No Association of CALCA Polymorphisms and Aseptic Loosening after Primary Total Hip Arthroplasty

Studies of aseptic loosening showed an influence of calcitonin and α-CGRP, both encoded from the calcitonin/α-CGRP (CALCA) gene by alternative splicing. The aim of this study was to detect a possible association of the CALCA polymorphisms P1(rs1553005), P2(rs35815751), P3(rs5240), and P4(rs2956) with the time to aseptic loosening after THA. 320 patients suffering from aseptic loosening after primary total hip arthroplasty were genotyped for CALCA-P1 polymorphism and 161 patients for CALCA-P2 and CALCA-P3 polymorphisms and 160 patients for CALCA-P4 polymorphism. CALCA genotypes were determined by polymerase chain reaction and restriction-fragment length polymorphism. The genotype distribution of CALCA-P1 was CC 10%, CT 43%, and 46% TT. CALCA-P2 showed a distribution of 90.7%II, 8.7% ID, and 0.6% DD. The CALCA-P3 genotype distribution was 97.5% TT and 2.5% TC. The CALCA-P4 genotype distribution was 48.1% AA, 40% AT, and 11.9% TT. Significant differences between the CALCA genotypes were not found concerning age at implantation and replantation, BMI, gender, and cementation technique. No associations of the time for aseptic loosening were found. In conclusion, we did not find a significant association of CALCA polymorphisms and the time to aseptic loosening after primary THA in a Western European group.