The Relativity Study Of The Anatomy. X Ratios And MRI To The TCL And FCL Of The Knee And Clinical Meaning

PrefaceThe tibial collateral ligament (TCL) and fibular collateral ligament (TCL) are important structure maintaining the medial and lateral stability of the knee . Their functions primarily restrain against external rotation of tibia and genu va-rum and valgum cooperating with the static stabilizers. There are a important significance to maintain medical and lateral stability and rotary instability of the knee. Their injures will result in relaxation of others ligament. Finally , occurring rotary instability in long time unless correctly diagnosed and treated on initial evaluation; moreover , associated cruciate ligament injures are common. The diagnosed failure of their injuries is the most common reason of the failure in the reconstruction of the ACL and PCL. The experiment is to solve and answer the function of medial and lateral collateral ligament through a careful anatomy of the knee in comparison with X ratios and MR. Through a deep research of their attachment, we look for a relative isometric point on medial and lateral femoral epicondyle during flexion - extension motion of the knee joint in order to provide theoretic foundation of TCL and FCL reconstruction . In addition, their courses are marked, which provide theoretic foundation to MR examination so that they can direct clinic best.MethodMaterialDisssections were performed on 10 embalmed and 4 fresh cadaveric knees .All of the knees had at least 15. Ocm of bone and soft tissue proximal and distal 20.0cm to the joint line. Method1. The cadaveric knees were carefully dissected and the attachments of the TCL and FCL were exposed . Finally, their length and course were measured.2. The attachment centers on tibia and fibula of the FCL and TCL were seen as start point; The medial and lateral femoral epicondyle were seen as insertion . The variation of their length was observed during flexion - extension motion of the knee joint ; The relative isometric point was looked for in the nearby of the TCL and FCL insertion on the medial and lateral femoral epicondyle ( bias < 2mm).3. Attachments of the TCL and FCL were marked with metal thread; Then, X ratios was examined , the coursed angles of the FCL and TCL on sagittal plane were measured . transfusion pipe which was affused water is sutured and marked the FCL andTCL, finding out these structures and measuring the angle in the sagittal and coronal plane. Magnetic resonance imaging of the knee were performed on a 1. 5 - T MRI unit (Toshiba). fast spin - echo, proton density and T2 -weighted sequences: TR4000 -5000ms, TE:90/18ms , thickness, 3mm; slice gap, 0.6mm; T1 -weighted sequences-. TE : 15ms, thickness, 2mm; slice gap, 0.4mm; FOV, 16 x l6cm; matrix, 192 x 256. TR 486 ms.Result1. The TCL is divided into superficial layer , deep layer and posterior olique ligament . Superficial layer is long , rather narrow , well - delineated structure lying superficial to the medial capsule and capsular ligament originating below the adductor tubercle and inserting 6 to 7 cm below the joint lion on the posterior half of the medial surface of tibial metaphysis deep to the pes anserinus tendons, it glide forward over the side of the femoral condyle in extension posterior in flexion on the fresh knee specimens. The deep layers is the true capsule of the knee joint, it originates from the femoral condyle and epicondyle and in-tertion just below the tibial articular margin, it is divided into a meniscofemoralportion extending from the meniscotibial portion extending as the meniscofemoral portion is the much longer and stronger of these two divisions . The posterior oblique ligament attach proximal to the adducter tubercle of the femur and distally to the tibia and distally to the tibia and posterior aspect of the capsule extending to the insertion the direct head of the semimembranosus. The average total length of the TCL between its attachment sits was 9. 5cm; The FCL is measured in the coronal oblique poterior plane angled about 9 degrees to the long axis of the tibia.2. We found that the FCL attached on the femur proximal and posterior to the lateral epicondyle , some fibers extended proximally and anteriorly over the lateral epicondyle in a fan - like fashion . The TCL coursed distally and attached on the lateral aspect of the fibular head bony depression on average 1/3 of the total width of the fibular head from the anterior edge of the fibular head; The average total length of the FCL between its attachment sits was 5. Ocm . The FCL is measured in the coronal oblique anterior plane angled about 12 degree to the long, axis of the tibia.3. On sagittal MRI, the angle between the FCL and fibular neck long axis is 11.5 degrees , the angle between TCL and tibial long axis is 8 degrees . In coronal MRI , The FCL is completely shown in only one plane at posterior oblique plane 11 degrees; The TCL can be completely shown at anterior oblique plane 8 degrees.4. The relative isometric point of the TCL lies in the anterior border of medial femoral epicondyle, which the FCL lies in the anterior border of lateral femoral epicondyle and above popliteal tendon. The distant from the relative isometric point to the attachment of tibia and fibula is the shortest when the knee joint is extended straightly and flexion, it is relative stability at 20 to 30 degrees of flexion.5. during flexion of the knee from 20 degrees to all degrees, the movement point of the medial femoral condyle relative to tibia lies in the anterior and posterior border of the FCL; The movement point of the lateral femoral condyle lies in the anterior and posterior border of the FCL and the popliteal tendon.Conclusion1. In coronal MRI, The FCL is completely shown in only one plane at posterior oblique plane 11 degrees to the long axis of the fibular neck; The TCL can be completely shown at anterior oblique plane 8 degrees to the long axis of the tibia.2. The relative isometric points of the TCL and FCL lie in the anterior border of medial and lateral femoral epicondyle.3. During flexion of the knee from 20 degrees to all degrees, the TCL. FCLand PT can prevent medial and lateral shift of tibial condyle.