The Mid-term Results Of Ceramic To Ceramic Coupled Cementless Total Hip Arthroplasty

BackgroundAs one of the most successful surgical techniques in the20th century,total hip arthroplasty has been widely used for the treatment of end-stage hip arthrosis.In the past, the most appropriate age at the time of the hip arthroplasty was65-75years old. With the development of prosthetic material, especially the maturity of ceramic materials, the service life of the artificial hip was longer than before. So the indications of total hip arthroplasty have expanded to the younger patients.Metal-polyethylene hip implants has been widely used as standard artificial joint materials untile now. However, it had a high wear rate, wear debris induced serious osteolysis, tissue inflammation, which seriously affects survival of implant. Over the years, people have been looking for a method to solve this problem. Friction interface material with low wear rates as well as good tissue compatibility is considered to be the preferred solution to improve the survivorship of the prosthesis. Ceramic materials came into being.Although the ceramic material has been used in the artificial interface for40years, the first and second generation ceramic material exist some problem, such as larger grains and heterogeneity, big brittleness, bad mechanical properties, which lead to higher rate of breakage of ceramic components. The third-generation ceramic-on-ceramic has mature prosthesis design and material quality to resolve this problem. It have the advantages of good biocompatibility and low wear rate as high hard inert material, which to become the preferred interface materials at upgrading artificial hip prosthesis.The third-generation ceramic interface materials have been used in foreign countries more than20years. But it was not longer than10years, which was widely used for hip arthroplasty in our countries. Besides, due to the differences in living habit and body conditions, whether the intermediate-term or even long-term results associated with the use of the third-generation ceramic interface materials in China is comparable with previous literatures in developed countries is still unknown. So the further research about the third-generation ceramic interface materials is needed.ObjectiveTherefore we evaluated the clinical outcome, and radiographic findings at3-7years follow-up to review the results of49primary cementless hip arthroplasties which were performed in38patients by the same professor with the third-generation ceramic-ceramic joint prosthesis in Nanfang Hospital from January2005to December2009and to provide references for orthopedists for prosthesis selection.Materials and MethodsA series of69primary cementless hip arthroplasties in52patients was suggested to revisit the out-patient clinic for an evaluation, which was contacted through telephone and letters.Assessment methodsPostoperative clinical and radiograph review were performed at each follow-up. Harris hip score, sf-36, pain extinction time, crutch walking time, functional capabilities, complications and patient satisfaction were the clinical items. Radiographic evaluation indicators included:ceramic fragmentation, cortical hypertrophy, radiolucent lines, osteolysis and heterotopic ossification. Data acquisition and evaluation were completed by the same investigator. Imaging data was measured on radiograghs and was corrected for magnification by comparing the diameter of the femoral head on each individual radiogragh with the known diameter of cup.Result1.53patients (69hips) met the inclusion criteria,13patients (18hips) were lost to follow-up by the time of the latest follow-up. One patient had died of cardiovascular disease and one femoral implant had loosening and required revision at one year after the primary hip arthroplasty.38patients (49hips) were accepted ultimately effective follow-up. The mean age of the patients at the time of the arthroplasty was44.2±15.3years (range19to77years old), and25were man. There were11bilateral arthroplasties at the same time.2. The average follow-up time was52.5±17.3months (rang,36to85months).The mean Harris hip score had improved from50.9±11.4(rang,10to73points) before surgery to92.9±6.6points (rang,67to100points) at the time of the latest follow-up (t=-24.7, P<0.05). The score of each dimension of SF-36were higher after primary hip arthroplasty (P<0.01). The pain relief occurs in a month after hip arthroplasty. The average time of patients walking without crutches was2.1±0.3months (rang,1to6months). Apart from a patient with severe joint abnormal sound and one patient with brooker Ⅳ heterotopic ossification, the other patients were satisfied with the hip arthroplasty.3. Evaluated the X-ray at each follow-up, there was no case with ceramic hip prosthesis fragmentation and no bright lines around acetabulum, the average abduction angle of the acetabular cup prosthesis was43.9±8.5°(rang,27°to58°) and the average acetabular cup anteversion was19.5±5.9°(rang,8°to25°). No patients appear prosthesis loosening of the acetabular cup. According to the Gruen zone, the Gruen zone2,3,5,6around the femoral stem prosthesis in49hips (100%) were observed in dotted welding. Bone densityin Gruen3or5was increased in30hips (61%). There were14hips (29%) with bright line in zone1and15hips (31%) with bright line in zone7,which was no bright line progress trends in X-ray imaging data to contrast with earlier observation.4. Two patients (two hips) appears squeaking hip.18patients (25hips,51%) of the patients appears heterotopic ossification. Brooker Ⅰ10hips, Brooker Ⅱ6hips Brooker III4hips, BrookerⅣ2hips. Heterotopic ossification of BrookerⅣwas occursed around prosthetic femoral neck of one patient (2hips), which was confirmed hip ankylosis through X-ray fluoroscopy. One femoral revision was done due to aseptic loosening at the1year after the primary hip arthroplasty. The overall survival rate of the implants was85.4%(95%confidence interval:84.7to86.1%) at five years with revision for any reason as the end point. The the acetabular prosthesis survival rate was100%and the femoral stem prosthesis survival rate was98.6%(95%CI:90.5%to99.8%).Conclusion1、Mid-term clinical curative effect were good at3to7years after the cementless primary total hip arthroplasty with ceramic-on-ceramic friction interface prosthesis;2、The implant with a third-generation ceramic-on-ceramic friction interface had a high implant survival rate;3、This mid-term results confirmed that the third generation of ceramic to ceramic friction interface combination had almost negligible low risk of fracture;4、No periprosthetic osteolysis was occursed around the ceramic prosthesis in our study.It suggest that the implant with the third-generation ceramic-on-ceramic friction interface had a high implant survival rate;5、The heterotopic ossification around the ceramic hip prosthesis had a high incidence in our series.The heterotopic ossification of brooker IV would affect the range of motion of hip;6、The squeaking rate of the third-generation ceramic-on-ceramic friction interface in our series was4%. It appears that exact etionlogy of squeaking of ceramic-on-ceramic bearing still unknown and further research of this problem was needed.