PLC

后外侧结构（PLC, Posterolateral Corner）

Function

功能

  • Works synergistically with the PCL to control external rotation and posterior translation
    与后交叉韧带（PCL）协同控制胫骨的外旋和后移

Anatomy

解剖结构

Included Structures 包括的结构：

  • LCL (295 N)
    外侧副韧带，强度为295 N

  • Popliteus muscle and tendon (680 N)
    腘肌及其肌腱，强度为680 N

  • Popliteofibular ligament (229 N)
    腘腓韧带，强度为229 N

  • Lateral capsule
    外侧关节囊

  • Variable 可变结构：

    • Arcuate ligament 弓状韧带
    • Iliotibial band 髂胫束
    • Fabellofibular ligament 髌骨腓韧带

Biomechanics

生物力学特性

  • The PLC provides both static and dynamic stability to the posterolateral corner, preventing hyperextension, tibial external rotation, and varus angulation
    后外侧结构提供静态和动态稳定性，防止过度伸展、胫骨外旋和内翻角度

  • Injury to the PLC can lead to significant instability and is often associated with injuries to the ACL and PCL
    后外侧结构的损伤可能导致显著的不稳定性，且常与前交叉韧带（ACL）和后交叉韧带（PCL）的损伤相关

Clinical Significance

临床意义

  • Accurate diagnosis and treatment of PLC injuries are crucial to prevent chronic knee instability and failure of cruciate ligament reconstructions
    准确诊断和治疗后外侧结构损伤对于防止慢性膝关节不稳定和交叉韧带重建失败至关重要

  • Surgical reconstruction of the PLC aims to restore the normal anatomy and biomechanics of the knee
    后外侧结构的手术重建旨在恢复膝关节的正常解剖结构和生物力学特性

MCL

内侧副韧带（MCL, Medial Collateral Ligament）

Function

功能

  • Resists valgus angulation
    抵抗外翻应力（valgus angulation）

  • Works in concert with ACL to provide restraint to axial rotation
    与前交叉韧带（ACL）协同限制轴向旋转

Anatomy

解剖结构

  • Origin 起点
    Medial femoral epicondyle 股骨内侧髁

  • Insertion 止点
    Medial condyle of tibia 胫骨内侧髁

  • Structure 结构

    • Broad, flat, membranous band 宽而扁平的膜状带
    • Divided into superficial and deep components 分为浅层和深层部分

Superficial MCL 浅层内侧副韧带

  • Lies just deep to gracilis and semitendinosus
    位于缝匠肌和半腱肌的深层

  • Originates from medial femoral epicondyle and inserts into the periosteum of proximal tibia
    起于股骨内侧髁，止于胫骨近端的骨膜

  • Contributes 57% and 78% of medial stability at 5° and 25° of knee flexion, respectively
    在膝关节屈曲5°和25°时，分别提供57%和78%的内侧稳定性

  • Primary stabilizer to valgus stress at all angles
    在所有角度下抵抗外翻应力的主要稳定结构

Deep MCL 深层内侧副韧带

  • Separated from superficial portion by a bursa
    与浅层之间有滑囊分隔

  • Attaches to medial meniscus (coronary ligament)
    附着于内侧半月板（冠状韧带）

  • Divided into meniscofemoral and meniscotibial portions
    分为半月股骨部和半月胫骨部

  • Posterior fibers blend with posteromedial capsule and posterior oblique ligament (POL)
    后部纤维与后内侧关节囊和后斜韧带（POL）融合

  • Acts as secondary restraint to valgus stress at full knee extension
    在膝关节完全伸展时作为抵抗外翻应力的次要稳定结构

Biomechanics

生物力学特性

  • Strength: 4000 N (vs valgus stress)
    抵抗外翻应力的强度为4000 N

Posteromedial Corner

后内侧结构（Posteromedial Corner）

Function

功能

  • Important for rotatory stability
    对旋转稳定性至关重要

Anatomy

解剖结构

  • Lies deep to MCL
    位于内侧副韧带（MCL）的深层

  • Formed by 由以下结构组成：

    Ligaments of the Knee（膝关节的韧带）下篇
    • Insertion of semimembranosus 半膜肌的止点
    • Posterior oblique ligament (POL) 后斜韧带
    • Oblique popliteal ligament 斜腘韧带
    • Posterior capsule 后关节囊

  • Resists valgus load and tibial internal rotation in full extension
    在完全伸展时抵抗外翻负荷和胫骨内旋

Medial Patellofemoral Ligament (MPFL)

内侧髌股韧带（MPFL, Medial Patellofemoral Ligament）

Function

功能

  • Provide restraint against lateral translation of the patella from 0° to 30° of knee flexion
    在膝关节屈曲0°至30°时，限制髌骨的外侧移位

Characteristics

特征

  • Low tension throughout flexion-extension (2–10 N of force)
    在屈伸过程中张力较低（2–10牛顿）

  • Isometric between 0° and 90°, then becomes slack beyond 90°
    在0°至90°之间等长，超过90°后变得松弛

  • Can withstand 200 N before tearing
    撕裂前可承受200牛顿的拉力

  • Much lower load to failure than ACL (1725 N)
    承载失败的负荷远低于前交叉韧带（ACL）的1725牛顿

Anatomy

解剖结构

  • Lies in 2nd layer of medial soft tissue complex
    位于膝关节内侧软组织复合体的第二层

  • Bundles 束：

    • Short oblique bundle, inserts on superior patellar pole
      短斜束，止于髌骨上极
    • Inferior straight bundle
      下直束

  • Femoral insertion 股骨附着点：

    • Schottle’s point：

      • 1.3 mm anterior to posterior femoral diaphyseal cortex
        距股骨干后皮质前方1.3毫米
      • 2.5 mm distal to posterior origin of medial femoral condyle
        距股骨内侧髁后部起点远端2.5毫米
      • Proximal to the level of the posterior point of Blumensaat’s line
        位于Blumensaat线后点的近端
      • Medial femoral condyle, distal to adductor tubercle and proximal to MCL attachment
        股骨内侧髁，位于收肌结节远端和内侧副韧带附着点近端之间

  • Patellar attachment 髌骨附着点：

    • Fan-like structure inserting at junction between proximal-middle thirds of superomedial border of patella
      扇形结构，附着于髌骨上内侧边缘近端和中部三分之一交界处

Pathoanatomy

病理解剖

  • Tears off femoral attachment > patellar attachment
    股骨附着点的撕裂多于髌骨附着点

  • Some studies show otherwise
    一些研究显示相反的结果

  • Risk of 2nd dislocation is 13%
    第二次脱位的风险为13%

  • Risk of 3rd dislocation (after 2nd dislocation) is 50%
    第三次脱位（在第二次脱位后）的风险为50%

Anterolateral Ligament (ALL)

前外侧韧带（ALL, Anterolateral Ligament）

Function

功能

  • Rotational stability
    提供旋转稳定性

Anatomy

解剖结构

  • Lies in Layer 3 with LCL
    与外侧副韧带（LCL）同位于第三层

  • Characteristics 特征：

    • Width: 7 mm at midpoint/near joint line
      中点/接近关节线处的宽度为7毫米
      • Femoral attachment width: 8 mm
        股骨附着点宽度为8毫米
      • Tibial attachment width: 11 mm
        胫骨附着点宽度为11毫米
    • Length: 59 mm
      长度为59毫米

  • Attachments 附着点：

    • Femoral 股骨：

      • Lateral femoral epicondyle
        股骨外上髁

    • Tibial 胫骨：

      • Midway between Gerdy’s tubercle and head of fibula
        位于Gerdy结节和腓骨头之间的中点
    • Attachments to middle third of lateral meniscus body：
      • Meniscotibial portion (dot)
        半月板-胫骨部分（点）

      • Meniscofemoral portion (asterisk)
        半月板-股骨部分（星号）
  • Lateral inferior genicular artery and vein contained between lateral meniscus and ALL at level of joint line
    外侧下膝动脉和静脉位于外侧半月板和前外侧韧带之间，处于关节线水平

  • NO connections to ITB
    与髂胫束（ITB）无连接

Pathoanatomy

病理解剖

  • Segond’s fracture (associated with ACL rupture) is avulsion fracture of ALL
    Segond骨折（与前交叉韧带断裂相关）是前外侧韧带的撕脱性骨折