Cemented modular metal backed total hip prostheses have the theoretical advantage to allow different inlays to be used. Asymetric or snap inlays are some of the options. First attempts with this kind of implant failed due to PE quality. A novel implant has been specifically designed and constructed for the use of cement. In vitro testing has shown results equal to other cemented cups. Aim of this study is to investigate the first clinical results of this implant with special consideration to intraoperative complications, intraoperative change of inlays, postoperative complications and clinical results.
Patients and Methods: Study setup was prospective, location a university hospital, approval for this study was granted by the local ethical committee. Inclusion criteria were patients with a biological age over 70 years that suffered a recent fractured neck of femur with the general indication for arthroplasty. Exclusion criteria were the inability for full informed consent, ASA IV and current infection. Thirty patients were included in this study. Mean age was 78.6 years (55.1 to 88.6), 23 patients were female (77%). The mean BMI was 25.3 (17.5–41).
The implant under investigation was a cemented modular acetabular component (C-MIC, ESKA Implants, Germany). The inlays are manufactured of highly crosslinked polyethylene. The standard protocols regarding DVT prophylaxis and antibiosis for HHS and the Barthel index.
Results: Implantation of the C-MIC component was possible in all cases. In 1 case (3.3%) the inlay was changed and replaced by an asymmetrical anti-luxation inlay intraoperatively as there was a luxation tendency. There were no other intraoperative complications. There was no case of infection or significant hematoma. In 1 case there was a DVT of the lower leg diagnosed by ultrasound on day 21. The mean Barthel index preop. was determined with 96.5 of 100, the mean Harris Hip Score with 89. At 3 months F/U the Barthel index was mean 96.1, at 6 months 96. The Harris Hip Score at 3 months was mean 72 points (17 pts below the preoperative status), at 6 months mean 79 points (10 pts below preoperative status).
Discussion: The C-MIC acetabular component does not show increased complication rates when compared to published results of hemiarthroplasty. The Barthel index as an outcome measurement of mobility and activities of daily living showed a return to the preoperative level. The HHSshowed a satisfactory result at 12 weeks, it also showed that patients of a geriatric population have problems to regain their full hip function after a fractured neck-of-femur.
We can conclude that the C-MIC acetabular component is safe to use. Due to limitations of this study we are not able to state if THA is superior to hemiarthroplasty in geriatric patients.
