Fatigue fractures of the femoral diaphysis in the skeletally immature simulating malignancy

Distal Femur Insufficiency Fracture in a Pediatric Patient: An Atypical Presentation of Osteogenesis Imperfecta: A Case Report

CASE

We present an unusual case of a distal metaphyseal femur insufficiency fracture in an adolescent with a history of multiple low-energy appendicular fractures. A genetic workup was significant for a variant of unknown significance to the Col1A1 gene.

CONCLUSIONS

To our knowledge, this is the first report of this collagen gene variant as a risk factor for multiple fractures. The case illustrates the presentation of this gene's phenotype and suggested medical management.

Intra-medullary osteosclerosis of the tibia in children

BACKGROUND

Intra-medullary osteosclerosis of the tibia is a rare condition characterised by chronic pain due to diaphyseal hyperostosis with no detectable triggering factor. The main differential diagnoses are stress fracture and osteoid osteoma. Of the few cases reported to date, most were in adults. The objective of this study was to assess paediatric patients with intra-medullary osteosclerosis to determine whether the first visit provides sufficient information to establish the diagnosis and rule out both osteoid osteoma and stress fracture, whether a biopsy is required, and which treatment is optimal.

HYPOTHESIS

The diagnosis of intra-medullary osteosclerosis of the tibia can be made at the first visit.

PATIENTS AND METHODS

Seven paediatric patients, 4 males and 3 females, with a mean age of 11 years, were included in this retrospective study. We evaluated the clinical features, findings from imaging studies (standard radiographs, computed tomography, magnetic resonance imaging, and bone scintigraphy), and treatment outcomes.

RESULTS

At the first visit, all patients had a painful swelling at the middle of the shin and imaging study evidence of antero-lateral tibial cortical thickening extending into the medullary cavity; in 5 patients, a linear lucency was visible. No other bone abnormalities were seen. Treatments included non-operative measures, pinning, and nailing. None of these treatments provided permanent bone healing or pain relief, although transitory freedom from pain with or without radiological bone healing was achieved.

DISCUSSION

Intra-medullary osteosclerosis of the tibia is rarely reported and therefore probably underdiagnosed. Distinctive characteristics of the cortical and endosteal thickening include location at the antero-lateral mid-diaphysis and, in some cases, the concomitant presence of a linear lucency that can provide the early diagnosis. The distinctive radiological features allow differentiation from a stress fracture. The management is challenging.

LEVEL OF EVIDENCE

IV, retrospective observational study.

Stress fracture of the femoral neck in a child: a case report

A 7-year-old boy developed complaints of pain in the left groin. These complaints started spontaneously. Initial plain radiographs of the pelvis indicated no abnormalities. As the symptoms persisted for 6 weeks, the young patient and his parents visited our institution. Clinical investigation showed a slight extension deficit of the left hip. New radiographs and MRI indicated a fracture line with sclerosis along the inferior border of the left femoral neck. In retrospect, this stress fracture of the femoral neck was also visible on the initial radiographs. Seven months after the onset of complaints in the left groin and prescribed partial weight bearing with crutches, callus formation with consolidation of the femoral neck was observed on radiographs. Eleven months after onset, the patient recovered fully without any residual symptoms. After 21 months, the young patient did not have any complaints or restrictions in physical activity. Because of its highly rare nature, stress fractures of the femoral neck in children are easy to miss initially. This was also applicable in our case. Extensive differential diagnosis of a child with pain in the groin furthermore adds to the difficulty in the diagnosis of a stress fracture of the femoral neck. This case report emphasizes the importance of the evaluation of radiographs and observation in children with hip complaints. Similarly, interdisciplinary consultation and cooperation between the general practitioner, orthopaedic surgeon, radiologist and paediatrician is essential in the diagnosis, evaluation and treatment of these young patients.

Taking the stress out of evaluating stress injuries in children

Pediatric stress injuries result from a mismatch between (a) the burden of activity on growing bone and cartilage and (b) their intrinsic biomechanical properties. Although the presentation of stress injuries varies with the specific physical activity and the site of injury, in children it varies primarily with the degree of skeletal maturation. During the past several years, there has been a substantial increase in the incidence of pediatric stress injuries. The differential diagnosis of a stress injury in a child or adolescent can be challenging because the injury sometimes can appear aggressive at imaging assessment. Awareness of the spectrum of imaging features of stress injuries can help the radiologist to reach the correct diagnosis and prevent unnecessary anxiety. This review depicts the range of stress injuries in children and adolescents in various anatomic locations, with emphasis on their appearances at magnetic resonance imaging.

Displaced stress fracture of the femoral neck in young active adults

Stress fractures of the femoral neck in healthy individuals are rare and most prevalent among long-distance runners and military recruits. Women seem to be at higher risk of developing stress fractures because of possible eating disorders and, thereby, following amenorrhoea and osteoporosis. The majority of fractures of the femoral neck are undisplaced. However, they might progress into displaced fractures with avascular necrosis of the femoral head and following development of osteoarthritis as a probable consequence even when treated properly. Early diagnosis with MRI or radionuclide scanning in patients with a history of pain in the groin region during training might be crucial in detecting the fractures at early stages; thereby preventing possible complications following surgical treatment of displaced fractures. The authors present a report of two young adults who developed displaced fractures of the femoral neck and were treated with closed reduction and internal fixation.

Stress fractures of the femoral diaphysis in children: a report of 5 cases and review of literature

The authors report five new cases of the stress fracture of the femoral diaphysis in children. These injuries usually occurred without a history of recent increase of activity. Recently regained normal activity after long-term immobilization and a fibrous cortical defect were predisposing factors. The periosteal reactions were usually identified in the initial radiograph and were not confined to the medial cortex of the distal femur; they might occur in any part of the femoral diaphysis, and also concomitantly on the multiple cortex. The atypical radiographic presentations frequently required MRI for differential diagnosis. Even though the MRI may be confusing to the inexperienced observer, it can lead to the diagnosis of a stress fracture with confidence, negating the need for biopsy. Clinicians should be aware of this diagnostic entity in the differential diagnosis of femoral diaphyseal lesions in children because the occurrence might be more common than reported. Serial simple radiographic examinations taken at intervals to look for the evidence of progressive fracture healing and the restriction of activity or immobilization may be an adequate approach for management.

Distinction of Long Bone Stress Fractures from Pathologic Fractures on Cross-Sectional Imaging: How Successful Are We?

OBJECTIVE

The objectives of our study were to define CT and MRI features that distinguish pathologic fractures from stress fractures and to compare the performance of CT and MRI with radiography.

MATERIALS AND METHODS

Two reviewers retrospectively reviewed 45 MR images, 37 CT scans, and 43 radiographs in 59 patients (30 biopsy-proven pathologic fractures and 29 stress fractures followed to resolution). The features observed on MRI were abnormal bone marrow (well-defined, ill-defined); intracortical, periosteal, or muscle T1 or T2 signal; endosteal scalloping; and a soft-tissue mass. The features seen on CT were marrow abnormality and character (well-defined, ill-defined, permeative, moth-eaten), endosteal scalloping, periosteal reaction (benign, aggressive), and a soft-tissue mass. Reviewers rated their confidence for diagnosing a pathologic fracture on a 1-3 scale (< 50%, 50-95%, > 95% sure, respectively) with each technique. Performance of each technique was defined by reviewer accuracy and area under the receiver operating characteristic curve (Az); the frequency with which the MRI and CT features were associated with pathologic and stress fractures was calculated.

RESULTS

For both reviewers, accuracy for differentiating pathologic from stress fractures was highest on MRI (accuracy/Az: reviewer 1, 98%/0.97; reviewer 2, 93%/0.99); CT (reviewer 1, 88%/0.83; reviewer 2, 82%/0.90) was less accurate than radiography (reviewer 1, 94%/0.98; reviewer 2, 88%/0.96). On MRI, pathologic fractures compared with stress fractures exhibited well-defined T1 marrow signal (83% vs 7%, respectively; p < 0.001), endosteal scalloping (58% vs 0%, p < 0.001), muscle signal (83% vs 48%, p = 0.026), and a soft-tissue mass (67% vs 0%, p < 0.001). On CT, pathologic fractures compared with stress fractures exhibited marrow abnormality (84% vs 17%, respectively; p = 0.001), endosteal scalloping (44% vs 0%, p = 0.006), and aggressive periosteal reaction (36% vs 0%, p = 0.04).

CONCLUSION

MRI is useful for distinguishing pathologic from stress fractures, especially after inconclusive radiographic findings. Specifically, pathologic fractures exhibit well-defined T1 marrow alterations, endosteal scalloping, and adjacent soft-tissue abnormalities.

Fatigue fracture of the distal femur arising in the elderly

Fatigue fractures most frequently involve the tibia and metatarsal bones in the young. We report a very unusual case of fatigue fracture in the distal femur of a 62-year-old man. The differential diagnosis was a pathological fracture due to a metastatic bone tumor. The diagnosis of fatigue fracture was based on the fact that the patient walked every day for a long time, together with the following radiological features: no definite cortical destruction, a radiolucent area surrounded by sclerosis on CT, no extraskeletal mass, and sharp linear low signal intensities in the center of the lesion on MR images. Rest and restricted walking improved his symptoms and fracture healing. Fatigue fracture should be ruled out even in the elderly, especially those who engage in sports activities for long periods.

Adductor insertion avulsion syndrome, "thigh splints": relevance of radiological follow-up

We present a case of chronic osteomyelitis in a 13-year-old girl which was originally diagnosed as adductor insertion avulsion syndrome ("thigh splints") on the basis of the clinical presentation, patient history, initial radiographs and MRI examination. However, at follow-up with persistent pain and altered radiographic and MRI appearances, surgical biopsy was indicated. Histopathological findings confirmed a bone abscess. This case underlines the necessity of clinical follow-up and imaging in certain patients with apparent thigh splints.

MR Imaging of sports-related pseudotumor in children: mid femoral diaphyseal periostitis at insertion site of adductor musculature

OBJECTIVE

The objective of this study was to review the imaging appearance of the femurs of five patients who had been referred from outside institutions after presenting with thigh pain and being given a preliminary diagnosis of primary malignant bone tumor. Typically, when making a diagnosis, physicians place emphasis on the characteristic appearances of diseases on MR imaging, but such appearances may be misleading. An awareness of the specific MR imaging pattern of stress-related partial muscle avulsion can lead to the correct diagnosis.

CONCLUSION

Femoral diaphyseal periostitis after a sports injury to the adductor musculature in children has a characteristic imaging appearance. This condition can initially appear to be misleadingly aggressive. Knowledge of the findings-particularly of the findings on MR imaging-in the proper clinical setting can help physicians make the correct diagnosis and eliminate unnecessary biopsy or inappropriate treatment.

Imaging in skeletal paediatric oncology

The prognosis for the child presenting with a bone sarcoma has improved dramatically with the introduction of adjuvent chemotherapy. As a result the majority of patients can now expect to undergo limb salvage surgery. The role of imaging in the management of the child presenting with a suspected sarcoma is presented. This commences with tumour detection, through diagnosis and surgical staging, re-staging with assessment of response to chemotherapy and follow-up surveillance for the development of local recurrence and/or metastases. The importance of the multidisciplinary approach to the management of bone sarcomas is emphasised.

Magnetic resonance imaging appearances of fatigue fractures of the long bones of the lower limb

Fatigue fractures may be confused with malignant bone lesions on radiography and hence are periodically referred for further imaging assessment with computed tomography (CT) and magnetic resonance imaging (MRI). The appearances on MRI are characteristic although not pathognomonic. Typical findings include: intramedullary bands of low signal intensity, continuous at some point with the cortex, indicative of a fracture line; intramedullary areas of high signal on both T2-weighted and short-tau inversion recovery (STIR) images representing marrow oedema or haemorrhage, together with evidence of periosteal oedema. We present seven cases of fatigue fractures of the long bones of the lower limb and discuss the MRI findings and compare CT and MRI in imaging these lesions.

Femoral stress fractures in children

Stress fractures reported in the medical literature almost exclusively affect young athletes, military recruits and patients with metabolic bone disease. The classification of stress-induced bone injury is somewhat confused and includes "fatigue" stress fractures which occur in previously normal bones and "insufficiency" stress fractures which occur in bones weakened by various causes. Femoral stress fractures in children are extremely rare, and we report 5 cases in young patients who sustained their injuries during the course of normal play activities. It is well-known that these lesions can simulate malignant lesions; however, we believe that careful review of the radiographs in the context of the clinical history can in many cases lead to the correct diagnosis being made and obviate the need for further intervention.

Case report 686. Stress fracture at distal end of femur simulating "periosteal desmoid"

A 13-year-old female presented after repeated trauma with pain of the distal end of the thigh. The findings on plain films, bone scan, and CT were indeterminate. MRI accurately demonstrated a fracture line with bone marrow edema, suggesting the diagnosis of stress fracture. MRI patterns of stress fracture were considered and the importance of establishing the correct diagnosis was emphasized.