MRI Safety - Surgeon Information

The results of the MR safety tests for the Smith & Nephew devices indicated the following for the implants:

Titanium Intramedullary Nail - titanium Al/4V
Cobalt Chrome Staple - ASTM F75 cobalt chrome
Compression Hip Screw Plate and Lag Screw - 316L stainless steel
Oxidized Zirconium Knee Femoral Component - Oxinium material

Based on this MR safety test information, it appears that these Smith & Nephew implants will not present additional hazards or risks to patients undergoing an MR procedure using an MR system operating with a static magnetic field of 1.5-Tesla or less. As such, these devices should be considered “MR safe” according to the specific conditions used for testing.

This testing was performed using a shielded, 1.5-tesla 64 MHz MR system made by GE.
Regarding image artifacts, the report states:

For these devices, the artifacts that appeared on the MR images were relatively minor in relation to the size and shape of the metallic components of these devices. Basically the artifacts were shown as localized signal voids (i.e. signal loss) and distortions of the images.

External Fixators: Smith & Nephew’s policy is not to recommend MRI for patients with Ilizarov, Taylor Spatial Frame, or other external frames due to the possibility of magnetic field response causing undesired movement of the frame. Many of the accessory components of external fixators are made using hardenable stainless steels that do exhibit varying levels of magnetic permeability and it is not possible to guarantee use with MRI is safe.

Safety and magnetic resonance imaging

... Static hardware, including most of that used for orthopaedic and spinal work (with the exception of halo fixation devices), does not contraindicate magnetic resonance imaging; the procedure should, however, be stopped if patients experience pain in the region of large implants.1 Ventricular shunts used to treat hydrocephalus and most haemostatic clips do not pose problems.

Prevention of Secondary Osteoporotic Fractures -- Why Are We Ignoring the Evidence?

All orthopaedic surgeons are aware of the tremendous impact that osteoporosis has on our patients, and the public health implications of this are staggering. It has been suggested that the cost of treating the upcoming epidemic of femoral neck fractures alone may overwhelm the healthcare system.

Orthopaedic surgeons are in a position to identify many of these patients when they first present with a "fragility" fracture. For all of these patients, medical intervention is indicated. Many orthopaedic organizations, including the American Academy of Orthopaedic Surgeons, have made the identification of osteoporosis and the appropriate referral of patients for treatment a major initiative.

In this study, the authors (from Derriford Hospital, Plymouth, United Kingdom) looked at the first 100 femoral neck fractures operated upon beginning January 1, 1998. All patient notes, drug charts, and discharge summaries were reviewed 3 years later. The authors noted whether these patients suffered any further fractures associated with osteoporosis, prior to or since their hip fracture, and determined what advice and treatment had been documented in the records (if any).

The authors found that for almost all of the patients, the diagnosis of osteoporosis was essentially ignored, despite the well-known fact that such patients often present with further fractures. Only 3% of the patients were discharged on treatment for osteoporosis after their hip fracture. Twenty-three percent of the patients suffered later fragility fractures, and no further treatment was started in these patients despite refracture. Thus, a number of patients suffered 2 fractures associated with osteoporosis and still were not provided advice, referral, or simple, inexpensive therapies.

The authors concluded that orthopaedic surgeons are failing to initiate simple medical measures that not only improve the quality of life of their patients, but also would lessen the demands upon them to provide fracture care. The situation is likely very similar at many North American hospitals, and each of us should do everything that we can to ensure that these patients do not fall through the cracks of our disjointed healthcare system.