Search

Bone stress injuries (BSIs) are a frequent finding in athletes, particularly of the foot and ankle. A BSI is caused by recurring microtrauma to the cortical or trabecular bone exceeding the repair capacity of normal bone. The most frequent fractures at the ankle are low risk, characterized by a low risk for nonunion. These include the posteromedial tibia, the calcaneus, and the metatarsal diaphysis. High-risk stress fractures have a higher risk for nonunion and need more aggressive treatment. Examples are the medial malleolus, navicular bone, and the base of the second and fifth metatarsal bone. Imaging features depend on the primary involvement of cortical versus trabecular bone. Conventional radiographs may remain normal up to 2 to 3 weeks. For cortical bone, early signs of BSIs are a periosteal reaction or the "gray cortex sign," followed by cortical thickening and fracture line depiction. In trabecular bone, a sclerotic dense line may be seen. Magnetic resonance imaging enables early detection of BSIs and can differentiate between a stress reaction and a fracture. We review typical anamnestic/clinical findings, epidemiology and risk factors, imaging characteristics, and findings at typical locations of BSIs at the foot and ankle that may help guide treatment strategy and patient recovery. [ABSTRACT FROM AUTHOR]

Purpose To evaluate magnetic resonance (MR) perfusion and diffusion imaging characteristics in patients with transient bone marrow edema (TBME), avascular necrosis (AVN), or subchondral insufficiency fractures (SIF) of the proximal femur. Materials and methods 29 patients with painful hip and bone marrow edema pattern of the proximal femur on non-contrast MR imaging were examined using diffusion-weighted and dynamic gadolinium-enhanced sequences. Apparent diffusion coefficients (ADCs) and perfusion parameters were calculated for different regions of the proximal femur. Regional distribution and differences in ADC values and perfusion parameters were evaluated. Results Seven patients presented with TBME, 15 with AVN and seven with SIF of the proximal femur. Perfusion imaging showed significant differences for maximum enhancement values ( E max ), slope ( E slope ) and time to peak (TTP) between the three patient groups ( p < 0.05). In contrast, no significant differences for ADC values were calculated when comparing TBME, AVN, and SIF patients. Conclusion Diffusion weighted imaging of bone marrow of the proximal femur did not show significant differences between patients with TBME, AVN or SIF. In contrast, MR perfusion imaging demonstrated significant differences for the different patient groups and may as a complementary imaging technique add information to the understanding of the pathophysiology of diseases associated with bone marrow edema. [ABSTRACT FROM AUTHOR]

Objective: To evaluate diagnostic signs and measurements in the assessment of capsular redundancy in atraumatic multidirectional instability (MDI) of the shoulder on MR arthrography (MR-A) including abduction/external rotation (ABER) images. Methods: Twenty-one MR-A including ABER position of 20 patients with clinically diagnosed MDI and 17 patients without instability were assessed by three radiologists. On ABER images, presence of a layer of contrast between the humeral head (HH) and the anteroinferior glenohumeral ligament (AIGHL) (crescent sign) and a triangular-shaped space between the HH, AIGHL and glenoid (triangle sign) were evaluated; centring of the HH was measured. Anterosuperior herniation of the rotator interval (RI) capsule and glenoid version were determined on standard imaging planes. Results: The crescent sign had a sensitivity of 57 %/62 %/48 % (observers 1/2/3) and specificity of 100 %/100 %/94 % in the diagnosis of MDI. The triangle sign had a sensitivity of 48 %/57 %/48 % and specificity of 94 %/94 %/100 %. The combination of both signs had a sensitivity of 86 %/90 %/81 % and specificity of 94 %/94 %/94 %. A positive triangle sign was significantly associated with decentring of the HH. Measurements of RI herniation, RI width and glenoid were not significantly different between both groups. Conclusions: Combined assessment of redundancy signs on ABER position MR-A allows for accurate differentiation between patients with atraumatic MDI and patients with clinically stable shoulders; measurements on standard imaging planes appear inappropriate. Key Points: • MR arthrography has the possibility to accurately identify patients with atraumatic MDI. • Imaging of the shoulder in abduction and external rotation provides additive information. • Capsular enlargement of the shoulder can be diagnosed on MR arthrography. [ABSTRACT FROM AUTHOR]

Traumatic instability of the elbow is a common problem among patients presenting to emergency departments. As recurrent instability is more common than previously thought and the knowledge of the most frequent underlying causes increases, treatment of elbow instability is becoming increasingly sophisticated. Therefore, it is mandatory for the radiologist to be familiar with the important osseous and soft-tissue stabilisers of the elbow joint and to know the pathomechanisms that lead to a spectrum of joint instability. This article discusses the relevant anatomy in elbow stability with respect to imaging and function, states the mechanisms leading to elbow dislocation and displays the types of traumatic instability of the elbow on radiography, computed tomography, and magnetic resonance imaging. Key Points • Expert imaging helps the management of traumatic instability of the elbow • The lateral ulnar collateral ligament is the cornerstone for elbow stability • Soft-tissue disruption is important in posterolateral rotatory instability • Identification of small coronoid process fragments is essential for optimal surgical therapy [ABSTRACT FROM AUTHOR]

Septic arthritis of the pubic symphysis is a potentially severe disease. Athletes are at risk of this form of spontaneous arthritis, as inflammation of the pubic bone due to muscular stress is relatively common. Oedema due to inflammation might predispose to infection through bacteraemia or local bacterial translocation. Suspicion should be raised when an athlete complains of groin pain and has signs of infection (i.e., fever, elevated white blood cell count, and elevated C-reactive protein). Diagnosis is made by imaging showing signs of inflammation combined with positive (blood) cultures. Broad spectrum antibiotics should be started upon suspicion and adjusted according to cultures. An abscess causing clinical deterioration under antibiotic treatment is an indication for invasive intervention (i.e., surgical or image-guided drainage). This is the first case of spontaneous septic arthritis of the pubic symphysis in an athlete requiring surgical and additional image-guided drainage. [ABSTRACT FROM AUTHOR]

Purpose: To determine the impact of axial traction during high resolution 3.0T MR imaging of the ankle on morphological assessment of articular cartilage and quantitative cartilage imaging parameters.Materials and Methods: MR images of n=25 asymptomatic ankles were acquired with and without axial traction (6kg). Coronal and sagittal T1-weighted (w) turbo spin echo (TSE) sequences with a driven equilibrium pulse and sagittal fat-saturated intermediate-w (IMfs) TSE sequences were acquired for morphological evaluation on a four-point scale (1=best, 4=worst). For quantitative assessment of cartilage degradation segmentation was performed on 2D multislice-multiecho (MSME) SE T2, steady-state free-precession (SSFP; n=8) T2 and SSFP diffusion-weighted imaging (DWI; n=8) images. Wilcoxon-tests and paired t-tests were used for statistical analysis.Results: With axial traction, joint space width increased significantly and delineation of cartilage surfaces was rated superior (P<0.05). Cartilage surfaces were best visualized on coronal T1-w images (P<0.05). Differences for cartilage matrix evaluation were smaller. Subchondral bone evaluation, motion artifacts and image quality were not significantly different between the acquisition methods (P>0.05). T2 values were lower at the tibia than at the talus (P<0.001). Reproducibility was better for images with axial traction.Conclusion: Axial traction increased the joint space width, allowed for better visualization of cartilage surfaces and improved compartment discrimination and reproducibility of quantitative cartilage parameters. [ABSTRACT FROM AUTHOR]

Purpose To determine the impact of axial traction during high resolution 3.0 T MR imaging of the ankle on morphological assessment of articular cartilage and quantitative cartilage imaging parameters. Materials and Methods MR images of n = 25 asymptomatic ankles were acquired with and without axial traction (6 kg). Coronal and sagittal T1-weighted (w) turbo spin echo (TSE) sequences with a driven equilibrium pulse and sagittal fat-saturated intermediate-w (IMfs) TSE sequences were acquired for morphological evaluation on a four-point scale (1 = best, 4 = worst). For quantitative assessment of cartilage degradation segmentation was performed on 2D multislice-multiecho (MSME) SE T2, steady-state free-precession (SSFP; n = 8) T2 and SSFP diffusion-weighted imaging (DWI; n = 8) images. Wilcoxon-tests and paired t -tests were used for statistical analysis. Results With axial traction, joint space width increased significantly and delineation of cartilage surfaces was rated superior ( P < 0.05). Cartilage surfaces were best visualized on coronal T1-w images ( P < 0.05). Differences for cartilage matrix evaluation were smaller. Subchondral bone evaluation, motion artifacts and image quality were not significantly different between the acquisition methods ( P > 0.05). T2 values were lower at the tibia than at the talus ( P < 0.001). Reproducibility was better for images with axial traction. Conclusion Axial traction increased the joint space width, allowed for better visualization of cartilage surfaces and improved compartment discrimination and reproducibility of quantitative cartilage parameters. [ABSTRACT FROM AUTHOR]

Background: MRI plays a major role in follow-up of patients with malignant bone tumors. However, after limb salvage surgery, orthopaedic tumor endoprostheses might cause significant metal-induced susceptibility artifacts. Purposes: To evaluate the benefit of view-angle tilting (VAT) and slice-encoding metal artifact correction (SEMAC) for MRI of large-sized orthopaedic tumor endoprostheses in an experimental model and to demonstrate clinical benefits for assessment of periprosthetic soft tissue abnormalities. Methods: In an experimental setting, tumor endoprostheses (n=4) were scanned at 1.5T with three versions of optimized high-bandwidth turbo-spin-echo pulse sequences: (i) standard, (ii) VAT and (iii) combined VAT and SEMAC (VAT&SEMAC). Pulse sequences included coronal short-tau-inversion-recovery (STIR), coronal T1-weighted (w), transverse T1-w and T2-w TSE sequences. For clinical evaluation, VAT&SEMAC was compared to conventional metal artifact-reducing MR sequences (conventional MR) in n=25 patients with metal implants and clinical suspicion of tumor recurrence or infection. Diameters of artifacts were measured quantitatively. Qualitative parameters were assessed on a five-point scale (1=best, 5=worst): “image distortion”, “artificial signal changes at the edges” and “diagnostic confidence”. Imaging findings were correlated with pathology. T-tests and Wilcoxon-signed rank tests were used for statistical analyses. Results: The true size of the prostheses was overestimated on MRI (P<0.05). A significant reduction of artifacts was achieved by VAT (P<0.001) and VAT&SEMAC (P=0.003) compared to the standard group. Quantitative scores improved in the VAT and VAT&SEMAC group (P<0.05). On clinical MR images, artifact diameters were significantly reduced in the VAT&SEMAC-group as compared with the conventional-group (P<0.001). Distortion and artificial signal changes were reduced and diagnostic confidence improved (P<0.05). In two cases, tumor-recurrence, in ten cases infection and in thirteen cases other pathologies were diagnosed. Conclusions: Significant reduction of metallic artifacts was achieved by VAT and SEMAC. Clinical results suggest, that these new techniques will be beneficial for detecting periprosthetic pathologies during postoperative follow-up. [ABSTRACT FROM AUTHOR]

Objectives: To test the hypothesis that bone marrow oedema (BME) observed on MRI in patients with avascular necrosis (AVN) of the femoral head represents an indicator of subchondral fracture. Methods: Thirty-seven symptomatic hips of 27 consecutive patients (53 % women, mean age 49.2) with AVN of the femoral head and associated BME on magnetic resonance (MR) imaging were included. MR findings were correlated with computed tomography (CT) of the hip and confirmed by histopathological examination of the resected femoral head. Imaging studies were analysed by two radiologists with use of the ARCO classification. Results: On MR imaging a fracture line could be identified in 19/37 (51 %) cases, which were classified as ARCO stage 3 ( n = 15) and stage 4 ( n = 4). The remaining 18/37 (49 %) cases were classified as ARCO stage 2. However, in all 37/37 (100 %) cases a subchondral fracture was identified on CT, indicating ARCO stage 3/4 disease. The extent of subchondral fractures and the femoral head collapse was graded higher on CT as compared to MRI ( P < 0.05). Histopathological analysis confirmed bone necrosis and subchondral fractures. Conclusions: In patients with AVN, BME of the femoral head represents a secondary sign of subchondral fracture and thus indicates ARCO stage 3 disease. Key Points: • BME on MRI in AVN of femoral head indicates a subchondral fracture. • BME in AVN of the femoral head represents ARCO stage 3/4 disease. • CT identifies subchondral fractures and femoral head collapse better than MR imaging. • This knowledge helps to avoid understaging and to trigger adequate treatment. [ABSTRACT FROM AUTHOR]

Purpose: Traumatic shoulder dislocation may be complicated by concomitant bony injury of the glenoid rim or the humeral head. In Hill-Sachs lesions, reconstruction techniques vary widely and range from open reduction to tendon transposition or humeral head derotation. These operations are extensive and have questionable outcomes. With the expertise from vertebral compression fracture reduction by kyphoplasty, we examined in a cadaver feasibility study whether reduction of the Hill-Sachs lesion via hydraulic lift might be an anatomical and minimally invasive treatment option. We postulated that the use a of a balloon- assisted kyphoplasty reduction could achieve almost anatomical correction of the defect. Methods: We created Hill-Sachs lesions in six humeral specimens and performed a computed tomography (CT) scan before and after reduction with the kyphoplasty system. The entry point at the greater tuberosity and balloon positioning was visualised by fluoroscopy. The size of the Hill-Sachs lesion before and after reduction was measured using CT scans in the axial orientation. Results: Using the balloon kyphoplasty system, we achieved a statistically significant reduction (80 % ) of the Hill-Sachs lesion. Conclusion: In a preliminary cadaver study we show that using a balloon kyphoplasty system might be an alternative treatment option for Hill-Sachs lesions, with reduced collateral damage that can occur with other minimally invasive techniques. Future work is needed to evaluate the technique under arthroscopic conditions. [ABSTRACT FROM AUTHOR]

A response by Gunther H. Sandmann to a letter to the editor about their study on the use of balloon osteoplasty as a new treatment option for Hill-Sachs lesions in a cadaver model in a 2012 issue is presented.

Background. To retrospectively determine the diagnostic value of computed tomography arthrography (CTA) of the ankle in the evaluation of (osteo)chondral lesions in comparison to conventional magnetic resonance imaging (MRI) and intraoperative findings. Methods. A total of N=79 patients had CTAs and MRI of the ankle; in 17/79 cases surgical reports with statements on cartilage integrity were available. Cartilage lesions and bony defects at talus and tibia were scored according to defect depth and size by two radiologists. Statistical analysis included sensitivity analyses and Cohen’s kappa calculations. Results. On CTA, 41/79 and 31/79 patients had full thickness cartilage defects at the talus and at the tibia, respectively. MRI was able to detect 54% of these defects. For the detection of full thickness cartilage lesions, interobserver agreement was substantial (0.72 ± 0.05) for CTA and moderate (0.55 ± 0.07) for MRI. In surgical reports, 88–92% and 46–62% of full thickness defects detected by CTA and MRI were described. CTA findings changed the further clinical management in 15.4% of cases. Conclusions. As compared to conventional MRI, CTA improves detection and visualization of cartilage defects at the ankle and is a relevant tool for treatment decisions in unclear cases. [ABSTRACT FROM AUTHOR]

Purpose: Traumatic shoulder dislocation may be complicated by concomitant bony injury of the glenoid rim or the humeral head. In Hill-Sachs lesions, reconstruction techniques vary widely and range from open reduction to tendon transposition or humeral head derotation. These operations are extensive and have questionable outcomes. With the expertise from vertebral compression fracture reduction by kyphoplasty, we examined in a cadaver feasibility study whether reduction of the Hill-Sachs lesion via hydraulic lift might be an anatomical and minimally invasive treatment option. We postulated that the use a of a balloon- assisted kyphoplasty reduction could achieve almost anatomical correction of the defect.Methods: We created Hill-Sachs lesions in six humeral specimens and performed a computed tomography (CT) scan before and after reduction with the kyphoplasty system. The entry point at the greater tuberosity and balloon positioning was visualised by fluoroscopy. The size of the Hill-Sachs lesion before and after reduction was measured using CT scans in the axial orientation.Results: Using the balloon kyphoplasty system, we achieved a statistically significant reduction (80 % ) of the Hill-Sachs lesion.Conclusion: In a preliminary cadaver study we show that using a balloon kyphoplasty system might be an alternative treatment option for Hill-Sachs lesions, with reduced collateral damage that can occur with other minimally invasive techniques. Future work is needed to evaluate the technique under arthroscopic conditions. [ABSTRACT FROM AUTHOR]

Objective To prospectively compare an indocyanine green (ICG)-enhanced optical imaging system with contrast-enhanced magnetic resonance imaging (MRI) for the detection of synovitis in the hands of patients with rheumatologic disorders. Methods Forty-five patients (30 women [67%], mean ± SD age 52.6 ± 13.4 years) in whom there was a clinical suspicion of an inflammatory arthropathy were examined with a commercially available device for ICG-enhanced optical imaging as well as by contrast-enhanced 3T MRI as the standard of reference. Three independent readers graded the degree of synovitis in the carpal, metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints of both hands (1,350 joints), using a 4-point ordinate scale (0 = no synovitis, 1 = mild, 2 = moderate, 3 = severe). Statistical analyses were performed using a logistic generalized estimating equation approach. Agreement of optical imaging ratings made by the different readers was estimated with a weighted kappa coefficient. Results When MRI was used as the standard of reference, optical imaging showed a sensitivity of 39.6% (95% confidence interval [95% CI] 31.1-48.7%), a specificity of 85.2% (95% CI 79.5-89.5%), and accuracy of 67.0% (95% CI 61.4-72.1%) for the detection of synovitis in patients with arthritis. Diagnostic accuracy was especially limited in the setting of mild synovitis, while it was substantially better in patients with severely inflamed joints. Moderate interreader and intrareader agreement was observed. Conclusion The evaluated ICG-enhanced optical imaging system showed limitations for the detection of inflamed joints of the hand in comparison with MRI. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the prevalence, imaging characteristics and anatomical distribution of tears at the rotator cuff (RC) footprint with MR arthrography (MR-A) of the shoulder.Methods: MR arthrograms obtained in 305 patients were retrospectively reviewed. Partial articular-sided supraspinatus tendon avulsions (PASTA), concealed interstitial delaminations (CID), reverse PASTA lesions and full-thickness tears (FT) at the humeral tendon insertion were depicted. Anatomical locations were determined and depths of tears were classified.Results: 112/305 patients showed RC tears, including 63 patients with 68 footprint tears. 34 PASTA lesions were detected with 20/34 involving the anterior supraspinatus (SSP) tendon and 17/34 PASTA lesions were grade I lesions. Most CID lesions (14/23) occurred at the posterior SSP and 20/23 were classified as grade I or II. 9 FT and 2 reverse PASTA lesions were found. Statistical analysis revealed no difference in anatomical location (p = 0.903) and no correlation with overhead sports activity (p = 0.300) or history of trauma (p = 0.928). There were significantly more PASTA lesions in patients < 40 years of age (p = 0.029).Conclusions: Most RC tears detected with MR-A involve the SSP footprint and are articular-sided with predominance in younger patients, but concealed lesions are not as uncommon as previously thought. [ABSTRACT FROM AUTHOR]