Purpose: It is known that severe distention of the inferior glenohumeral ligament (IGHL) during anteror-inferior shoulder instability is an important factor of poor functional prognosis after arthroscopic stabilisation. O. Gagey proposed a clinical test to assess laxity of the IGHL. The purpose of this study was to assess the laxity of the IGHL using a dynamic radiological test (AP view in passive abduction of the glenohu-meral joint) and to correlate findings with arthroscopic observations..

Material and methods: We performed a prospective study in 21 patients scheduled for arthroscopic stabilisation for anteroinferior shoulder instability. Mean age was 24.6 years, 17 men and 4 women. The test was performed in the supine position with a strictly AP view of the shoulder. Bilateral comparative images were obtained. The shoulder was brought to forced passive abduction in neutral rotation without general anaesthesia or locoregional anaesthesia. The angle between the axis of the humeral diaphysis and the line passing through the inferior border of the glenoid cavity and the lateral border of the scapular tubercle was measured. Vuillemin has demonstrated that this test is reliable and reproducible. During arthroscopy performed for diagnostic and therapeutic purposes, the degree of distension was quantified using the Detrisac classification of four stages. We considered that stages 3 and 4 were frank pathological distension. We used the threshold of 15° for the difference between the healthy and pathological side for the radiological test. We assessed the ability to demonstrate severe laxity of the IGHL.

Results: For differences in abduction less than 15°, the test sensitivity was 77%, specificity 91%, positive predictive value 87% and negative predictive value 84%.

Discussion: A careful physical examination and appropriate complementary tests are essential for the evaluation of anteroinferior instability of the shoulder joint in order to obtain a precise diagnosis and search for contraindications for arthroscopic cure. The rate of recurrence after arthroscopic stabilisation remains above that obtained with open techniques. It has been demonstrated that major laxity of the IGHL constitutes a relative contraindication for arthroscopic stabilisation. Radiographic measurements provide precise information for evaluating the laxity of the IGHL. Taking a positive threshold of 15° difference identifies 87% of the cases of Detrisac stage 3 or 4 ligament distension.

Conclusion: We propose a preoperative complementary test using standard x-rays together with our dynamic radiological test of passive shoulder abduction. If the difference between the healthy and pathological side is greater or equal to 15°, the therapeutic strategy should include not only reinsertion of the rim but also retight-ening the ligament complex, or open stabilisation.