Imaging of the Unstable Shoulder.

BACKGROUND: Unstable shoulder can occur in different clinical scenarios with a broad spectrum of symptoms and presentations: first-time (or recurrent) traumatic acute shoulder anterior dislocation or chronic anterior instability after repeated dislocations.Imaging in unstable shoulder is fundamental for choosing the right treatment preventing recurrence.The goal of imaging depends on clinical scenario and patient characteristics. METHOD: Careful selection and evaluation of the imaging procedures is therefore essential to identify, characterize and quantify the lesions. Proper imaging in unstable shoulder cases is critical to the choice of treatment to prevent recurrence, and to plan surgical intervention. RESULTS: In acute setting, radiographs have to roughly detect and characterize the bone defects present. At about 7 days, it is recommended to perform a MR to demonstrate lesions to labrum and/or ligaments and bone defects: in acute setting, the MRA is not necessary, because of effusion and hemarthrosis that behave as the contrast medium.In recurrence, it is fundamental not only to detect lesions but characterize them for planning the treatment. The first study to do is the MRI (with a magnetic field of at least 1.5 Tesla), and if possible MRA, above all in younger patients. Then, on the basis of the pathologic findings as bipolar lesion or severity of bone defects, CT can be performed. PICO method on 2D or 3D CT is helpful if you need to study a glenoid bone loss, with the "en face view" of glenoid, while a 3D CT reconstruction with the humeral head "en face view" is the gold standard to assess an Hill-Sachs lesion. CONCLUSION: The clinical diagnoses of anterior shoulder instability can be different and acknowledgement of imaging findings is essential to guide the treatment choice.Imaging features are quite different in chronic than in acute scenario. This requires appropriate indications of many different imaging techniques.

Causes and treatments of lag screw's cut out after intramedullary nailing osteosinthesis for trochanteric fractures.

Background. Superior cut-out of a lag screw remains a serious complication in the treatment of trochanteric or subtrochanteric fractures and it is related to many factors: the type of fracture, osteoporosis and the stability of fracture reduction. Little is known about the outcome after revision surgery for complications of the gamma nail. We assessed the outcome in patients who had revision surgery because of lag screw's cut out after gamma nailing for a trochanteric fracture.Material and Method. We present a study of 20 consecutive patients who underwent treatment after 20 cut-out of the lag screw fixation of a trochanteric fracture with Gamma Locking Nail from September 2004 to November 2010. In 16 patients hip prothesis was performed, in 1 the removal of the implant and in 3 the reosteosynthesis. We reviewed 13 patients: 10 total hip arthroplasty, 2 endoprothesis and 1 reosteosynthesis of nail and lag screw (mean follow up: 26 months, mean age: 73 years old), 7 patients died. Patients were reviewed retrospectively by an independent observer. Clinical evaluation was performed, Oxford score and Harris Hip score were measured. X-Ray examination was performed after a minimum of 12 months of follow up.Results. Mean Harris Hip Score mean was 67 and mean Oxford score was 32 in hip prothesis group (12 patients). We had several complications, Implant-related complications were: 2 ipometria > 2cm, 2 recurrent hip arthroplasty dislocations (1 reoperated), 4 persistent thigh pain. In only 4 patients none complications were observed. Another patient,  who had been subjected to reosteosinthesis, obtained better results (HHS:95, Oxford score:45) but with a 2 cm ipometria and occasional pain in the thigh.Conclusion. Cut out after gamma nail is consequent to biological or mechanical causes. Treatment of this complication is hip prosthesis (parzial or total hip arthroplasty), reosteosynthesis of the lag screw and/or the nail and the removal of the implant. Conversion to total/parzial hip arthroplasty may be a demanding operation with a higher complication rate respect to the standard, while reosteosynthesis is possible in selected patients and early cutting out.

Assessment of bone defects in anterior shoulder instability.

Glenohumeral bone defects are a common finding in shoulder instability and they are strongly correlated with recurrence of dislocation and failure following arthroscopic Bankart repair. Most authors agree that open surgery should be considered in the presence of certain conditions: glenoid bone loss > 25%, a lesion involving > 30% of the humeral head, an engaging Hill-Sachs lesion, bipolar bone lesions even without engagement. A careful imaging evaluation must therefore be performed in order to identify, quantify and characterize the bone defects. Even though magnetic resonance has important additional value in the assessment of the glenoid labrum and rotator cuff, computed tomography scan is the examination of choice for studying bone defects. Several methods have been proposed to quantify the extent of the glenoid bone defect; the most accurate ones utilize two-dimensional computed tomography images with multiplanar reconstructions (PICO method) or more sophisticated three-dimensional reconstruction software. Conversely, the literature lacks studies that accurately quantify humeral bone defects and, above all, that demonstrate definitively the clinical and prognostic significance of the lesion location and size.