Health, Hip Replacement, Journal of Bone & Joint Surgery, Journal of Bone & Joint Surgery | Article, Medicine, metal, science, Scientific literature, surgery, University of British Columbia, Vancouver
Prevalence of Pseudotumor in Asymptomatic Patients After Metal-on-Metal Hip Arthroplasty
The cause of recently reported pseudotumor formation in patients with metal-on-metal hip replacements is unknown. It has been postulated that there is an association between elevated levels of serum metal ions and pseudotumor formation. The primary purpose of this study was to assess the prevalence of pseudotumor formation in asymptomatic patients with a metal-on-metal total hip replacement after a minimum duration of follow-up of two years. A secondary purpose was to assess whether a correlation exists between elevated serum metal ion levels and pseudotumor formation.
In the present study, the prevalence of pseudotumor formation, as detected with ultrasound, was evaluated for thirty-one asymptomatic patients with a metal-on-metal total hip arthroplasty, twenty-four asymptomatic patients with a metal-on-polyethylene total hip arthroplasty, and twenty asymptomatic patients with a metal-on-metal hip resurfacing arthroplasty. Serum levels of cobalt and chromium were measured in the metal-on-metal total hip arthroplasty and hip resurfacing arthroplasty groups.
Ten patients (32%) in the metal-on-metal total hip arthroplasty group had a solid or cystic mass, with another three patients (10%) having a substantial fluid collection. Five patients (25%) in the hip resurfacing arthroplasty group had a solid or cystic mass, with another patient (5%) having a fluid collection. Pseudotumor formation was significantly more frequent in the metal-on-metal total hip arthroplasty group compared with the metal-on-polyethylene total hip arthroplasty group (p = 0.015). We did not detect a significant correlation between the serum metal ion levels and the size of pseudotumor abnormality. The median serum metal ion level was greater in patients with pseudotumor formation than it was in those without pseudotumor formation, but the difference was not significant.
We recommend high-resolution ultrasound surveillance of all asymptomatic patients with a metal-on-metal implant that is known to result in high serum metal ion levels. Once a metal-on-metal implant is known to be associated with high serum metal ions, the measurement of ion levels does not helpfully contribute to surveillance.
- Ion levels poor indicator for hip arthroplasty debris (earlsview.com)
- Cementless Metaphyseal Fitting Anatomic Total Hip Arthroplasty with a Ceramic-on-Ceramic Bearing in Patients Thirty Years of Age or Younger (earlsview.com)
- Smith & Nephew BHR – A benign psoas mass following metal-on-metal resurfacing of the hip (earlsview.com)
- Instability after total hip arthroplasty (earlsview.com)
- One- Versus Two-stage Bilateral Total Hip Arthroplasty | Orthopedics (earlsview.com)
- MRI Findings in Painful Metal-on-Metal H… [AJR Am J Roentgenol. 2012] – PubMed – NCBI (earlsview.com)
- Prediction of Functional Outcome at Six Months Following Total Hip Arthroplasty (earlsview.com)
- Hip Replacement – Effect of high-dose preoperative methylprednisolone on recovery after total hip arthroplasty: a randomized, double-blind, placebo-controlled trial (earlsview.com)
- New Zealand – Medical Devices – Medsafe Guidelines for MoM hips (earlsview.com)
- Patients with metal-on-metal hips being contacted after UK officials issue alert | Orthopedics Today (earlsview.com)