myosesh Musculoskeletal post lateral collateral ligament injury in the knee

lateral collateral ligament injury in the knee

This is uncommon injuries of the knee in comparison to with any other knee injuries such as ACL and meniscus.  Lateral collateral ligament (LCL) locates outside of the knee and connects fibula and femur (lateral femoral epicondyle), inserting into biceps femoral tendon before it attaches to the head to the head of fibula. This ligament has a role to stabilise the knee joint from the varus force as well as restraint to external rotation.  LCL sprain by itself happens only 2 % of the knee injury and but usually occurs with other knee ligaments such as ACL and meniscus tear.  *1,2

Structure of the LCL *3

  • A width of 4-5mm, 2.6mm thick and 69.9mm long 
  • Independent and cordlike
  • It is located on proximal (1.4mm) and posterior (3.1mm) to lateral epicondyle
  • Located deep to the superficial layer of ITB 
  • Gives stability to posterolateral corner of the knee (LCL, popliteus tendon and popliteofibular ligament)


The role of lateral collateral ligament of the knee is to stop knee from going laterally too much which means to resist varus force (pressure from inside to outside), and give a resistance to posterior tibial displacement and tibial external rotation in conjunction with PFL. *4

  • Sudden trauma such as sports accident and car accident 
  • Weakness of the muscles can cause problems
  • Athletes in tennis, gymnastics, soccer, basketball, ski, netball and rugby 

Signs and symptoms

  • Swelling of the knee (lateral side)
  • Stiffness of the knee joint
  • Weakness and instability of the knee
  • Pain with varus force


  1. Grade 1 LCL sprain (mild tear)

Grade 1 is mild sprain that ligament is slightly over-stretched and defined as a subcutaneous fluid surrounding the mid substance of the ligament at one of both insertions. 

  • Grade 2 LCL tears (partial tear)

In this grade, ligament is partly torn. Swelling and bruising are often seen over the knee area. You may feel instability of the knee and pain with movement. 

  • Grade 3 LCL sprain (Severe)

Grade 3 is the condition where ligament is completely torn, which causes swelling and sometimes bleeding underneath the skin. Other symptoms are fluid in the bursa, loss of demarcation and avulsion of the ligament insertion. Therefore, you would feel instability of the knee joint and difficult to do weight-bearing movement. At this grade, other structures injuries such meniscus, ACL and other ligaments can occur with LCL sprain as these other structures have to compensate LCL to stabilise the joint. 

Special test for LCL Sprain


  • Ice
  • Surgery
  • Do rehabilitation
  • Tape to help stabilise the joint
  • Splint or supporter

Unlike the MCL, LCL takes longer or barely heals when it is torn. Thus, non-conservative treatment is often delivered.  *6

Grade 1 and 2 seems manageable with conservative treatment. 


  1. M. Alex Haddad, Justin M. Budich and Brian J. Eckenrode Conservative management of an isolated grade 3 lateral collateral ligament injury in an adolescent multi-sport athlete: a case report Int J sports phys Ther. 2016 Aug: 11(4): 596-606
  2. Grawe Brian, Schroeder Amanda, Kakazu Rafael and Messer Malynda Lateral collateral ligament injury about the knee: Anatomy, Evaluation and management 2018 journal of the AAOS 26(6): 120-127
  3. Moorman CT III, LaPrade RF: Anatomy and biomechanics of the posterolateral corner of the knee. J KneeSurg 2005;18(2):137-145
  4. Buzzi R, Aglietti P, Vena LM, Giron F: Lateral collateral ligament reconstruction using a semitendinosus graft. Knee Surg Sports Traumatol Arthrosc 2004;12(1)
  5. Majewski M, Susanne H, Klaus S: Epidemiology of athletic knee injuries: A 10-year study. Knee2006;13(3):184-188
  6. Wilson WT, Deakin AH, Payne AP, Picard F, Wearing SC: Comparative analysis of the structural properties of the collateral ligaments of the human knee. J Orthop Sports Phys Ther 2012;42(4):345-351

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