Imaging the problem scaphoid

Scaphoid fractures can be difficult to diagnose on X-ray, even at 2 weeks. We have compared prospectively bone scanning versus MRI scanning in 22 patients with persistent signs and symptoms suggestive of a scaphoid fracture at 2 weeks and found both methods to be sensitive, but MRI to be more specific, particularly in diagnosing soft tissue injuries like scapho-lunate ligament ruptures and triangular fibrocartilage tears. An early MRI scan at 2 weeks allows the clinician to make the appropriate decision in this group of patients whose diagnoses include; occult scaphoid fractures, other occult carpal and radial fractures, ligamentous injuries and those without apparent injuries. MRI has also been useful in defining the group of injuries which may imitate a clinically occult scaphoid fracture.     

Fifteen minutes bone scintigraphy in patients with clinically suspected scaphoid fracture and normal x-rays

Occult fractures of the scaphoid bone occur frequently and may lead to non-union. The use of three-phase bone scintigraphy in patients with normal x-rays of the scaphoid after carpal injury is widely advocated.In this study, 40 patients with negative radiographs but clinically suspected scaphoid fracture, all had rapid bone scintigraphy with images taken 15 min after intravenous injection of 99 m-Technetium Hydroxymethylene diphosphonate. The scan was performed approximately 2 weeks after the trauma. We found 8 fractures of the scaphoid bone and 13 fractures of other carpal bones. In 5 cases the images were inconclusive. At follow-up 6 months to 2 years later we found no patients with non-union.We find this rapid version of the bone scan useful as a second line investigation for continuing wrist pain following trauma in the presence of normal radiography. This can result in a reduction in both time and costs required for the diagnostic process. If the results are inconclusive we recommend a delayed image. CT or MRI could also be considered. In rare cases a wrist arthroscopy may be considered.     

Magnetic resonance imaging in stress fractures and shin splints

The purpose of the current study was to determine whether stress fractures and shin splints could be discriminated with MRI in the early phase. Twenty-two athletes, who had pain in the middle or distal part of their leg during or after sports activity, were evaluated with radiographs and MRI scans. Stress fractures were diagnosed when consecutive radiographs showed local periosteal reaction or a fracture line, and shin splints were diagnosed in all the other cases. In all eight patients with stress fractures, an abnormally wide high signal in the localized bone marrow was the most detectable in the coronal fat-suppressed MRI scan. In 11 patients with shin splints, the coronal fat-suppressed MRI scans showed a linear abnormally high signal along the medial posterior surface of the tibia, and in seven patients with shin splints, the MRI scans showed a linear abnormally high signal along the medial bone marrow. No MRI scans of shin splints showed an abnormally wide high signal in the bone marrow as observed on MRI scans of stress fractures. This study showed that fat-suppressed MRI is useful for discrimination between stress fracture and shin splints before radiographs show a detectable periosteal reaction in the tibia.     

The role of imaging in the assessment of vascularity at hand and wrist

The viability of the bone is compromised in two main situations at the wrist: Kienb?ck's disease and scaphoid nonunion with avascular necrosis. Plain radiography and CT allow an accurate anatomical approach of morphological changes associated with avascular necrosis of the lunate and the scaphoid fracture with complications. CT is readily available to detect nondisplaced fractures. However, early forms of necrosis can be misdiagnosed and evaluation of bone vitality is impossible. MRI is the best imaging modality to detect avascular necrosis and the intravenous injection of gadolinium improves the specificity of diagnosis of necrosis. The lack of enhancement of the proximal fragment of the scaphoid leads the surgeon to use a vascular graft in the treatment of nonunion. The technique has its limitations. The bone necrosis is histologically complex and contrast enhancement does not mean necessarily viability. However, MRI is still the most powerful imaging modality in the assessment of the bone marrow.     

Predictive value of magnetic resonance imaging in avascular necrosis following talar fractures

Ischemic bone necrosis following talar fractures is a problematic complication and its early diagnosis is important. Patients with Hawkins Type II and III talar fractures received internal fixation using titanium alloy screws, and chronological bone changes were observed with Magnetic Resonance Imaging (MRI). With the Type II patient, Hawkins' sign was radiographically confirmed 2 months after the surgery. Furthermore, there were no changes of MR images for 2 years and a good clinical outcome was obtained. However, in the Type III patient, Hawkins' sign was negative and MRI revealed a low signal-intensity band on the talus 2 months after the surgery and then necrosis was radiographically confirmed; pain appeared 10 months later. These 2 cases suggest that MRI is a useful means for detecting bone necrosis with talar fractures in the early post-operative period.     

Die Stressfraktur des tarsalen Os naviculare

Stress fractures of the tarsal navicular bone are a challenge in diagnosis and therapy. First and foremost you have to think about this fracture. The origin of the injury can be detected in a wrong or too heavy strain of the bone especially in long distance runners and recruits. The MRI is the diagnostic tool of first choice. Therapy of displaced or comminuted fractures as well as pseudarthrosis is best done with surgical procedures like direct screw fixation or interposition of autologous bone depending on the circumstances and the age of injury. Conservative treatment with a plaster of Paris is useful in non-displaced and non-comminuted fractures. Prophylaxis with technical aids and a changing habits is recommended.     

Stress Fracture of the Femoral Neck in a Young Female Athlete

Abstract   Stress fractures have been reported to occur in association with running. They typically involve the lower extremity. Although relatively rare, unrecognized or untreated femoral neck fractures carry a much higher morbidity rate than other stress fractures. Stress fractures of the femoral neck should even be considered in young amateur athletes with hip pain. If X-ray is inconclusive, radionuclide bone imaging and MRI can be useful in diagnosing these fractures. This rare diagnosis, as well as classification and treatment options, will be discussed.     

Apport de l’imagerie dans le diagnostic de la vascularisation osseuse à la main et au poignet

The viability of the bone is compromised in two main situations at the wrist: Kienböck's disease and scaphoid nonunion with avascular necrosis. Plain radiography and CT allow an accurate anatomical approach of morphological changes associated with avascular necrosis of the lunate and the scaphoid fracture with complications. CT is readily available to detect nondisplaced fractures. However, early forms of necrosis can be misdiagnosed and evaluation of bone vitality is impossible. MRI is the best imaging modality to detect avascular necrosis and the intravenous injection of gadolinium improves the specificity of diagnosis of necrosis. The lack of enhancement of the proximal fragment of the scaphoid leads the surgeon to use a vascular graft in the treatment of nonunion. The technique has its limitations. The bone necrosis is histologically complex and contrast enhancement does not mean necessarily viability. However, MRI is still the most powerful imaging modality in the assessment of the bone marrow.     

Spontaneous bilateral fractures of the femoral neck. Etiology-frequency-diagnosis-therapy

INTRODUCTION: Medial and pertrochanteric fractures of the femoral neck occur commonly in patients with bone weakness due to osteoporosis or osteomalacia. Combined bilateral hip injury is much rarer. PATIENTS AND METHODS: The case of a Turkish woman with bilateral fractures of the femoral neck due to secondary hyperparathyroidism caused by nutritional vitamin-D 3 deficiency is described and compared to 80 cases of bilateral hip fractures mentioned in English and German literature. RESULTS: Until the late 1950's the most common reason for simultaneous bilateral femoral neck fractures was convulsive therapy of psychosis by drug or electroshock without use of relaxants, followed by seizures of other origin. Primary and secondary bone diseases are the most common reason for two-fold spontaneous bilateral fractures of the femoral neck. CONCLUSION: At the time of first pain radiological findings are often normal. In this situation MRI, isotope bone scanning or additional chemical diagnostics have proved to be useful. The medical regulation of the bone disease is of highest priority. On account of the pain, bone stability and deformation, conservative and operative therapy such as osteosynthesis or THR has to be performed.     

A review of the recent advances in magnetic resonance imaging in the assessment of osteoporosis

Osteoporosis is a common metabolic disorder with considerable associated morbidity and mortality. The loss of bone mineral integrity and the resultant occurrence of atraumatic fractures are typically symptomatic of the disease. Currently skeletal status is commonly assessed using non-invasive conventional radiography and scintigraphy as well as densitometric techniques such as quantitative computed tomography and dual-energy X-ray absorptiometry. But, apart from gross bone mineral density, the fine structure of trabecular bone also plays an important role in defining the biomechanical competence of the skeleton. Recently attention has been focused on deriving measures that provide information about not only trabecular bone density but also microstructure. Magnetic resonance imaging (MRI) is one such new technique which potentially may provide information pertaining to bone density and structure as well as to occult fracture detection. Cortical bone produces a signal void in MR images, due to the fact that it contains very few mobile protons that give rise to a signal in MRI; also the MR relaxation time T2 of these protons is very short which produces a very fast decay of the MR signal during image acquisition. However, the trabecular bone network affects the MR properties of bone marrow. The difference in the magnetic properties of trabecular bone and bone marrow generates local imperfections in the magnetic field. The MR signal from bone marrow is modified due to these imperfections and the MR relaxation time T2* of marrow is shortened. The extent of relaxation time shortening and hence loss of signal intensity is proportional to the density of trabecular bone and marrow interfaces and their spatial architecture. Recent investigation in this area include studies aimed at quantifying marrow relaxation times and establishing their relationship to trabecular bone density and structure. In addition, with advances in imaging software and hardware, MR images at in-plane resolutions of 78–200 µm may be obtained. The trabecular bone structure is clearly revealed in such images and studies aimed at the development of high-resolution MRI techniques combined with quantitative image analysis techniques are currently under way. These potentially useful techniques for assessing osteoporosis and predicting fracture risk are reviewed in this paper.     

Stress fracture in athletes

Stress fractures are widely encountered in sport medicine and rheumatology. Stress fractures result from abnormal and repetitive loading on normal bone that lead to microdamage and then fracture. They occur after sudden increase in physical activity. They appear mostly at lower limbs. Women are at higher risk than men. Patients complain of mechanical pain. Clinical findings include focused pain and sometimes swelling. No biological test is useful for diagnosis. Plain radiographs are normal in early stage disease. MRI is the gold standard to confirm stress fracture. Treatments of stress fracture always involve rest and analgesics. Non-steroidal anti-inflammatory should be use cautiously because they may inhibit callus formation. Extracorporeal shockwave may be a new approach for SF not healing with rest. Surgical treatment is often needed in high risk stress fracture of delayed healing, non-union or complete fracture.     

Microarchitecture et résistance mécanique osseuse

Although bone mass is the main determinant of bone mechanical resistance, it explains only 30% to 40% of the variability of this characteristic, indicating that other factors are involved. Among these factors is bone tissue quality, which depends on bone mineralization, bone turnover, and bone microarchitecture. Several parameters for characterizing bone microarchitecture have been developed over the last 15 years. The simplest (Parfitt’s parameters) are trabecular count, width, and separation. A binary image (two levels of gray) of bone tissue can be expanded and used to determine the trabecular bone pattern factor. This method tends to overestimate the number of convex surfaces, which are characteristic of trabecular network disruption. The binary image can be further simplified (skeletonized) and used to count the number of nodes (anastomoses between trabeculae) or free ends (segments disconnected from the network). The bone marrow star volume, the marrow interconnectivity index, and the Euler-Poincaré number are useful for characterizing the bone marrow. These parameters can be measured on bone specimens or on computed tomography (CT) or magnetic resonance imaging (MRI) scans, although in-plane resolution is far lower with scans than with specimens. Two-dimensional analysis is widely used, although three-dimensional studies are more satisfactory. Finally, fractal analysis is an original approach in which fractal dimension measurement, which is fairly simple, is used to determine the degree of network disruption. Ex vivo histomorphometric data suggest that microarchitecture-related factors may explain 10% to 30% of the variability in bone mechanical resistance beyond the proportion explained by bone mass. Similar results have been obtained in microimaging, CT, and MRI studies. Discrepancies across studies exist, however, in the strength of the relationship between bone mass and bone mechanical resistance; they are probably ascribable to differences in measurement sites and to errors in the measurement of variables characterizing bone mechanical resistance. The finite element method may be a means of sidestepping these problems. It can be used, in particular, to calculate Young’s modulus of elasticity from three-dimensional bone segment reconstructions. The results of the few studies of the finite element method are promising but require confirmation. Finally, a more clinical approach consists in comparing bone architecture in patients with osteoporotic fractures and in controls matched on bone mass. A few cross-sectional studies have used this approach. Bone architecture was evaluated using histomorphometry, CT, or MRI. The results indicate that trabecular network disruption is more severe in patients with than without fractures.     

Magnetic resonance imaging of periarticular titanium screws

Magnetic resonance imaging (MRI) may be the most sensitive modality for detecting post-traumatic degeneration of articular cartilage. Magnetic resonance imaging must accurately depict articular cartilage in the presence of periarticular fracture stabilization devices to be effective for postoperative imaging of articular fractures. This study examines how close titanium screws can be inserted to tibial articular surfaces and still allow accurate MRI of the overlying articular cartilage. Cannulated titanium screws were inserted at varying distances from subchondral bone in the proximal and distal tibiae of embalmed human cadaveric legs, which were then imaged using a standard nonfat-saturated fast low angle shot two-dimensional sequence (FLASH 2D). The distance from the center of the screw to the subchondral bone and the thickness of the articular cartilage directly overlying the screw was then determined by direct measurement and by measurement on the scanned images. To allow FLASH 2D MRI of the articular cartilage, 7.3-mm screws had to be at least 13 mm from the subchondral bone, and 4.5-mm screws had to be at least 12 mm from the subchondral bone. For MRI to be effective for the postoperative imaging of the articular surface following severe articular fractures of the tibia, titanium fracture hardware must be farther away from the articular surface than these minimum distances. Alternate materials for stabilizing articular fractures are available and may allow clearer and more accurate imaging of the articular cartilage when inserted close to the articular surface.     

Note technique: utilisation des ancres en traumatologie de la cheville et du pied

Anchors are commonly used in ligament and arthroscopic surgery. They may also be useful in treating small bone avulsions. It is a very simple procedure that does not require the removal of the anchors. Anchors are useful in a number of foot and ankle trauma procedures: proximal fifth metatarsal fractures, navicular avulsions, Achille’s avulsions, fractures of the great toe and medial malleolus, and ankle sprains.     

Diagnostic accuracy of imaging modalities for suspected scaphoid fractures: meta-analysis combined with latent class analysis

Follow-up radiographs are usually used as the reference standard for the diagnosis of suspected scaphoid fractures. However, these are prone to errors in interpretation. We performed a meta-analysis of 30 clinical studies on the diagnosis of suspected scaphoid fractures, in which agreement data between any of follow-up radiographs, bone scintigraphy, magnetic resonance (MR) imaging, or CT could be obtained, and combined this with latent class analysis to infer the accuracy of these tests on the diagnosis of suspected scaphoid fractures in the absence of an established standard. The estimated sensitivity and specificity were respectively 91.1% and 99.8% for follow-up radiographs, 97.8% and 93.5% for bone scintigraphy, 97.7% and 99.8% for MRI, and 85.2% and 99.5% for CT. The results were generally robust in multiple sensitivity analyses. There was large between-study heterogeneity for the sensitivity of follow-up radiographs and CT, and imprecision about their sensitivity estimates. If we acknowledge the lack of a reference standard for diagnosing suspected scaphoid fractures, MRI is the most accurate test; follow-up radiographs and CT may be less sensitive, and bone scintigraphy less specific.     

Anatomical and biomechanical evaluation of the tension band technique in patellar fractures

Tension band wiring for patellar fractures is common, but some recent reports refer to disadvantages of this approach. Our anatomical and biomechanical study focused on use of tension band techniques in patellar fractures. The anatomy of the patella and tendon insertion was examined with knee magnetic resonance imaging (MRI) and correlated with the technical requirements of the tension band. Tension band wiring over tendinous tissue was simulated and calculated with a cyclic biomechanical test on cow patellae. According to tension band templating on the MRI section, Kirschner wire insertion was needed for the tension band to turn over the tendinous tissue. The tension band became more stable while turning over less tendinous tissue and more adjacent bone surface. Nevertheless, cyclic loading tests indicate that all tension band applications in this study lose their initial stability. Excessive initial compression by the tension band resulted in bending of the Kirschner wire and thus reduction failure. For optimum stabilisation, tension force transfer should be done directly on bone or at least material that protects the tendon would be useful.     

Management of scaphoid nonunions

Scaphoid nonunions can exist with or without avascular necrosis of the proximal pole, and waist fractures may have an associated humpback deformity. CT best shows the deformity and bone loss, whereas MRI will show avascular necrosis. Operative treatment should be directed at correcting the deformity with open reduction and internal fixation and bone grafting. Vascularized bone grafts should be used in cases of avascular necrosis.     

Prospective comparison of MR imaging and direct magnification radiography in occult scaphoid fractures

Summary The diagnosis of occult fractures of the scaphoid bone is even more challenging than that of conventional fractures of the scaphoid. This study aimed to compare prospectively the gold standard method (plain radiographs in four projections, after about 14 days) and the primary findings with direct magnification radiography (DIMA) and magnetic resonance imaging (MRI). Primary MRI showed much higher diagnostic power than plain radiography at 10–14 days in occult scaphoid fractures and in detection of associated carpal injuries. This may lead to a decreasing time of disease. DIMA was inferior in detecting occult fractures of the scaphoid.      

Stress fractures presenting as tumours: a retrospective analysis of 22 cases

Frequently, the imaging features of stress fractures may be misinterpreted as tumour-like lesions. The aim of this study was to analyse the quality of different examinations in detecting stress fractures mimicking tumour-like lesions in magnetic resonance imaging (MRI). We evaluated 22 cases which were referred to our department with the suspected diagnosis of bone tumours turning out to be stress fractures. Whenever the MRI did not lead to a diagnosis after a second review, computed tomography (CT) scans and, if still required, additional examinations were performed until the fracture was detected. A stress fracture was diagnosed in 15 cases after the additional CT scan, in five cases with the review of the MRI and in two cases with a combination of several examinations. Especially in stress fractures of the tibia and the femur, CT scanning was essential for making a diagnosis by detecting the fracture line. Bone scans and biopsies, in contrast, were not helpful in making a correct diagnosis.     

Schmorl's nodes and low-back pain

Summary Magnetic resonance imaing (MRI) findings in cases with symptomatic and asymptomatic Schmorl's nodes have been analysed. In all symptomatic cases, the vertebral body marrow surrounding the Schmorl's node was seen as low signal intensity on T1-weighted images and as high signal intensity on T2-weighted images. It was confirmed by histological examination that the MRI findings indicated the presence of inflammation and oedema in the vertebral bone marrow. These MRI findings were not seen in asymptomatic individuals. Inflammatory changes in the vertebral body marrow induced by intraosseous fracture and biological reactions to intraspongious disc materials might cause pain. We postulate that after fracture healing and subsidence of inflammation, the Schmorl's nodes become asymptomatic, in analogy with old vertebral compression fractures. MRI is not only useful in detecting the recently developed Schmorl's nodes but also in differentiating between symptomatic and asymptomatic Schmorl's nodes.