gms | German Medical Science

Objectives/Interrogation: The purpose of this study is to evaluate the accuracy of the arthroscopic hook test in determining the presence of a foveal insertion tear using dry arthroscopy of the radiocarpal and distal radioulnar joint.

Methods: 63 dry arthroscopies of the distal radioulnar joint were performed between July 2016 and 2017 for the management of painful distal radioulnar joint instability. The presence of a positive or negative hook test was documented. The integrity of the foveal insertion was determined using debridement, visualisation with a 1.9mm arthroscope and probing.

Results and Conclusions: Of these 63 cases, 44 (70%) had a positive hook test and 19 (30%) had a negative hook test.

Of the 44 cases with a positive hook test, 38 (60%) were found to have an intact fovea (false positive) and 6 (9.5%) were found to have a foveal tear (true positive). Of the 19 cases with a negative hook test, 17 (27%) were found to have an intact fovea (true negative) and 2 (3%) were found to have a foveal tear (false negative). By applying these values to the Statistical Measures of Validity, the specificity, sensitivity, false positive rate, false negative rate and diagnostic accuracy of the hook test in determining the presence of foveal pathology can be determined.

The specificity of the hook test in determining the presence of foveal pathology was found to be 0.31. The sensitivity was found to be 0.75. The false positive rate was found to be 0.69 and the false negative rate 0.25. The diagnostic accuracy was found to be 0.36.

All cases with a positive hook test were associated with a tear of the triangular fibrocartilage. However, the hook test was not found to be an indicator of the specific nature of the tear. It is important to debride and feel the mechanical integrity of the foveal insertion in order to determine if a foveal, peripheral or both foveal and peripheral repair is required.