Clinical consequences of posttraumatic bone bruise in the knee

BACKGROUND: Bone bruise is often seen in posttraumatic knees, but the clinical relevance is unclear. HYPOTHESIS: The presence of bone bruise is associated with increased pain severity in patients with sustained knee trauma. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: We collected prospective data of 132 patients visiting their general practitioner after sustained knee trauma. Patients with bone bruise underwent a magnetic resonance imaging follow-up study that was discontinued when the bone bruise could no longer be discerned or after 1 year of follow-up. Bone bruise was assessed on magnetic resonance imaging, and pain severity was scored on a numeric rating scale (0-10) at baseline, and at 3, 6, and 12 months after trauma. The presence of bone bruise and pain severity (over time) were compared using linear regression analyses for repeated measurements. Adjustment was made for possible confounders: presence of meniscal tears, cruciate or collateral ligament ruptures, severe effusion, osteoarthritis, obesity, age, gender, work load, and sports load. RESULTS: At baseline as well as during follow-up, bone bruise was associated with a slightly higher pain score. The differences, however, were very small (adjusted difference in pain severity 0.34 or less) and not statistically significant nor clinically relevant. CONCLUSION: There is no statistically significant relationship, nor a clinically relevant relationship, between the presence of bone bruise and pain severity in patients with sustained knee injury in general practice.     

Effect of joint position and ligament tension on the MR signal intensity of the cruciate ligaments of the knee

Six cadaveric lower extremities were imaged with T1-weighted spin-echo pulse sequences with the knees extended and flexed to 90°. Magnetic resonance signal intensities of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were compared. Changing from extension to flexion resulted in decreased signal intensity in six of six ACLs and five of six PCLs. Two of the knees were then imaged with and without tension applied to the ACL. Both specimens showed a decrease in signal intensity with tension, followed by an increase in signal intensity with release of the tension. Finally, in three of the limbs the ACL was surgically reconstructed and then imaged with and without tension applied to the tension graft. Signal intensity decreased with tension and increased with release of the tension in all three specimens. Thus, joint position and changes in ligament tension affect the signal intensity of the ACL and PCL, generally resulting in a signal intensity decrease with tension.     

Magnetic resonance evaluation of anterior cruciate ligament repair using the patellar tendon double bone block technique

The magnetic resonance (MR) appearance of the anterior cruciate ligament reconstruction was determined in 20 clinically stable and 2 clinically unstable knees for a total of 22 examinations. All patients studied had undergone knee reconstruction using the patellar tendon as graft material. The reconstructed anterior cruciate ligament varies in appearance. It appeared as a thick, well-defined, low signal band on T1- and T2- weighted sagittal and coronal images in 14 of 22 examinations. The remaining 8 knees showed a graft having one or more thin and attenuated, low signal intensity bands in the sagittal and/or coronal plane. In 3 of these cases, the grafts appeared thicker in the coronal plane. All cases, including the two clinically unstable knees, showed no break in graft continuity. Arthroscopy confirmed an intact but lax graft in the clinically unstable knees.     

Health technology assessment of magnetic resonance imaging of the knee

A search of the available literature was performed and the role of MR imaging of the knee is discussed. Based on this search the authors concluded that MR has a high sensitivity in detecting any abnormalities in the knee but it does not have the same diagnostic accuracy as a clinical investigation performed by a trained knee specialist when all knee injuries are taken together. It does lead to a decrease in the number of surgical interventions due to its high negative predictive value. For the detection of meniscal injury, MR has the same accuracy as arthroscopy and should be performed in order to avoid unnecessary surgical interventions. A negative MR also obviates further investigation in suspected cartilage damage. This is not true for anterior and posterior cruciate ligament problems where MRI is less accurate than clinical investigation.     

Three-tesla imaging of the knee: initial experience

Purpose To assess 3-T imaging of the knee.Materials and methods We reviewed 357 3-T magnetic resonance images of the knee obtained using a dedicated knee coil. From 58 patients who had arthroscopy we determined the sensitivity and specificity for anterior cruciate ligament (ACL) tear and medial and lateral meniscal tear.Results A chemical shift artifact showed prominently at 3 T even after improvements had been made by increasing the bandwidth. For complete ACL tear the sensitivity was 100% (95% confidence interval, CI, 75.30–100.00), and the specificity was 97.9% (95% CI 87.7–99.9). For the medial meniscus the sensitivity was 100.00% (95% CI 90.0–100.00), and the specificity was 83.3%(95% CI 66.6–95.3). For the lateral meniscus the sensitivity was 66.7% (95% CI 38.4–88.2), and the specificity was 97.6% (95% CI 87.1–99.9).Conclusions In general 3-T imaging allows a favorable display of anatomy and pathology. The lateral meniscus was assessed to be weaker than the other anatomic structures. Three-tesla imaging allows increased signal-to-noise ratio, increased resolution, and faster scanning times.     

Ultrasound of the knee

Ultrasound is emerging as a viable imaging modality in the diagnosis and assessment of the musculoskeletal system. Advantages of ultrasound include its easy availability and multiplanar capability, as well as economic advantages. Unlike magnetic resonance imaging, ultrasound demonstrates the fibrillar microanatomy of tendons, ligaments and muscles, enhancing its diagnostic capability. The ability to compress, dynamically assess structures and compare easily with the contralateral side is advantageous. The patient’s exact point of clinical tenderness can be correlated with underlying anatomical structures and associated pathology. The main strength of knee ultrasound is the assessment of para-articular disease. The specific structures best suited for ultrasound assessment include tendons, muscles and ligaments, as well as periarticular soft tissue masses. Joint effusions, synovial thickening, bursal fluid collections, intra-articular loose bodies, ganglion cysts, ligament and tendons tears, tendonitis and occult fractures can be diagnosed. With experience, ultrasound is a time-efficient, economical imaging tool for assessment of the knee. Received: 28 November 2000 Revision requested: 26 January 2001 Revision received: 10 April 2001 Accepted: 10 April 2001     

Avulsion fractures and chronic avulsion injuries of the knee: role of MR imaging

Avulsion fractures and chronic avulsion injuries of the knee are common lesions in sports-related trauma, especially among adolescents. Magnetic resonance imaging may prove useful in detecting and characterizing such lesions, and has several advantages with regard to other imaging modalities. We review, illustrate, and discuss the MR imaging features of some of the more frequent avulsion fractures and chronic avulsion injuries of the knee, including avulsion fractures of the cruciate ligaments, avulsion fractures of lateral and medial stabilizers, avulsion fractures and chronic avulsion injuries of the extensor mechanism, and avulsive cortical irregularities of the distal femur. The role of MR imaging in evaluating such lesions is emphasized.     

Musculoskeletal MR: knee

Magnetic resonance imaging is the most sensitive, specific, and accurate noninvasive method for diagnosing internal derangement of the knee. During the past 15 years knowledge of pathologic conditions of the knee had evolved significantly. Beyond the basic principles of imaging knee injuries great impact was made on the understanding of indirect or collateral findings, even in rare diseases. In this article the spectrum of disorders of the knee are reviewed and an overview of the current literature is given. This includes considerations about how to achieve a high-standard MR imaging study of the knee, and principles of imaging anterior cruciate ligament and meniscal tears. A focus is put on distinct diseases including intra-articular and intraosseous ganglion cysts, iliotibial band friction syndrome, transient osteoporosis, osteonecrosis, osteochondritis dissecans, and imaging of the articular cartilage.     

MR imaging evaluation of knee collateral ligaments and related injuries: Comparison of T1-weighted,T2-weighted,and fat-saturated T2-weighted sequences—correlation with clinical findings

The objectives of this study were to compare the ability of T1-weighted (T1W), proton density/T2-weighted (PD/T2W), and fat saturation (FS) PD/T2W magnetic resonance (MR) sequences for depiction of the knee collateral ligaments and related injuries, and to compare MR findings with clinical findings. Ten subjects with normal knee ligaments and 64 patients with suspected collateral ligament injuries underwent coronal T1W, PD/T2W, and FS PD/T2W imaging. Abnormalities ranged from edema surrounding the collateral ligaments (grade I) to complete disruption of ligamentous fibers (grade III). FS PD/T2W images improved definition of the medial collateral ligament (MCL) and lateral collateral ligament (LCL) compared with other sequences in 78% and 81% of patients, respectively. While the apparent grade of collateral ligament injury was similar with all pulse sequences in most patients, depiction of such injury was usually most conspicuous on FS PD/T2W images (MCL, 92% of patients; LCL, 38% of patients). In no patients were clinically diagnosed collateral ligament injuries undetected or understaged with MR imaging. MR findings indicated higher-grade MCL and LCL injuries than did clinical examination in 24 and 15 patients, respectively.     

Correlation of Histological Examination of Meniscus with MR Images: Focused on High Signal Intensity of the Meniscus Not Caused by Definite Meniscal Tear and Impact on MR Diagnosis of Tears

Objective

To document the causes of high signal intensity of the meniscus which is not caused by definite meniscal tears on MR imaging, through correlation with histological examination.

Materials and Methods

For the correlation between the MR image and histology, we obtained prospectively 31 meniscal specimens from 21 patients. Proton density-weighted turbo spin-echo MR images were used. Minimal tear, thinning of the lamellar layer, degeneration of the central layer, and radial tie fibers were detected upon histological examination, and were correlated with the corresponding MR images.

Results

Minimal tear of the lamellar layer was seen in 60 zones out of 100 slides. On MR images, 29 (48.3%) of these 60 zones had high signal intensity. Thinning of the lamellar layer was seen in 24 zones, with 7 (29.2%) having high signal intensity. 57 central zones showed degenerative change in the central layer and high signal intensity on all corresponding MR images. Radial tie fibers in the central layer appeared as high signal intensity areas.

Conclusion

Minimal tear and thinning of the lamellar layer, degeneration and radial tie fibers of the central layer of the meniscus cause high signal intensity on MR images.     

Ultrasound in degenerative cystic meniscal disease of the knee

Ultrasonography of the knee joint using small-parts probes was performed on 27 patients with clinical findings suggestive of meniscal cystic degeneration. Surgical or arthroscopic confirmation of sonographic findings was obtained in all cases. Sonography delineated the shape and structure of the meniscal profile and any degenerative changes. In the initial stage (6/27 patients, 22%), minor structural irregularities could be observed. Small, round, transonic cysts were found in 8 patients (30%); these lay mainly within the meniscus and were movable during stress flexion of the leg. In more advanced cases (8/27, 30%), larger cysts sometimes protruded on the skin surface. In 3 patients (12%), the soft tissue swelling was associated with a normal sonographic aspect of the menisci, but sonography could demonstrate an effusion of extra-articular origin. Ultrasound is a simple and effective method for the assessment of degenerative cysts of the menisci. It allows a reliable differential diagnosis between meniscal cysts and other causes of soft tissue swelling, and it is well suited for monitoring the course of the disease.     

Chondromalacia of the knee: Evaluation with a fat-suppression three-dimensional SPGR imaging after intravenous contrast injection

Twenty-one MRI studies with a fat-suppression three-dimensional spoiled gradient-recalled echo in a steady state (3D SPGR) pulse sequence after intravenous contrast injection were evaluated to assess the accuracy in depicting chondromalacia of the knee. On the basis of MR images, chondromalacia and its grade were determined in each of five articular cartilage regions (total, 105 regions) and then the results were compared to arthroscopic findings. The sensitivity, specificity, and accuracy of MRI were 70%, 99%, and 93%, respectively. MR images depicted 7 of 11 lesions of arthroscopic grade 1 or 2 chondromalacia, and seven of nine lesions of arthroscopic grade 3 or 4 chondromalacia. The cartilage abnormalities in all cases appeared as focal lesions with high signal intensity. Intravenous contrast-injection, fat-suppression 3D SPGR imaging showed high specificity in excluding cartilage abnormalities and may be considered as an alternative to intra-articular MR arthrography when chondromalacia is suspected.     

Value of the coronal plane in MRI of internal derangement of the knee

Sagittal images usually receive the most scrutiny in the magnetic resonance evaluation of meniscal and anterior cruciate ligament tears. We assessed the relative contribution of the coronal view. All knee magnetic resonance examinations performed over a 2-year period that had surgical confirmation were reviewed with respect to the presence of meniscal and anterior cruciate ligament tears. The appearance of an attenuated but uninterrupted anterior cruciate ligament was also evaluated. The coronal and sagittal plane images were evaluated separately. The study included 68 medial menisci, 67 lateral menisci, and 71 anterior cruciate ligaments. The coronal view is especially useful in the evaluation of the lateral meniscus. An anterior cruciate ligament that appears attennated but uninterrupted should be considered intact. The anterior cruciate ligament may be evaluated on the coronal view. The coronal view should be regarded as similar to the lateral chest radiograph, which supplements, but does not replace, the frontal chest radiograph.Presented at the Annual Meeting of the Radiological Society of North America, December 2, 1992, Chicago, Illinois     

MRI评价膝关节半月板的桶柄状撕裂

目的 明确5种MRI征象对膝关节半月板桶柄状撕裂的诊断价值。方法 回顾135例患者139个经关节镜证实的膝关节MR图像，其中19个存在半月板桶柄状撕裂。在均不告知关节镜结果的条件下，由2名有经验的放射医生对所有图像进行独立读片，差异协商解决。每个膝关节均记录如下5种MRI征象：双后交叉韧带征(双PCL征)、半月板翻转征、空领结征、碎块内移征和外周残半月板征。分别计算每种征象诊断半月板桶柄状撕裂的敏感度、特异度、阳性预测值、阴性预测值和准确度。结果 5种征象的诊断敏感度分布于52．6％和89．5％之间，特异度分布于83．3％和98．3％之间，阳性预测值分布于42．9％和88．2％之间，阴性预测值分布：于92．7％和98．3％之间，准确度分布于82．7％和96．4％之间。“碎块内移征”和“外周残半月板征”的诊断敏感度最高，“双PCL征”的诊断特异度和阳性预测值最高，而“碎块内移征”具有最高的阴性预测值和诊断准确度。结论 半月板桶柄状撕裂在MRI上可以有多种表现，各种征象对诊断的能力有所不同。     

膝关节损伤的MRI诊断

目的：探讨膝关节损伤的MRI特点、病理基础及临床意义。方法：分析52例膝关节损伤的MRI资料。结果：半月板损伤45例,MRI表现为黑色的半月板内出现结节状、线状、放射状裂隙样异常高信号,延伸达或未及关节软骨面两种,前交叉及后交叉韧带损伤24例,MRI表现为在条索状黑色韧带影中出现短T1长T2异常高信号,韧带变形,呈波浪状或不连续,胫骨移位,内、外侧副韧带损伤28例,表现为信号增高,形态增粗,边缘模糊,隐匿性骨折8例,表现为干骺端边界模糊的片状T1低信号影,T2信号多样,讨论：MRI对膝关节半月板、韧带损伤及隐匿性骨折的诊断有重要的临床意义,可对治疗方案的选择提供详尽的依据。     

Biomechanics of the meniscus-meniscal ligament construct of the knee

The menisci of the knee act primarily to redistribute contact force across the tibio-femoral articulation. This meniscal function is achieved through a combination of the material, geometry and attachments of the menisci. The main ligaments that attach the menisci to the tibia (insertional ligaments, deep medial collateral ligament), the femur (meniscofemoral ligaments, deep medial collateral ligament) and each other (the anterior intermeniscal ligament) are the means by which the contact force between tibia and femur is distributed into hoop stresses in the menisci to reduce contact pressure at the joint. This means that the functional biomechanics of the menisci cannot be considered in isolation and should be considered as the functional biomechanics of the meniscus-meniscal ligament construct. This article presents the current knowledge on the anatomy and functional biomechanics of the meniscus and its associated ligaments. Much is known about the function of the meniscus-meniscal ligament construct; however, there still remain significant gaps in the literature in terms of the properties of the anterior intermeniscal ligament and its function, the properties of the insertional ligaments, and the most appropriate ways to reconstruct meniscal function surgically.     

Evaluation of grades 3 and 4 chondromalacia of the knee using T2*-weighted 3D gradient-echo articular cartilage imaging

Objective. To determine the accuracy of T2*-weighted three-dimensional (3D) gradient-echo articular cartilage imaging in the identification of grades 3 and 4 chondromalacia of the knee. Design and patients. A retrospective evaluation of 80 patients who underwent both arthroscopic and MRI evaluation was performed. The 3D images were interpreted by one observer without knowledge of the surgical results. The medial and lateral femoral condyles, the medial and lateral tibial plateau, the patellar cartilage and trochlear groove were evaluated. MR cartilage images were considered positive if focal reduction of cartilage thickness was present (grade 3 chondromalacia) or if complete loss of cartilage was present (grade 4 chondromalacia). Comparison of the 3D MR results with the arthroscopic findings was performed. Results. Eighty patients were included in the study group. A total of 480 articular cartilage sites were evaluated with MRI and arthroscopy. Results of MR identification of grades 3 and 4 chondromalacia, all sites combined, were: sensitivity 83%, specificity 97%, false negative rate 17%, false positive rate 3%, positive predictive value 87%, negative predictive value 95%, overall accuracy 93%. Conclusion. The results demonstrate that T2*-weighted 3D gradient-echo articular cartilage imaging can identify grades 3 and 4 chondromalacia of the knee. Received: 18 April 2000 Revision requested: 18 July 2000 Revision received: 10 October 2000 Accepted: 27 November 2000     

Deep lateral femoral sulcus: study of 124 patients with anterior cruciate ligament tear

Abnormal deepening of the lateral femoral sulcus has been proposed as a potential indirect sign allowing the diagnosis of an anterior cruciate ligament (ACL) tear on conventional lateral knee radiographs. We studied a large group of patients with proven ACL tears during the acute injury and at 5-year follow-up to determine (a) the normal range of the depth of this sulcus and (b) the sensitivity, specificity, and positive predictive value of a deepened lateral sulcus. One hundred fifty patients with suspected ACL tears after sustaining unilateral injuries to their knees were referred to a specialty clinic for further evaluation. The injury was based on the presence of hemarthrosis, pathologic joint motion, and/or instability of the tibiofemoral joint. From this group, 124 patients were diagnosed with complete ACL tears (112 cases confirmed by arthroscopy, 12 cases diagnosed by the presence of pathologic motion with a KT-1000 arthrometer). Conventional radiographs of the injured knee were obtained in all 150 patients at the time of the acute injury. Five years later, radiographs of both the injured knee and the uninjured contralateral knee were evaluated. The lateral femoral condylopatellar sulcus, or notch, was measured on the acute injury and 5-year follow-up radiographs, and this measurement was compared to that on radiographs of the uninjured contralateral knee. The depth of the lateral sulcus consistently was noted to be similar in both knees in a given patient. Two groups of patients were identified: one group consisted of 124 patients with torn ACLs with a mean notch depth on the injured side of 0.57 mm [range, 0.0–3.3 mm; standard deviation (SD), 0.57 mm] and on the uninjured contralateral side of 0.43 mm (range, 0.0–2.0 mm; SD, 0.42 mm); and a second group consisted of those 26 injured patients with intact ACLs with a mean notch depth on the injured side of 0.31 mm (range, 0.0–1.0 mm; SD, 0.35 mm) and on the uninjured contralateral side of 0.27 mm (range, 0.0–0.8 mm; SD, 0.26 mm). Four of the 124 patients with a proven ACL tear had lateral notch measurements greater than 2.0 mm in depth. No patient with an intact ACL demonstrated a lateral sulcus that exceeded 2.0 mm in depth. A depth greater than 2.0 mm had a specificity of 100%, sensitivity of 3.2%, accuracy of 60%, and a positive predictive value of 100% for complete ACL tear. This work was supported in part by Veterans Affairs Grant SA 206.     

膝关节半月板损伤的MRI诊断

目的：探讨膝关节半月板损伤的MRI临床诊断价值。方法：回顾性分析108例膝关节半月板损伤的MRI表现。并按Mink和Fischer方法进行分级。结果：108例216个半月板中有159个损伤，其中I级损伤36个，Ⅱ级损伤78个。Ⅲ级损伤45个(经手术证实)。结论：MRI对膝关节半月板损伤具有很高的诊断价值及临床意义，可以清晰地显示半月板的形态、位置及其信号的变化，为临床治疗提供可靠的依据，是目前诊断半月板损伤最好的检查方法。