A study of diagnostic reliability in inferior shoulder instability: Measurement of inferior humeral displacement using arthroscopy.

Purpose: The purpose of this study was to define arthroscopic measurement of inferior humeral displacement, which allows an objectively estimated reduction of capsular volume using arthroscopic techniques.

Type Of Study: Prospective controlled study.

Methods: Based on a 3-grade classification, inferior displacement caused by axial traction was measured arthroscopically at 15 degree of forward flexion and 70 degree of abduction and neutral rotation over the humeral head in 143 patients (146 shoulders) who underwent surgery consecutively; 99 shoulders because of recurrent dislocations and 47 because of pain in the shoulder.

Results: Grades II and III were considered pathologic; grade I (from 0 to 1 cm) was only considered doubtfully positive or within physiologic values. Testing showed a specificity of 96.20%.