Sensitivity and specificity of the posterolateral rotatory drawer test in the diagnosis of lateral collateral ligament insufficiency of the elbow.

Abstract

Numerous clinical tests are described for the diagnosis of chronic lateral collateral ligament (LCL) insufficiency of the elbow; however, none of these tests have been adequately assessed for sensitivity, with at most 8 patients included in previous studies. Furthermore, no test has had specificity assessed. The posterolateral rotatory drawer (PLRD) test is thought to have improved diagnostic accuracy over other tests in the awake patient. The aim of this study is to formally assess this test using reference standards in a large cohort of patients. A total of 106 eligible patients were identified for inclusion from a single-surgeon database of operative procedures. Examination under anesthetic (EUA) and arthroscopy were chosen as the reference standards to compare the PLRD test against. Only patients with a clearly documented PLRD test finding performed preoperatively in the clinic, and a clearly documented EUA and/or arthroscopic findings from surgery were included. A total of 102 patients underwent EUA, 74 of whom also underwent arthroscopy. Twenty-eight patients had EUA, and then an open procedure without arthroscopy. Four patients had arthroscopy without a clearly documented EUA. Sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) were calculated with 95% confidence intervals. Thirty-seven patients had a positive PLRD test, and 69 had a negative test. Compared to the reference standard of EUA (n=102), the PLRD test had a sensitivity of 97.3% (85.8%-99.9%) and a specificity of 98.5% (91.7%-100%) (PPV=0.973, NPV=0.985). Compared to the reference standard of arthroscopy (n=78), the PLRD test had a sensitivity of 87.5% (61.7%-98.5%) and a specificity of 98.4% (91.3%-100%) (PPV=0.933, NPV=0.968). Compared to either reference standard (n=106), the PLRD test has a sensitivity of 94.7% (82.3%-99.4%) and a specificity of 98.5% (92.1%-100%) (PPV=0.973, NPV=0.971). The PLRD test demonstrated an overall sensitivity of 94.7% and specificity of 98.5% with high positive and negative predictive values. This test is recommended as the primary diagnostic tool for LCL insufficiency in the awake patient and should be widely incorporated into surgical training.