PA pressure again on the most painful lumbar level

 

Positive Outcome: Pain upon PA pressure on the most painful level is reduced when the patient lifts the feet off the ground and thus compensates spinal instability by contracting the erector spinae

Study Reliability Sn Sp LR+ LR-
Fritz et al. (2005) Inter к= 0.69 61 57 1.41 0.69
Ferrari et al. (2015) NA 71.4 57.1 1.67 0.5
Hicks et al. (2003) Inter к= 0.87 NA NA NA NA
Schneider et al. (2008) Inter к= 0.46 NA NA NA NA
Rabin et al. (2013) Inter к= 0.67 NA NA NA NA
Comment: This test has a poor diagnostic value but is used in the clinical prediction rule by Hicks et al. (2005) to determine the success of a stabilization program