PURPOSE OF THE STUDY Aseptic loosening of endoprosthetic components is the most frequent reason for total hip arthroplasty revision. This paper aimed to verify the influence of the type of hip-component fixation of total hip replacement in correlation with the age of patients on aseptic loosening of components during mid-term survival. MATERIAL AND METHODS The retrospective, monocentric study statistically evaluated the data of 67 cases of implanted total hip replacements in 66 patients with the loosening of at least one of the components requiring a revision of the total number of 1,488 primary total hip replacements implanted during the 1995 to 2006 period at a single department. The study compares the implants by Johnson&Johnson (Ultima threaded cups, Duraloc sector, Ultima UHMWPE cups. Mecroblock MR, AML and Ultima straight stems, Charnley and Elite plus cups and stems), Fehling Medical AG (HPQ and Müller cups, Müller Geradschaft stems) and Biomet (Mallory-Head and Müller cups, Bi-Metric cemented and uncemented stems) with respect to the age of patients. First-generation and second-generation cementing techniques were used. Primary arthroplasty of revised endoprostheses were indicated for primary and post-dysplastic coxarthrosis not requiring skeletal reconstruction. In order to determine the influence of age, three age categories were considered: under 54 years of age, 55 to 64 years of age, and elderly individuals aged 65 and over. The data was statistically evaluated by the test for two proportions and the Student's t-test. RESULTS The mean age of patients with total hip replacement loosening was lower than the mean age of the other patients (p < 0.05). The age category 55-64 reported a significantly higher failure rate only for HPQ - Müller-Geradschaft endoprosthesis compared to the uncemented and hybrid version of Mallory-Head - Bi-Metric, Duraloc - AML and Charnley group (p < 0.05). Duraloc - Charnley showed worse results than Mallory-Head - Bi-Metric porous (p = 0.0437). Except for HPQ - Müller-Geradschaft endoprosthesis, there were no statistically significant differences in the achieved revision rate of components used in endoprostheses. In the younger age category, only uncemented and hybrid versions were assessed. Hybrid endoprostheses made by Fehling and Biomet failed more often than uncemented Mallory-Head - Bi-Metric porous (p < 0.05) and Duraloc - AML (p < 0.01). For the category of 65 plus, cemented and hybrid endoprostheses were assessed. A higher revision rate was seen only in HPQ - Müller-Geradschaft endoprosthesis compared to the cemented version of Biomet (p < 0.05). No difference was reported in mid-term survival of the applied cemented and uncemented cups. DISCUSSION Despite the development of uncemented versions of total hip arthroplasty components, the current literature includes opinions supporting the cemented technique of total hip replacement. Especially for elderly patients the implant of uncemented components is questionable. The presented study did not identify a higher mid-term revision rate of uncemented implants, namely with respect to acetabular components, not even in the elderly patients. CONCLUSIONS No difference was found in the mid-term revision rate of evaluated endoprostheses for the medium age category of 55-64 years, regardless of whether cemented or uncemented components were implanted. The only exception was represented by hybrid HPQ-Müller Geradschaft endoprosthesis with a higher revision rate of the femoral and acetabular components. The younger age category showed a lower revision rate for uncemented versions than for the used hybrid versions of endoprostheses. For the group of elderly patients, there was no difference between the survival rate of hybrid and cemented joint replacement. Key words:arthroplasty with total hip replacement, cemented joint replacement, uncemented joint replacement, joint replacement failure, aseptic loosening of total replacement, age, joint replacement survival. 046_053_kubinec 20.2.18 14:12 Stránka 46 47/ Acta Chir Orthop Traumatol Cech. 85, 2018, No. 1 PŮVODNÍ PRÁCE.

Fakultná nemocnica s poliklinikou F D Roosevelta Ortopedická klinika SZU Banská Bystrica

Influence of the type of hip-component fixation and age of patients on mid-term revision rate of total hip replacement