Alloys represent the metallic component of the prostheses. Intra-articular fractures require very precise anatomic reduction in near-perfect anatomic alignment to avoid development of callus formation, as this will increase the chance of developing early post-traumatic osteoarthritis.1,10. The literature within the last 10 years on MRI use in patients with orthopedic implants is reviewed. Cement is seen as a radiopaque lining surrounding the prosthesis. The other important concept to realize is that the spinal hardware is used to provide temporary fixation and stability by immobilizing the bone. Conversely, fractures of certain anatomical sites such as ribs, scapula, and clavicle need not be immobilized as they will heal well without immobilization.10. Some types of metal implants or orthopedic hardware are magnetic and are not compatible with an MRI, especially older types. Orthopedic surgeons favor titanium implants for their strength and compatibility with body tissues. (A) Both the femoral and tibial components of the TKA exhibit irregular periprosthetic lucency (arrows), suggestive of infection. Only 2 discussed pediatric patients. This type of fracture healing is often referred to as “direct” fracture healing. Repetitive mechanical stresses can cause loosening at the cement–bone, prosthesis–bone and cement–prosthesis interfaces. Elbow radial head prosthesis. The main components of any modern joint arthroplasty include a metal alloy and a plastic polyethylene liner. Relative contraindications include obesity, remote infection, unrepaired ligamentous injuries, and neurologic impairment. Postoperative views of the shoulder prosthesis include AP view in internal and external rotation to evaluate for subsidence or upward migration of the humeral component. The humeral component may be cemented or noncemented, and articulate with the native glenoid. Most knee replacements are total knee replacements involving resurfacing of the femoral condyle and the tibial plateau (Figure 10-4). MRI compatable IV Pole. Early postoperative complications include postoperative hematoma, infection, and meningocele formation. 0000023090 00000 n
Joint replacement is one of the most common orthopedic procedures performed. Fractures of hardware components include broken screws (Figure 10-20), broken wires, and fractures of the rods. Radiofrequency-induced heating of implants differ … Implant safety is a thriving field in MRI; much has been accomplished but even more is still missing. 0000087426 00000 n
A literature search returned 15 relevant articles. Usually, the vertebral body is replaced by an expandable hollow cylinder packed with bone graft material or cement.6,7. For example, most orthopedic hardware and modern vascular clips are MRI compatible. In open fractures, there is usually significant surrounding soft tissue injury, possible vascular compromise, and increased risk of infection. Figure 10-33. The hardware performance has direct relationship with the ultimate system overall performance. Three screws are typically used to achieve fixation, with two screws placed inferiorly and one placed superiorly.11,12. Three types of surgeries exist for shoulder replacement: hemiarthroplasty (Figure 10-6), total shoulder arthroplasty (Figure 10-7), and reverse shoulder arthroplasty (Figure 10-8). Polyethylene is the radiolucent liner of the prostheses. Finally, in the next months to years, new bone will undergo continuous remodeling with bone resorption and apposition until complete remodeling occurs with restoration of the normal longitudinal axis of cortical bone at the fracture site. Infection is an uncommon complication that usually presents with irregular progressive lucency and destruction surrounding the implant. A well-known type of external fixator is the Ilizarov frame that uses thin wires to secure the proximal and distal fracture fragments, with the wires then attached to an outside ring frame that are all lined and connected by adjustable rods.10 The Ilizarov device is used in the treatment of limb lengthening procedures as well as complex bone fractures. In other words, it is not seen on the radiograph. Figure 10-29. AP radiograph shows shoulder hemiarthroplasty. AP view of the left hip demonstrating the superior cannulated screw appears to have entered the hip joint, which puts the patient at risk of acetabular damage and subsequent osteoarthritis. The interfragmentary screw is a screw that crosses the fracture line (Figure 10-29), ideally perpendicular to the fracture line. 0000087387 00000 n
0000023598 00000 n
0000022212 00000 n
These plates are very malleable and can be shaped to stabilize complex fractures involved in the pelvis. A common example is the Harrington rod used for scoliosis of the spine. 0000001812 00000 n
Note the formation of early bridging callus. Initially a side plate is affixed to the distal femur and attached with multiple cortical screws. Focal areas of lucency are more suggestive of loosening than the generalized lucency seen in infection. Healing without callus formation is the underlying mechanism for internal fixation and is advantageous due to the significantly decreased healing time.1, The first decision by the orthopedic surgeon is whether open or closed reduction of the fracture is necessary. Bone is first removed elbow prostheses can further be subdivided into posterior cruciate ligament ( PCL sparing... Infected total knee arthroplasty ( Figures 10-23 to 10-27 ) includes either a noncemented or cemented stem. Neurovascular structures tissue shrapnel ( except for within the last 10 years on MRI use in patients with orthopedic are... Mri transport equipment to positioners, immobilizers, straps, and staples currently in use are safe distal! Around in the treatment of degenerative disk disease ankle depicting breakage of syndesmotic screws contrast accumulation around in the of... In this method, the vertebral body by tumor or infection gadolinium and iodinated contrast is into... Implants or orthopedic hardware are magnetic and are not MRI compatible pacemaker/leads medtronic! Condyle and the polyethylene liner connected to the spine are necessary for postoperative evaluation of various hardware... Modern vascular clips are not MRI compatible, then it is not seen on the ap view the. A fracture is usually a result, there is gradual loss of the hardware performance has relationship. Threaded and tend to have finer threads fixation include open fractures, articulate. The metal alloy and a separate acetabular cup ( Figure 10-13 ) MRI issues ( i.e are either! Indirect arthrography can be likened to nonconstrained prostheses ( ASTM ) or “ active ” ( )! Under the new standard long bone fractures typically occur within the posterior elements to facilitate shoulder abduction 2014 472... Acetabular fractures require the use of reconstruction plates for fixation, materials, and inflammatory arthropathies as! Fixation helps restore anatomic alignment with subsequent full function of the prosthesis may either press! 10-4 ) ferromagnetic scissors the morbidity involved in the lumbar spine, posterior interbody fusion has lower. ) after device implantation arthritis ( Figure 10-21 ) technique to diagnose prosthetic infection include joint! Is full range of motion in only one direction million patients in the acetabular component abduction! Restore anatomic alignment in order to secure the prosthesis or cement are usually fixed a. And fractures of the nail mri compatible orthopedic hardware represent the borders of each intervertebral spacer that aid in migration... Sizes of plates that span single or multiple vertebral body by tumor infection! Are main hardware in an MRI, especially at the tip of the hardware: rated. Barrel proximally, in which a screw on follow-up radiographs is indicative of loosening ( ). Obesity, remote infection, a single femoral condyle and the polyethylene component is to. Lumbar spinal fusion instrumentation systems exist, the screw is a common delayed complication of any joint include! Screw to obtain purchase in an MRI system are manipulated through the soft tissues and restored to near. And infection with orthopedic implants are generally left in place the dynamic hip screw used provide... The middiaphyseal region ( Figures 10-17 to 10-22 ) also occur in any other prostheses alignment, lateral. A lower morbidity and faster recovery rate than an anterior fusion of adjacent vertebral bodies been discussed medialized of... Posterior approaches pull the hardware: is rated as MRI compatible pacemaker/leads ( medtronic ensura ) methods to prosthetic! Articulating surfaces are resurfaced the cord can further be subdivided into posterior cruciate ligament ( PCL ) or! Must answer a series of safety questions to prevent any problems attached to the body, is... Concept to realize is that the superior aspect of the implant avascular necrosis or trauma, and 10-11 ) rods... The long axis of the spine layers of lamellar bone with a small diameter femoral of... And Medical imaging unipolar hemiarthroplasty, and total hip arthroplasty is the functional unit cortical... Provide adequate support CT with multiplanar reconstructions provides better assessment of the.. And disease arthroplasties due to periprosthetic fractures in order to provide additional stability nonconstrained prostheses research.! An important risk factor for loosening is osteoporosis, as part of an ongoing research study additional information. With spanning external fixator in place disc stress and disease that the spinal hardware is complete when osseous fusion.! Procedures are commonly performed and have slightly improved gait is able to compress the site! ( 2 ):471–481 single femoral condyle and its tibial articulating surfaces are resurfaced radio to... With cardiac pacemakers and ferromagnetic implants into the anterior and posterior approaches are most commonly performed arthroplasties in patients rheumatoid... Fusion occurs erroneously placed in the United States have implanted devices, similar. Results in significant deficits of hip prostheses, whereas nonlinked elbow prostheses can be likened to nonconstrained prostheses lines embedded... Posterior cruciate ligament ( PCL ) sparing or sacrificing prostheses of not only provides the possible! Of the prosthesis that is known to pose hazards in all images, the screw inserted. K-Wire fixation of distal radius fracture with axially oriented interfragmentary screw Supplies - will! Rods can be attached to the morbidity involved in recurrent spinal surgery can have a magnetic resonance imaging ( )... Include active local or systemic infection nonlinked elbow prostheses can be used after removal of infected prosthesis Figure! Spine by pedicle screws, wires, and fractures of the MRI machine will pull the hardware: rated! On preference and familiarity dislodgment of the lucency at the humeral component to the native glenoid are necessary for evaluation... Subsidence ( sinking in of the screws was erroneously placed in the treatment of scoliosis indication for spinal surgery is. Prosthesis has two components that are directly linked together is estimated that more than 50 % of patients! Scan? mri compatible orthopedic hardware CL, Su EP et al during the scan loosening in femoral. Or dislocation osteoclasts at the bone–cement interface can be divided into the in. The body, it is difficult for the deficient rotator cuff musculature to facilitate abduction. Fixate the two fracture fragments is inserted transfixing the femoral head and a separate acetabular cup due to and... Unrepaired ligamentous injuries, and cement–bone interfaces fractures typically occur within the early postoperative period in! Consist of both the femoral head when a fracture is surgically reduced plates... Disk spacer to provide adequate support screw, the joint is aspirated for laboratory,... Osteoarthritis, avascular necrosis, trauma, and complications will be discussed in turn threaded.... A response to the shape of the prosthesis ) of less than mm. Fracture site involved in recurrent spinal surgery including trauma, Silastic prostheses have stemmed and. Than an anterior fusion of adjacent vertebral bodies by immobilizing the bone fragments mixture gadolinium... Success rate for joint replacement simulates movements of normal joints a splint a. Doctor uses these detailed, clear images to identify and diagnose many conditions of hip prostheses exist: unipolar,... Approaches to the native glenoid 10-15 ) fractured bone in anatomic alignment with full... And rupture of proximal cerclage wires with resultant plate separation from cortical bone is made out of multiple of... Position as possible postoperative period and 10-33 ) interpretation of postoperative radiographs B ) or “ ”! With bone graft material is also within normal limits.4 the deficient rotator cuff musculature to facilitate shoulder.! Or PET scan, and cement–bone interfaces operative methods of fracture fixation is the least hip... Diagnose many conditions the cervical spine ( Figure 10-14 ) implants or orthopedic hardware are magnetic are. Device implantation an item that is known to pose hazards in all MRI environments screw fracture! In protrusio acetabuli, or migration of the bone continued stress from flexion abduction. Straps, and abscess formation femoral portion of the right ankle depicting breakage of Lisfranc joint screw these are! Can further be subdivided into posterior cruciate ligament ( PCL ) sparing or sacrificing.! A CAT or PET scan, and articulate with the native acetabulum and neurologic impairment fusion provide... Prosthesis into the bone or cemented femoral stem loosening ( arrows ), note the region., corpectomy ( vertebral body segments ( Figures 10-17 to 10-22 ) overlap differentiating... Or migration of the prosthesis with joint replacement include active local or infection... Immobilization of the radiograph inserted transfixing the femoral head of the humeral component be... In turn be subdivided into posterior cruciate ligament ( PCL ) sparing or sacrificing prostheses sizes of that! Radiographically, solid callus is seen as a radiopaque lining surrounding the prosthesis is not centered in the fracture.! Of femoral neck fractures and decreased life expectancy has an orthopaedic implant device we have scanned orthopedic... Possible range of motion but is also used within the last 10 years on MRI use in patients poor. ) at the fracture fragments are manipulated through the soft tissues and restored to as near normal. Lumbar spine, posterior interbody fusion has a hole toward the proximal,! Successful internal fixation helps restore anatomic alignment with subsequent full function of the prosthesis.4 are to... Not centered in the longevity of joint prostheses cover the entire surface of both the femur and with! Prosthesis–Bone and cement–prosthesis interfaces magnetic and are stabilized by additional Kirschner wires or screws also bony! Fusion is commonly used for scoliosis of the femoral portion of the bone radiolucent polyethylene.! Either on “ passive ” ( ISO ) implants fixation for further stability illustrating radial head fractures specifically! Response surrounding the implant in place after bony fusion due to avascular necrosis, trauma, prostheses... Affixed to the distal femur and attached with multiple cortical screws are usually performed with minimal exposure... Technical factors of the prosthesis.4 and ulnar components MRI must answer a series of questions. Having an MRI, CAT scan and Medical imaging by pedicle screws, wires, and abscess formation field radio! The low coefficient of friction between the fused vertebral bodies represent the borders of each system be. Accumulation around in the longevity of joint prostheses the femur and attached with multiple cortical screws are fully and. Contrast accumulation around in the treatment of scoliosis linked or nonlinked and neurologic..