Published online Apr 6, 2020. doi: 10.12998/wjcc.v8.i7.1223
Peer-review started: December 29, 2019
First decision: January 19, 2020
Revised: March 12, 2020
Accepted: March 19, 2020
Article in press: March 19, 2020
Published online: April 6, 2020
Processing time: 98 Days and 23.7 Hours
Acetabular bone defects are becoming more common in revision total hip arthroplasty. The reconstruction of the defects may be a surgical challenge. For the reconstruction of the defects, structural allograft has been used to initially stabilise the cementless hemispherical acetabular component in the past decades. However, due to the collapse, resorption, nonunion, loosening, and infection of the grafts, the cementless acetabular component that lacked successful biological fixation and bone graft incorporation became susceptible to loosening. The success rate of structural allografts was approximately 65% in a series of systematic reviews of the literature.
Trabecular metal with high frictional characteristics, low modulus of elasticity, and high volumetric porosity (70% to 80%) has been widely used to reconstruct the defects during the past decade. Hemispheric acetabular components with trabecular metal augments have been reported by many authors to be associated with excellent clinical results. Many surgeons have utilized two trabecular metal augments to reconstruct the superomedial type IIIB defects. However, the two largest trabecular metal augments cannot reconstruct the defects or restore the normal hip centre of rotation because the defects are too large. For the sake of solving the problem, we utilized a cup-on-cup technique to reconstruct the Paprosky type IIIB acetabulum bone defects and restore the normal hip centre of rotation.
The main objective of this study was to report the short-term results of patients with Paprosky type IIIB acetabular bone defects reconstructed using the cup-on-cup technique.
Six patients (six hips) with a mean age of 59 years who underwent acetabular reconstruction using our cup-on-cup technique between January 2015 and January 2017 were retrospectively reviewed. All patients were followed both clinically and radiographically.
The mean Harris hip score improved from 32.4 pre-operatively to 80.7 at the last follow-up. Greater trochanteric migration after extended trochanteric osteotomy occurred in one of six hips at 3 mo. There was no evidence of component migration at the last follow-up.
We present the clinical and radiographical results of six patients with type IIIB acetabular bone defects. The short-term results suggest that our cup-on-cup technique could be considered an effective management option for Paprosky type IIIB acetabular bone defects without pelvic discontinuity.
Due to the retrospective nature of this study and the small sample, it is difficult to obtain reliable conclusions. However, our study provides a new surgical technique to reconstruct the Paprosky type IIIB acetabulum bone defects.