Early surveillance of ceramic-on-metal total hip arthroplasty

Abstract

Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8(o) (28(o) to 63(o)), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 μg/L (0.24 μg/L to 27.56 μg/L) and 0.78 μg/L (0.21 μg/L to 8.84 μg/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%). Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly.

Clinical Results and Serum Metal Ion Concentrations following Ceramic-on-Metal Total Hip Arthroplasty at a Mean Follow-Up of 60 Months

“…Yi et al [7] and Hill et al [3] recently reported their results determining metal ion concentrations following CoM THA with a mean follow-up of 50 and 34 months, respectively (Table 2). Like in the current series, the serum levels of Co and Cr were significantly elevated compared to normal values without stabilization or downward trend after a running in period of the tribological bearing.…”

“…Ultrahigh crosslinked polyethylene and ceramic-on-ceramic (CoC) bearings are known to perform very well [2, 3]. Nevertheless, hard-on-hard bearings for THA continue to be in the focus of attention, especially due to the increasing number of revision surgeries for metal-on-metal (MoM) articulations [4].…”

“…Nevertheless, hard-on-hard bearings for THA continue to be in the focus of attention, especially due to the increasing number of revision surgeries for metal-on-metal (MoM) articulations [4]. An ideal bearing surface is characterized by low wear with biological inert debris, availability of different sizes, and toleration in terms of component position [2, 3, 5, 6]. …”

“…The ceramic-on-metal coupling (CoM), a ceramic femoral head articulating with a metal acetabular insert, was a novel option for hard-on-hard bearing surfaces introduced several years ago [3, 6–8]. Several in vitro analyses showed a lower risk of implant fracture, reduced wear, and metal debris, as well as squeaking phenomena compared to CoC and MoM bearings [2, 5–7, 9].…”

Chemistry‐driven structural alterations in short‐term retrieved ceramic‐on‐metal hip implants: Evidence for in vivo incompatibility between ceramic and metal counterparts

“…However, while investigative studies are yet underway to assess the real extent of these potential benefits, only few published evidence by clinical reports are yet available and very little is known about the actual material response in CoM articulations when introduced in the human body . A recent review on 56 CoM hips implanted between 2008 and 2009 at a single hospital by a single surgeon showed a high early failure rate of 10.7% within a mean of 1.5 years because of femoral stem loosening caused by high frictional forces .…”