You are in: eMedicine Specialties > Radiology > PEDIATRICS Salter-Harris FracturesArticle Last Updated: Mar 21, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: William Moore, MD, Staff Physician, Department of Radiology, State University of New York at Stony Brook University Medical Center William Moore is a member of the following medical societies: Association of University Radiologists and Radiological Society of North America Coauthor(s): Thomas H Smith, MD, Associate Professor, Departments of Radiology and Pediatrics, State University of New York at Stony Brook Editors: Beverly P Wood, MD, MS Ed, PhD, Professor, Departments of Radiology and Pediatrics, Division of Medical Education, Keck School of Medicine, University of Southern California; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Marta Hernanz-Schulman, MD, FAAP, Professor, Radiology, Radiological Sciences, and Pediatrics, Director, Department of Pediatric Radiology, Radiologist-in-Chief, Director, Department of Diagnostic Imaging, Vanderbilt University Medical Center, Vanderbilt Children's Hospital; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Felix S Chew, MD, EdM, MBA, Professor, Department of Radiology, Section Head of Musculoskeletal Radiology, Vice Chairman for Radiology Informatics, University of Washington Author and Editor Disclosure Synonyms and related keywords: growth plate fractures, pediatric fractures, physeal injuries, childhood fractures, Salter-Harris fractures type I, Salter-Harris fractures type II, Salter-Harris fractures type III, Salter-Harris fractures type IV, Salter-Harris fractures type V, Salter-Harris fractures type VI, Salter-Harris fractures type VII, Salter-Harris fractures type VIII, Salter-Harris fractures type IX INTRODUCTIONSection 2 of 10
  BackgroundSalter-Harris fractures are fractures through a growth plate; therefore, they are unique to pediatric patients. Several types of fractures have been categorized by the involvement of the physis, metaphysis, and epiphysis. The classification of the injury is important because it affects the treatment of the patient and provides clues to possible long-term complications. PathophysiologyThe histologic features of the physis are important for understanding the prognosis of physeal fractures. The germinal layer of the cartilage is on the epiphysis and derives nutrition from the epiphyseal vessels. Cartilage cells grow from the epiphysis toward the metaphysis, forming columns of cells that degenerate, fragment, and undergo hypertrophy. The fragments of cells mineralize. This is the zone of provisional calcification forming the metaphyseal border and is not bone. Note that no circulation exists in the cartilage zone. Neovascularization occurs from the metaphysis toward the epiphysis. Endothelial cells transform into osteoblasts and use the degenerate cell debris to form primary immature bone. This immature bone progressively is remodeled to mature woven bone and, further, is remodeled by cutting cones to form mature haversian system bone. Damage to either epiphyseal or metaphyseal vascular supply disrupts bone growth; however, damage to the layer of cartilage may not be significant if the surfaces are reapposed, and vascular supply to the growing cartilage is not permanently interrupted. When the 2 vascular beds touch, the physis is closed (fused) and no further bone growth is possible. AgeSalter-Harris fractures are injuries through the physis. Therefore, by definition, they must occur before the physis closes. Typically, physis closure occurs during the teenage years. Clinical DetailsThe classification of Salter-Harris fractures is used to describe the extent and site of the epiphyseal injuries. The basic types of Salter-Harris fracture include the following:
When all types of Salter-Harris fractures are considered, the rate of growth disturbance is approximately 30%. However, only 2% of Salter-Harris fractures result in a significant functional disturbance. Rare types of Salter-Harris fractures include the following:
Preferred ExaminationRadiography always is the preferred examination in a suspected fracture. The use of another modality should not be considered until appropriate plain film radiography has been performed. In cases of severe injury in which the patient has acute pain, appropriate radiographic examination of the involved area may be difficult because of inadequate patient positioning. In these cases, CT may be beneficial in evaluating the injury after a radiologist has evaluated the plain radiographs. However, the cost of CT may prohibit its use in all cases in which the area of interest is suboptimally evaluated. CT should be considered only when radiographic findings are insufficient. Typically, an orthopedic surgeon and a radiologist make the decision to perform CT. If an additional study is performed, its purpose is to determine the appropriate management and to assist in surgical planning. Thus, the surgeon performing the operation is best suited to request the imaging study. When further definition of fractures may help in making management decisions or when the injury does not respond to conservative management, the radiologist or orthopedic surgeon can recommend an appropriate examination to perform after plain radiography. Currently, 2 radiologic examinations can be performed to further evaluate fractures: (1) CT with multiplanar reconstruction and (2) MRI. MRI depicts marrow edema, whereas CT shows cross-sectional bone detail and tomographic multiplanar information. The use of MRI in the evaluation of fractures is described below, but it is still in its infancy. At the present time, MRI is not the standard of care. CT is used more commonly; typically, it is used for planning surgery. Limitations of TechniquesThe primary disadvantages of MRI are related to its expense, time requirement, and availability, which limit the routine use of MRI. As techniques and software improve, the use of MRI in the acute trauma setting is likely to increase. DIFFERENTIALSSection 3 of 10
[Elbow Trauma - Pediatric] Ankle, Fractures Wrist, Scaphoid Fractures and Complications RADIOGRAPHSection 4 of 10
FindingsX-ray findings vary according to the type of Salter-Harris fracture. With type I fractures, initial radiographs may suggest separation of the physis, but this separation may not be apparent. However, soft-tissue swelling is present, and its center typically overlies the physis (see Image 2). Follow-up radiographs obtained 7-10 days after injury help establish the diagnosis. New bone growth (ie, adjacent sclerosis and periosteal reaction) along the epiphyseal plate confirms the diagnosis of a Salter-Harris type I fracture. In type II fractures, the fracture line passes through the metaphysis into the epiphyseal plate, but no fracture is observed in the epiphysis (see Image 3). The metaphyseal fragment is sometimes called the Thurston-Holland fragment. Type III fractures pass through the hypertrophic layer of the physis and extend to split the epiphysis (see Image 4). The fracture crosses the physis and extends into the articular surface of the bone. Type IV fractures pass through the epiphysis, physis, and metaphysis (see Image 5). Similar to a type III fracture, a type IV fracture is an intra-articular fracture. In type V injuries, initial plain radiographs may not show a fracture line, similar to images of type I fractures (see Image 6). However, soft-tissue swelling at the physis is present. A compression or crush injury of the epiphyseal plate is present without associated epiphyseal or metaphyseal fracture. CT SCANSection 5 of 10
FindingsCT has an important role in the evaluation of epiphyseal injuries. Rogers and Poznanski1 discussed the role of CT along with the use of a bone algorithm and multiplanar reconstruction of multiplanar initial images. With CT, a considerable amount of information regarding the nature of the fracture can be gathered. CT techniques typically are used in patients prior to surgery, after a fracture is diagnosed on the basis of plain radiographic findings. Multiplanar CT findings are similar to plain radiographic findings. Degree of ConfidenceThe computer program is able to compensate for imprecise patient positioning. True lateral and true anteroposterior (AP) views of the bone in question can be obtained. As with any study, physicians who request these costly studies should have the knowledge and experience needed to interpret the images. Orthopedic surgeons may be the ones to request CT examinations; however, any physician can order them in consultation with a radiologist. The advantages of CT over MRI are its greater availability and the faster speed in obtaining images. The disadvantage is that CT requires a relatively large dose of radiation for diagnostic imaging. Raw-data images typically are obtained with 1-mm sections and a high milliampere technique; however, the high collimation reduces the total amount of exposure. In the near future, multi–detector row technology is likely to affect the utility of CT in the detailed evaluation of fractures. MRISection 6 of 10
FindingsOn MRIs, the typical findings of Salter-Harris fractures include a signal void on T1-weighted images. On T2-weighted images, increased signal intensity, which is consistent with edema, is depicted around the fracture site. MRI is used for surgical planning. Craig et al2discussed the use of MRI in evaluating partial closure of the growth plates. Patients with functional or growth abnormalities were examined with MRI, and the exact nature of the defects were well described. These findings helped orthopedic surgeons plan appropriate surgery. Currently, no imaging technique is recommended and uniformly accepted for use in the evaluation of a Salter-Harris injury in children. However, from data in this section, one could conclude that MRI with multiple sequences provides more information than MRI with a single sequence. Thus, T1-weighted, T2-weighted, and gradient-echo imaging without contrast enhancement can be used to evaluate the bony structures, soft tissues, and physis well. In a recent article, Craig et al2 suggested that a sagittal 3-dimensional (3D) spoiled gradient-recalled (SPGR) sequence is the best sequence for the evaluation of the physeal plate. (According to the article, this sequence is widely available.) They examined 22 patients with this sequence and claimed that it provided excellent detail of the physeal plate. In addition to the SPGR sequence, they used 2-dimensional (2D) sagittal and coronal fast spin-echo sequences (with an echo train length of 3) and 3-mm-thick sections with a 1-mm gap. The field of view was 14 cm. They also used 2D axial and coronal fast spin-echo imaging with fat saturation (with an echo train length of 8) and 5-mm-thick sections with a 1.5-cm gap. The field of view was 18 cm. If findings from the cited articles are compared, the use of a single sequence does significantly decrease the imaging time; in children, examination time is an important factor. However, Craig and coworkers2 strongly argue that SPGR provides the best images of the physis. To the author's knowledge, no group has used SPGR alone in the examination of children with trauma. Again, the evaluation of Salter-Harris injuries in children is a new use of MRI technology, and no standard is uniformly accepted at this time. Degree of ConfidenceMRI is a relatively new technique. MRI is limited in the assessment of acute injuries because of the length of time involved in the examination. Another limitation is the relative isolation of the patient within the machine. Currently, MRI has limited utility in the evaluation of Salter-Harris fractures. Therefore, it is most efficiently applied by specialists with specific treatment questions. Orthopedic surgeons are the most appropriate physicians to request MRI; however, in consultation, a radiologist and a clinician may determine a specific need for MRI findings in a given case. Consultation with an orthopedic surgeon is likely to be helpful in complicated injuries that require treatment. MRI in the setting of acute trauma has been discussed in 2 recent articles. Close and Strouse3 retrospectively evaluated 315 consecutive knee MRIs in children with a history of trauma. They reported that MRI revealed 8 additional fractures that were not fully identified on plain radiographs, and of the 8 fractures found with MRI, 7 had MRI findings that changed the clinical management. This study was limited because of its retrospective nature and selection bias; however, the authors indicate that MRI is better than plain radiography in delineating the exact nature of an injury. In complex cases, this advantage may be of clinical importance. False Positives/NegativesCarey et al4 reviewed the correlation between MRI results and plain radiographic findings in Salter-Harris fractures and found a trend similar to that of Close and Strouse.3 In 2001, a Finnish study revealed no misclassification in patients with minor ankle fractures; MRI was helpful in evaluating complex injuries in the ankle.5 A study performed in 1996 by Petite et al6 revealed a small benefit with the use of MRI versus plain radiography They found a misclassification rate of only 3% in patients with acute trauma. This study was limited because only gradient-echo imaging was used. Carey et al4 and Close and Strouse3 used multiple MRI techniques. The conclusion of Petite et al6 is similar to that of the other studies: MRI can be helpful in complex cases or when plain radiographic findings are normal and the clinical findings are highly suggestive of fracture. ULTRASOUNDSection 7 of 10
FindingsUltrasonography (US) has a limited role in the diagnosis of fractures. Degree of ConfidenceIn a recent study, Hubner et al7 compared the results of primary US diagnosis of fractures with the results of plain radiography. They were able to accurately diagnose fractures with US; however, complex fractures were more difficult to assess with US. Salter-Harris type I fractures and nondisplaced fractures with less than 1 mm of separation were reliably detected with US. NUCLEAR MEDICINESection 8 of 10
FindingsAlthough nuclear medicine studies had a role in the diagnosis of Salter-Harris fractures in the past, MRI and CT have replaced nuclear medicine study in the evaluation of subtle fractures. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
Salter-Harris Fractures excerpt Article Last Updated: Mar 21, 2007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
