ASSESSMENT OF THE USE OF AN INDIVIDUAL TOOL FOR KNEE ARTHROPLASTY

Abstract

Objective. On the basis of comparative radiometric analysis, before and after surgery, to assess the accuracy of the knee arthroplasty with an individual instrument. Methods. The analysis of knee arthroplasty of 26 patients operated with a special instrument was performed. Age: 50–59 years — 6, 0–69 — 12, 70–79 — 5, 80 and older — 3 patients. Men — 3, women — 18. Before the operation performed a computed tomography of the lower extremities, and after operation radiography of the lower extremities completely with the vertical positions of the feet. Patient specific instrument made according to the original method. The results of the analysis were performed by comparing X-ray parameters before and after operations: 1) position of the mechanical axis in the frontal plane on the plateau of the tibia in percent; 2) medial tibial resection angle to the mechanical axis; 3) the size of the components of the endoprosthesis (femoral, tibial and liner height). Results. Deviations in the values of the medial tibial and of the lateral femoral angles between the planned and actually obtained value was an average of 0.7 %, which can be considered a high indicator of the accuracy of the implant position. The position of the mechanical axis of the limb after the operation differed from the planned by a little more than 0.9 %. The dimensions of the endoprosthesis components and the height of the tibial insert fitted to the patients matched the planning results in 100 % of the cases, with the tibial insert height being 9 mm in all cases. The use of an individual tool made it possible to reduce the time of the operation, not to open the bone marrow canal of the thigh Conclusions. The use of the original individual tool for knee arthroplasty provided a high precision to install the components of the arthroplasty.