Diagnostic accuracy of 3D color volume-rendered CT images for peroneal tendon dislocation in patients with acute calcaneal fractures.

BACKGROUND: Use of three-dimensional (3D) color volume-rendered (VR) images has been reported to be more time-efficient compared to that of cross-sectional computed tomography (CT) images for the diagnosis of peroneal tendon dislocation. However, the diagnostic performance of this technique has not been studied. PURPOSE: To test diagnostic accuracy of 3D color VR CT images of ankle for peroneal tendon dislocation in patients with acute calcaneal fractures. MATERIAL AND METHODS: The study consisted of 121 ankle CT studies from 105 consecutive patients (85 men, 20 women; mean age, 42 years; age range, 16-75 years) with acute calcaneal fractures. Peroneal tendon dislocation was diagnosed on multiplanar CT images by consensus of two experienced musculoskeletal radiologists, which served as the reference standard. Three other musculoskeletal radiologists independently reviewed 3D images alone on a workstation. The readers determined whether or not there was peroneal tendon dislocation using three degrees of certainty (definite, probable, and possible). Diagnostic performance of 3D images for peroneal tendon dislocation was evaluated by calculating the sensitivities, specificities, and area under the receiver-operating characteristic (ROC) curves. RESULTS: Forty-eight (40%) out of 121 studies showed peroneal tendon dislocation based on the expert readings using multiplanar reformatted images. Sensitivities/specificities of 3D images measured 0.92/0.81, 0.88/0.90, and 0.81/0.92 for three readers, respectively. The area under the proper binormal ROC curve based on all three readers (0.93, 0.94, and 0.92) measured 0.93 with a 95% confidence interval of 0.89-0.98. CONCLUSION: Diagnostic accuracy of 3D images is comparable to, but not as good as that of MPR images for the diagnosis of peroneal tendon dislocation in patients with acute calcaneal fractures.

Masses in the extensor mechanism of the knee: an unusual presentation of gout.

Tophaceous gout presenting as a soft tissue mass in an unusual location can pose a diagnostic challenge for radiologists. Tophi sometimes occur in a variety of unusual anatomic locations making them difficult to distinguish from tumors such as sarcomas. We report two cases of gout in the extensor mechanism of the knee, with imaging findings that were initially concerning for a neoplasm. One mass occurred in the patellar tendon and the other mass involved the quadriceps tendon. Both lesions had enigmatic imaging findings and to arrive at a definitive diagnosis, incisional biopsies were performed.

A primer on skeletal dysplasias.

Skeletal dysplasia encompasses a heterogeneous group of over 400 genetic disorders. They are individually rare, but collectively rather common with an approximate incidence of 1/5000. Thus, radiologists occasionally encounter skeletal dysplasias in their daily practices, and the topic is commonly brought up in radiology board examinations across the world. However, many radiologists and trainees struggle with this issue because of the lack of proper resources. The radiological diagnosis of skeletal dysplasias primarily rests on pattern recognition-a method that is often called the "Aunt Minnie" approach. Most skeletal dysplasias have an identifiable pattern of skeletal changes composed of unique findings and even pathognomonic findings. Thus, skeletal dysplasias are the best example to which the Aunt Minnie approach is readily applicable.

Occult fractures of extremities.

Recent advances in cross-sectional imaging, particularly in CT and MR imaging, have given these modalities a prominent role in the diagnosis of fractures of the extremities. This article describes the clinical application and imaging features of cross-sectional imaging (CT and MR imaging) in the evaluation of patients who have occult fractures of the extremities. Although CT or MR imaging is not typically required for evaluation of acute fractures, these modalities could be helpful in the evaluation of the occult osseous injuries in which radiographic findings are equivocal or inconclusive.

Role of magnetic resonance imaging in musculoskeletal trauma.

The unique ability of magnetic resonance (MR) imaging to visualize injuries of bone, cartilage, bone marrow, and supporting soft tissue structure makes it ideally suited for the evaluation of musculoskeletal trauma. Magnetic resonance imaging also offers exquisitely detailed anatomical information on the musculoskeletal system. The widespread availability of MR imaging and the constantly improving technology make it the imaging modality of choice for the patients with a musculoskeletal trauma. This review discusses the role and applications of MR imaging for musculoskeletal trauma. It covers traumatic conditions of the musculoskeletal system, including hemarthrosis, lipohemarthrosis, stress fracture, occult fractures, cartilage injuries, the muscle and tendon trauma, avulsion injuries, extensor mechanism injuries, and traumatic conditions of joints.

Bone contusion progression from traumatic knee injury: association of rate of contusion resolution with injury severity.

BACKGROUND: Bone contusions are frequently encountered in magnetic resonance imaging (MRI) evaluation of knee anterior cruciate ligament (ACL) injuries. Their role as indicators of injury severity remains unclear, primarily due to indeterminate levels of joint injury forces and to a lack of preinjury imaging. PURPOSE: The purpose of this study was to 1) quantify bone contusion pathogenesis following traumatic joint injuries using fixed imaging follow-ups, and 2) assess the feasibility of using longitudinal bone contusion volumes as an indicator of knee injury severity. STUDY DESIGN: Prospective sequential MRI follow-ups of a goat cohort exposed to controlled stifle trauma in vivo were compared to parallel clinical MRI follow-ups of a human ACL tear patient series. METHODS: Reproducible cartilage impact damage of various energy magnitudes was applied in a survival goat model, coupled with partial resection of anterior portions of medial menisci. Both emulate injury patterns to the knee osteochondral structures commonly encountered in human ACL injury imaging as well as instability from resultant ligament laxity. Longitudinal clinical MRI sequences portrayed stifle bone contusion evolution through 6 months after the inciting event. RESULTS: In the first 2 weeks, biological response variability dominated the whole-joint response with no apparent correlation to trauma severity. Control goats subjected to partial meniscectomy alone exhibited minimal bone response. Thereafter, 0.6 J impact bone contusions portrayed a faster rate of resolution than those induced by 1.2 J cartilage impacts. CONCLUSION: Bone contusion sizes combined with time of persistence are likely better measures of joint injury severity than isolated bone contusion volume.

Pediatric stress fractures: a pictorial essay.

More children are participating in organized and recreational athletics at a younger age. It has been well documented that increased athletic specialization and year-round activities have resulted in higher incidences of overuse injuries, including stress fractures and stress reactions. Initially, stress fractures can be radiographically occult. Continued stress on the injured bone or cartilage can lead to progressive radiographic changes. Because of the prevalence of these injuries, both orthopedic surgeons and radiologists should be aware of the radiographic and magnetic resonance imaging (MRI) features of common stress fractures in children. This article reviews frequently encountered stress fractures involving various bones in the pediatric population.

Spondyloarthropathies: ankylosing spondylitis and psoriatic arthritis.

As advances in the treatment of ankylosing spondylitis continue, TNF-alpha blocking agents may eventually be used as a first-line treatment. MR imaging could then be used to aid in the early diagnosis of ankylosing spondylitis by identifying early sacroiliitis, followed by immediate initiation of treatment to prevent the progression of the disease with its accompanying morbidities. Currently, radiographic identification of sacroiliitis remains the mainstay in diagnosing ankylosing spondylitis. In ankylosing spondylitis and psoriasis, MR imaging can demonstrate areas that are undergoing active inflammatory changes and enthesitis, aiding in the diagnosis of a spondyloarthropathy.

SAPHO syndrome--a pictorial assay.

SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome is a distinct clinical entity representing involvement of the musculoskeletal and dermatologic systems. It is well known to rheumatologists because of characteristic skin manifestations and polyarthropathy. However, few reports exist in the orthopaedic literature. It is important to be aware of sAPHO syndrome as it can mimic some of the more common disease entities such as infection, tumor, and other inflammatory arthropathies. Anterior chest wall pain centered at sternoclavicular and sternocostal joints is an important and characteristic clinical finding which can point to its diagnosis. A patient may undergo different diagnostic tests and invasive procedures such as biopsies before a diagnosis is made. Imaging can be helpful by offering a detailed evaluation of the abnormalities. More importantly it helps in revealing subclinical foci of involvement due to the polyostotic nature of the disease. The treatment is mostly nonsurgical. NSAIDS are the first line agents. However multiple new agents are being used for refractory cases. Surgery is reserved to treat complications.

Clinical role of radiography for thoracic spine fractures in daily practice in the MDCT era: a retrospective review of 255 trauma patients.

PURPOSE: To retrospectively assess the diagnostic efficacy of radiography in detecting vertebral body fractures of the thoracic spine compared with MDCT, to assess the confounding factors reducing the diagnostic efficacy, and to investigate the outcomes of radiographically overlooked patients. MATERIALS AND METHODS: Two hundred fifty-five patients suspected of thoracic spine fractures were enrolled. We assessed the diagnostic efficacy of radiography for the patients sub-grouped based on five confounding factors: chest abnormalities, head injuries, cervical spine fractures, upper extremity injuries, and age of 65 years or older. We investigated the outcomes of radiographically overlooked patients. RESULTS: Three hundred fifty-one vertebral body fractures were detected. The per-fracture sensitivities and specificities were 55 % and 94 % for vertebral body fractures and 41 and 99 % for unstable fractures. In patients with upper extremity injuries or aged 65 years or older, radiography was less sensitive in detecting the unstable fractures (P < 0.05). Nineteen patients were overlooked by radiography; two had neurological deficits and needed surgical fixation; 15 with no neurological deficit were conservatively treated with uneventful outcomes. CONCLUSION: Radiography had low sensitivity but high specificity. In daily practice, primary use of MDCT is beneficial for patients with neurological deficit or upper extremity injuries or elderly patients.

Early spondylodiscitis presenting with single vertebral body involvement: a report of two cases.

Infectious spondylodiscitis is an uncommon disease with increasing incidence that typically presents with abnormalities in two adjacent vertebral bodies and the intervening disk. We describe two cases that initially presented with imaging abnormalities in only a single vertebral body. Both patients had a history of lumbar back pain and elevated inflammatory markers, but the lack of classical spondylodiscitis imaging findings led to diagnostic delay and confusion. It is likely that the incidence of atypical presentations of spondylodiscitis will increase as the disease incidence increases and imaging is performed at an earlier stage. It is important to recognize the disease early because early diagnosis is the key to preventing serious complications like epidural abscess and spinal cord compression.

Cervical facet joint septic arthritis: a case report.

Facet joint septic arthritis is a rare but severe infection with the possibility of significant morbidity resulting from local or systemic spread of the infection. Pain is the most common complaint on presentation followed by fever, then neurologic impairment. While the lumbar spine is involved in the vast majority of cases presented in the literature, the case presented here occurred in the cervical spine. The patient presented with a three week history of neck and left shoulder pain and was diagnosed by MRI when his pain did not respond to analgesics and muscle relaxants. The only predisposing factor was a history of diabetes mellitus and the infection most likely resulted from hematogenous spread. MRI is highly sensitive in diagnosing septic arthritis and it is the preferred modality for demonstrating the extent of infection and secondary complications including epidural and paraspinal abscesses as seen in this case. Without familiarity with this entity's predisposing factors, clinical symptoms and appropriate lab/imaging work up, many patients experience a delay in diagnosis. Treatment involves long term parenteral antibiotics or percutaneous drainage. Surgical debridement is reserved for cases with severe neurologic impairment. The incidence of facet joint septic arthritis is increasing likely related to patient factors (increasing number of patients >50 yo, immunosuppressed patients, etc), advancement in imaging technology, availability of MRI, and heightened awareness of this rare infection which is the aim of this case presentation.

Conical utility of CT-guided biopsies in orthopaedic oncology.

BACKGROUND: CT-guided biopsy is a minimally invasive diagnostic method of evaluating musculoskeletal lesions. Other options include incisional and excisional biopsy with the possibility of intraoperative frozen section. The clinician's decision to order a CT-guided biopsy requires an understanding of the likelihood that this biopsy will affect treatment This requires an understanding of both diagnostic yield and accuracy. Furthermore, the clinical utility of a biopsy is affected by factors other than the yield and accuracy as the clinical setting may render a technically diagnostic biopsy unhelpful. METHODS: A retrospective review of the electronic record at an orthopedic oncology referral center identified all patients who had undergone CT-guided percutaneous needle biopsy of musculoskeletal lesions after being evaluated by an orthopedic oncologist in clinic over a period of 5 years. 53 CT-guided biopsies of bone lesions and 16 CT-guided biopsies of soft tissue lesions were identified. The diagnostic yield (rate of obtaining tissue from which the pathologist could report a diagnosis) and clinical utility (rate at which biopsy results guided treatment decisions) were calculated and statistically compared. RESULTS: The overall diagnostic yield of CT-guided bone biopsies was 94% (50 of 53 biopsies) and the clinical utility was 70% (37 of 53 biopsies). In the first 2 years of the study the diagnostic yield was 95% (21 of 22 biopsies) and the clinical utility was 86% (19 of 22 biopsies). In the remaining 3 years the diagnostic yield was 91% (28 of 31 biopsies) and the clinical utility was 58% (18 of 31 biopsies). This decrease in clinical utility over time was statistically significant (p = 0.01). Suspicion of metastasis resulted in a diagnostic yield of 100% (11/11) and a clinical utility of 91% (10/11). Suspicion of primary tumor resulted in a diagnostic yield and clinical utility of 93% (39/42) and 67% (28/42), respectively. This difference in clinical utility was statistically significant (p = 0.02). The diagnostic yield of CT-guided soft tissue biopsies was 75% (12 of 16 biopsies) and the clinical utility was 69% (11 of 16 biopsies). The diagnostic yield was significantly lower for soft tissue biopsy than bone biopsy (p = 0.01). There was no relationship between the rate of diagnostic biopsies and the evaluating pathologist or the location of the lesion within the body. CONCLUSIONS: CT-guided biopsy is useful in the diagnosis of musculoskeletal lesions, however, its clinical utility is substantially lower than its diagnostic accuracy and yield due to a significant rate of diagnostic biopsies that fail to guide treatment, particularly when a primary lesion is suspected. The disparity in clinical utility based on preoperative suspicion of metastasis was even greater in our study than previously shown. CT-guided percutaneous needle biopsy is much more likely to guide treatment in the setting of suspected bone metastasis as opposed to biopsies of suspected primary bone lesions and soft tissue lesions.

Musculoskeletal CT: recent advances and current clinical applications.

This article discusses the indications for CT in the management of acute fractures and postoperative complications related to orthopedic procedures. The current clinical use of CT in spine injuries, pelvic/acetabular fractures, and major fractures in the extremities is discussed. Multidetector CT techniques to minimize metal artifacts and common hardware complications are reviewed.

Radiologic evaluation of chronic foot pain.

Chronic foot pain is a common and often disabling clinical complaint that can interfere with a patient's routine activities. Despite careful and detailed clinical history and physical examination, providing an accurate diagnosis is often difficult because chronic foot pain has a broad spectrum of potential causes. Therefore, imaging studies play a key role in diagnosis and management. Initial assessment is typically done by plain radiography; however, magnetic resonance imaging has superior soft-tissue contrast resolution and multiplanar capability, which makes it important in the early diagnosis of ambiguous or clinically equivocal cases when initial radiographic findings are inconclusive. Computed tomography displays bony detail in stress fractures, as well as in arthritides and tarsal coalition. Bone scanning and ultrasonography also are useful tools for diagnosing specific conditions that produce chronic foot pain.

Imaging of the acetabulum in the era of multidetector computed tomography.

Acetabular fractures are often complex injuries and the result of high-energy trauma with associated injuries. Understanding and classification of these rare injuries using radiography can be difficult and are much facilitated by the addition of computed tomography (CT). The purpose of this paper is to briefly review some of the underlying physical principles and technical factors for multidetector CT (MDCT) and to describe its use and imaging findings in the evaluation of acetabular fractures. Using MDCT with two-dimensional multiplanar reformatted (MPR) images and three-dimensional volume rendered images, the supplemental oblique radiographic Judet views can be omitted. MDCT is now an indispensable tool in preoperative imaging of acetabular fractures and also in postoperative imaging in complicated cases. Not only is MDCT excellent for a general overview but also for detailed imaging of fracture extent, joint congruency, step-offs or gaps in the joint surface, and entrapped osteochondral fragments.

Sleeve fracture at the superior pole of the patella.

We present a sleeve fracture at the superior pole of the patella in a 12-year-old boy. Sleeve fractures at the inferior pole of the patella have been well described in the orthopedic and radiologic literature. However, a similar injury at the superior pole of the patella is relatively rare. We hope that awareness of this unusual injury and its imaging findings will allow timely diagnosis and intervention.

Imaging of cervical spine injuries of childhood.

Cervical spine injuries of children, though rare, have a high morbidity and mortality. The pediatric cervical spine is anatomically and biomechanically different from that of adults. Hence, the type, level and outcome of cervical spine injuries in children are different from those seen in adults. Normal developmental variants seen in children can make evaluation of the pediatric cervical spine challenging. This article reviews the epidemiology of pediatric cervical spine trauma, normal variants seen in children and specific injuries that are more common in the pediatric population. We also propose an evidence-based imaging protocol to avoid unnecessary imaging studies and minimize radiation exposure in children.