Acetabular revision arthroplasty using jumbo cups: an experience in Asia.

INTRODUCTION

Variable degrees of bony deficiencies often complicate revisional arthrolasties of acetabular components and represent challenges to orthopedic surgeons. Many solutions exist and cementless jumbo cup reconstruction had been proven to be a feasible and successful method. Our study aimed to access the results of these cementless giant cups for managing acetabular bony defect at one institute.

MATERIALS AND METHODS

Between March 2000 and March 2003, 47 revisions of the failed acetabular components using the so-called "Jumbo Acetabular Cups" were enrolled in our study. All cases were followed for at least 4 years. We defined the size of the jumbo cups for the Asians to be of an outside diameter of 64 mm for men and 60 mm for women, which were 2 mm smaller than the commonly used definition in the Western countries. The radiographic outcomes and the migration of hip centers were analyzed. The endurance of these giant sockets was estimated by the Kaplan-Meier analysis.

RESULTS

After a mean follow-up of 65 months, only three implant failures requiring re-revision were identified. The estimated 5-year survival rate according to the Kaplan-Meier analysis was 94.5%. Radiographic analysis demonstrated an improvement of vertical hip center from 31 to 27 mm proximal to the interteardrop line. Eight (17%) cups exhibited radiolucent line around the bone-prosthesis interface but did not attenuate implant instability. The complication rate was not high. Dislocation happened in five (11%) patients. One deep infection was successfully reconstructed in stage surgeries after eradication of the infection.

CONCLUSION

With the aid of novel implant-coating technique and materials, jumbo cup reconstruction can achieve stability and longevity through an adequate peripheral ring-contact, regardless of inadequate implant to host bone contact. We believe that this is a reliable and easily performed reconstruction for acetabular defect.