Computer-Assisted Modeling of Greater Tubercle Transposition Effect on Stress Distribution in Shoulder.

BACKGROUND: The aim of the work was to investigate the influence of the position of a fractured greater tubercle of the humerus on stress distribution in the glenohumeral joint (GHJ) at shoulder abduction by performing stress-strain analysis (SSA). MATERIAL AND METHODS: A simulated 3D model of the shoulder was constructed on the basis of anatomical and anthropometric data as close as possible to real ones using the SolidWorks software package. RESULTS: A finite-element model (FEM) was generated in a semi-automatic mode composed mostly of tetrahedral and hexagonal elements < 1 mm in dimensions. CONCLUSION: The simulated 3D model of the shoulder, based on anatomical and anthropometric data as close as possible to the real ones, makes possible highly accurate determination of the optimal mutual position of the movable elements of the real joint individually for each specific patient, and makes it possible to accurately perform a minimally invasive surgical operation.

Clinical Evaluation and Instrumental Diagnostics in Acute Acromioclavicular Joint Dislocation.

BACKGROUND: The aim was to improve the diagnosis of acromioclavicular joint dislocation by studying the capabilities and characteristics of clinical and instrumental diagnostic methods. The idea is expressed that modern clinical and instrumental diagnostic methods comprise a large number of techniques, but no single algorithm for diagnosing injury to the AC joint has been developed. A gold standard for investigating and diagnosing acute AC joint dislocation does not currently exist. MATERIALS AND METHODS: A retrospective study of the characteristics and capabilities of clinical and instrumental diagnostic methods was performed in 152 patients with traumatic shoulder pathology. The patients were divided into two groups: Group I of 102 patients (67%) with acromioclavicular joint dislocation type III-VI according to Rockwood classification and Group II of 50 patients (33%) with a partial tear of the rotator cuff. Clinical and instrumental examinations involved specific provocative tests; the radiological diagnostics comprised conventional radiographs with the Zanca, axillary and Alexander views, and CT, MRI, and ultrasound examinations. RESULTS: The characterization of examination methods was based on the records of patients in Group I and II. The most sensitive clinical test to establish Rockwood type V of acromioclavicular joint dislocation was the Paxinos test (91%). The lowest sensitivity across the tests used was observed with the active compression test to diagnose type IV of dislocation (50%). As regards the X-ray examination, the axial view was 100% sensitive for detecting type IV and VI AC joint dislocation. The Zanca view is highly sensitive for patients with Rockwood type V and Alexander view for Rockwood type III and V dislocations. The accuracy of ultrasound work-up in Group I was 95%, with 96% sensitivity and 93% specificity, while MRI accuracy was 97%, with 96% sensitivity and 98% specificity, and CT accuracy was 81%, with 83% sensitivity and 75% specificity. CONCLUSIONS: 1. Determination of the sensitivity and specificity of the X-ray examination revealed the absence of a 100% effective X-ray view for type III and V AC joint dislocation. 2. The accuracy and sensitivity of the ultrasound, MRI, and CT examinations are high. 3. There is currently no consensus on a protocol to view acute AC joint injuries. 4. Complete and timely early diagnosis of acromioclavicular dislocation allows for a diffe-rentiated approach to surgical treatment tactics, preventing possible complications and restoring the function of the injured shoulder joint to the fullest extent.