You are in: eMedicine Specialties > Radiology > MUSCULOSKELETAL Calcaneus, FracturesArticle Last Updated: Jul 22, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, LRCP, Chairman of Medical Imaging, Professor of Radiology, NGHA, King Fahad National Guard Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia Ali Nawaz Khan is a member of the following medical societies: American Institute of Ultrasound in Medicine, Radiological Society of North America, Royal College of Physicians, Royal College of Physicians and Surgeons of the United States, Royal College of Radiologists, and Royal College of Surgeons of England Coauthor(s): Rumana Rahim, MBBS, MRCS, Staff Physician, Department of Radiology, North Manchester General Hospital; Klaus L Irion, MD, PhD, Consulting Staff, The Cardiothoracic Centre Liverpool NHS Trust, The Royal Liverpool University Hospital, UK; Sumaira MacDonald, MBChB, PhD, MRCP, FRCR, Lecturer, Sheffield University Medical School; Endovascular Fellow, Sheffield Vascular Institute Editors: Michael A Bruno, MD, Associate Professor, Departments of Radiology and Medicine, Pennsylvania State University College of Medicine; Director, Radiology Quality Management Services, Milton S Hershey Medical Center, Pennsylvania State University College of Medicine; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Thomas Lee Pope Jr, MD, FACR, Professor of Radiology and Orthopedics, Department of Radiology, Medical University of South Carolina; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Felix S Chew, MD, MBA, EdM, Professor, Department of Radiology, Vice Chairman for Radiology Informatics, Section Head of Musculoskeletal Radiology, University of Washington Author and Editor Disclosure Synonyms and related keywords: calcaneus fracture, calcaneal fracture, tarsal fracture, foot fracture, heel fracture, talus fracture, calcaneum fracture, os-calcis fracture, os calcis fracture, Lover fracture, Lover's fracture INTRODUCTIONSection 2 of 11
  BackgroundThe calcaneus is the most frequently fractured tarsal bone. Calcaneus fractures may occur as a result of falls from heights or from twisting injuries or through a pathologic process such as osteoporosis, cysts, and tumors. Os calcis fractures can be broadly classified into intra-articular and extra-articular types. The calcaneus functions as a lever arm for the gastrocsoleus complex, providing a foundation or vertical support for one's body weight and providing support for and maintaining the lateral column of the foot. Any fracture that impairs one of these functions substantially affects the person's gait if not restored. These fractures may remain undiagnosed clinically, as there may be no obvious deformity. Often, a history of the patient falling from a height and landing on his or her heels is helpful, but radiographic examination is essential to confirm fracture. Management of these fractures depends on the type of fracture. Therefore, imaging plays a primary role. The management of calcaneus fractures and their associated soft tissue injuries are controversial. Open reduction and stable internal fixation with a lateral plate and without joint transfixation are established as standard therapy for displaced intra-articular fractures. Good to excellent results are achieved in two thirds to three quarters of all cases, as shown in large clinical series. Anatomic reduction of joint congruity and the overall shape of the calcaneus are important prognostic factors. The quality of joint reduction should be proved intraoperatively with the acquisition of Broden views, high-resolution fluoroscopy, or open subtalar arthroscopy.1, 2, 3, 4, 5 PathophysiologyInjuries associated with fractures of the calcaneusCalcaneus fractures resulting from falls onto the heels from heights are bilateral in 5-9% of patients; they are associated with compression fractures of the lumbar and/or dorsal spine in 10%. These fractures are complicated by a compartment syndrome in 10% of cases, with half of these involving development of clawing of the lesser toes or other chronic problems, such as stiffness and neurovascular dysfunction. Other fractures around the ankle and soft tissue injuries are encountered in a quarter of all cases of calcaneus fracture. Soft tissue injuries include subluxation or dislocation of the peroneal tendons from the fibular sulcus, entrapment of neurovascular bundle, and interposition of the flexure hallucis longus tendon between bone fragments from sustentaculum tali (see Images 4-7). Extra-articular and intra-articular fractures of the calcaneusCalcaneus fractures can be classified as extra-articular (25-30%) or intra-articular (70-75%) fractures. Extra-articular fractures Extra-articular fractures can be further subdivided into those involving the anterior process and those of the tuberosity. Extra-articular fractures are more common in people with diabetes than in others. Atkins and associates reviewed 400 patients with calcaneus fractures who were treated at their institution over a period of 10 years. In about 5% of the patients, the major fracture involved the tuberosity. In 3 cases, the fracture occurred in elderly osteoporotic patients as a result of sudden contraction of the gastrocnemius muscle. In these fractures, a triangular fracture fragment, which included the upper border of the calcaneus and the insertion of the tendo Achilles, was apparently avulsed from the remainder of the bone and displaced upward. In the remaining 17 cases, the fracture occurred in young patients as the result of a significant fall. In all cases, there was an identical fracture of the medial tuberosity of the calcaneus. This fracture was isolated in 2 cases. In the remaining cases, the triangular fragment described in the osteoporotic avulsion fractures also occurred; however, in 13 cases, its anterior extension involved the posterior facet of the subtalar joint. Detailed analysis of CT scans showed that, in all cases, the usual coronal primary line described in the standard intra-articular fracture of the calcaneus was absent. The primary fracture line was in the coronal plane, which separates the anterior part of the posterior facet of the subtalar joint from the posterior. The authors postulated that, in the younger patients, the fracture of the medial calcaneus tuberosity occurred first and weakened the surrounding bone so that the triangular fragment of the upper part of the tuberosity of the calcaneus was avulsed by the pull of the gastrocnemius. In osteoporotic patients, the bone is sufficiently weak that the upper part of the tuberosity can be avulsed without a prior fracture of the medial process. Thus, the medial-process fracture and the osteoporotic fracture seen in elderly patients form 2 ends of a spectrum of tuberosity fractures. Intra-articular fractures Approximately 70-75% of all calcaneus fractures are intra-articular fractures. A wide spectrum of associated fragment displacement is seen. The fracture lines may adopt 1 of 2 patterns. The primary fracture line runs from the plantar aspect obliquely upwards into the posterior facet, which divides the calcaneus into anteromedial and posterolateral fragments. The secondary fracture line begins at the angle of Gissane and extends posteriorly. Essex-Lopresti subdivided these fractures into 2 distinct subtypes. The first, the tongue type, occurs when the secondary fracture line extends directly posteriorly, producing a large superior, posterior, and lateral fragment, with the rest of the body forming the inferior fragment. The second, the joint-depression type, which is the more frequent of the two, occurs when the secondary fracture line begins at the crucial angle, extends posteriorly, but deviates dorsally to exit the bone just posterior to the posterior articular facet. This fragment contains most of the posterior facet. Types of calcaneus fracturesRowe analyzed 154 calcaneus fractures and classified them into 5 groups. Types I-III do not involve the subtalar joint. Type I fractures represent approximately 20% of cases. The fracture line may be through the tuberosity, the sustentaculum tali, or the anterior process of the calcaneus. Type II beak fractures are uncommon. Type III fractures represent almost 20% of cases; these are oblique fractures. Types IV and V involve the subtalar joint; they represented almost 60% of the analyzed group. Type V fractures are comminuted fractures with a centrally depressed fragment. Stress fractures of the calcaneus Stress fractures of the calcaneus are uncommon. Maenpaa and associates reviewed 24 cases involving stress fractures in the metatarsal bones or in the ankle region in 17 patients with inflammatory arthritides.6 Of these, 16 were metatarsal fractures, 4 were distal fibular fractures, 2 were distal tibial fractures, and 2 were calcaneus fractures. Radiographic analyses were performed to determine whether predisposing factors for stress fractures were present. Metatarsal and ankle-region stress fractures were analyzed separately. Stress fractures occurred most frequently in the second and third metatarsals. In metatarsal fractures, varus alignment of the ankle tended to cause fractures of the lateral metatarsal bones and valgus alignment of the medial metatarsal bones. Among patients with fractures of the ankle region, valgus deformity of the ankle was present in those patients with distal fibular fractures. Calcaneus fractures showed neutral ankle alignment. Malalignment of the ankle and hindfoot is often present in distal tibial, fibular, and metatarsal stress fractures. Additionally, the patients tended to have long histories of osteoporosis and of treatments with diverse medications and reconstructive surgeries. The authors concluded that if such patients experience sudden pain, tenderness, or swelling in the ankle region, stress fractures should be suspected, and the necessary examinations should be performed. Mortality/MorbidityPatients with extra-articular calcaneus fractures generally do well in terms of functional recovery and fracture healing. The results are good, even if there is displacement at the fracture site. Fracture union always occurs, and with early movement, joint stiffness is a minimal long-term problem. See also Outcomes, Clinical Details. Race
SexPester and Smith found a significant gender difference in the anatomic distribution of stress fractures.8
AgeCalcaneus fractures are encountered in all age groups: 5% occur in pediatric patients. In adults, 75% of all calcaneus fractures are intra-articular, compared with 8-37% in children. Mora and associates retrospectively reviewed 22 skeletally immature patients with 23 calcaneus fractures before their distal tibial physis had fused. Eighteen fractures (78%) were intra-articular; five (22%) were extra-articular. Nine patients underwent follow-up examinations for an average of 4.4 years; of these, 8 were treated nonoperatively, and 1 was treated with open reduction and internal fixation. A modification of the American Orthopaedic Foot and Ankle Society scoring system, which focuses on residual pain, work or sports restrictions, and the patient's ability to walk on different surfaces and gait abnormalities, was used to assess outcomes. Seven of the 9 patients were free of pain, had unrestricted foot function, and possessed no apparent gait abnormalities. Two had activity- and cold weather–related pain. The excellent prognosis both for patients with intra-articular fractures and for those with extra-articular fractures was thought to result from several factors: First, the immature talus and calcaneus have a superior capacity to remodel. Second, pediatric calcaneus fractures are usually the consequence of low-energy trauma. Third, a favorable intra-articular fracture pattern, unique to the skeletally immature calcaneus, may exist and may be conducive for a good prognosis. AnatomyThe superior surface of the calcaneus is divided into 3 articular facets: (1) the posterior facet, which is the largest in surface area and has a convex shape; (2) the middle facet, which overlies the sustentaculum tali and which is concave in shape; and (3) the anterior facet, which is concave and is often confluent with the middle facet (see Images 1-3). The calcaneal groove lies between the middle and posterior facets. The anterior surface is saddle shaped, articulating with the cuboid bone. The calcaneus functions as a lever arm for the gastrocsoleus complex, providing a foundation or vertical support for one's body weight and providing support for and maintaining the lateral column of the foot. Igbigbi and Mutesasira reported racial differences in the calcaneal angle.7 They investigated the calcaneal angle on 206 unilateral radiographs of the lateral aspect of the foot in Ugandans (114 men, 92 women; age range, 20-40 y). In men, the mean angle was 35.1°; the standard deviation (SD) was 7.5°. In women, the mean angle was 37.6°; the SD was 5.6°. The range of the angle for both sexes together was 20-50°; women had a significantly higher mean value than men (P <0.01). The authors observed a significant difference in the calcaneal angle in Ugandan men and Nigerian men (P <0.01); they observed a similar difference in the calcaneal angle in Ugandan women and Nigerian women (P <0.001). Their reported range was the widest that has been documented so far in Africans. The study reinforced the need to establish the normal range of the angle in a given population; it also highlights the clinical importance of the calcaneal angle to orthopedic surgeons managing calcaneus fractures in different parts of the world. Clinical DetailsHistory Patients with calcaneus fractures present with a history of trauma. Older children may give a history of falls from heights or sport-related injuries. Physical examination Patients with calcaneus fractures present with pain, swelling, and deformity; they have a history of trauma. Toddlers with calcaneus fractures may present with limping and an inability to bear weight; there may be associated swelling and tenderness around the heel. In 1964, Lance reviewed 227 intra-articular fractures. In this study, results of conservative treatment were favorable in only 55% of patients, although this rate was better than that of the group treated operatively. Lindsay and Dewar reviewed 147 patients. After 8 years, results of conservative treatment were good in 76% of patients, whereas the results were good in only 60% of patients treated with primary or late arthrodesis. The ultimate results depend on several prognostic factors: (1) the degree of displacement of the posterior facet, (2) the degree of reduction of Bohler tuber angle, and (3) the patient's age. Essex-Lopresti recommended that patients older than 50 years should not be treated as aggressively because the results are worse in this group of patients.9 In 5-15% of intra-articular fractures, the fractures are so comminuted that they are not amenable to surgery; in such cases, the outcome is poor. Premature weight bearing before 6 weeks is associated with repeat displacement of the fracture fragments. Therefore, weight bearing after surgery should be delayed for 12 weeks. Persistent pain around the ankle Persistent pain around the ankle and in the heel may follow calcaneus fractures; the cause of the pain is multifactorial. Patients with secondary osteoarthritis in the subtalar joint may present with pain on weight bearing; the pain is aggravated by inversion and eversion. Subtalar arthrodesis alone may not control the symptoms, because unrecognized degenerative changes in the calcaneocuboid or talonavicular joint will not be corrected through a limited hindfoot fusion. Secondary osteoarthrosis of the calcaneocuboid joint may be another source of pain; should symptoms persist, treatment usually is with local steroid injections or a triple fusion. The exact incidence of peroneal tendinitis occurring as a complication of calcaneus fractures is not known. Stenosing tenosynovitis of the peroneal tendon sheath may occur as a complication in such fractures. Surgical decompression and rerouting of the tendons can give relief. Heel spurs may occur in association with fracture malunion. Such spurs can become painful. Primary treatment involves use of pressure-relieving pads. Surgical excision should only be undertaken as a last resort. Nerve entrapment may occur with calcaneus fracture and may be a source of constant causalgia. Jung and associates reported 2 cases of calcaneus fractures with posterior heel pain associated with a prominent superior calcaneal tuberosity impinging on the Achilles tendon after a tongue-type fracture. Malunion of the tongue fracture fragment resulted in the symptomatic bony prominence, which has been defined as the secondary Haglund deformity. In both cases reported by Jung et al, the patients continued to experience symptoms after nonsurgical treatment; they subsequently underwent resection of the superior calcaneal tuberosity. The clinical results of the operations were satisfactory, and both patients had complete pain relief. Open calcaneus fractures are associated with a high risk of deep infection, despite the use of an aggressive treatment protocol to prevent it. Preferred ExaminationPhysical examination Physical examination usually is required to assess the integrity of tendons and ligaments. Approximately 75% of calcaneus fractures are intra-articular and involve the subtalar articular surface. Because these injuries are associated with a poor prognosis, it is important to identify patients with these fractures. Imaging examinations Conventional radiographs provide a benchmark for the diagnosis of fractures around the ankle in general, and they usually suffice for the diagnosis of the osseous component of the injury. In general, conventional radiographs suffice; however, in most cases, supplemental imaging is needed to define characteristics fully, owing to the complex anatomy of this region. Comminuted fractures with fragment displacement of the calcaneus are common, and the relationship of the multiple fragments is difficult to appreciate on conventional radiographs. Tenography is useful for assessing large lesions of the tendons. CT is the investigation of choice in calcaneus fractures. Coronal and axial views are generally taken. CT best defines the relationship of bone fragments. MRI is increasingly being used to characterize ankle sprains, occult fractures, bone bruises, growth-plate injuries, and ligamentous/tendon injuries. MRI is the criterion standard for identifying peroneal tendon injury. This injury is identified by the high signal intensity in tendon on T2-weighted axial views. Scintigraphy may be useful in occult fractures and in the differential diagnosis of pathologic fractures. Pathologic features may become apparent on scintigraphy a few weeks before they become apparent on plain radiographs because the increased osteoblastic activity associated with stress fractures is more easily detected with scintigraphy.10 Limitations of TechniquesConventional radiographs may be negative in cases involving subtle fractures, particularly in cases involving stress fractures. Comminuted fractures and displacement are common in fractures of the calcaneus, and the relationship of the multiple fragments is difficult to appreciate on conventional radiographs. CT is the modality of choice, especially in complex fracture patterns, although it is expensive and it imparts a relatively high dose of radiation; it should be used sparingly in young patients or in pregnant patients. It is noteworthy that CT tends to be somewhat overutilized in the United States; this tendency has increased in recent years. MRI is expensive and may cause problems in patients with claustrophobia. MRI is sensitive in the immediate documentation of stress changes in osseous structures. MRI is well known to show even minor stress changes (eg, after a marathon) that occur before the actual stress fracture. A severe bone contusion is associated with multiple microfractures, whereas a stress fracture involves a linear component; the distinction between the 2 diagnoses may seem arbitrary. In the absence of a linear component, it may be difficult to distinguish an underlying severe stress reaction associated with a bone contusion from a stress fracture on MRI. Bone contusion associated with a stress fracture may be difficult to distinguish from red marrow. With MRI, it may be difficult to detect small intra-articular fragments — a fact that likely limits the use of MRI on a routine basis. Scintigraphy is sensitive in imaging bone trauma but lacks the specificity and the spatial resolution that MRI provides. A physiologic periosteal reaction, bone tumor, avascular necrosis, plantar fasciitis, or bone spur can cause false-positive findings. RADIOGRAPHSection 3 of 11
FindingsConventional radiographyConventional radiographic examination consists of axial and lateral views of the calcaneus and an anteroposterior (AP) view of the foot. However, because of the complexity of the anatomy, multiple radiographic views are often necessary. Giannestras and Sammarco suggested that multiple views be used, including the oblique view.11 Radiographs of the dorsal and lumbar spine are also often indicated, because an associated fracture is seen in a vertebral body in 10% of all patients. Further fractures of the tibia and fibula are seen in 9% of patients. Calcaneus fractures are bilateral in 5% of patients (see Images 9-24, 73, 76-84). Lateral view and the Bohler angle The lateral view is the primary projection on which a diagnosis of a fracture is made, although some subtle fractures may be missed when reliance is placed on a lateral view only. Lateral views show the Bohler tuber angle and the crucial angle of Gissane clearly. Lorenz Bohler described the tuber-joint angle (the so-called Bohler angle). In determining the Bohler angle, a line is drawn between the posterior superior aspect of the calcaneus and the highest point of the posterior subtalar articular surface; a second line, which intersects the first, is drawn from the highest point of the anterior process to the posterior margin of the subtalar surface. The angle that results from their intersection measures 20-40° (see Image 8). In intra-articular fractures of the calcaneus, the subtalar joint is depressed, causing a decrease in the Bohler angle. The Bohler angle may also be decreased in some calcaneus fractures that do not involve the subtalar joint. A flat Bohler angle is associated with intra-articular fractures; in such cases, the prognosis is poorer than it is in cases in which the angle is maintained. Axial view The axial view is used to evaluate the subtalar joint and the width of the calcaneus. Normally, in an adult, the calcaneus measures 30-35 mm in width. A fracture may cause the calcaneus to increase in width; the expanded, fractured calcaneus may then impinge upon the fibula, causing entrapment of the peroneal tendons. AP view The AP view is essential for evaluating the calcaneocuboid joint. This view also demonstrates avulsion fractures of the anterior lateral aspect of the calcaneus. Oblique views Various oblique views have been advocated. These are valuable in demonstrating fracture extending into the joint and loss of parallelism of articular surfaces. Oblique views (ie, the Broden view) can define incongruity of the subtalar joint. These images are obtained by internally rotating the foot 45°, with the heel resting on the radiographic plate; the beam is directed cephalad in angles varying from 10° to 40°. Peroneal tenographyPeroneal tenography involves injecting iodinated contrast material into the peroneal tendon sheaths under fluoroscopic guidance. The contrast material then descends behind the lateral malleolus. Peroneal tenography helps in diagnosing abnormal conditions after calcaneus fractures or other trauma, such as peroneal tendon dislocation resulting from skiing accidents. Compression of the tendon sheath associated with partial or complete obstruction of the flow of contrast and tendon displacement may be depicted. Aspiration of the injected contrast material following use of a local anesthetic may relieve pain and help determine the source of the pain. Degree of ConfidenceConventional radiography is the primary imaging modality in cases of suspected ankle fractures. Radiography may be the only modality required, though it is not always capable of depicting the relationship of bone fragments to the joint and to each other. In complex fractures, CT scanning is used in addition to conventional radiography. Conventional radiography is inexpensive and is universally available. It exposes the patient to a modest radiation dose. Study results are reproducible, and the images are easy to interpret. Measuring the various angles not only enables reliable diagnosis but also helps in determining the ultimate prognosis. False Positives/NegativesVarious anatomic variants in the calcaneus may mimic fractures. Os subcalcis is a calcaneal apophysis seen in the adolescent on the posteroinferior plantar surface of the calcaneus, which is normally not visible on lateral radiographs. The unfused secondary ossification center for calcaneal tuberosity may produce a simulated fracture. Failed union of a portion of calcaneal apophysis in an adult may superficially mimic a fracture. Calcaneus secundarius is an accessory ossicle attached to the posterosuperior aspect of the calcaneus. The sustentaculum tali can produce a simulated fracture on the superior margin on lateral views. Prominent trabeculation can simulate a fracture on plain radiographs and CT scans. False-negative radiographic findings may occur when images show subtle fracture lines. These fractures may be confirmed with scintigraphy and/or MRI. CT SCANSection 4 of 11
FindingsCT is the modality of choice for calcaneus fractures. Coronal and axial views are generally obtained. Involvement of the subtalar joint can be clearly appreciated, and CT enables optimal evaluation of calcaneal widening (see Images 25-72).12 Classification system In 1992, Sanders developed a classification system based on coronal and axial CT scans of the calcaneus. This classification is the one used most frequently today in treatment decision making and reporting of results. This system defines 4 types of calcaneus fractures:
Stress fractures CT is occasionally performed to diagnose stress fractures. CT is capable of demonstrating disruption of the bony cortex and periostitis in most individuals. Its sensitivity is higher than that of plain radiography. However, compared with MRI or bone scanning, CT has low sensitivity for stress reactions and fractures; this leads to a high rate of false-negative results. Soft tissue abnormalities Bradley and Davies studied soft tissue abnormalities occurring after calcaneus fractures.14 CT scans of 50 acute calcaneus fractures were compared with scans of 77 fractures in which the date of injury preceded the CT study by 6 months or more. The investigators found that 42 of the fractures (84%) in the acute group and 55 in the chronic group (71%) were classified as intra-articular; these fractures formed the basis of the study. The alterations in the position of the peroneal tendons in the 2 groups were similar, with a 5% or smaller difference in each category. In the acute group, the peroneal tendons were of normal location in 40.4% of cases; in 11.9% of cases, the peroneal tendons were entrapped by bone; subluxation was evident in 33.3% of cases; and dislocations were present in 14.2% of cases. Structural abnormalities of the peroneal tendons and surrounding soft tissues were identified in 52.4% of patients in the acute group and in 61.1% of patients in the chronic group. The incidence of partial rupture of the peroneal tendons in the chronic group was approximately one third that in the acute group, but the low incidence of complete tendon rupture remained unchanged. The inference from these observations is that, in most cases, partial peroneal tendon rupture is reversible, whereas complete rupture is not. Seven fractures were common to both series; from this limited group, the identification of hemorrhage around the peroneal tendons in the acute phase was shown not to be related to the subsequent development of chronic stenosing tenosynovitis. Various abnormalities of the medial tendons of the hindfoot were identified in 17% of patients in the acute group and in 18% of patients in the chronic group. The authors found that, after calcaneus fractures, CT in both the immediate postfracture period and in the late phase may be used to detect and classify soft tissue changes. Degree of ConfidenceCT is the modality of choice for calcaneus fractures. Confidence in the diagnosis made on the basis of a positive CT scan of the affected area is high. Furey evaluated 30 calcaneus fractures to assess the degree of interobserver variability by using the Sanders classification system.15 Thirty CT scans of calcaneus fractures taken over a 5-year period in 2 tertiary care centers were chosen randomly. Three orthopedic surgeons and 1 senior orthopedic resident reviewed the scans and classified the fractures. The results were analyzed by using a weighted kappa test that included the subcategories. The weighted kappa value was 0.56, with a 95% confidence interval (CI) of 0.45-0.67. The subcategories of the classification were further combined, and a second analysis was performed to assess agreement between general classes. The weighted kappa value was 0.48, with a 95% CI of 0.37-0.59. The authors concluded that the Sanders classification system achieved moderate agreement among users and was thus useful. False Positives/NegativesIn cases of stress fractures, a well-defined cortical discontinuity is suggestive of a fracture. However, the rate of false-negative results is high. Therefore, in the appropriate clinical setting, CT may be skipped, and either MRI or bone scanning may be performed. Repeat CT scanning is not an attractive alternative, though it may result in the correct diagnosis because of interval development of necrosis. Prominent trabeculation can simulate a fracture on CT. MRISection 5 of 11
FindingsMRI is generally not used in the diagnosis of calcaneus fractures. However, MRI is often useful in patients with suspected stress fractures, particularly those with severe osteoporosis in whom skeletal scintigraphy may produce false-negative findings as a result of generalized poor uptake of tracer (see Images 74, 85). MRI is highly sensitive for the detection of bone marrow changes. Anatomic resolution is better with MRI than with radionuclide imaging. Bone contusions are also well depicted on MRI. On MRI, stress fractures typically appear as areas of low signal intensity on T1- and T2-weighted images. They often appear as a band of low signal intensity that arises from the cortex of the bone and extends perpendicular to the surface of the bone. If imaging is performed within 4 weeks of the injury, an area of high signal intensity often can be observed on T2-weighted images; this represents associated edema or hemorrhage. Fat-suppressed sequences are sensitive to bone marrow edema, which accompanies bone bruises and stress fractures. MRI also has a place in the investigation of ligamentous and tendon injury in association with calcaneus fractures. Degree of ConfidenceConfidence in the imaging findings is usually high in a patient who is believed on clinical grounds to have a stress fracture. MRI findings may be positive within 24 hours of the onset of symptoms. Stress fractures may take longer to become evident on radionuclide bone scans, particularly in patients with osteoporosis. MRI may be used to evaluate tendon and ligamentous injuries noninvasively. False Positives/NegativesMany pathologies can cause bone marrow edema; in patients with a history of trauma, the presence of edema may lead to an incorrect diagnosis of fracture. Pathologies associated with edema include osteomyelitis and neoplasm. The linear hypointensity is usually helpful in identifying stress fractures. ULTRASOUNDSection 6 of 11
FindingsUltrasonography of the foot region is indicated for the evaluation of the presence of foreign bodies. It is also indicated for the evaluation of dislocation of the peroneal tendons; lesions in the flexor and extensor tendons; and osseous capsular and ligamentous avulsions. Signs of pathology that are apparent on sonograms of soft tissue include articular effusion, fluid conglomeration, ossification, and the development of vascular lesions. Ultrasonography is useful for detecting all types of peroneal lesions. In particular, real-time ultrasonography may be performed to assess dynamic stability.16, 17, 18 Degree of ConfidenceUltrasonography is operator and institution dependent. Musculoskeletal ultrasonography is not universally available. False Positives/NegativesSonograms of the hindfoot and ankle commonly depict articular, bursal, and tendon-sheath fluid in asymptomatic volunteers. The presence of fluid in these locations, even when unilateral or asymmetric, does not necessarily imply underlying abnormality. NUCLEAR MEDICINESection 7 of 11
FindingsBone scintigraphy is typically utilized in cases in which radiographic and CT findings are negative for suspected fractures (see Image 75). Stress fractures are associated with hyperemia in the first 2 phases of the 3-phase bone scan. The injury is manifested by increased radionuclide uptake at the fracture site. In adults, detection of hyperemia is straightforward, but problems may arise in children, because in children, the uptake of radionuclide is often increased around the epiphyses; contralateral images are often needed for comparison. The first phase demonstrates increased flow of blood in the arterial phase, and the second phase demonstrates tissue hyperemia. The third phase demonstrates increased osteoblastic activity in response to the stress fracture.19 Degree of ConfidenceStress fractures are relatively easily diagnosed with skeletal scintigraphy. The degree of confidence is high, because the diagnosis of stress fracture may be reliably excluded when bone scans are normal. False Positives/NegativesOsteomyelitis, calcaneonavicular bars, osteoarthritis, erosive arthritis, tumors, and pathologic fractures may have an appearance similar to that of fractures on scintigraphy. In patients with multiple stress fractures, an accurate determination of the age of the fracture is not always possible. In children, epiphyseal uptake may mask increased radionuclide uptake caused by osteoblastic activity. In patients with severe osteoporosis, the level of tracer uptake by the bone may be too low, and false-negative results may be produced. INTERVENTIONSection 8 of 11
Extra-articular fractures Extra-articular fractures are managed conservatively with elevation, ice packs, and a compression bandage. Once the swelling resolves, vigorous exercises are commenced to regain subtalar and ankle movement. If there is significant widening of the calcaneus fracture, some clinicians perform a closed manual manipulation to decrease heel width and to decrease the risk of late peroneal tendon irritation. If the Bohler angle is reduced by more than 10º, use of a transverse pin, with the subsequent incorporation of the pin in a plaster-of-Paris cast for 4 weeks, may restore calcaneal height. Intra-articular fractures The treatment of intra-articular fractures is controversial; 4 treatment options are available: (1) conservative management, (2) closed reduction and fixation, (3) open reduction and internal fixation, and (4) primary arthrodesis. With conservative management, patients are treated with compression dressing; elevation and ice packs; early movement, beginning at 24 hours after treatment; non–weight-bearing mobilization after the first week; surgical shoe fitting at 14 days; and partial weight bearing in the shoe after 6 weeks, progressing to full weight bearing after 8 weeks. Reduction is not employed. Closed reduction and fixation may be used in certain types of fractures. In this approach, a Steinman pin is used to maneuver the fragment and advance the pin to hold the fracture. Open reduction and internal fixation are achieved by use of a lateral approach in which the subtalar joint is reduced and held with reconstruction plates. Problems with this treatment option include skin edge necrosis (8%) and deep infection (2%). Primary arthrodesis may be achieved by means of either isolated subtalar fusion or triple fusion, because unrecognized damage to the calcaneocuboid joint or talonavicular joint may occur. Cochrane Collaborative review of the literature A Cochrane Collaborative review of interventions for calcaneus fractures identified 6 relevant randomized trials, 4 of which were included, 1 excluded, and 1 ongoing. The review found that all 4 trials had methodologic flaws. Three trials, involving 134 patients, compared open reduction and internal fixation with nonoperative management of displaced intra-articular fractures. Pooled results showed no apparent difference in residual pain (24/40 vs 24/42; Peto odds ratio of 0.90; 95% CI: 0.34, 2.36). However, a lower proportion of the patients in operative group were unable to return to the type of work they were engaged in before the injury (11/45 vs 23/45; Peto odds ratio of 0.30; 95% CI: 0.13, 0.71); in addition, they were unable to wear the same shoes they wore before the injury (12/52 vs 24/54; Peto odds ratio of 0.37; 95% CI: 0.17, 0.84). One trial, involving 23 patients, evaluated impulse compression therapy. At 1 year, there was a mean difference of 1.40 pain units on a visual analogue score (scale of 0-10; 95% CI: 0.02, 2.82) in favor of the treated group. The impulse compression group had greater degree of subtalar movement (mean difference of 14.0°; 95% CI: 3.2, 24.6) at 3 months. On average, patients in the impulse compression group returned to work 3 months earlier than those in the control group. The reviewers concluded that randomized trials of the management of calcaneus fractures are few, small, and generally of poor quality. Although some evidence suggests that there is a benefit with operative treatment compared with nonoperative treatment, it remains unclear whether the possible advantages of surgery are worth its risks. In light of this, it seems best to wait for the results of a large ongoing trial comparing open reduction and internal fixation with conservative treatment. Results of 1 small trial suggested that impulse compression therapy for intra-articular calcaneus fractures may be beneficial. More large-scale, high-quality, randomized, controlled trials are needed to confirm these results and to test other interventions in the treatment of calcaneus fractures.20, 21, 22, 23, 24, 25, 26 Medical/Legal Pitfalls
ACKNOWLEDGMENTSSection 9 of 11
We gratefully acknowledge the contributions of Shazeya Sarwar, MBBS, MRCP, in the creation of this article. MULTIMEDIASection 10 of 11
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