The collateral ligaments are found on the sides of the knee and stabilize the joint. The medial collateral ligament (MCL), located on the inside of the knee, connects the femur (the thigh bone), to the tibia. The lateral collateral ligament (LCL), on the outside surface of the knee, connects the femur to the fibula (the smaller bone in the lower leg). The collateral ligaments are strong, fibrous connective tissues that limit sideways motion of the knee and brace it against unusual movement. The knee ligaments keep the knee in a rigid position while standing, and assists the joint when the leg is in motion.

The LCL is also referred to as the fibular collateral ligament (FCL) but the term LCL is still in common usage. That may change, as FCL is more specific and descriptive terminology, and since lateral collateral ligaments exist in many places in the body, including the fingers, the thumb, the wrist, the elbows, and the ankles.

LCL anatomy

Recent research points out that the anatomy of this ligament is highly inconsistent, and suggests a new classification for it altogether. These findings were based on dissection of 111 lower limbs, which found that the FCL (as it was referred to in the study) originated most commonly (72% of cases) from the lateral femoral epicondyle, and inserted on the lateral surface of the head of the fibula.

knee ligaments

Image: BruceBlaus

In other variations, nearly 13% were divided into two branches (bifurcated), and nearly 1% were divided into three branches (trifurcated) and ligaments were also found with two and three distal bands. One limb had a double FCL, and another had a fusion of the FCL and ALL (antero-lateral ligament).This seems like a lot of variations in a relatively small study, but variations in anatomy of the ligaments of the knee are an important consideration when physicians are deciding how to treat tears.

A study of 23 cadavers found that the femoral insertion of the antero-lateral ligament (ALL) overlapped the LCL in all dissected knees, and 15 of them also had thin attachments to the lateral meniscus.

The LCL nerve supply originates from the common fibular nerve. Blood is supplied from the popliteal artery, from branches of the superior and inferior lateral genicular arteries.

What causes a LCL injury or tear?

Injured ligaments are considered sprains (stretching of the ligament), and are graded on a scale according to the severity. A Grade 1 sprain indicates mild damage and the ligament is still able to keep the knee joint stable.

A Grade 2 sprain, usually referred to as a partial tear, indicates the ligament has stretched to the point of being loose and making the knee unstable. A complete tear of the ligament is referred to as a Grade 3 sprain. These classifications apply to LCL tear or injury, MCL injury, ACL injury, and in fact, all ligaments of the body.

An LCL tear may be caused by direct force to the side of the knee when the foot is on the ground, such as being tackled on the football field. Awkward landings from a jump, such as in basketball or volleyball, may also cause an LCL sprain. As is the case with trauma to other ligaments of the knee, twisting the knee is also a common cause, so it’s a common injury among athletes in contact sports, particularly those that require fast pivoting, such as basketball, hockey, and soccer.

The LCL is subject to varus deformity (bent or twisted inward) forces at all knee flexion angles and is also resistant to external rotation near extension. In the opposite condition, an injured knee may be subject to valgus deformity, a condition in which the bone segment distal to a joint is angled outward, that is, angled laterally, away from the body’s midline. The Q-angle can be measured by a goniometer or viewed as imaginary straight lines, if you aren’t familiar with using one.

The Q-angle is formed by these imaginary intersecting from the anterior superior iliac spine of the pelvis to the midline of the kneecap (one line) and from the midline of the kneecap to the tibial tuberosity, the small bump that is about an inch under the patella (second line). The intersection represents the lines of action of the quadriceps and patellar tendons, respectively, on the kneecap. The measurement can be taken with the client/patient in the standing or lying position measured with the knee slightly flexed, to center the patella in the trochlea. Standing is preferred, as it is a more accurate representation of the weight-bearing forces on the knee.

Foot pronation (pes planus or flat feet) and valgus both increase the Q-angle. The range of normal for the Q-angle varies within the literature, and there’s speculation whether the broader pelvic anatomy in women is the cause of a greater Q-angle. The average values of Q-angles are 10 degrees for men and 15 degrees for women.

Patellar alignment can be affected by the degree of valgus at the knee, but the degree of valgus of the knee is not considered dependable as an indicator for severity of symptoms. Either condition, varus or valgus, may be present at birth, caused by injury, or due to osteoarthritis–and the risk of developing osteoarthritis is greatly increased by knee injuries.

In a longitudinal cohort study of young adults, age 25 to 34, 5,247 people with previous knee injuries and 142,825 persons who had not been injured, concluded that those with a previous injury are six times more likely to develop osteoarthritis, with highest risks found after injury to the cruciate ligament, meniscus, and intra-articular fracture.

Medial vs lateral injury: what’s the difference?

Although anterior cruciate ligament (ACL) tears get more publicity, possibly due to the athletes who get injured during televised games, the medial collateral ligament (MCL) is the most commonly injured knee ligament overall. Athletes and those with other injuries, such as knee dislocations, are most apt to have a torn lateral collateral ligament (LCL). The medial collateral ligament (MCL), which is a major stabilizer of the knee joint, is reportedly torn in nearly 8% of all knee injuries. The lateral collateral ligament (LCL) and posterior collateral ligament (PCL) are less frequently injured, but can be involved in severe injuries involving multiple ligament tears.

Most studies involving athletes consider the “return to play” rate—how many who are injured are able to return to participating in competitive sports. A study examining the return to play (RTP) rate for athletes with knee injuries involving more than one ligament found that the RTP rate is significantly less than the RTP rate for athletes with isolated ACL tears. Athletes with ACL and MCL tears also have a far better RTP rate, a substantially shorter time to RTP, and are much more likely to return to prior performance than athletes with ACL and PCL(posterior cruciate ligament)/LCL tears.

It is an interesting side note that a 2019 study was conducted to review the accuracy of Internet images of ligamentous knee injuries. A search query was conducted on Google and Bing for ACL tear,’ ‘PCL tear,’ ‘MCL tear,’ and ‘LCL tear.’ Three orthopedic doctors analyzed the first 100 images of each search. In the ACL group, Bing returned images that were 60% correct, compared to 45% correct on Google. Google was also less accurate than Bing for PCL (39% versus 38%), and LCL (32% to 30%). Both Bing and Google were 48% accurate for MCL tear.

That’s not a very good commentary on accuracy from either search engine, but we have to consider the source. Images on the Internet may be uploaded by anyone, so we should make it a point to depend on images (and health topics in general) from science websites, academic healthcare publishers, and online anatomy books, rather than those from unknown sources.

The study concluded that physicians should be proactive in making anatomic diagrams and easily understood explanations available to their patients to avoid confusion and improve the layperson’s understanding when searching the internet for additional information about their condition. The reader can conclude that we need better and more accurate information!

Symptoms of LCL Injury

The symptoms of LCL injury are:

  • Pain at the sides of your knee. MCL injury results in pain on the inside of the knee; an LCL injury results in pain on the outside of the knee.
  • Swelling and bruising over the site of the injury.
  • The feeling that the knee is unstable.
  • A person suffering a traumatic tear of any ligament may hear the “popping” sound at the time of the injury.

Assessment for damage to collateral ligaments can be assessed by having the patient medially and laterally rotate the leg. Pain during medial rotation indicates damage to the medial ligament, pain during lateral rotation indicates damage to the lateral ligament.

Risk factors of LCL Injury

There are few studies concerning LCL injury available on non-athlete populations. Studies involving injury of multiligament knee injuries (MLKI)  are also much more prevalent than studies involving isolated LCL injuries. A 2020 study states that although LCL injury is the least frequent of all knee injuries, that high suspicion is warranted on knee exams.

One study of adolescent athletes concluded that isolated collateral ligament injuries are rare in adolescent athletes. MCL injuries, 25% of which occurred with patellar instability injuries, were 4 times more prevalent than injuries to the LCL, 25% of which also have trauma to other posterolateral corner structures. Football and soccer players suffer the most Grade III collateral ligament injuries, accounting for 20% to 25%.

A study of NFL players also concluded that isolated complete tears of the lateral collateral ligament (LCL) of the knee are rare, as the majority of injuries are part of broader damage to the posterolateral corner. There is limited data about the ideal management of isolated LCL injuries, especially in professional athletes.

Playing contact sports, and/or those involving jumping and quick pivots seems to be the biggest risk factor for knee ligaments injury on the whole. In fact, “jumper’s knee” is a term often used to describe chronic patellar tendinosis, a common problem among athletes, the cause of which is still uncertain.

The main theory is that it is caused by chronic overuse and overload, but patella height, the Q-angle, the flexibility of the extensor muscles, ankle and knee joint dynamics, and the performance of the leg extensors (as inherent factors) and the high frequency and intensity of sporting activity, especially on a hard playing surface, as well as the sport (as outside factors).

One case report of multi-ligament injuries involved a healthy 28-year-old female Olympic alpine skier who sustained a deep knee flexion with varus force injury to her right knee during a competitive skiing event. A physical assessment and MRI revealed that the knee was basically destroyed, with complete tears of the ACL and LCL, a medial meniscus tear, a complex radial tear of the lateral meniscus, proximal tibiofibular joint ligament tear, a popliteofibular ligament tear, and a common peroneal nerve neuropraxia. The athlete underwent a complete knee reconstruction surgery, including a novel meniscus radial repair technique, and went on to compete in the 2018 Olympic trials 12 months later and the 2018 Winter Olympics 14 months after the surgery.

According to a literature review, the rate of injury in alpine ski racing is high, averaging 23.5 to 36.7 per 100 skiers injured per season. Knee injuries are the most common injury, with anterior cruciate ligament (ACL) injuries being the most significant in terms of time loss from sport, but about 30% have concomitant ligament injuries, according to the review, which covered injury reports from 1976-2018. Most injuries take place during competition rather than training, and are more likely to happen late in competition, when the athlete is fatigued. A majority are able to return to competition, though the time varies according to the severity of the injury.

The US Army conducted an analysis of soft-tissue knee injury (STKI) in 2013, of soldiers who were on active duty between 2000-2005. The study looked at a variety of STKI, and considered different risk factors, including length of service, deployment, previous knee injury, previous upper leg injury, and previous lower leg injury. Demographics such as gender, marital status, age, rank, education level, and ethnicity were also considered. LCL and MCL injuries were considered together. Women accounted for 15% of the population studied. The analysis concluded that injuries increased with increased years of length of service and increased age. Overwhelmingly, those who suffered non-soft tissue injuries to the patella experienced a 10-fold increased risk of soft-tissue injury within the two years following the injury. Deployment increased the risk of soft-tissue injury 33% to 39%.

There are other pathologies related to the knee. Pain behind the knee is a symptom of  Baker’s cyst, a fluid-filled cyst that forms at the back of the knee. On a personal note, a friend was treated for one earlier this week, put on antibiotics due to infection, and a few days later, it was aspirated to drain the fluid. It’s a painful condition (it’s impossible to have on a pair of pants without being aware of it), and is sometimes misdiagnosed.

Deep vein thrombosis (DVT) has similar symptoms to a  ruptured Baker’s cyst, severe pain in the calf and inflammation. Doppler ultrasound imaging must be used to ascertain the diagnosis, because treating suspected DVT with therapeutic doses of low molecular weight heparins (LMWHs) can cause dangerous bleeding and worsen the prognosis of complicated Baker’s cyst.

A 2018 study discusses seven consecutive cases in which the patients were misdiagnosed with DVT without imaging. LMWHs were administered to all patients, but the erroneous treatment caused the further complication of compartment syndrome in the leg. Four patients required emergency fasciotomy, cutting away the fascia to relieve the pressure.

Another condition, Patellofemoral Pain Syndrome (PFPS) is the most common cause of anterior knee pain in active young adults. PFPS is anterior knee pain involving the patella, retinaculum and surrounding soft tissues, which is diagnosed after ruling out other pathology of the knee joint. It is a chronic disease caused by overuse and misuse, instead of acute trauma.

In addition to pain, which is made worse by climbing or squatting, the patient may experience a grinding sensation on the kneecap, and “catching” when rising from a seated position. Exercises to strengthen the quadriceps have shown to be the most effective treatment for PFPS.

LCL injury treatments

Treatment is dependent on severity of the injury, which may be preliminarily diagnosed by physical examination, but is confirmed with MRI. It also depends on whether the injury is isolated to the LCL or involves multiple ligaments. Immediately following the injury, all grades of injury can be treated with rest, compression, NSAIDs, and ice (Gabe Mirkin’s retraction of his RICE theory hasn’t fully caught on and may never fully catch on). To avoid causing cold injury to the common peroneal nerve, ice should be applied to the lateral knee for no longer than 15 minutes at a time.

For Grade I and II injuries, treatment is usually a conservative therapeutic approach of crutches for one week, followed by three to six weeks of hinged bracing and rehabilitative physical therapy. For Grade III injuries (complete tear), reconstructive surgery is the treatment of choice to reduce pain and restore range of motion. Reconstructive surgery of an isolated LCL tear is normal a graft taken from the semitendinosus allograft.

The previously mentioned study on NFL athletes examined surgical vs. conservative treatment for isolated Grade III (complete tear) LCL and concluded that nonoperative management of MRI-documented collateral ligament injuries in NFL athletes results in more rapid return to play without the risks of surgery, with an equal likelihood of returning to professional-level play. Football players who underwent surgery missed an average of 14.5 weeks at play, while those who didn’t were only sidelined for an average of two weeks.

LCL injury prevention

Weakness in the quadriceps is a common contributor to knee injury, as well as a consequence of it, but there’s the catch. While strengthening the quads and the legs in general is a good idea for anyone who is participating in any kind of sport, there’s no guarantee that an injury won’t occur in spite of those efforts. You can’t play soccer, football, basketball, hockey, tennis, or ski without risking a contact injury or injury caused by sudden pivoting. You can’t run without pounding the feet. It’s easy to say “be cautious,” but actually doing so in the heat of competition isn’t likely.

Considerations for Massage Therapy

As with all clients, the massage therapist should collect a health history and perform a thorough intake. A visual gait assessment will allow you to observe if the client is limping, bearing more weight on the uninjured leg.

For those clients who state “I’ve hurt my _____,” it’s important to find out if they have seen a doctor for a diagnosis, and if so, what that was, and what treatment, if any, is being done for it. People are often uncooperative if they don’t like what the doctor says, such as “wear a brace,” or “stay off of it for two weeks,” or other advice that they find inconvenient. Hopefully, they aren’t looking at massage as a quick fix for a serious issue.

If they haven’t had a diagnosis, you are not going to make one, but there are orthopedic assessments that are within scope of practice, that may indicate to you that the client needs a referral to a physician. The varus stress test is used to test the integrity of the structures that prevent lateral instability at the knee (lateral collateral ligament, joint capsule, cruciate ligaments). To perform the test:

  • The client is supine with the affected knee in full extension.
  • The therapist stabilizes the affected leg in slight external rotation with one hand on the lateral malleolus.
  • The therapist places their other hand on the medial aspect of the knee.
  • The therapist applies a laterally directed stress on the medial knee.
  • The therapist flexes the client’s knee to 30 degrees, applying the same pressure on the lateral knee to isolate the lateral collateral ligament


The positive sign is the presence of pain and hypermobility at the lateral aspect of the knee. Again, this is an assessment, not a diagnosis. Particularly if the client reports that they did something, such as hurting the knee while playing ball, or skiing, suggest that they see a physician.

If the client is more comfortable, use a bolster or pillow underneath the knee. Another word about orthopedic assessment: While the term orthopedic massage gets bandied about in massage therapy, there is not strictly one technique that is described as orthopedic massage. The orthopedic part of it is the assessment. The massage therapist may integrate any number of different techniques into the massage, with the intention of helping restore restricted movement and treating musculoskeletal pain. Many therapists, as well as sports medicine physicians subscribe to the theory that you should perform cross-fiber friction “to break up scar tissue/adhesions,” but that should be done lightly on any recent injury—and if the client has had a recent surgery for the injury, it shouldn’t be done at all without the doctor’s permission.

We need to keep in mind that massage is not going to repair a torn ligament. It may help the pain, but that depends on the technique and the pressure applied, which should never be beyond the client’s pain tolerance. We are here to help, not harm. If it brings the client comfort and pain relief, we have done our job.

Laura Allen
Laura Allen, LMT
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Laura Allen is President of Sales & Marketing of CryoDerm. A graduate of Shaw University and The Whole You School of Massage Therapy, Allen has been a licensed massage therapist since 1999 and an Approved Provider of Continuing Education under the NCBTMB since 2000. She has taught classes all over the U.S., Canada, and Europe.

She is the author of The Educated Heart, Cultural Crossroads of Healthcare and Healing, and numerous other books. Allen resides in North Carolina with her husband, James Clayton, and their two rescue dogs.