Longitudinal stress fracture of the tibia: MR demonstration

Bone stress injuries of the leg in athletes

Bone stress injuries, whose incidence is increasing among competitive and recreational athletes, represent a pathophysiological continuum along which a bone responds to a changing mechanical environment. Frank stress fracture is the endpoint of this process, resulting from the accumulation of microinjuries due to repeated abnormal stresses. The legs are largely the most frequently affected bone district. The aim of this paper is to review the imaging findings of the whole spectrum of stress-induced bone lesions of the leg in athletes. We emphasise the role of computed tomography and magnetic resonance imaging, which allow recognition of early alterations.

Lower extremity and pelvic stress fractures in athletes

Stress fractures occur following excessive use and are commonly seen in athletes, in whom the lower limbs are frequently involved. Delayed diagnosis and management of these injuries can result in significant long-term damage and athlete morbidity. A high index of suspicion may facilitate diagnosis, but clinical presentation may be non-specific. In this regard, imaging in the form of plain radiograph, CT, MRI and bone scintigraphy may be of value. This article reviews the incidence, presentation, radiological findings and management options for athletes with stress fractures of the lower limb.

Multiple tibial insufficiency fractures in the same tibia: a case report

Stress fractures were first described by Briethaupt in 1855. Since then, there have been many discussions in the literature concerning stress fractures, which have been described in both weight-bearing and non-weight-bearing bones. Currently, the tibia is the most frequent location, but multiple stress fractures in the same tibia are rare. This paper presents an unusual case of a 60-year-old woman with multiple tibial stress fractures of spontaneous onset.

Stress-related bone injuries with emphasis on MRI

Stress-related bone injuries are common in professional athletes and in military personnel. However, in an increasingly health conscious society undertaking more, and often unsupervised, exercise regimes, these injuries may increase. Early diagnosis is of paramount importance to detect the signs of stress reaction, allow healing, and prevent progression to frank fracture. This review illustrates the classical magnetic resonance imaging (MRI) features of stress injury and fracture with emphasis on its role in the diagnosis and follow-up, as well as its limitations.

High-Resolution CT Grading of Tibial Stress Reactions in Distance Runners

OBJECTIVE

The purpose of this study was twofold: to determine whether asymptomatic distance runners exhibit cortical tibial abnormalities on CT and to determine the diagnostic accuracy of CT in athletes with medial tibial stress syndrome.

MATERIALS AND METHODS

A cross-sectional study with high-resolution CT of both tibiae was performed on 41 subjects: 20 asymptomatic distance runners, 11 distance runners with unilateral or bilateral pain due to medial tibial stress syndrome (14 painful tibiae), and 10 volunteers not involved in a sport. The group was composed of 13 women and 28 men, ranging in age from 18 to 26 years. A total of 82 tibiae, 14 painful and 68 painless, were evaluated. On the basis of CT findings, tibiae were classified in three groups, and correlation between CT classification and symptoms was made.

RESULTS

Among distance runners, the presence of CT abnormalities was found in 14 (100%) of 14 painful tibiae in patients with medial tibial stress syndrome and in 8 (16.6%) of 48 painless tibiae. The difference was statistically significant (p < 0.001, Fisher's exact test). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT in diagnosing medial tibial stress syndrome were 100%, 88.2%, 63.6%, 100%, and 90.2%, respectively.

CONCLUSION

High-resolution CT has high diagnostic accuracy in depicting medial tibial stress syndrome. Cortical abnormalities can also be seen in some asymptomatic distance runners.

CT and MR imaging findings in athletes with early tibial stress injuries: comparison with bone scintigraphy findings and emphasis on cortical abnormalities

PURPOSE

To prospectively compare computed tomography (CT), magnetic resonance (MR) imaging, and bone scintigraphy in athletes with clinically suspected early stress injury of tibia.

MATERIALS AND METHODS

Medical ethics committee approval and informed consent were obtained. A total of 42 patients experiencing tibial pain due to early stress injuries were evaluated. Eight patients had bilateral involvement; thus, 50 tibiae were evaluated. All patients underwent initial radiography that was negative for injury. MR imaging, CT, and bone scintigraphy were performed in all patients within 1 month of onset of symptoms. Ten asymptomatic volunteers served as the control group. Location of stress injuries, types of bone alterations, and presence of periosteal and bone marrow edema were evaluated. Sensitivity, specificity, accuracy, and positive and negative predictive values of MR imaging and CT were assessed, as was sensitivity of bone scintigraphy. McNemar test was used to detect statistically significant differences.

RESULTS

Sensitivity of MR imaging, CT, and bone scintigraphy was 88%, 42%, and 74%, respectively. Specificity, accuracy, and positive and negative predictive values were 100%, 90%, 100%, and 62%, respectively, for MR imaging and 100%, 52%, 100%, and 26%, respectively, for CT. Significant difference in detection of early tibial stress injuries was found between MR imaging and both CT and bone scintigraphy (McNemar test; P < .001 and P = .008, respectively).

CONCLUSION

MR imaging is the single best technique in assessment of patients with suspected tibial stress injuries; in some patients with negative MR imaging findings, CT can depict osteopenia, which is the earliest finding of fatigue cortical bone injury.

Insufficiency fracture. A survey of 60 cases and review of the literature

We report findings on the site, risk factors and imaging of insufficiency fractures (IF) in 60 patients admitted to our department between 1989 and 1997.

RESULTS

Fifty-five women (mean age 72.5 years) and five men (mean age 59 years) had 91 fractures, accounting for 0.32% of admissions. Fractures occurred most commonly in the pelvic girdle (30.7%, 28/91) and in the sacrum (29.6%, 27/91). In eight patients fractures of the sacrum were associated with fractures of the pelvic girdle. The next most common sites of occurrence were the tibia (16.5%, 15/91: 11 transverse, four longitudinal) and the femoral neck (9.9%, 9/91). There were three subchondral fractures of the femoral head, three fractures of the femoral diaphysis (two longitudinal, one transversal), two of the astragalus, and one each of the ilium, perone, calcaneum and sternum. Thirty patients had osteoporosis: six had received fluoride treatment and five had corticosteroids. Other risk factors were rheumatoid arthritis (4), osteomalacia (4), corticosteroid treatment (4), and hyperparathyroidism (1). Radiography showed a fracture line or osteocondensation in 65% (39/60) of cases. Scintigraphy was positive in 87.5% of cases (21/24), showing a fracture line (15) or a callus (6). Bone computed tomography (CT) scan was positive in 98.1% (54/55) of cases. IF occurs in elderly women with osteoporosis and most commonly in the pelvis.

CONCLUSIONS

Since radiologic signs are inconstant, scintigraphy is the choice procedure.

The knee: bone marrow abnormalities

MRI is clearly the imaging modality of choice for detecting and exploring joint, osseous, and soft tissue injuries in the lower extremity and throughout the musculoskeletal system. Its ability to detect and differentiate the various forms of marrow pathology is unrivaled, and as such it should be obtained early in the work-up of a patient with a suspected marrow abnormality. Additionally, the radiologist must be familiar with the MRI appearances of normal marrow and the most common types of marrow pathology if its diagnostic power is to be fully realized.

Longitudinal tibial fatigue fracture: an uncommon stress fracture with characteristic features

PURPOSE

The author reports three cases of longitudinal tibial fatigue fractures, reviews the literature, and discusses characteristic features that suggest the diagnosis may be made by bone scintigraphy.

METHODS

Radiographs and two- or three-phase bone scintigraphs with Tc-99m MDP were obtained in three runners who had exercise-related leg pain and whose clinical symptoms suggested either stress fractures or shin splints. The literature was reviewed and previously reported scintigraphic findings were compared with those seen in these three cases.

RESULTS

In contrast to the focal, elliptical, cortex-based abnormal activity usually seen in the upper or middle tibia in patients with tibial stress fractures, all three patients had a long area of abnormal diffusely increased tibial activity that extended from the tibiotalar region proximally. This finding was seen on the 3-hour delayed static images of all three patients and was suggested on the blood-pool (tissue phase) images. The literature also contained reports of these same scan characteristics. Radiographs subsequently disclosed a longitudinal tibial stress fracture in one patient, computed tomography was positive in the second patient, and findings of clinical follow-up and radiographs were consistent with this diagnosis in the third patient.

CONCLUSION

In the appropriate clinical setting and with normal or nondiagnostic radiographs, the presence of a long area of diffusely increased activity in the distal tibia extending proximally from the tibiotalar junction is indicative of a longitudinal fatigue fracture.

Trends in pediatric emergency imaging

Abdominal pain, respiratory infections, and skeletal trauma are among the most common reasons for imaging infants and children in the emergency department. The types of pathology and the imaging findings for the various causes of these conditions often differ significantly from those seen in adults with similar symptoms. Although radiographs remain the primary imaging tool, ultrasound, helical CT, and MR imaging play an increasingly important role in solving diagnostic problems in emergency pediatrics. This article highlights some of the common diagnostic dilemmas and discusses current trends in the use of advanced imaging in pediatric patients.