Failed Metal-on-Metal Hip Arthroplasties: A Spectrum of Clinical Presentations and Operative Findings

Abstract

Background A number of recent reports have described novel failure mechanisms of metal-on-metal bearings in total and resurfacing hip arthroplasty. Hip arthroplasties with metal-on-metal articulations are also subject to the traditional methods of failure seen with different bearing couples. There is currently little information in the literature to help guide timely clinical evaluation and management of these patients. Questions/purposes We therefore describe the (1) clinical presentations; (2) reasons for failure; (3) operative findings; and (4) histologic findings in patients with failed metal-onmetal hip arthroplasties. Methods We retrospectively identified all 37 patients (37 hips) with metal on metal total hip or resurfacing arthroplasties who underwent revision over the past 3 years at our institution. Relevant clinical, radiographic, laboratory, intraoperative, and histopathologic findings were analyzed for all patients. Results Of the 37 patients, 10 were revised for presumed hypersensitivity specific to the metal-on-metal articulation. This group included eight patients with tissue histology confirming chronic inflammation with lymphocytic infiltration, eight with aseptic loosening of a monoblock screwless uncemented acetabular component, two with iliopsoas impingement associated with a large-diameter femoral head, and three with femoral neck fracture after resurfacing arthroplasty; the remainder of the patients were revised for infection, instability, component malposition, and periprosthetic fracture. Conclusions Increased awareness of the modes of failure will bring to light the potential complications particular to metal-on-metal articulations while placing these complications into the context of failures associated with all hip arthroplasties. This novel clinical information should be valuable for the practicing surgeon faced with this patient population.

Revisions of Monoblock Metal-on-metal THAs Have High Early Complication Rates

“…In light of the differences in failure rates and mechanisms between MoM THAs and those with polyethylene bearings, it seems important to look at complications and reoperations after revision of MoM THAs as well as to try to identify any factors that might be associated with complications after revision of MoM THA. Currently, there is a paucity of literature, with limited patient numbers, examining the outcomes of MoM THA revisions [10,31,35], and no papers to our knowledge have examined the clinical and demographic factors associated with postrevision complications. We therefore described, with the largest series of which we are aware to date, (1) the frequency of early complications; and (2) the clinical and demographic factors associated with complications after revision of monoblock MoM THA.…”

“…Although initial reports were satisfactory [5,14,22,28,29], subsequent research demonstrated unacceptable early failure rates of monoblock MoM THAs, resulting in a substantial revision burden [2-4, 6, 7, 10, 12, 13, 15, 18, 19, 21, 24, 25, 27, 30, 32, 33, 36]. These revisions can be complicated by extensive soft tissue and bony defects, persistence of adverse local tissue reaction as well as problems associated with the general need to reduce the head size at the time of revision, perhaps increasing the likelihood of dislocation [1,3,7,10,13,18,19,23,25,31,33]. Previous studies reporting on the early complications after these revisions are limited and generally of small number [3,10,31,35].…”

“…These revisions can be complicated by extensive soft tissue and bony defects, persistence of adverse local tissue reaction as well as problems associated with the general need to reduce the head size at the time of revision, perhaps increasing the likelihood of dislocation [1,3,7,10,13,18,19,23,25,31,33]. Previous studies reporting on the early complications after these revisions are limited and generally of small number [3,10,31,35]. Furthermore, the clinical and demographic factors associated with these complications have yet to be clearly elucidated.…”

Complications Are Not Increased With Acetabular Revision of Metal-on-metal Total Hip Arthroplasty

“…with a specific diagnosis or operative procedure, it is limited in the level and type of information that can be provided compared with other types of studies. For example, the data in operative reports and radiographs, which would be used to determine the indication for revision, surgical approach, amount of bone loss [33], acetabular cup position, and soft tissue damage [7], are not available. In addition, the sizes of the removed and revision acetabular components, femoral heads, and retained femoral components are not available.…”

“…The rates of survival have been reported from 92% to 100% at 5 years and 82% to 100% at 10 years [1,13,30,40]. The most common indications for revision of MoM hips include adverse local tissue reaction (ALTR), aseptic loosening of the acetabular component, infection, and persistent groin pain [7]. Although many of these complications can occur with other bearing surfaces, ALTR related to particulate metal debris, molecular effects of metal ions, or corrosion products may contribute to extensive soft tissue destruction [36].…”