Revision of a Monoblock Metal-on-Metal Cup Using a Dual Mobility Component: Is It a Reasonable Option?

Abstract

Revision of large-diameter, monoblock acetabular components for both hip resurfacing arthroplasty and metal-on-metal (MoM) total hip arthroplasty (THA) is correlated to a high amount of complications. For this reason, performing a limited revision by conversion to a dual mobility (DM) without acetabular component exchange has been proposed in order to limit these complications. Although DM bearing offers an easy solution avoiding the intraoperative and time-associated complications, concern about polyethylene wear and stability remains due to the difference regarding the design, the coverage angle and the clearance of the two implants. In order to evaluate the performance of this new solution with the new material to prevent the possibility of failure it is essential to conduct a review of the literature A qualitative systematic review of the literature has been conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of PubMed, EMBASE, Google Scholar, and Scopus for English and French articles between January 2000 and October 2019 was performed, with the primary objective of finding articles about dual mobility bearing coupling with large metal-on-metal cup in the case of hip revision procedure. Various combinations of the key words were used in the search strategy. Thirteen articles with DM bearing mated with MoM cup were analyzed. Of the 130 hip revisions selected, with a follow-up from 6 to 53 months, there were a total of 14 with complications (10.77%): four true dislocations (3.08%); six intra-prosthetic dislocations (IPD, 4.6%), two of which presented plastic deformation and polyethylene wear; four other complications (3.08%), included a cup osteolysis, a clicking noise, a superficial infection and a periprosthetic fracture. All the mentioned true dislocations occurred during the first month while IPDs appeared during the first two years from the index revision. In conclusion, according to the literature analyzed, we can stress that the concerns and doubts about mating a DM bearing with large MoM cup cannot be dissolved. It has been pointed out that a DM bearing is not designed for a MoM cup; it is not mechanically tested on MoM cups, which presents different clearance and coverage angles. Predictable complications may occur, such as IPD, polyethylene wear and true dislocation. These complications have been reported at an even higher rate than they were in the eighties, when the first generation of DM implants were of a lower quality of polyethylene and the characteristic of the design was less optimal than modern ones.

No dislocation and low complication rate for a modern dual mobility cup with pre-impacted femoral head in primary hip replacement: A consecutive series of 175 hips at minimum 5-year follow-up

“…The partially extended rim of this implant allows an increased coverage angle of up to 12°participating in this anti-dislocation shield [49]. This increased coverage being only on the upper side, this increased stability was not at the expense of a rising risk of psoas impingement nor to symptomatic cam effect as those complications were not recorded in this study.…”

Hip stability parameters with dual mobility, modular dual mobility and fixed bearing in total hip arthroplasty: an analytical evaluation

“…In the past, JD changes were studied according to femoral head offset, head size and cup position [ 17 ]. However, these studies evaluated only standard implants and sub-hemispherical cups for large head diameters (above 38 mm), specifically designed for metal-on-metal implants, which have a negative effect on JD, due to their smaller coverage angle and higher head offset [ 29 , 30 ].…”

EFORT recommendations for off-label use, mix & match and mismatch in hip and knee arthroplasty

“…Dual mobility acetabular components on conventional stems have been reported as producing encouraging results after excision of the femoral head in revisions of surface replacements, where the acetabular component is being retained. 86 , 87 Long-term reports are not yet available and it could be that there will be a potential wear problem as a consequence of incompatible clearance. 88 …”