Abstract
The alumina on alumina articulation in THA has induced less macrophage reaction and cytokine section than polyethylene bearings. Thus THA using alumina on almina articulation has induced little periprosthetic osteolysis. However alumina fracture is still a concern.
We had underwent 100 THAs that it was a cemented polyethylene backed acetabular component with an alumina inlay(ABS Cup; Kyocera, Kyoto, Japan), PHS stem(Kyocera) and 28mm alumina femoral head. This system was formerly used in only Japan, over 10 years results have not reported yet.
We retrospectively reviewed 94 patients(100 hips) with cemented alumina on alumina THAs to identify factors relating to alumina failure, and to evaluate mid-term(>10years) results. 16 patients died from unrelated causes within 10 years of the operation and 14 patients was lost to follow up. The remaining 70 patients(79 Hips) were evaluated after a mean follow-up of 10 years.
We performed clinical evaluation using the JOA score, and radiological evaluation was performed that inclination and anteversion angle of cup measurement with 2D template system at anteroposterior radiograph. On the radiographs at the final examination, radiolucency and osteolysis were evaluated around the acetabular component, and around the femoral component. These evaluations were scheduled for 3,6,9, and 12 months and yearly thereafter. All the operations were performed by same surgeon, at same center. Cumulative survival rates were calculated using the Kaplan-Meier method with failure defined as the end point of revision for alumina failure or for any reason. To compare groups with and without alumina failures in age, BMI, gender, activity, function, abduction angle, size of component, or existence of radiolucent lines, we used the nonparametric Mann-Whitney U-test.
The mean age of the patients at surgery was 63.0 years. The mean follow up term was 13.8 years. Inclination and anteversion mean angle of cup were 45.6°and 14.2°.ã��Revision surgery was performed because of alumina inlay failure in 4hips(2 fractures and 2 dissociation;5.1%), loosening in 2 hips(2 cup loosenings; 2.5%) recurrent dislocation in 1 hip, and femoral fracture in 1 hip, no deep infection and DVT.
The 10-year survival rate was 92.4% with revision for any reason and 95.9% with revision for alumina failure as the end point. We detected 3 ceramic failures at a mean of 8.9 years(4.1ï¼ï¿½12.5) after the index operation.
There were no differences in BMI, function, cup angles(inclination and anteversion), and cup loosening among the 4hips with alumina failure. But there were differences in age, gender, and activity with alumina failure.
This alumina on alumina THA yielded passably mid-term results, but it was occurred a high rate of catastrophic alumina inlay failure. In July 2000, we discontinued use of this type of THA to avoid alumina failure. This ABS cup was banned in 2002, because of numerous alumina failures. We suggest all patients with this type of acetabular component be followed carefully.
Cemented polyethylene-backed alumina-on-alumina THA with a composite of alumina inlay had a relatively high rate of catastrophic alumina inlay failure(5.1ï¼ï¿½) during a mean of 13.8 years' follow up. There were differences in age, gender, and activity with alumina failure.
