In order to assess the strength of the bone tissue in patients undergoing joint replacement of the knee or hip joint, resected bone fragments were tested on a test-stand, ИСС/М-Scaime ZF-500, installed at the department of traumatology and orthopedics of the Rostov state medical university. Later, the bone strength indicators were compared to the following: data obtained from densitometry, gender, age and the osteoporosis risk factors of the patient. Based on multivariate analysis, medical treatment and rehabilitation methods were devised for the patients after a joint replacement of the knee or hip joint.

Keywords: osteoporosis, osteopenia, bone strength, knee joint replacement, hip joint replacement, test-stand.

In order to improve minimally invasive technique knee arthroplasty the authors developed a device for carrying minimally invasive arthroplasty allowing without patellar dislocation, align total knee replacement through proper channel formation in epimetaphysis thigh where installed Cutting Guide, with the block for trimming the articular surface of the femur. Using the device improves the accuracy of implantation of the prosthesis.

Keywords: invasive knee replacement, gonarthrosis, medical instruments

In order to improve minimally invasive technique knee arthroplasty authors propose "retractor to retract the patella in minimally invasive total knee arthroplasty," which can improve visualization during surgery to protect the extensor apparatus of the knee joint and reduce the number of complications and "Apparatus for carrying a minimally invasive knee arthroplasty" to improve the accuracy of the endoprosthesis implantation through access «quadriceps-sparing».

Keywords: invasive knee replacement, gonarthrosis, medical instruments

In order to improve techniques of minimally invasive total knee arthroplasty (IEAC) based on anatomical studies, we have developed a mathematical model and a computer program IEAC preoperative planning that takes into account the anthropometric data of the patient (body type, size patellar index Insall-Salvati), type and size of prosthesis and allows to calculate minimal incision and maximum elongation wound during surgery. Use of this software improves the accuracy of the planning and preparation of surgery, to improve the accuracy of implantation of the prosthesis.

Keywords: minimally invasive replacement of knee joint, computer modelling, preoperative planning, computer software preoperative planning