Ceramic–ceramic coupling with big heads: clinical outcome

Third generation delta ceramic-on-ceramic bearing for total hip arthroplasty at mid-term follow-up

Purpose

to evaluate the results of Delta ceramic-on-ceramic (CoC) for total-hip-arthroplasty (THA).

Methods

261 THA using Delta-CoC, retrospectively analyzed. A 36 mm head was used in 189 cases and a 32/40 mm in the others. The series have been compared to a group of 89 THA with Forte-CoC.

Results

The Harris-Hip-Score improved from 49.1 ± 14.3 to 92.0 ± 8.9 (P < 0.001). In the Delta group there were one ceramic fracture and 2 dislocations. Two hips underwent revision. There were one revision in the Forte group for instability and one squeaking hip.

Conclusions

The new ceramic bearings provides a safe bearing for THA, with rare complications.

Advances in hip arthroplasty surgery: what is justified?

Total hip arthroplasty (THA) surgery has shown dramatic changes in terms of increased number of procedures and of technical development in recent years. It has been described as “the operation of the 20^th century” for the excellent results, the high satisfaction of the patients and the improvement of the quality of life.

A lot of variations have been introduced over the last few decades in THA especially in terms of indications (both in younger and older patients), techniques and devices (approaches, tissue preservation, biomaterials and industrial finishing), per-operative management (blood loss and pain control) and post-operative protocols (the so called “fast track” surgery). Looking at all these advances the emerging question is: have all of them been justified both in terms of improvement of the results for the patients and of the cost/benefit ratio from an economical point of view?

The purpose of this paper is to critically analyse the advantages and the disadvantages of the theoretically proposed “advances in hip arthroplasty” and attempt to understand which are justified of such “advances” nowadays, based on the international and the European perspective with a focus on the author’s personal clinical experience.

Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.170008. Originally published online at www.efortopenreviews.org

Wear of 36-mm BIOLOX® delta ceramic-on-ceramic bearing in total hip replacements under edge loading conditions

Ceramic-on-ceramic bearings have become of great interest due to the substantial improvements in the manufacturing techniques and material properties and due to polyethylene wear debris–induced osteolysis and the issues with metal wear debris and ion release by metal-on-metal bearings. Edge loading conditions due to translational malpositioning (microseparation conditions) have been shown to replicate clinically relevant wear mechanisms and increase the wear of ceramic-on-ceramic bearings; thus, it was necessary to test new bearing materials and designs under these adverse conditions. The aim of this study was to assess the effect of increasing head size on the wear of BIOLOX® delta ceramic-on-ceramic bearings under edge loading conditions due to rotational (steep cup inclination angle) and translational (microseparation) malpositioning. In this study, six 36-mm ceramic-on-ceramic bearings (BIOLOX delta, CeramTec, Germany) were tested under standard and edge loading conditions using the Leeds II hip simulator and compared to the 28-mm bearings tested and published previously under identical conditions. The mean wear rate under standard gait conditions was below 0.1 mm3/million cycles for both the 28-mm and the 36-mm ceramic-on-ceramic bearings, and increasing the inclination angle did not affect the wear rates. The introduction of microseparation to the gait cycle increased the wear rate of ceramic-on-ceramic bearing and resulted in stripe wear on the femoral heads. Under microseparation conditions, the wear rate of size 36-mm bearings (0.22 mm3/million cycles) was significantly higher ( p = 0.004) than that for size 28-mm bearings (0.13 mm3/million cycles). This was due to the larger contact area for the larger bearings and deprived lubrication under edge loading conditions. The wear rate of BIOLOX delta ceramic-on-ceramic bearings under microseparation conditions was still very low ( <0.25 mm3/million cycles) compared to earlier generation ceramic-on-ceramic bearings (BIOLOX forte, 1.84 mm3/million cycles) and other bearing materials such as metal-on-metal bearings (2–8 mm3/million cycles).