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Lateral Collateral Ligament Injury of the Knee

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Original Editors - Wouter Claesen

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Heleen Van Cleynenbreugel, Darrell Blommaert and Wouter Claesen  


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Key words: Lateral Collateral Ligament knee injury, Knee sprains, peroneal nerve injury, instability LCL injury, Instability knee lateral collateral ligament, Lateral collateral ligament injury definition, lateral collateral ligament injury examination, lateral collateral ligament injury etiology, lateral collateral ligament injury epidemiology, lateral collateral ligament injury characteristics.


An injury to the lateral collateral ligament of the knee can be caused by a varus stress, lateral rotation of the knee when weight-bearing or when the LCL loses it’s elasticity caused by repeated stress [1][2][3][4].The LCL can be sprained (grade I), partially ruptured (grade II) or completely ruptured (grade III) [3]. Additional damage of the ACL, PCL and medial knee structures is possible when the lateral knee structures are injured [5](A2).

LCL physiopedia.jpg
Clinically Relevant Anatomy

The lateral collateral ligament is a structure of the arcuate ligament complex, together with the biceps femoris tendon, popliteus muscle and tendon, popliteal meniscal and popliteal
LCL physiopedia.jpg

fibular ligaments, oblique popliteal, arcuate and fabellofibular ligaments and lateral gastrocnemius muscle[5](A2). The lateral collateral ligament is a strong connection between the lateral epicondyle of the femur and the head of the fibula, with the function to resist varus stress on the knee and tibial external rotation and thus a stabilizer of the knee. When the knee is flexed to more than 30°, the LCL is loose. The ligament is strained when the knee is in extension.[3][6][7]

Epidemiology /Etiology

Injuries to the lateral and medial collateral ligaments are common, but the MCL injuries occur more often than the LCL injuries. 25% of the patients in the United States with an acute knee injury in the emergency rooms, have a collateral ligament injury. Adults of 20-34 and 55-65 years old have the highest incidence. LCL (and MCL) injuries occur equally for men and women as for different races. These injuries are succesfully treated with conservative methods. Even when surgery is necessary, there is normally a good prognosis. [2][8](A2)[9]

An injury of the lateral collateral ligament most often occurs from a varus force or by twisting the knee. Such an injury occurs in sports with a lot of quick changes in direction or with violent collusions. Examples are soccer, basketbal, skiing, footbal or hockey. An LCL injury can also be caused by repeated stress or when an elderly person falls. [1][3][4]

Characteristics/Clinical Presentation

The LCL is not connected with the lateral meniscus, so it is not automatically associated with a meniscal tear. However, an LCL injury often occurs along with other ligament injuries, including ACL, PCL, and MCL, and is frequently seen along with knee dislocations.

Differential Diagnosis [7][10][11]

- Injury at the posterolateral corner
- PCL tear
- MCL tear
- ACL tear
- Meniscus tear/ injuries
- Chondral injury
- Tibial Plateau Fractures
- Patellar/ knee dislocation
- Popliteus avulsion
- Iliotibial Band Syndrome
- Biceps femoris tendinitis

Diagnostic Procedures

The elements that occur when there is a lateral collateral ligament injury are: [1][12]

- Ask if the patient felt or heard a ‘pop’ in the knee and have an ustable feeling in the knee[13]
- Look for swelling, bruising, stiffnes, erythema (after several days) or deformity of the knee[14]
- Palpate the knee and serach for tenderness, warmth, swelling, etc.
- No significicant joint effusion, unless there is also a cruciate ligament or meniscal rupture

The lateral collateral ligament injury can be a grade I, II or III and these can be distinguished by the symptoms. [1][7][11][15]
Grade I:
- Mild tenderness and minor pain over the lateral collateral ligament
- Usually no swelling
- The varustest in 30° is painful but doesn’t show any laxity (< 5 mm laxity)
Grade II:
- Significant tenderness and pain on the lateral collateral ligament and on medial side of the knee
- Swelling in the area of the ligament
- The varustest is painful and there is laxity in the joint with a clear endpoint. (5 -10mm laxity)
Grade III:
- The pain can vary and can be less than in grade II
- Tenderness and pain at the medial side of the knee and at the injury
- The varustest shows a significant joint laxity (>10mm laxity)
- The feeling of having a very unstable knee
- Swelling

To determine the severity and laxity of the knee the therapist can carry out a varustest. To determine whether it is a grade 2 sprain or 3, you can take the test in extension. When the patient has a severe grade 3 sprain, the knee will show laxity, while a grade 2 sprain won’t. Also the grade 3 sprain will not have a demonstrable endpoint at 30 degree flexion.[16]When the varustest is done in extension, there is also an evaluation of the posterolateral corner structures and cruciate ligaments. [11]

You can also take an MRI scan of the knee. It is an accurate way to see how badly the lateral collateral ligament has been torn and to detect other injuries to the knee. Noticing a partial rupture with an MRI scan is difficult. To make sure that the bones of the knee are not broken, you can take an X-ray.[1][5](A2)[9][17]

The peroneal nerve can also be injured. This type of injury requires surgical repair because of the complex structures which are involved. Damage is easily spotted if you see a foot drop of the patient while he is walking or when the patient feels a numbness or weakness in the foot. [1][18]

Outcome Measures

A committee of international knee experts created the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), which is a knee-specific, rather than a disease-specific, measure of symptoms, function, and sports activity. IKDC-SKF is a reliable and valid knee-specific measure of symptoms, function, and sports activity that is appropriate for patients with a wide variety of knee problems. Outcome is related to the severity of the injury and the functional rehabilitation possible.

International Knee Documentation Committee Subjective Knee Form


LCL test

Medical Management

Grade 3 sprains are more severe, the anterior cruciate or posterior cruciate ligaments may also have become damaged. In this case surgery can be needed to prevent further instability of the knee joint.[19] Of course there would be a much longer revalidation needed for the patient to recover from this injury. The kind of surgery for reconstruction of the ligaments which are damaged isn’t that important. It is far more the experience and teamwork of the surgeons and physiotherapists involved in the treatment that makes the difference.[20] Total immobilization of the knee is not a good method of recovery for any type of knee sprain. This would lead to atrophy of the muscle groups of the upper leg and a weak feeling of the knee joint.[21]

Physical Therapy Management [1][3][4][9][25]

 When a patient suffers a direct impact to the inner surface of the knee joint, the therapist can automatically assume that the lateral collateral ligament is damaged because of an abnormal stretch of the ligament caused by the joint from gapping at the outer surface. The first thing to do is applying the RICE method. The doctor may give some NSAIDs and a brace. The patient’s injured knee is placed in a functional rehabilitative brace with limits set 0° extension and 90° flexion to control ligament stress yet still allow motion. The brace is worn for three to six weeks. When the pain and swelling are reduced, you can start with excersises to restore the strength, normal range of motion, aerobic conditioning, technique refinement and proprioceptive retraining. Electrical stimulation can also prevent the muscles wasting due to immobilization. [26]

A combination of open and closed kinetic chain exercises is used to increase hamstrings, quadriceps, gluteal and triceps sural strength. The goal of these exercises is to improve the control of the knee joint with weight-bearing activities.These exercises must not produce patellofemoral pain or increase collateral ligament pain. Once the patient is ambulating in full weight bearing, stork standing (Therapist flexes patients hip on the involved side to 90 degrees and applies direct downward force through the femur while stabilizing sacrum) and other balance activities can begin.[25] The patient can be treated with specific techniques, including isometric, isotonic, isokinetic and eccentric exercices. [26]

Normal range of motion:
If full motion is not achieved by around week 5 or 6, joint mobilization techniques and prolonged stretches may be required.[25]

Aerobic conditioning:
Walking on the treadmill with progression to jogging occurs once a normal walking gait has been achieved. Jogging then progresses to running and sprinting as long as pain and edema are avoided.[25]

Proprioceptive retraining:
Just as with others injured areas, balance, agility, and coordination must be restored following knee injury or surgery. Proprioception is the element basic to these parameters. Early proprioception exercises before weight bearing can include a variety of activities. For example, with eyes closed the patient can move the involved knee to mimic the uninvolved knee’s position, or with eyes closed can position the knee at a designated angle.[25]

Massage and ultrasound are also a part of the treatment. The revalidation takes 2- 8 weeks, depending on the severity of the injury.

Most of the time an injury of ligaments will take quite a long time, because of the difference in density. It’s important to work as well psychical as physical. The patient has to be motivated and encouraged for a longstanding, intensive rehabilitation.[26]

LCL injuries can be grouped into classes. Grade 1 injuries show normal or up to 5 mm of joint space opening with a solid endpoint. A similar solid endpoint is observed with grade 2 injuries, but opening up to 10mm. Grade 3 injuries demonstrate greater than 10 mm of joint space opening and often are associated with other ligament injuries. There are differences in treatment in the classes. With grade I and II injuries, a brace at 45 degrees for 4-6 weeks is enough. Progressive range of motion after 3 weeks as comfort allows enables progression in rehabilitation. But with an injury grade III there is a surgery necessary due to rotational instability, because they usually involve the posterolateral cornor of the knee. After the surgery, you need a brace and physical therapy for prevent the instability.
Periodic evaluations at 2 to 4 weeks are required for operative and nonoperative management[27][28][29]

Key Research

Daniël Haverkamp et al. Translation and Validation of the Dutch Version of the International Knee Documentation Committee Subjective Knee Form, internet, 26/11/13, (


HOUGLUM, Peggy A. Therapeutic exercise for musculoskeletal injuries. USA, Human Kinetics, 2005, p.858, 867

Clinical Bottom Line

An injury to the lateral collateral ligament of the knee can be caused by a varus stress, lateral rotation or when the LCL loses it’s elasticity. There are three degrees distinguishable. Additional damage of the ACL, PCL and medial knee structures is possible when the lateral knee structures are injured. In case of grade 3 surgery can be needed to prevent further instability of the knee joint. Otherwise exercises to restore strength,  

Recent Related Research (from Pubmed)

1) Lateral stabilizing structures of the knee: functional anatomy and injuries assessed with MR
2) Importance of the different posterolateral knee static stabilizers: biomechanical study:[22](A2)


1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Cedars Sinai. Health conditions. (accessed 2 May 2011)
2. ↑ 2.0 2.1 Medscape reference. Drug, Conditions & Procedures. (accessed 2 May 2011)
3. ↑ 3.0 3.1 3.2 3.3 3.4 J. A. K. Davies, P. Gayle, A. Brochert. LCL injury- Lateral Collateral Ligament Injury. (accessed 5 May 2011)
4. ↑ 4.0 4.1 4.2 PhysioAdvisor. LCL Tear (Lateral Collateral Ligament) (accessed 6 May 2011)
5. ↑ 5.0 5.1 5.2 5.3 J. A. Recondo, E. Salvador, J.A. Villanúa, M.C. Barrera, C. Gervás, J.M. Alústiza. Lateral Stabilizing Structures of the Knee: Functional Anatomy and Injuries Assessed with MR Imaging. Radiographics 2000; 20 Spec No: S91-102. full text: (accessed 2 May 2011)
6. ↑ Medscape reference. Drugs, Conditions &amp;amp;amp;amp;amp; Procedures. (accessed 4May 2011)
7. ↑ 7.0 7.1 7.2 eOrif. Lateral Collateral Ligament Tear. (accessed 8 May 2011)
8. ↑ M.Majewski, H. Susanne, S. Klaus. Epidemiology of athletic knee injuries: a 10-year study.The knee Volume 13, Issue 3, 2006, pages 184-188, full text in pdf:;_imagekey=B6TCJ-4JRKCV4-1-1&amp;_cdi=5172&amp;_user=1011600&amp;_pii=S0968016006000032&amp;_origin=gateway&amp;_coverDate=06%2F30%2F2006&amp;_sk=999869996&amp;view=c&amp;wchp=dGLbVtz-zSkzV&amp;md5=2e67d2c214e0fac0b96730da4a77a107&amp;ie=/sdarticle.pdf (accessed 10 May 2011)
9. ↑ 9.0 9.1 9.2 Knee Pain Info. Collateral ligament injuries. (accessed 9 May 2011)
10. ↑ Medscape reference. Drugs, Conditions & Procedures. (accessed 12 May 2011)
11. ↑ 11.0 11.1 11.2 Medscape reference. Drugs, Conditions & Procedures. (accessed 12 May 2011)
12. ↑ Medscape reference. Drugs, Conditions &amp; Procedures. (accessed 12 May 2011)
13. ↑ FRANK R. NOYES, MD, LONNIE PAULOS, MD, LISA A. MOOAR, BA, and BEN SIGNER, BA Knee Sprains and Acute ; Knee Hemarthrosis ,Misdiagnosis of Anterior Cruciate Ligament Tears, Physical Therapy December 1980 vol. 60 no. 12 1596-1601
14. ↑ Hai-ning Zhang, Jie Zhang, Cheng-yu Lv, Ping Leng, Ying-zhen Wang, Xiang-da Wang, and Chang-yao Wang Modified biplanar open-wedge high tibial osteotomy with rigid locking plate to treat varus knee J Zhejiang Univ Sci B. 2009 September; 10(9): 689–695
15. ↑ Sports Injury Clinic. Knee Pain, Lateral Ligament Sprain. (accessed 12 May 2011)
16. ↑ Reider B Medial collateral ligament injuries in athletes. Sports Med 21(2): 147- 156, 1996
17. ↑ UCSF Medical Center. Conditions &amp; Treatments, Orthopedics, LCL Tear. (accessed 12 May 2011)
18. ↑ Jennifer Baima , Lisa Krivickas Evaluation and treatment of peroneal neuropathy Curr Rev Musculoskelet Med. 2008 June; 1(2): 147–153
19. ↑ Pekka Kannus, MD Nonoperative treatment of Grade II and III sprains of the lateral ligament compartment of the knee , Am J Sports Med January 1989 vol. 17 no. 1 83-88
20. ↑ Michael T Hirschmann, Nadia Zimmermann, Thomas Rychen, Christian Candrian, Damir Hudetz, Lukas G Lorez, Felix Amsler, Werner Müller and Niklaus F Friederich Clinical and radiological outcomes after management of traumatic knee dislocation by open single stage complete reconstruction/repair, BMC Musculoskelet Disord. 2010; 11: 102
21. ↑ Reider B Medial collateral ligament injuries in athletes. Sports Med 21(2): 147- 156, 1996
22. ↑ R.Lasmar, A. Marques de Almeida, J.W. Serbino JR., R. Freire da Mota Albuquerque, A. J. Hernandez. Importance of the different posterolateral knee static stabilizers: biomechanical study. Clinics 2010; 65(4):433-40 (accessed 6 May 2011)
23. Irrgang JJ et al. Development and validation of the international knee documentation committee subjective knee form, internet, 23/11/13, ( (2)

24. Daniël Haverkamp et al. Translation and Validation of the Dutch Version of the International Knee Documentation Committee Subjective Knee Form, internet, 26/11/13, ( (2)

25. HOUGLUM, Peggy A. Therapeutic exercise for musculoskeletal injuries. USA, Human Kinetics, 2005, p.858, 867 (1A)

26. Dr Pekka Kannus, Markku Järvinen, Nonoperative Treatment of Acute Knee Ligament Injuries, sports medicine, 1990, Volume 9, p244-260 (2C)

27. Adam B Agranoff et al. Medial Collateral and Lateral Collateral Ligament Injury, Medscape, 2013 (5)

28. Michael P Nogalski et al. , Collateral Ligament Pathology, Medscape, 2012 (5)

29. Michael P Nogalski et al. , Collateral Ligament Pathology Treatment & Management, Medscape, 2012 (5)

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