Stability Reliability and External Validity of Myrick THIRD Test for Hip Labral Tears

Abstract

The purpose of the study is to examine whether the physical examination technique, Myrick The Hip Internal Rotation with Distraction (THIRD), is reliable and valid. The Myrick THIRD test has previously established and documented sensitivity, specificity, positive predictive value, and internal and external validity. The goal of this original research was to demonstrate stability reliability of the Myrick THIRD test when the study is conducted in a clinical setting where the test has not previously been performed, as well as to demonstrate that the Myrick THIRD test has external validity when conducted across multiple examiners in a new setting. The importance of the study reflects current clinical practice and the lack of specific clinical assessment techniques used to determine the source of intra-articular hip pain successfully. Testing included the Myrick THIRD test, magnetic resonance arthrogram (MRA), and arthroscopy. The primary outcomes included the results of the MRA, magnetic resonance imaging (MRI), Myrick THIRD test, and arthroscopy. The inclusion criteria were 18- to 49-year-olds presenting with hip pain. The exclusion criteria included patients younger than 18 and older than 49 years and patients who were willing to undergo MRI arthrogram. A test of paired proportions, correlation, sensitivity, and specificity was performed. The significance level was preset at .05. All 86 patients had a positive Myrick THIRD test, which was confirmed with arthroscopy. Eight of the 11 positive MRI results and 64 of the 74 positive MRA results were confirmed with arthroscopy. The Myrick THIRD test had a statistically significant higher accuracy rate than the MRA (p = .002) but not the MRI (p = .08). Myrick THIRD test showed a significantly higher accuracy rate than MRA.