LCL Tear

What an LCL tear is

The lateral collateral ligament is a narrow, cord-like structure running from the outer end of the thigh bone down to the head of the fibula, the smaller bone in the lower leg. It resists forces that push the knee outward and is tightest when the knee is straight. Unlike the ligament on the inner side, it has no attachment to the meniscus.

The LCL rarely acts alone. It belongs to a group of structures at the back and outer corner of the knee, the posterolateral corner, which together control sideways opening and rotation. An injury that tears the LCL frequently damages neighboring structures, which is why isolated LCL tears are uncommon and why the injury is taken seriously. The usual mechanism is a blow to the inner side of the knee that drives it outward, or a twisting or hyperextension injury. The common peroneal nerve, which supplies the muscles that lift the foot, runs close to the ligament around the fibula and can be injured too.

Symptoms that often bring people in

• Tenderness along the outer side of the knee, often toward the top of the fibula
• Bruising or swelling on the outer aspect of the joint
• A sense that the knee opens or gives way, particularly with the leg straight
• Difficulty on uneven ground or slopes, or when pivoting away from the injured leg
• Numbness over the outer shin or top of the foot, or difficulty lifting the foot

How it is evaluated

Examination looks at more than the ligament itself. The surgeon applies a gentle outward stress with the knee straight and slightly bent to see whether the outer side opens, and adds rotational tests that assess the posterolateral corner as a whole. Because nerve involvement is possible, sensation over the outer shin and foot and the strength of the muscles that lift the foot are checked. Leg alignment matters too, since a knee bowed outward loads these structures continuously. X-rays look for fractures and for a fragment pulled from the fibular head; MRI defines which structures are involved.

Treatment options in general terms

Low-grade, genuinely isolated injuries may be managed without surgery. That can involve:

• Protected motion. A brace that keeps the knee from opening on the outer side while movement is restored.
• Rehabilitation. Rebuilding quadriceps and hip strength and control during walking and turning.
• Monitoring nerve recovery. Following sensation and foot movement where the peroneal nerve is affected.

Surgery is considered more readily than for inner-side injuries, and may be discussed when:

• The posterolateral corner is involved. Combined outer-corner injuries, which are often repaired or reconstructed rather than left to heal.
• A bony avulsion is present. The ligament has pulled a fragment from the fibular head and may be reattached.
• A cruciate ligament is also torn. Untreated outer-corner laxity strains a cruciate reconstruction, so the two are often planned together.

What to expect when you consult Dr. Wolfson

Dr. Wolfson is board certified in the United States and Canada and has a background in orthopedic trauma as well as sports injury. A consultation covers how the injury happened, examination of the outer and posterior structures of the knee, assessment of nerve function, review of imaging, and whether rehabilitation or surgery fits your case. Second opinions are welcome.

This page provides general information about LCL tears and is not medical advice. It is not a substitute for examination, imaging and diagnosis by a qualified physician. Every case is different and requires individual evaluation. If you have severe pain, an obvious deformity, loss of function, fever, or an injury from a significant accident, seek medical care promptly.

Contact Dr. Wolfson if you would like to setup an appointment. If you are a new patient, please book all in-person appointments with Dr. Wolfson via telephone.

If you live outside of the San Francisco Bay Area, you can request a complimentary phone consultation with Dr. Wolfson to assess your case. Please call or e-mail us to set up your complimentary consultation.

Call: (415) 221-4400

E-mail: [email protected]