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Knee

FCL / LCL Sprains

What is a Lateral Collateral Ligament (LCL) Injury?

The lateral collateral ligament (LCL) is one of the key stabilizing ligaments of the knee, located on the outer (lateral) side of the joint. It connects the femur (thighbone) to the fibula (the smaller bone of the lower leg) and prevents excessive side-to-side movement.

An LCL injury occurs when this ligament is stretched or torn, usually due to a force that pushes the knee inward (varus stress). These injuries are less common than medial collateral ligament (MCL) injuries but are often more complex, as they may involve the posterolateral corner (PLC) of the knee—a group of structures that also help stabilize rotation.

The knee is stabilized by four major ligaments:

  • Anterior cruciate ligament (ACL): Prevents forward movement of the tibia (shin bone) relative to the femur (thigh bone).
  • Posterior cruciate ligament (PCL): Prevents backward movement of the tibia relative to the femur.
  • Medial collateral ligament (MCL): Resists inward (valgus) stress.
  • Lateral collateral ligament (LCL): Resists outward (varus) stress.

The LCL works closely with the popliteus tendon, popliteofibular ligament and biceps femoris muscle as part of the posterolateral corner (PLC) to provide stability during walking, pivoting, and cutting. Injury to one or more of these structures can lead to significant instability and functional impairment.

LCL injuries typically occur when a direct blow or force pushes the knee outward, overstretching the ligament on the outside of the joint.

Common causes include:

  • Sports collisions (e.g., football, soccer, hockey) where the inside of the knee is struck.
  • Falls or awkward landings that twist the knee outward.
  • Motor vehicle or skiing accidents involving a varus stress and rotation.
  • Hyperextension injuries with rotational force.

Because of the LCL’s location, isolated tears are relatively uncommon; they often occur alongside injuries to the ACL, PCL, or posterolateral corner.

Symptoms can vary depending on the severity of the tear:

  • Grade I (mild sprain): Stretching or small tears of the ligament fibers; mild pain and tenderness along the outer knee, but no significant instability
  • Grade II (partial tear): Moderate pain, swelling, and a variable amount of looseness with side-to-side testing.
  • Grade III (complete tear): Significant pain initially, followed by instability and a feeling that the knee might “give out.”

Common symptoms include:

  • Pain and tenderness along the outer side of the knee.
  • Swelling and bruising around the lateral joint line.
  • A feeling of looseness or instability, especially during side-to-side movement.
  • Difficulty walking, pivoting, or changing direction.
  • Possible numbness or tingling if the nearby peroneal nerve is irritated or stretched.

Diagnosis begins with a careful physical examination by Dr. José Vega, Cleveland’s trusted orthopedic knee specialist.

During the exam, Dr. Vega will:

  • Assess for tenderness along the outer knee.
  • Perform varus stress testing at different angles to evaluate ligament integrity.
  • Examine the posterolateral corner and check for involvement of other ligaments.
  • Evaluate nerve function, particularly the common peroneal nerve, which runs near the fibular head.

Imaging Studies

  • X-rays may reveal associated fractures or joint alignment abnormalities.
  • MRI is the gold standard for identifying the location and severity of LCL and posterolateral corner injuries, as well as any involvement of the ACL, PCL, or meniscus.

Yes — most Grade I and II LCL injuries heal successfully with nonsurgical management.

Nonsurgical Treatment

  1. Bracing: A hinged knee brace protects the ligament and limits side-to-side motion while allowing controlled flexion and extension.
  2. Activity Modification: Avoid twisting, pivoting, or high-impact activity during early recovery.
  3. Physical Therapy:
    • Early range of motion to prevent stiffness.
    • Progressive strengthening of the quadriceps, hamstrings, and hip muscles.
    • Balance and proprioception training to restore stability.
  4. Ice and Anti-inflammatory Medication: Helps control pain and swelling during initial healing.

Most patients regain full motion and stability within 3 months with structured therapy.

Surgery is indicated when:

  • The LCL is completely torn (Grade III).
  • There are combined injuries to the posterolateral corner, ACL, or PCL.
  • The knee remains unstable despite bracing and therapy.
  • There is avulsion of the ligament from bone or associated nerve injury.

These more severe injuries often require reconstruction rather than simple repair.

LCL reconstruction involves replacing the torn ligament with a tendon graft—either from the patient (autograft) or a donor (allograft).

Surgical Steps

  • Small incisions are made along the outer knee.
  • The torn ligament is identified, and tunnels are created in the femur and fibula.
  • The graft is secured to restore the ligament’s original tension and alignment.
  • In cases with posterolateral corner involvement, additional structures are reconstructed to fully restore stability.

Recovery Timeline

  • Brace and crutches: Used for 6 weeks to protect the graft.
  • Physical therapy: Begins early with gentle range-of-motion exercises, followed by progressive strengthening.
  • Return to activity:
    • Light activity at 3 months.
    • Full sports participation between 6–9 months, depending on recovery and sport demands.

With proper surgery and rehabilitation, most patients achieve excellent stability and return to their pre-injury activity level.

While not all injuries are avoidable, risk can be reduced by:

  • Maintaining balanced lower-body strength (quads, hamstrings, hips).
  • Warming up properly before athletic activity.
  • Using proper landing and cutting techniques in sports.
  • Wearing knee braces for protection in contact sports if previously injured.

Early diagnosis and appropriate treatment are essential to prevent chronic instability and early joint degeneration.

LCL injuries, though less common than other knee ligament injuries, can significantly affect stability and athletic performance. Most mild to moderate injuries heal with bracing and rehabilitation, while more severe or combined injuries may require surgical reconstruction for optimal recovery. If you’re experiencing pain, swelling, or instability along the outer side of your knee, contact Dr. José Vega’s office in Cleveland to schedule a detailed evaluation and personalized treatment plan.

References

  1. Geeslin AG, LaPrade RF. Outcomes of treatment of acute grade-III isolated and combined posterolateral knee injuries: a prospective case series and surgical technique. J Bone Joint Surg Am. 2011;93(18):1672–1683.
  2. Moulton SG, Geeslin AG, LaPrade RF. A systematic review of the outcomes of posterolateral corner knee injuries, part 1: surgical treatment of acute injuries. Am J Sports Med. 2016;44(5):1336–1342.
  3. Engebretsen L, Wijdicks CA. An evidence-based approach to the management of collateral ligament injuries of the knee: isolated and combined injuries. Knee Surg Sports Traumatol Arthrosc. 2015;23(11):3157–3166.
  4. Dean RS, LaPrade CM, Chahla J, et al. Outcomes after isolated lateral collateral ligament reconstruction: a systematic review. Orthop J Sports Med. 2019;7(4):2325967119833568.
  5. Tanaka MJ, Chahla J, Farr J, et al. Posterolateral corner knee injuries: current concepts and management. J Bone Joint Surg Am. 2016;98(10):867–876.
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Dr. Jose Vega

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