Bony Bankart is a positive predictive factor after primary shoulder dislocation.

It would be a great advantage if it were possible to categorise the patients with first time dislocations to an initial treatment with the most beneficial outcome. MRI could be a useful method for finding lesions after shoulder dislocation. Fifty-eight patients with traumatic anterior shoulder dislocation were treated by closed reduction and were examined by MRI after a maximum of 2 weeks. The hemarthrosis or effusion present in the joint after the primary dislocation could be used as a contrast for arthrography to identify the lesions present on MRI. At follow-up more than 8 years later, the MRI findings were compared to the shoulder function, shoulder stability, Rowe score and Western Ontario Shoulder Instability Index (WOSI). Besides the age of the patient being above 30, the MRI findings analysed showed that an isolated fracture of the major tubercle, as well as a bony Bankart lesion are prognostic factors for a good functional result and a stable shoulder after a primary dislocation. The glenoid rim fracture was only detected on plain radiographs in 6 out of 10 findings on MRI. MRI findings of a gleniod rim fracture, equal to a bony Bankart lesion, were found to be a prognostic factor for stability and a good functional outcome.