Individual Preoperative Planning for RSA
Individual Preoperative Planning for RSA
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 the 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.

 All patients are performed computed tomography scans (CT) of the shoulder joint. Then, were
 reconstructed 3D model. To determine the position of the components is mounted a scapular
 plane was created based on 3 points on the 3D reconstructed scapula: center of the glenoid
 fossa, most medial point on the spinal border of the scapula, and most distal point on the
 inferior angle of the scapula. The investigators use a scapular plane for to determine the
 optimal angles of inclination of the reverse baseplate. Then the position and direction of
 the pilot pin is determined. The position of the fixing screws and their length are also
 calculated. A resection line is planned for the humerus.

 Preoperative virtual templating can be used to translate the preoperative plan into the
 operating suite in the form of patient specific instrumentation (PSI) and intraoperative
 navigation. PSI to reference the local anatomy in order to place the guide pin in the desired
 location, version, and inclination based on the preoperative plan. After surgery, all
 patients undergo a CT scan of the shoulder joint. These data are compared with CT scan of
 patients operated on according to the standard method. The range of motion is also assessed
 and compared.
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.

 Construction of a 3D model is carried out using the obtained data first group patients.
 Taking into account the individual features of the bone structure of the shoulder joint,
 images of the pilot wire guides, fixing screws and a resection template for the humerus are
 created. Holes for fixing spokes for the planned structures are also calculated.

 Using a 3D printer, models of guides and a resection template are printed. During the reverse
 shoulder arthropalsty, instead of a standard guide, patient-specific instrumentation are used
 for first group patients.

 In the early postoperative period, all patients are performs MSCT of the shoulder joint. The
 obtained data are compared with the results of MSCT of the shoulder joints of patients
 previously operated on using the standard technique. Functional outcomes are assessed
 according to the Constant-Murley Score, the University of California, Los Angeles Shoulder
 Assessment, and (Shoulder assessment form american shoulder and elbow surgeons, (ASES)
 Shoulder Outcome Score). Functional results are seen after 1, 6 and 12 months.

 Planned results: in this study, we hope to prove the effectiveness of preoperative planning.
 The investigators expect that the precise positioning of the components using
 patient-specific instrumentation will increase the range of motion in the shoulder joint,
 reduce the complication rate, and also improve the quality of life of patients after reverse
 shoulder arthroplasty.
Inclusion Criteria:

 Clinical diagnosis: multifragmental fracture of the humerus head; aseptic necrosis of the
 humerus head; arthrosis of the shoulder joint.

 Must be have pain and limitation of movement of the shoulder joint.

 Exclusion Criteria:

 massive glenoid injury. Damage to the deltoid muscle.