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Novel Approach towads Knee Injury Reporting- Correlating Bone Marrow Edema Patterns & Soft Tissue Injuries Poster No.: C-0274 Congress: ECR 2015 Type: Educational Exhibit Authors: S. Devu, U. Matapathi, S. V. Muddana, S. Marda, S. Polineni, S. Athne; Hyderabad/IN Keywords: Acute, Structured reporting, MR, Musculoskeletal joint DOI: 10.1594/ecr2015/C-0274 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myESR.org Page 1 of 23 Learning objectives 1.To understand the dynamic anatomy of knee joint. 2.To characterise the pattern of contusions . 3.To characterise the soft tissue injuries. 4.To evaluate a pattern, correlating specific patterns of bone contusions and soft tissue . Background Knee joint is the largest and maximum weight-bearing joint in humans and is mobile hinge joint which is second commonly injured joint after wrist and is most commonly imaged joint. The knee permits flexion and extension about a virtual transverse axis, as well as a slight medial and lateral rotation about the axis of the lower leg in the flexed position. The centre of the transverse axis of the extension/flexion movements is located where both collateral ligaments and both cruciate ligaments intersect. This centre moves upward and backward during flexion, while the distance between the centre and the articular surfaces of the femur changes dynamically with the decreasing curvature of the femoral condyles. The total range of motion is dependent on several parameters such as soft-tissue restraints, active insufficiency, and hamstring tightness. Anatomy in extended position: With the knee extended both the lateral and medial collateral ligaments, as well as the anterior part of the anterior cruciate ligament, are taut. During extension, the femoral condyles glide into a position which causes the complete unfolding of the tibial collateral ligament. During the last 10° of extension, an obligatory terminal rotation is triggered in which the knee is rotated medially 5°. The final rotation is produced by a lateral rotation of the tibia in the non-weight-bearing leg, and by a medial rotation of the femur in the weight-bearing leg. This terminal rotation is made possible by the shape of the medial Page 2 of 23 femoral condyle, assisted by contraction of the popliteus muscle and the iliotibial tract and is caused by the stretching of the anterior cruciate ligament. Anatomy in flexed position: In the flexed position, the collateral ligaments and anterior cruciate ligaments are relaxed while the posterior cruciate ligament is taut. Rotation is controlled by the twisted cruciate ligaments; the two ligaments get twisted around each other during medial rotation of the tibia - which reduces the amount of rotation possible - while they become unwound during lateral rotation of the tibia. Because of the oblique position of the cruciate ligaments at least a part of one of them is always tense and these ligaments control the joint as the collateral ligaments are relaxed. Furthermore, the dorsal fibers of the tibial collateral ligament become tensed during extreme medial rotation and the ligament also reduces the lateral rotation to 45-60°. The patellar ligament is the anterior ligament of the knee joint. It is the distal part of the quadriceps tendon and attaches to the tibial tuberosity. The vastus medialis and lateralis contribute to the patellar ligament medially and laterally through the medial and lateral retinacula, which make up the joint capsule of the knee on either side of the patella. The retinacula also maintain alignment of the patella relative to the patellar surface of the femur. The LCL extends from the lateral epicondyle of the femur to the lateral surface of the fibular head. The LCL is separated from the lateral meniscus by the popliteus tendon. The LCL also splits the tendon of the biceps femoris into 2 parts. The MCL extends from the medial epicondyle of the femur to the medial condyle and superior part of the medial surface of the tibia. The MCL is firmly attached to the medial meniscus, which is why these are commonly torn at the same time in contact sports. The oblique popliteal ligament and arcuate popliteal ligament reinforce the joint capsule on the posterior aspect. The oblique popliteal ligament is a recurrent expansion of the tendon of the semimembranosus, and it arises from the medial tibial condyle and passes toward the lateral femoral condyle, where it blends in with the rest of the joint capsule. The arcuate popliteal ligament arises from the posterior fibular head and passes over the tendon of the popliteus and spreads over the posterior surface of the knee. The ACL attaches posterior to the attachment of the medical meniscus on the anterior intercondylar area of the tibia and passes superior, posterior, and lateral, where it attaches to the posterior part of the medial side of the lateral condyle of the femur. Page 3 of 23 The PCL arises from the posterior intercondylar area and passes on the medial side of the ACL to attach to the anterior part of the lateral surface of the medial condyle of the femur. The menisci are wedge shaped and attach at their ends to the intercondylar area of the tibia. The medial meniscus is C shaped and firmly adheres to the deep surface of the MCL medially, the ACL anteriorly, and the PCL posteriorly. Because of these attachments, the medial meniscus is less mobile than the lateral meniscus. Flexion is produced by the hamstring muscles, which consist of the semitendinosus, semimembranosus, and long head of the biceps femoris along with the short head of the biceps and, weakly, the gracilis, sartorius, gastrocnemius, and popliteus. The medial rotators of the knee are the semitendinosus, semimembranosus, popliteus, gracilis, and sartorius. The lateral rotator of the knee is the biceps femoris. Images for this section: Page 4 of 23 Fig. 8: Relaxed ACL in flexed position Page 5 of 23 Fig. 9: Taut ACL in extension position Page 6 of 23 Fig. 10: Relaxed PCL in extension position Page 7 of 23 Fig. 11: Taut PCL in flexion position Page 8 of 23 Fig. 12: Relaxed Collaterals in flexion position Page 9 of 23 Fig. 13: Taut Collaterals in extension position Page 10 of 23 Findings and procedure details MR IMAGING PROTOCOL: Patient Positioning :Supine with 10- 15 degree external rotation Imaging Planes: An axial acquisition through the patello-femoral joint is used as initial localiser for subsequent sagittal and coronal imaging. Slice Thickness: 4mm sections are used for axial and coronal plane and 3 to 4 mm thick sections are used for sagittal images T2 contrast highlights ligamentous edema and haemorrhage in collateral ligaments in coronal plane and cruciate ligaments in sagittal plane as demonstrated by FS PD FSE sequence(TR of 3000 to 4000 msec and TE of 40 to 50 msec). STIR(TR of 4000 msec, TE of 18 msec,TI of 140 msec,and an ETL of 4) and FS PD FSE sequences are more sensitive than T2 or T2* weighted imaging for identification of trabecular bone contusions and fractures. A. PIVOT SHIFT PATTERN OF INJURY: Most commonly identified pattern of injury in most of the hospitals,either associated with sports or road traffic accidents associated with sudden deceleration and rotating for change in direction. Valgus load and rotational force in flexed position of knee with external rotation of tibia or internal rotation of femur causes injury/rupture of ACL, causing anterior subluxation of tibia resulting in impaction of posterior tibia and posterolateral femoral condyles. The resulting bone contusion pattern involves the posterior aspect of the lateral tibial plateau and the mid-portion of the lateral femoral condyle near the condylo-patellar sulcus. The exact location of the lateral femoral condyle injury depends on the degree Page 11 of 23 of flexion of the knee at injury. Increasing degrees of flexion result in a more posteriorly located bone bruise, whereas less flexion results in a more anteriorly located edema. Soft-tissues injured with the pivot shift injury include anterior cruciate ligament,tears of the posterior capsule and arcuate ligament, the posterior horn of the lateral or medial meniscus , and the medial collateral ligament . Representative case :Figures 1 and 2 B. CLIP INJURY: Results from direct contact injury on lateral femoral condyle, with valgus force on medial collateral ligament and avulsion force at its femoral attachment on medial femoral condyle. Seen in road traffic accidents,when hit on side by a vehicle,and in sports like American football and Kabbadi(An Indian Originated Contact Sport). Direct contact/hit to lateral femoral condyle with traction force at medial femoral condyle causing injury of Medial collateral ligament.With increased flexion,injury to ACL and medial meniscus do occurs. Bone marrow edema is seen in the lateral femoral condyle (from the direct blow), area of edema may be present in the medial femoral condyle (secondary to avulsive stress to the MCL).Varying degrees of MCL injury are associated. Representative case : Figure 3 C. HYPEREXTENSION INJURY: Results from direct application of force on the anterior tibia while the foot is planted or from an indirect force, such as a forceful kicking . The most severe cases often result from direct injury (eg, a car bumper hitting the anterior tibia of a pedestrian). During the brief moment of hyperextension, the anterior aspect of the tibial plateau strikes the anterior aspect of the femoral condyle, resulting in the "kissing" contusion pattern of bone injury . Page 12 of 23 If a valgus force is also applied at hyperextension, the kissing contusions will be located medially. Direct force to anterior tibia when foot is planted; indirect force like with kicking causing kissing contusions of tibia and femur and injury to ACL ,PCL, and posterior structures .In cases of severe trauma neurovascular and gastrocnemius injury may be also seen. During the brief moment of hyperextension, the anterior aspect of the tibial plateau strikes the anterior aspect of the femoral condyle, resulting in the "kissing" contusion pattern of bone injury. If a valgus force is also applied at hyperextension, the kissing contusions will be located medially. Depending on the amount of force applied, associated soft-tissue abnormalities may include injury to either the ACL or PCL and a meniscal injury . If a substantial force is applied, dislocation of the knee may occur , along with injury of the popliteal neurovascular structures , complete disruption of the posterolateral complex, and, possibly, gastrocnemius injury. Representative case : Figures 4 and 5 D. DASHBOARD INJURY: Results from direct impaction of tibia with a hard surface,as seen with direct striking of tibia against the dashboard in automobile accident ,or fall on ground with tibia hitting directly in a flexed position. Direct force on tibia with knee in flexed position causes contusions in anterior tibia and posterior patella and injury of PCL and posterior Capsule. Tibia is forced posteriorly relative to the femur wherein the PCL which is taut in flexion is prone for disruption. Representative case : Figure 6 E. PATELLAR SUBLUXATION: Page 13 of 23 Seen in young individuals with shallow trochlear groove,and can be associated with repeated attacks and self correction. Twisting motion of knee in flexion causes internal rotation of femur on fixed tibia with qaudriceps contraction causing lateral patellar subluxation resulting in contusions at anterolateral femoral condyle and inferomedial patella. Representative case : Figure 7 F. UNCLASSIFIABLE INJURIES: Pre-existing conditions such as osteoarthritis causing significant subchondral edema & in sceanrios of very Subtle and severe trauma . Images for this section: Page 14 of 23 Fig. 1: CASE 1:HISTORY OF KNEE INJURY WHILE PLAYING FOOTBALL. FINDINGS:SAGITTAL T2 FAT-SAT IMAGE SHOWS CONTUSIONS IN POSTEROLATERAL TIBIAL CONYLE AND LATERAL ASPECT OF INTERCONDYLAR SULCUS OF FEMUR.ALSO SEEN ARE VERTICAL TEAR OF POSTERIOR HORN OF LATERAL MENISCUS AND GRADE-2 SPRAIN OF ARCUATE LIGAMENT Page 15 of 23 Fig. 2: FINDINGS:SAGITTAL T2 FAT-SAT IMAGE SHOWS AVULSION OF ACL AT ITS TIBIAL ATTACHMENT,INJURED POSTERIOR CAPSULE,COMPLEX TEAR OF POSTERIOR HORN MEDIAL MENISCUS ,SIGNIFICANT EDEMA IN POSTERIOR SOFT TISSUES Page 16 of 23 Fig. 3: CASE 2:ROAD TRAFFIC ACCIDENT,HIT BY CAR FROM SIDE. FINDINGS:CORONAL T2 FAT-SAT IMAGING SHOWS ILL DEFINED SUBCHONDRAL EDEMA ON LATERAL FEMORAL CONDYLE,AND ON THE MEDIAL FEMORAL CONDYLE AT THE LEVEL OF MCL ATTACHMENT.ALSO NOTED IS FLUID AROUND THE INTACT MCL(GRADE-1 SPRAIN) Page 17 of 23 Fig. 4: CASE 3:HISTORY OF KNEE INJURY WHILE PLAYING FOOTBALL. FINDINGS:SAGITTAL T2 FAT-SAT IMAGE SHOWS EDEMA IN ANTERIOR ASPECT OF FEMORAL CONDYLE AND TIBIAL TUBEROSITY.TORN ACL MIDBODY FIBRES AND SIGNIFICANT INFLAMMATORY CHANGES IN POSTERIOR SOFT TISSUES Page 18 of 23 Fig. 5: CASE 3B:CORONAL T2 FAT-SAT IMAGE SHOWS DEPRESSION FRACTURE OF MEDIAL TIBIAL PLATEAU,AND SUBCHONDRAL EDEMA IN FEMORAL CONDYLE,ALSO NOTED IS DISRUPTED MEDIAL COLLATERAL LIGAMENT. Page 19 of 23 Fig. 6: CASE 4:HISTORY OF FALL FROM BIKE IN A ROAD TRAFFIC ACCIDENT. FINDINGS:SAGITTAL T2 FAT-SAT IMAGE SHOWS SIGNIFICANT EDEMA IN THE ANTERIOR TIBIA,COMPLETE AVULSION OF POSTERIOR CRUCIATE LIGAMENT AT ITS TIBIAL ATTACHMENT,POSTERIOR CAPSULAR STRAIN AND SIGNIFICANT INFLAMMATORY CHANGES IN POSTERIOR SOFT TISSUES Page 20 of 23 Fig. 7: CASE 5:HISTORY OF KNEE PAIN SUDDENLY WHILE BENDING,WITH SIMILAR PREVIOUS ATTACKS. FINDINGS:AXIAL T2 FAT-SAT IMAGE SHOWS CONTUSIONS IN INFERIOMEDIAL PATELLA AND LATERAL FEMORAL CONDYLE, SHALLOW TROCHLEAR GROOVE,OSTEOCHONDRAL FRACTURE IN MEDIAL PATELLAR FACET,DISRUPTED MEDIAL RETINACULUM,INFLAMMATORY CHANGES IN PREPATELLAR SOFT TISSUES Page 21 of 23 Conclusion Imaging of acute injuries around knee joint is best done with MR imaging,to characterise involved bones and soft tissues. Contusions and fracture patterns are like road maps towards associated soft tissue injuries. Pattern recognition can be used as a guidance for reporting ,increased accuracy and to avoid missing of subtle injuries. Personal information References 1. Peter J. MacMahon and William E. Palmer .A Biomechanical Approach to MRI of Acute Knee Injuries .American Journal of Roentgenology. 2011;197: 568-577. 2. Murphy BJ, Smith RL, Uribe JW, Janecki CJ, Hetchman KS, Mangasarian RA. Bone signal abnormalities in the posterolateral tibia and lateral femoral condyle in complete tears of the anterior cruciate ligament: a specific sign? Radiology 1992; 182:221-224. 3. Schweitzer ME, Tran D, Deely DM, Hume EL. Medial collateral ligament injuries: Evaluation of multiple signs, prevalence and location of asso ciated bone bruises, and assessment with MR imaging. Radiology 1995; 194:825-829. 4. Miller TT, Gladden P, Staron RB, Henry JH, Feldman F. Posterolateral stabilizers of the knee: anatomy and injuries assessed with MR imaging. AJR Am J Roentgenol 1997; 169:1641-1647. 5. Sonin AH, Fitzgerald SW, Hoff FL, et al. MR imaging of the posterior cruciate ligament: normal, abnormal, and associated injury patterns. RadioGraphics 1995; 15:551-561. Page 22 of 23 6. Kirsch MD, Fitzgerald SW, Friedman H, Rogers LF. Transient lateral patellar dislocation: diagnosis with MR imaging. AJR Am J Roentgenol 1 993; 161:109-113. Page 23 of 23