Overview: Doctors need to evaluate patient symptoms as well as imaging techniques before performing revision surgeries on patients with metal-on-metal hip implants, a new study suggests. Researchers said that, although radiology findings are useful in deciding whether or not to revise a metal-on-metal hip implant patient, there are also cases where all-metal hip implant patients experience pain without obvious radiological symptoms. These findings have important implications for patients with metal-on-metal hip implants, which are notorious for having high failure rates.
- UK researchers recommend that physicians take patient symptoms into consideration, in addition to imaging techniques, before performing revision surgery
- The study was presented at the British Orthopaedic Association Congress
- Metal-on-metal hip implants tend to have a higher rate of revision compared to other types of implants, and reportedly cause symptoms due to the release of metal ions
Product & Manufacturer
|Johnson & Johnson/ DePuy Orthopaedics||Biomet||Smith & Nephew||Zimmer||Wright Medical Technology|
|ASR (recalled)||M2a Magnum||Oxinium||Durom||CONSERVE Hip Systems|
Side Effects & Complications
- High failure rate
- Necrosis (tissue death)
- Increased levels of cobalt and chromium ions
- Pain at the implant, sometimes spreading to the groin and back
- Osteolysis (bone loss)
- Fluid collections/solid masses around the hip joint
Doctors Should Evaluate Patients’ Symptoms before Revision Surgery
Findings presented at the British Orthopaedic Association Congress suggest that doctors need to evaluate patients’ symptoms in addition to using imaging techniques such as MRI or ultrasound in detecting complications among patients with metal-on-metal hip implants. Naveed Ahmed, MBBS, MSc and his colleagues evaluated imaging results from 25 hip implants (16 patients) between March 2011 and May 2012. Among these, 23 hips underwent ultrasound and 21 also had MRI scans. The researchers also collected fluids to check for metallosis. Overall, four patients had negative results for MRI and ultrasound, but underwent revision surgery due to pain; these patients were found to have “histopathology positive metallosis,” Ahmed stated.
Ahmed said in his presentation that “Although ultrasound and MRI are useful in the treating of metal-on-metal patients, there is a significant percentage of hips that have pain with negative radiology findings,”
Metal-on-Metal Hip Implants and High Revision Rates
Metal-on-metal hip implants have drawn scrutiny due to reports that the devices fail at higher rates compared to metal-on-plastic or metal-on-ceramic implants. The problem, experts suspect, is that the implants release metal particles when the metal surfaces rub together. In some patients, the metallic debris can lead to pain or other severe complications, prompting the need for revision surgery to have the implant removed.