Learning IRM. The Knee: lateral ligaments and anatomical quadrants.

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1 Learning IRM. The Knee: lateral ligaments and anatomical quadrants. Poster No.: C-1733 Congress: ECR 2014 Type: Educational Exhibit Authors: A. Amador Gil, M. D. C. Jurado Gómez, V. de Lara Bendahan ; Sevilla/ES, Cádiz/ES Keywords: Musculoskeletal joint, Musculoskeletal soft tissue, MR, Diagnostic procedure, Image verification DOI: /ecr2014/C-1733 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. Page 1 of 47

2 Learning objectives To review the anatomy of the lateral ligaments and anatomic quadrants of the knee through schemes and their correlation with magnetic resonance image (MRI) assessing the main stabilizing structures as well as the more common mechanisms that can injure it. Background Anatomical knowledge of the support structures that provide stability to the medial and lateral knee region has gained great interest, especially since the advent of MR imaging, allowing us to give detailed information to specialists in Traumatology and Orthopedics so that, in case of injury to any of them, they can carry out a suitable and satisfactory surgical repair [1]. Images for this section: Page 2 of 47

3 Fig. 1: Support structures of anatomic quadrants. Fig. 2: Anatomic quadrants and the main mechanisms of injury. Page 3 of 47

4 Fig. 3: Illustration and axial proton density weighted MR image of anatomic components. Page 4 of 47

5 Findings and procedure details A) LCL and posterolateral corner [1, 2, 3, 5]: They act limiting varus angulation and external rotation of the knee. All are inserted into the fibular head (Fig. 4 on page 9). Display better at: Coronal image: Lateral collateral ligaments, Arcuate ligaments, Popliteofibular ligament, Fabellofibular ligament and Biceps femoris tendon. Axial image: Popliteus muscle and tendon and Oblique popliteal ligament. Sagittal image: Popliteomeniscal fascicles and Lateral gastrocnemius muscle. 1- Lateral collateral ligaments (LCL): it inserts in the proximal femur, posterior to the lateral epicondyle. It extends posterolaterally to insert into the top facet of the fibular head, anterolaterally to the insertion of the Fabellofibular and Arcuate ligaments (Fig. 5 on page 10, Fig. 6 on page 12, Fig. 9 on page 15 ). 2- Popliteus muscle (PM): it inserts into the popliteal sulcus of the lateral femoral condyle, and extends medially through the popliteal hiatus to be inserted into the posteromedial aspect of the tibial metaphysis. PM help in the knee flexion and allows internal rotation. Protects the posterior horn of the lateral meniscus during flexion and rotation and stabilizes the posterolateral angle (Fig. 5 on page 10, Fig. 6 on page 12, Fig. 9 on page 15). 3- Lateral gastrocnemius muscle (LGM): it inserts behind the lateral epicondyle and condyle of the femur (Fig. 5 on page 10). 4- Biceps femoris tendon (BT)(Fig. 6 on page 12, Fig. 7 on page 13, Fig. 9 on page 15): it haves two heads: Long head: the direct arm is inserted into the fibular head. The anterior arm is inserted in front of the direct arm and continues distally as the anterior aponeurosis of the leg. Short head: the direct arm is inserted into the fibular head, medially to the long head. The anterior arm is inserted into the superolateral edge of the lateral tibial condyle, close to Gerdy tubercle. 5- Popliteofibular ligament (PFL): it begins from the confluence of the popliteal meniscal fascicles and is inserted into the fibular head (Fig. 8 on page 15). Page 5 of 47

6 6- Arcuate ligament (AL): It is Y-shaped. Arises from the styloid process of the fibula. The lateral arm runs straight up following the capsule to the lateral femoral condyle. The medial arm inserts into the posterior capsule medially, with the oblique popliteal ligament (Fig. 10 on page 16). 7- Oblique popliteal ligament (OPL): arises from semimembranosus fascicles and the lateral tibial condyle, joining the arcuate ligament at its femoral insertion (Fig. 4 on page 9). 8- Fabellofibular ligament (FFL): originates at fabela and is inserted on the styloid process (Fig. 9 on page 15, Fig. 11 on page 17, Fig. 12 on page 18). 9- Popliteomeniscal fascicles (PMF): extends from the posterior horn of the lateral meniscus to the popliteal tendon (Fig. 10 on page 16). Mechanisms of injury: It is less common than the injury of medial structures. The mechanisms are: Violent external rotation of the tibia with the knee extended. Impact at the medial portion of the proximal tibia towards posterolateral (Fig. 13 on page 19). Hyperextension (Fig. 14 on page 20). It is frequently associated with cruciate ligaments injury. The clinic is pain in the posterolateral aspect of the knee and feeling unsteady to extension. The most frequently injured structures are LCL, Joint capsule, BT, PT, AL and PFL. The popliteus muscle is the main lateral stabilizer of the knee. The ligament rupture could be complete or incomplete (Fig. 15 on page 21). If the rupture is complete all the fiber are disrupted while in the partial rupture only a portion has presence of fluid signal (Fig. 16 on page 22, Fig. 17 on page 23). The tendons tend to break in the myotendinous junction. If there is complete rupture of the tendon, the fibers retraction simulates a mass (Fig. 18 on page 24, Fig. 19 on page 25). Page 6 of 47

7 At radiography the only sign could be a subtle avulsion fracture of the upper portion of the fibular head (arcuate sign) (Fig. 20 on page 26, Fig. 21 on page 27). B) Anterolateral corner [1, 2, 4]: Is best assessed on coronal plane. 1- Knee Joint capsule (JC) 2- Iliotibial tract (ITT): formed by the fusion of the aponeurosis of tensor fascia lata, gluteus maximus and minimus. It origins on lateral supracondylar tubercle of the femur and inserts on Gerdy s tubercle of tibia, patella and patellar ligament (Fig. 22 on page 28, Fig. 23 on page 29). 3- Anterior oblique band (AOB): It joins the iliotibial tract and lateral collateral ligament. It inserts on the lateral tibia (Fig. 22 on page 28). Mechanisms of injury: It is most frequently than the injury of lateral structures. The mechanism is a combination of varus force and internal rotation of the knee (Fig. 24 on page 30). It is frequently associated with anterior cruciate ligament and medial meniscus injury. The most frequently injured structures are ITT and AOB (Fig. 25 on page 32). It may be associated with Segond fracture (a tibial avulsion fracture secondary to the abnormal tension) (Fig. 26 on page 33). C) Posteromedial corner [1, 5]: Is best assessed on coronal and axial plane. 1- Medial collateral ligament (MCL): It originates on medial femoral epycondile and extends anteriorly and inferiorly till its insertion on proximal tibia. It has been described in three layers based on the depth of the structure. The most superficial, composed of the deep fascia, invests the sartorius muscle posteriorly and extends in an anterior direction. Along the anterior margin of the knee it forms the superficial fascia of the vastus medialis and inserts onto the patella as the superficial fibers of the medial retinaculum. The most deep comprises the medial joint line capsule and joins the medial meniscus (Fig. 27 on page 35, Fig. 28 on page 36, Fig. 29 on page 36) Page 7 of 47

8 2- Semimembranosus tendon (SMT): It is primarily inserted into the posteromedial tibial plateau. It has other insertions on popliteal fascia, medial collateral ligament and oblique popliteal ligament (Fig. 27 on page 35, Fig. 29 on page 36). 3- Oblique popliteal ligament (OPL): It originates on medial condyle of tibia and the tendon of the Semimembranosus. Extends superiorly and medially till its insertion on lateral condyle of the femur (Fig. 29 on page 36). 4- Posterior oblique ligament (POL): thickening of the medial collateral ligament (MCL) attached proximally to adductor tubercle of femur and distally to tibia and posterior aspect of the capsule, next to the internal meniscus. Is best assessed on coronal oblique plane (Fig. 30 on page 37). 5- Medial gastrocnemius muscle (MGM): it originates from the medial condyle of the femur and area just above condyle. Its end forms a common tendon with the soleus and lateral gastrocnemius muscle: Achilles tendon. Inserts onto the posterior surface of the calcaneus. Mechanisms of injury: They are: Valgus force applied to the flexed knee Direct blow to the lateral aspect of the knee (Fig. 31 on page 38). Torque injury The most frequently injured structures are MCL (Fig. 32 on page 39, Fig. 33 on page 40) and POL. D) Anteromedial corner [1, 2, 4]: Is best assessed on coronal and axial plane. - Medial retinacular complex (MR) (Fig. 34 on page 41, Fig. 35 on page: 42) It is formed by several components: Medial patellofemoral ligament (MPFL): it is the cephalad edge of the complex. Originates at the level of the adductor tubercle and runs in a slight rostral direction to insert on the patella (Fig. 35 on page 42). Patellotibial ligament (PTL): originates on the tibia at the level of the insertion of the semitendinosus muscle and insert on the inferior aspect of the patella and on the patellar tendon (Fig. 35 on page 42). Page 8 of 47

9 Anterior portion of medial collateral ligament (APMCL): its anterior fibers extends above the vastus medialis. Mechanisms of injury: They are the same that injure posteromedial corner: Valgus force applied to the flexed knee Direct blow to the lateral aspect of the knee (Fig. 31 on page 38). The most frequently injured structures are MCL, anterior cruciate ligament (ACL) and internal meniscus (IM). The medial patellofemoral ligament or medial retinaculum injury may be associated with lateral patellar dislocation (Fig. 36 on page 43, Fig. 37 on page 44, Fig. 38 on page 45). Images for this section: Page 9 of 47

10 Fig. 4: Posterolateral corner anatomy. Posterior illustration of knee. Page 10 of 47

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12 Fig. 5: Oblique sagittal view of the outside of the knee. Page 12 of 47

13 Fig. 6: Coronal proton density weighted MR image with fat saturation: Lateral collateral ligament (LCL), Biceps femoris tendon (BT) and popliteus tendon (PT), Page 13 of 47

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15 Fig. 7: Coronal proton density weighted MR image with fat saturation: Biceps femoris tendon (BT). Fig. 8: Coronal proton density weighted MR image with fat saturation: Popliteofibular ligament (PFL) Page 15 of 47

16 Fig. 9: Oblique sagittal view of the outside of the knee. LCL: lateral collateral ligament. FFL: Fabellofibular ligament. BT: Biceps femoris tendon. ITT: Iliotibial tract. PT: Popliteus tendon. Page 16 of 47

17 Fig. 10: Sagital T2 GE weighted MR image: Superior popliteomeniscal fascicle (SPMF), inferior popliteomeniscal fascicle (IPMF) and Arcuate ligament (AL) Page 17 of 47

18 Fig. 11: Sagital T1 TSE weighted MR image: Fabellofibular ligament (FFL) Page 18 of 47

19 Fig. 12: Coronal proton density weighted MR image with fat saturation: Fabellofibular ligament. Page 19 of 47

20 Fig. 13: Impact at the medial portion of the proximal tibia towards posterolateral. Page 20 of 47

21 Fig. 14: Hyperextension Page 21 of 47

22 Fig. 15: Coronal view of the knee: a) Complete tear of Lateral collateral ligament. b) Partial tear of Lateral collateral ligament. Page 22 of 47

23 Fig. 16: Coronal proton density weighted MR image with fat saturation: LCL partial tear on its femoral insertion, with bone cysts and soft tissue edema. Page 23 of 47

24 Fig. 17: Axial proton density weighted MR image with fat saturation: LCL partial tear on its femoral insertion, with bone cysts and soft tissue edema. Page 24 of 47

25 Fig. 18: Coronal proton density weighted MR image with fat saturation: BT partial tear Page 25 of 47

26 Fig. 19: Axial proton density weighted MR image with fat saturation: BT partial tear Page 26 of 47

27 Fig. 20: Coronal view of the knee. Avulsion fracture of the styloid process of the fibula, with lateral collateral ligament (LCL), biceps tendon (BT) and popliteomeniscal fascicle (PMF) tear, and tibia fracture. MCL: Medial collateral ligament. EM: External meniscus. Page 27 of 47

28 Fig. 21: Anteroposterior radiograph of the knee: Avulsion fracture above the head of the fibula in relation to the "arcuate sign". Page 28 of 47

29 Fig. 22: Lateral view of the knee: Anterior oblique band (AOB) extends anteriorly and inferiorly to the lateral collateral ligament (LCL). ITT: Iliotibial tract. Page 29 of 47

30 Fig. 23: Coronal proton density weighted MR image with fat saturation: Iliotibial tract (ITT) Page 30 of 47

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32 Fig. 24: Mechanism of injury to the anterolateral corner: combination of varus force and internal rotation of the knee. Page 32 of 47

33 Fig. 25: Coronal proton density weighted MR image with fat saturation: Iliotibial tract (ITT) complete tear. Page 33 of 47

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35 Fig. 26: Anteroposterior radiograph of the knee: Avulsion fracture of the lateral tibial condyle (Segond fracture) Page 35 of 47

36 Fig. 27: Oblique sagittal view of the medial side of the knee: ACL: Anterior cruciate ligament. LCL: Lateral collateral ligament. MCL: Medial collateral ligament. PCL: Posterior cruciate ligament. PT: Patellar tendon. QT: Quadriceps tendon. Fig. 28: Coronal proton density weighted MR image with fat saturation: Medial collateral ligament (MCL) Page 36 of 47

37 Fig. 29: Oblique sagittal view of the posteromedial corner of the knee: AL: Arcuate ligament. MCL: Medial collateral ligament. POL: Posterior oblique ligament. PM: Popliteus muscle. SMT: Semimembranosus tendon. Page 37 of 47

38 Fig. 30: Sagital view of the knee: MCL: Medial collateral ligament. POL: Posterior oblique ligament. OPL: Oblique popliteal ligament. SMT: Semimembranosus tendon. Page 38 of 47

39 Fig. 31: Mechanism of injury to the posteromedial corner: Direct blow to the lateral aspect of the knee. Page 39 of 47

40 Fig. 32: Coronal proton density weighted MR image with fat saturation: Grade I medial collateral tear (microscopic, with normal thickness and signal) with surrounding edema. Page 40 of 47

41 Fig. 33: Coronal proton density weighted MR image with fat saturation: A) Medial collateral ligament partial tear with surrounding edema. B) Medial collateral ligament complete tear and edema. C) Dislocation of the medial meniscus body with medial collateral ligament partial tear and surrounding edema. Page 41 of 47

42 Fig. 34: Anterior view of the knee: BT: Biceps femoris tendon. ITT: Iliotibial tract. LCL: Lateral collateral ligament. LR: Lateral retinaculum. MCL: Medial collateral ligament. MR: Medial retinaculum. PA: Pes anserinus. PLM: Peroneus longus muscle. PT: Patellar tendon. QT: Quadriceps tendon. VL: Vastus lateralis. VM: Vastus medialis. Page 42 of 47

43 Fig. 35: Axial proton density weighted MR image with fat saturation: A) MPFL: Medial patellofemoral ligament. B) MR: Medial retinaculum. C) PTL: Patellotibial ligament. Page 43 of 47

44 Fig. 36: Axial proton density weighted MR image with fat saturation: medial patellofemoral ligament partial tear near its patellar insertion. Page 44 of 47

45 Fig. 37: Axial proton density weighted MR image with fat saturation: medial patellar retinaculum complete tear. Page 45 of 47

46 Fig. 38: Axial proton density weighted MR image with fat saturation: medial patellofemoral ligament partial tear with lateral patellar dislocation. Page 46 of 47

47 Conclusion Anatomical knowledge of the structures that provide stability to the lateral and medial regions of the knee is of great importance because of its complexity and need be familiar with both the normal anatomy as anatomical variants. The purpose of the assessment by MR imaging after injury is merely identify those anatomical elements or supporting structures that may be injured and to provide adequate information to specialists in trauma and orthopedics for repair. Personal information References 1.Beall DP, Googe JD, Moss JT et al. Imagen de RM de los ligamentos colaterales y de los cuadrantes anatomicos de la rodilla. Radiol Clin N Am 2007; 45: Recondo JA, Salvador E, Villanúa JA et al. Lateral stabilizing structures of the knee: functiuonal anatomy and injuries assessed with MR imaging. Radiographics 2000; 20:S91-S Hayes CW, Brigido MK, Jamadar DA y Propeck T. Mechanism-based pattern approach to classification of the complex injuries of the knee depicted at MR imaging. Radiographics 2000; 20 S121-S Ostlere S. The extensor mechanism of the knee. Radiol Clin N Am 2013; 51: Geiger D, Chang E, Pathria M y Chung CB. Posterolateral and posteromedial corner injuries of the knee. Radiol Clin N Am 2013; 51: Page 47 of 47