FCL and LCL Sprain Treatment Options
The lateral collateral ligament (LCL) and the posterolateral corner (PLC) are key stabilizers on the outer side of the knee. Together, they protect the knee from buckling outward (varus instability), control rotational movements, and provide support during cutting, pivoting, and directional changes. The PLC is a complex structure that includes the LCL, popliteus tendon, popliteofibular ligament, and supporting capsule. Injuries to this region often occur from high-energy sports trauma, direct blows to the inner knee, hyperextension, or twisting injuries. Because the PLC is biomechanically intricate, injuries in this region are frequently underdiagnosed—and when not treated correctly, they can lead to chronic instability, cartilage damage, and early arthritis.
Patients with LCL or PLC injuries commonly experience pain along the outer knee, swelling, difficulty walking on uneven ground, and a feeling that the knee may give way, especially with pivoting. Some describe a “shift” or “clunking” sensation during cutting movements. Early and accurate diagnosis is critical because PLC injuries rarely heal on their own and often occur alongside ACL or PCL tears.
Diagnosis begins with a careful physical exam. Dr. José Vega will evaluate for tenderness along the lateral knee, assess varus laxity, and perform specific tests—including the dial test, external rotation recurvatum test, and posterolateral drawer test—to determine the degree of instability. These specialized maneuvers help differentiate isolated LCL injuries from complex PLC injuries.
X-rays are used to evaluate for associated fractures or subtle signs of instability, such as widening of the lateral joint space. MRI is the gold standard for visualizing injury to the LCL, popliteus, popliteofibular ligament, and surrounding structures, as well as any associated ACL or PCL tears. Because the PLC is a three-dimensional structure, an MRI helps guide treatment decisions and predict prognosis.
Isolated Grade I or some Grade II LCL sprains can often heal successfully with nonsurgical treatment. These injuries involve stretching or partial tearing of the ligament but maintain reasonable structural integrity.
Nonsurgical management includes:
Bracing
A hinged knee brace protects the lateral side of the knee and limits varus stress during healing. Many patients wear a brace for several weeks during early recovery.
Physical Therapy
Therapy focuses on restoring range of motion, strengthening the quadriceps, hamstrings, and hip muscles, and improving balance and proprioception. Recovery for mild injuries may take 6 to 12 weeks, with gradual return to activity.
Activity Modification
Impact sports, running, pivoting, and lateral movements are avoided during the early phase of healing.
However, true PLC injuries, Grade III LCL tears, or combined ligament injuries almost always require surgery, as these structures do not predictably heal with conservative measures. Failure to address them properly can lead to chronic instability and graft failure if an ACL or PCL is reconstructed without addressing the PLC.
Surgery is recommended when:
- There is a Grade II LCL injury with significant laxity or a Grade III complete tear
- The PLC is injured (popliteus or popliteofibular ligament involvement)
- There is combined ACL or PCL injury, which must be treated in coordination
- Symptoms of persistent varus or rotational instability remain after conservative care
- There are fractures or avulsion-type injuries off the fibular head or lateral femoral condyle
Because the PLC is biomechanically essential for rotational control, even small injuries can compromise outcomes of cruciate ligament surgeries if left untreated.
LCL Repair or Reconstruction
If the ligament has torn cleanly from the bone and the injury is acute, LCL repair may be possible. This involves reattaching the ligament using sutures or small anchors.
For chronic injuries or poor-quality tissue, LCL reconstruction is performed using a graft, often from the hamstring tendons (autograft) or donor tissue (allograft). The graft is placed in the anatomic position of the native LCL to restore stability.
Posterolateral Corner Reconstruction
For PLC injuries, reconstruction is the standard of care. Several anatomic reconstruction techniques restore the function of the:
- Popliteus tendon
- Popliteofibular ligament
- LCL
Anatomic PLC reconstruction has been shown to significantly improve knee stability and reduce the risk of future ligament failures.
Combined Ligament Reconstruction
Because the PLC is intimately connected to the ACL and PCL, combined injuries require coordinated treatment. Failure to reconstruct the PLC alongside cruciate tears dramatically increases the risk of graft failure.
After surgery, patients typically undergo:
- A period of protected weight-bearing (often with crutches)
- Hinged bracing to limit stress on the reconstruction
- Gradual, structured rehabilitation emphasizing motion, strength, and neuromuscular control
Full return to sports generally occurs between 9–12 months, depending on injury severity, associated ligament involvement, and progress in rehabilitation.
LCL and posterolateral corner injuries can cause significant knee instability and, if untreated, may lead to long-term cartilage damage and chronic pain. While mild, isolated LCL sprains often heal with conservative care, most PLC injuries and complete LCL tears require surgical reconstruction to restore stability and protect the knee. With accurate diagnosis and a comprehensive treatment plan, patients can return to high-level activity with excellent outcomes.
If you have knee pain, instability, or difficulty with pivoting after an injury to the outer part of your knee, please contact Dr. José Vega’s office in Cleveland to schedule a consultation. Together, we will review your imaging, discuss your goals, and create a personalized plan to restore stability and get you safely back to activity.
References
- Geeslin AG, Moulton SG, 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.
- LaPrade R, Floyd E, Carlson G, Moatshe G, Chahla J, Monson J. The Posterolateral Corner: Explanations and Outcomes Journal of Arthroscopic Surgery and Sports Medicine Article in Press. Journal of Arthroscopic Surgery and Sports Medicine. 2021;2.
- LaPrade RF, Gerhold C, Kunze KN, et al. A Contemporary International Expert Consensus Statement on the Evaluation, Diagnosis, Treatment, and Rehabilitation of Injuries to the Posterolateral Corner of the Knee. Arthroscopy. Published online May 23, 2025:S0749-8063(25)00352-4.
- LaPrade RF, Wentorf F. Diagnosis and treatment of posterolateral knee injuries. Clin Orthop Relat Res. 2002;(402):110-121.
- White AE, Bryan MR, Thomas TL, et al. Repair Fails More Frequently Than Reconstruction in Acute Posterolateral Corner Knee Injuries: A Systematic Review of Outcomes Following Surgical Management. Arthroscopy. 2025;41(8):3223-3240.e8.
At a Glance
Dr. Jose Vega
- Board-certified orthopedic surgeon
- Fellowship-trained sports medicine specialist
- Author of industry leading peer reviewed publications
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