Scapholunate advanced collapse and scaphoid nonunion advanced collapse: MDCT arthrography features.

OBJECTIVE: The aim of this article is to present the imaging features of scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) on MDCT arthrography. CONCLUSION: MDCT arthrography is an excellent tool for patients with clinically suspected SLAC or SNAC wrist because it allows identification of the spectrum of findings for diagnosis and proper classification, which directly impact management.

Bony sequestrum: a radiologic review.

According to a pathological definition, a bony sequestrum is defined as a piece of devitalized bone that has been separated from the surrounding bone during the process of necrosis. However, the radiological definition of a sequestrum is different and refers to an image of calcification visible within a lucent lesion, completely separated from the surrounding bone, without referring to the vascular status and histological nature of the calcified tissue. The term "button sequestrum" has been used in calvarial lesions. The prototype conditions that may present with a bony sequestrum are osteomyelitis and skeletal tuberculosis. Other conditions such as radiation necrosis, eosinophilic granuloma, metastatic carcinoma, primary lymphoma of bone, aggressive fibrous tumors may also manifest as osteolytic lesions containing a sequestrum. In addition, some primary bone tumors produce a matrix that may mineralize and sometimes simulate a bone sequestrum. These include osteoid tumors (osteoid osteoma, osteoblastoma), cartilaginous tumors (chondroma and chondroblastoma), lipomatous tumors (lipoma), and benign fibrous tumors (fibromyxoma, myxoma, and desmoplastic fibroma). Therefore, various conditions may present at imaging as a small area of osteolysis containing central calcifications. However, a careful analysis of the sequestrum as well as the associated clinical and radiological findings often enables to point toward a limited number of conditions.

MDCT arthrography features of ulnocarpal impaction syndrome.

OBJECTIVE: The aim of this article is to present the imaging patterns of ulnocarpal impaction syndrome (Palmer class II lesions) on MDCT arthrography. CONCLUSION: MDCT arthrography is an excellent tool for imaging patients with clinically suspected ulnocarpal impaction syndrome, allowing identification of the spectrum of findings and proper classification according to Palmer class II (degenerative) lesions, which directly affects management.

Penetrating volar injuries of the hand: diagnostic accuracy of US in depicting soft-tissue lesions.

PURPOSE: To evaluate the effectiveness of ultrasonography (US) in depicting lesions of the tendons, arteries, and nerves caused by penetrating wounds of the volar aspect of the hand, with surgical exploration as the reference standard. MATERIALS AND METHODS: Consecutive patients seen at one center over a 2-month period in 2006 were prospectively included. The institutional review board approved the study, and each patient gave written informed consent. There were 30 injuries in 26 patients (19 men and seven women; median age, 34 years). US examination was performed before surgery. Surgeons were not informed of the US findings. For tendons, arteries, and nerves, the sensitivity, specificity, positive predictive value, and negative predictive value of US were computed. RESULTS: US depicted all tendon lesions, with no false-positive findings; two arterial lesions were missed, with no false-positive findings, and four nerve lesions were missed, with six false-positive findings. The negative predictive value was 100% (95% confidence interval: 95.5%, 100%) for tendons, 96.7% (95% confidence interval: 88.7%, 99.6%) for arteries, and 93.7% (95% confidence interval: 84.5%, 98.2%) for nerves. In three cases, US depicted foreign bodies missed at surgery. CONCLUSION: US was highly effective in identifying patients with no tendon or arterial lesions. Performance was poorer for diagnosing nerve lesions. US followed by a repeat physical examination after 72 hours to look for missed nerve damage may deserve evaluation as an alternative to routine surgical exploration when US findings are normal.

Ethnic Differences in Bony Hip Morphology in a Cohort of 445 Professional Male Soccer Players.

BACKGROUND: Participation in high-impact athletic activities has recently been associated with a higher prevalence of cam deformity. Bony hip morphology has also emerged as an important factor in the development of hip osteoarthritis. However, it is unknown whether bony morphology differs between ethnicities in athletes participating in high-impact sports. PURPOSE: To investigate whether the prevalence of specific bony hip morphological abnormalities differed between professional male soccer players of diverse ethnic backgrounds. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Professional male soccer players from an entire league attending preparticipation screening were invited to participate in this study. Ethnicity was registered, and standardized radiographs of anteroposterior pelvic and Dunn views were obtained. Cam and pincer deformity, and acetabular dysplasia were quantified using the alpha angle, triangular index, and lateral center-edge angle (LCEA). Regression analyses with generalized estimating equations were used to determine prevalence differences in bony hip morphology. RESULTS: A total of 445 male soccer players (890 hips; mean age ± SD, 25 ± 4.9 years) participated in the study, representing the following ethnic groups: Arabic (59%), black (24%), Persian (7%), white (6%), East Asian (2%), and other (2%). The prevalence of cam deformity (alpha angle >60°) ranged from 57.5% to 71.7% across 4 of the groups, but East Asians had a significantly lower prevalence (18.8%; P ≤ .032). A large cam deformity (alpha angle >78°) was more prevalent in white (33.3%) compared with black soccer players (17.8%; P = .041) and was absent in East Asian players. Pincer deformity (LCEA >40°) was uncommon (3%) in all ethnicities. The prevalence of acetabular dysplasia (LCEA <20°) ranged from 8.0% to 16.7%, apart from the white group, in which prevalence was only 1.9% (P = .03). CONCLUSION: The prevalence of a cam deformity and acetabular dysplasia differed between ethnicities in this cohort of professional male soccer players. These findings suggest that there may be ethnic differences in both acetabular morphology and femoral bony response to athletic load.

Constrained Statistical Modelling of Knee Flexion From Multi-Pose Magnetic Resonance Imaging.

Reconstruction of the anterior cruciate ligament (ACL) through arthroscopy is one of the most common procedures in orthopaedics. It requires accurate alignment and drilling of the tibial and femoral tunnels through which the ligament graft is attached. Although commercial computer-assisted navigation systems exist to guide the placement of these tunnels, most of them are limited to a fixed pose without due consideration of dynamic factors involved in different knee flexion angles. This paper presents a new model for intraoperative guidance of arthroscopic ACL reconstruction with reduced error particularly in the ligament attachment area. The method uses 3D preoperative data at different flexion angles to build a subject-specific statistical model of knee pose. To circumvent the problem of limited training samples and ensure physically meaningful pose instantiation, homogeneous transformations between different poses and local-deformation finite element modelling are used to enlarge the training set. Subsequently, an anatomical geodesic flexion analysis is performed to extract the subject-specific flexion characteristics. The advantages of the method were also tested by detailed comparison to standard Principal Component Analysis (PCA), nonlinear PCA without training set enlargement, and other state-of-the-art articulated joint modelling methods. The method yielded sub-millimetre accuracy, demonstrating its potential clinical value.

Diagnosis of Acute Groin Injuries: A Prospective Study of 110 Athletes.

BACKGROUND: Acute groin injuries are common in high-intensity sports, but there are insufficient data on injury characteristics such as injury mechanisms and clinical and radiological findings. PURPOSE: To describe these characteristics in a cohort of athletes. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 110 male athletes (mean age, 25.6 ± 4.7 years) with sports-related acute groin pain were prospectively included within 7 days of injury from August 2012 to April 2014. Standardized history taking, a clinical examination, magnetic resonance imaging (MRI), and/or ultrasound (US) were performed. RESULTS: The most frequent injury mechanism in soccer was kicking (40%), and change of direction was most frequent in other sports (31%). Clinically, adductor injuries accounted for 66% of all injuries and primarily involved the adductor longus on imaging (91% US, 93% MRI). The iliopsoas and proximal rectus femoris were also frequently injured according to all examination modalities (15%-25%). Acute injury findings were negative in 22% of the MRI and 25% of the US examinations. Of the clinically diagnosed adductor injuries, 3% (US) and 6% (MRI) showed a radiological injury in a different location compared with 35% to 46% for clinically diagnosed iliopsoas and proximal rectus femoris injuries. CONCLUSION: Adductor injuries account for the majority of acute groin injuries. Iliopsoas and proximal rectus femoris injuries are also common. More than 1 in 5 injuries showed no imaging signs of an acute injury. Clinically diagnosed adductor injuries were often confirmed on imaging, whereas iliopsoas and rectus femoris injuries showed a different radiological injury location in more than one-third of the cases. The discrepancy between clinical and radiological findings should be considered when diagnosing acute groin injuries.

[Hip anatomy and imagery]. / Anatomie et imagerie de la hanche.

Since the advent of new imaging methods (CT, MRI), plain radiographs still play a central role in the evaluation of the non-traumatic painful hip. In rheumatologic practice, standing antero-posterior views of the pelvis, bilateral antero-posterior views of the hips and bilateral lateral view of Lequesne should be performed. This first radiographic evaluation can be completed by a CT arthrogram in the first stage of osteoarthritis or by MRI in synovitis and epiphyseal disorders involving the femoral head (osteonecrosis, transient osteoporosis, subchondral fracture). The physician must be aware of the performance of each imaging in order to use the appropriate radiological exam in each situation.

Ligamentous Injuries and the Risk of Associated Tissue Damage in Acute Ankle Sprains in Athletes: A Cross-sectional MRI Study.

BACKGROUND: Ankle joint injuries are extremely common sports injuries, with the anterior talofibular ligament involved in the majority of ankle sprains. There have been only a few large magnetic resonance imaging (MRI) studies on associated structural injuries after ankle sprains. PURPOSE: To describe the injury pattern in athletes who were referred to MRI for the assessment of an acute ankle sprain and to assess the risk of associated traumatic tissue damage including lateral and syndesmotic ligament involvement. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 261 ankle MRI scans of athletes with acute ankle sprains were evaluated for: lateral and syndesmotic ligament injury; concomitant injuries to the deltoid and spring ligaments and sinus tarsi; peroneal, flexor, and extensor retinacula and tendons; traumatic and nontraumatic osteochondral and osseous changes; and joint effusion. Patients were on average 22.5 years old, and the average time from injury to MRI was 5.7 days. Six exclusive injury patterns were defined based on lateral and syndesmotic ligament involvement. The risk for associated injuries was assessed by logistic regression using ankles with no or only low-grade lateral ligament injuries and no syndesmotic ligament damage as the reference. RESULTS: With regard to the injury pattern, there were 103 ankles (39.5%) with complete anterior talofibular ligament disruption and no syndesmotic injury, and 53 ankles (20.3%) had a syndesmotic injury with or without lateral ligament damage. Acute osteochondral lesions of the lateral talar dome were seen in 20 ankles (7.7%). The percentage of chronic lateral osteochondral lesions was 1.1%. The risk for talar bone contusions increased more than 3-fold for ankles with complete lateral ligament ruptures (adjusted odds ratio [aOR], 3.43; 95% CI, 1.72-6.85) but not for ankles with syndesmotic involvement. The risk for associated deltoid ligament injuries increased for ankles with complete lateral ligament injuries (aOR, 4.04; 95% CI, 1.99-8.22) compared with patients with no or only low-grade lateral ligament injuries. CONCLUSION: About 20% of athletes referred for MRI after suffering an acute ankle sprain had evidence of a syndesmotic injury regardless of lateral ligament involvement, while more than half had evidence of any lateral ligament injury without syndesmotic involvement. Concomitant talar osseous and deltoid ligament injuries are common.

MR arthrography of the shoulder: optimizing pulse sequence protocols for the evaluation of cartilage and labrum.

OBJECTIVES: To compare axial T1weighted fat-saturated (T1w fs) and T1w non-fs sequences, and coronal T1w-fs and T2w-fs sequences, for evaluation of cartilage and labrum using CT arthrography (CTA) as the reference. METHODS: Patients had MR arthrography (MRA) and CTA of the shoulder on the same day. Cartilage was assessed for superficial and full thickness focal and diffuse damage. Labral lesions were graded for Bankart variants and SLAP lesions. CTA images were read for the same features. The diagnostic performance of MRA including area under the curve (AUC) was evaluated against CTA. RESULTS: When comparing axial sequences, the diagnostic performance for cartilage lesion detection on T1w non-fs was 61.9% (sensitivity) 93.6% (specificity) and 89.5% (accuracy) with AUC 0.782, while that for T1w fs was 61.9%, 94.0%, 89.8% and 0.783. For labral assessment, it was 89.1%, 93.0%, 91.4% and 0.919 for T1w non-fs, and 89.9%, 94.0%, 92.6% and 0.922 for T1w fs. Comparing coronal sequences, diagnostic performance for cartilage was 42.5%, 97.5%, 89.8% and 0.702 for T1w fs, and 38.4%, 98.7%, 90.2%, and 0.686 for T2w fs. For the labrum it was 85.1%, 87.5%, 86.2%, and 0.868 for T1w fs, and 75.7%, 97.5%, 80.8% and 0.816 for T2w fs. CONCLUSIONS: Axial T1w fs and T1w non-fs sequences are comparable in their ability to diagnose cartilage and labral lesions. Coronal T1w fs sequence offers slightly higher sensitivity but slightly lower specificity than T2w fs sequence for diagnosis of cartilage and labral lesions.

Radiographically occult and subtle fractures: a pictorial review.

Radiographically occult and subtle fractures are a diagnostic challenge. They may be divided into (1) "high energy trauma fracture," (2) "fatigue fracture" from cyclical and sustained mechanical stress, and (3) "insufficiency fracture" occurring in weakened bone (e.g., in osteoporosis and postradiotherapy). Independently of the cause, the initial radiographic examination can be negative either because the findings seem normal or are too subtle. Early detection of these fractures is crucial to explain the patient's symptoms and prevent further complications. Advanced imaging tools such as computed tomography, magnetic resonance imaging, and scintigraphy are highly valuable in this context. Our aim is to raise the awareness of radiologists and clinicians in these cases by presenting illustrative cases and a discussion of the relevant literature.