| PrefaceThe posterolateral static stabilizers of the knee contains several ligamentous and tendinous structures that are the fibular collateral ligament (FCL) , the arcuate ligament (AL) , the popliteus tendon (PT) , the popliteofibular ligament ( PFL) , and the fabellofibular ligament ( FFL). These structures, especially the first three, primary restrains against external rotation, posterior translation and varus angulation of the tibia . The dynamic stabilizers of the knee contains biceps femoris, iliotibial band and the lateral gastrocnemius musles. These structures restrains against external rotation, posterior translation and varus angulation of the tibia cooperating with the static stabilizers execept for knee flex-tion , strongly reinforce stability of the posterolateral aspect. Injuries to the posterolateral structures of the knee may result in posterolateral instability , which result in significant impairment unless correctly diagnosed and treated on initial evaluation, is the common reason of the failure in the reconstruction of the ACL and PCL. A reliable physical examination of the posterolateral structures of the knee may be difficult to obtain in this initial period after injuries. MRI has been overlooked in the filed because of a very complex and uncomprehensively anatomical structure. The experiment is to anatomy and measure the FCL, PT, PFL, BF and ITB, found out the relativity of the anatomy and MRI , and filtrate the best location and condition for MRI. The ultimate objective of this study is to determine whether MRI can reliably demonstrate injuries to individual components of the posterolateral knee and apply for diagnose in clinic.Method1. Material, anatomy and measureDissections were performed on 10 embalmed and 4 fresh cadaveric knees. All of the knees had at least 15. 0 cm of bone and soft tissue proximal and distal 20. 0 cm to the joint line. Posterolateral aspect of the knees were carefully dissected and identified the attachment of the PT on the lateral epicondyle, and FCL, PFL and BF on the fibular head or styloid, and the ITB on the femur lateral condyle and the Gerdy' s tubercle, which these structures were measured and defined the relationship.2 Confirmed the fibular neck long axis and measuered the angle between the fibular neck long axis and the individual stuctureThe standard sagittal and coronal plane is established by the plane of complete displaying fibular neck and stoylid . Fibular neck long axis is established by the fibular neck. Transfusion pipe which was affused water is sutured and marked the PFL, PT and FCL, finding out these structures and measuring the angle between the structure and the long fibular neck axis in the sagittal and coronal plane.2. MRI examination20 uninjured knees in clinical were examed by standard knee coil using for all images. Magnetic resonance imaging of the knee were performed on a 1.5 -T MRI unit (Toshiba). The MRI protocol chosen for this study used coronal, coronal posterior oblique plane 11° and 40° , sagittal medial oblique plane 40°, sagittal lateral oblique plane 30°; fast spin - echo, proton density and T2 -wighted sequences : TR 4000 -5000ms, TE:90/18ms, thickness, 3 mm; slice gap, 0.6 mm; T1 -wighted sequences : TR486ms, TE:15ms, thickness, 2 mm; slice gap, 0.4 mm; FOV, 16 × 16 cm; matrix, 192 ×256. We observed the MRI appearance of the difference location, appearance ratio and integrality.Result1. Anatomy of the posterolateral structureWe 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 FCL 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 ( anterior to posterior) from the anterior edge of the fibular head. The average total length of the fibular collateral ligament between its attachment sites was 67.08 ± 3.09 mm . The popliteus muscle coursed proximally and laterally over the posterolateral knee from its attachment on the posteromedial tibia, it gave rise to the popliteus tendon at the lateral one - third of the popliteal fossa . The popliteus tendon attachment was at the most anterior fifth of the popliteal sulcus, which it is always anterior to the fibular collateral ligament femoral attachment. The average total length of the popliteus tendon from its femoral attachment to its musculotendinous junction was 67.08 ±3.09 mm. The pop-liteofibular ligament originated at the musculotendinous junction of the popliteus and formed an average 63. 9 ±5. 43° angle with its medial attachment site, which is covered by the lateral gastrocnemius tendon. The distolateral attachment of the posterior division was at the tip and posteromedial aspect of the fibular styloid process. The average distances from the attachments to the fibular styloid process , the anterolateral and the posteriormadial divisions of the poplite-ofibular ligament is 15.20 ± 1.49 mm and 11. 20 ± 1.42 mm, width is 10.90 ± 1. 92 mm. The direct arm of the long head of the biceps femoris muscle inserts onto the posterolateral aspect of the fibular styloid, while the anterior arm attaches the far lateral edge of the fibular styloid and fibular head, also continues anteriorly and distally extension. The direct arm of the short head of the biceps femoris muscle inserts onto the posterolateral aspect of the fibular head, while the anterior arm passed medial to the FCL and insert on the posterolateral tibial tuberosity. Two layers of the iliotibial band can be dissected. The superficial layer is the main tendinous component of the iliotibial band, and it inserted distally at Gerdyts tubercle. The deep layer of the iliotibial band attaches to the distal femur lateral condyloid and intermuscular septum.2. In sagittal MRI ,the angle of between FCL and fibular neck long axis is 11.5 ± 1.65°, the angle of between intraarticular part of the PT and fibular neck... |
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