What is appropriate surveillance for metal-on-metal hip arthroplasty patients?

Abstract

The unexpected high revision rates of large-diameter (femoral head sizes of 36 mm or greater) metal-on-metal hip arthroplasties (MoMHAs) have led to worldwide regulatory authorities recommending regular surveillance, even for asymptomatic individuals. However, these recommendations are not evidence-based and are very costly. The rapidly evolving evidence base requires an update regarding the investigation and management of MoMHA patients. This article is the first of 2 (the second article in this series will consider the threshold for performing revision, and the outcomes following ARMD revision surgery: Matharu et al., Revision surgery of metal-on-metal hip arthroplasties for adverse reactions to metal debris: A clinical update. Acta Orthop 2018; in press), and considers the various investigative modalities used during surveillance, with specific focus on blood metal ion sampling and cross-sectional imaging. No single investigation can universally be used during MoMHA patient surveillance. Recent studies have now provided important information on interpreting blood metal ions (effective in identifying patients at low risk of problems), clarifying the roles of cross-sectional imaging (reserve combined ultrasound and MARS-MRI for complex cases), and providing parameters to safely exclude many asymptomatic patients from regular surveillance. This information will be useful when designing future surveillance protocols for MoMHA patients

Metal Ion Release, Clinical and Radiological Outcomes in Large Diameter Metal-on-Metal Total Hip Arthroplasty at Long-Term Follow-Up

“…Evaluation of systemic concentrations of metal ions has been proposed to detect wear, malposition of prosthesis components, poor hip function, early failure [ 13 ], local toxicity and systemic toxicity; it is also useful for follow-up [ 14 ]. However, there is still no international consensus on the surveillance protocols to follow-up MoM THA [ 4 , 15 ]. In addition, no clear thresholds of ion levels are available to identify poorly performing hips and patients at greater risk of developing ARMD [ 16 , 17 , 18 , 19 ].…”

Revision surgery of metal-on-metal hip arthroplasties for adverse reactions to metal debris

“…The first article considered the various investigative modalities used during MoMHA patient surveillance (Matharu et al. 2018a ). The present article aims to provide a clinical update regarding ARMD revision surgery in MoMHA patients (hip resurfacing and large-diameter MoM total hip arthroplasty), with specific focus on the threshold for performing ARMD revision, the surgical strategy, and the outcomes following revision.…”

“…The first article considered the various investigative modalities used during MoMHA surveillance, with specific focus on blood metal ion sampling and imaging (Matharu et al. 2018a ). The present article considers the threshold for performing revision, the surgical strategy, and the outcomes following ARMD revision surgery when performed in patients with MoM HRAs and MoM THAs with femoral head sizes of 36 mm or greater.…”

Metal-on-Metal Total Hip Arthroplasty: Current Recommendations and Lessons Learned

“…Plain radiography to assess component position, loosening, osteolysis, bone quality, and femoral neck erosion due to impingement (Fig 1a,e,f). [22,23] Radiographs are indicated in all symptomatic patients with MoM replacements or resurfacings. [24] Radiographs should be com-pared to evaluate osteolysis and component loosening.…”