Preoperative Planning for Reverse Shoulder Arthroplasty Using Individual Planing Strategy

Background: Degenerative diseases and traumatic injuries of the shoulder joint, lead to dysfunction of the arm. Arthroplasty has recently become an increasingly popular operation for severe damage to the shoulder joint. In clinical practice, the most effective operation today is the reverse shoulder arthroplasty (RSA), after the installation of which the pain syndrome disappears in patients and a satisfactory range of motion in the shoulder joint resumes. With the increasing use of reverse shoulder arthroplasty and its expanding indications, surgeons today are facing tougher reconstructive challenges while still providing the patient with a good clinical outcome. The damaged joint presents a problem for the surgeon during component positioning. Implants must place in a location and orientation that optimizes range of motion and stability while minimizing impingement. In order to address this, surgeons can look to the use of 3D imaging in order to better understand each patient's pathology.

Purpose: show the effectiveness of accurate preoperative planning and prove it using patient-specific instrumentation.

Methods: Patients aged 18 and older, male and female, are participating in our study. The established diagnosis: multifragmental fracture of the humerus head; aseptic necrosis of the humerus head; complete tears of the rotator cuff; arthrosis of the shoulder joint; rheumatoid arthritis of the shoulder joint. The study included 65 shoulders with shoulder joint pathology. The main group included 15 patients. This group of patients will undergo reverse shoulder arthroplasty with patient-specific instrumentation. Second group of patients will undergo conventional reverse shoulder arthroplasty.

In investigators work, all patients are performs MSCT of the shoulder joint, clinical assessment of the shoulder joint and assessment of neurological status.

The planning of the position of the endoprosthesis components in the main group of patients was carried out in several stages. The first stage: the position of the guide wire was calculated, taking into account the individual anatomy of the patient. The second step is to measure the angle of the pilot spoke in the axial projection. In the third stage, the planting depth is estimated. It is necessary to strive for complete adherence of the component, but at the same time, one should not forget about the preservation of the glenoid bone mass. At the fourth stage, the position of the fixing screws was calculated. Given the angle of inclination of the screws of 30 degrees, it is necessary to design the position of the screws on the 3D model so that they are as deep as possible in the bone mass. Due to this, we will obtain a reliable fixation for the glenoid base. Then we measure the length of the bone canals for the screws. The fifth stage is to calculate the direction of resection of the humeral head. For this, in a direct projection in the area of the anatomical neck, an angle of 135 degrees is built relative to the central axis of the bone.