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Knee Deep - The Low Down on Cartilage and Ligament Injuries

Updated: Jun 14, 2019

The knee is a complex weight-bearing joint in the body that is the junction between the femur (thigh bone) and the tibia (shin bone). It is technically a hinge joint, but there is also a great deal of twisting and rotation that occurs at the knee. All this movement and weight bearing can cause a great deal of wear and tear on the knee as you go through your normal daily activities in life.

To help absorb the excessive forces that occur at the joint, your body has two different kinds of cartilage; (i) articular cartilage and (ii) menisci (or meniscus - singular)

Articular cartilage

Articular cartilage lines the ends of all your bones. Any place that two bones come together to form a joint, you will find articular cartilage. The purpose of this cartilage is to allow smooth, pain free gliding of one bone on the other.

The ends of your bones are very rough and uneven and as bones are very rich in both blood and nerve supply, if you were to rub one bone on the other, the motion would not be smooth, and you would get a lot of pain and bleeding. The articular cartilage helps prevent this. By covering the end of your bones, it creates a smooth surface to move one bone on the other. As cartilage has no direct nerve or blood supply itself, when it comes in contact with another cartilage coated bone, there is no pain or bleeding. However, this comes at a cost; because there is no direct nerve or blood supply, articular cartilage cannot regenerate. In other words, once it’s gone, it’s gone. If the articular cartilage begins to wear away, or if it completely wears down to bone, there will be a significant increase in pain and swelling at the knee. This is osteoarthritis (OA).


Knee menisci (or a meniscus if talking about them singularly) are fibrocartilage kidney bean shaped wedge-like cushions that separate the thigh bone (femur) from your shin bone (tibia). It is commonly referred to as your "cartilage". Each knee joint has a medial meniscus and a lateral meniscus.

Menisci assist with the rotational stability created by the anterior cruciate ligament, but also crucially act as a shock absorber. They are there to absorb the forces when we walk, run and jump, so that the bone surfaces are not damaged. The amount of force increases exponentially as the speed of movement increases from walking to running to jumping. Your menisci therefore help to disperse these compressive forces over the entire knee rather than isolating them.They are attached to the tibial plateau (the top of the shin bone) along the outside edge, but the inside border is free floating. Like articular cartilage, menisci can wear down over time, but they can also tear.

What is a Meniscus Tear?

There are a number of potential causes of meniscal tears.

In the older adult, the tear may be due to a natural age-related degeneration of the meniscus or a rough arthritic femoral bone surface tearing into the softer meniscus. In this case, surgery may be required to attend to both the meniscal repair and to repair the damaged joint surface.
In younger individuals, the meniscus is more commonly torn traumatically, by twisting on a slightly flexed knee, especially if the foot is fixed in place.
The traumatic type of meniscal injuries are most often sports/activity-related.
If the knee is already loose or unstable from a previous ligament injury, this is even more likely to occur. This would be particularly true if a person with an unstable knee were participating in a sport that involves twisting or pivoting, such as soccer or any court sports.

Types of Meniscus Tear

The meniscus can be torn anterior to posterior, radially (parrot beak), or can have a bucket handle appearance, as illustrated below.

Depending on the type of meniscus tear, meniscus repair may be complicated. A large meniscus tear that is inadequately treated may cause premature degenerative bony (arthritis) changes.

Signs and Symptoms of a Meniscus Tear

The history of a painful twist occurring on a slightly flexed knee will indicate the likelihood of a meniscus tear. You may also experience clicking, popping, or locking of the knee. These symptoms are usually accompanied by pain along the knee joint line and a joint swelling.Clinical examination may reveal tenderness along the knee joint line. You will usually notice it is painful to squat.
Your physiotherapist or doctor will use McMurray's test and other clinical tests to confirm a meniscus tear diagnosis.

X-rays or MRI?

A MRI scan is the most accurate non-invasive test to confirm a meniscus tear. X-rays do not show a meniscus tear.

Does a Meniscus Tear Heal?

Meniscal blood supply is limited: your meniscus receives its nutrition from blood and synovial fluid within the joint capsule. Each menisci has two distinct regions that affect their ability to heal.

We call these the Red Zone and the White Zone.

Red Zone

The red zone has blood supply, whereas the the white zone doesn’t have a blood supply and won’t heal naturally. The outside of the meniscus has a blood supply from the synovial capsule. Lateral meniscal tears may heal without the need for surgery.

White Zone

The inside of the meniscus gets its nutrition from the synovial fluid. Due to this, tears of the inner meniscus do not usually heal due to a lack of blood supply to trigger an inflammatory healing response. These injuries often require surgery.

Treatment Options for a Knee Meniscus Tear

Initially, you should treat the knee injury with conservative techniques that include rest, ice, compression, and elevation, or the RICE method:

  • Rest your knee. Use crutches to avoid any weight bearing on the joint. Avoid any activities that worsen your knee pain.

  • Ice your knee every two waking hours for 10-15 minutes.

  • Compress or wrap the knee in an elastic bandage to reduce inflammation.

  • Elevate your knee to reduce swelling

A small meniscus tear, or a tear in the red zone, will usually respond quickly to physiotherapy treatment. One of the major roles of your meniscus is shock-absorption. Luckily, the other vital shock absorbers around your knee are your muscles. Researchers have discovered that if you strengthening your leg muscles, your bone stresses will reduce as your muscle strength improves and your knee becomes more dynamically stable.
Taking a conservative (non-surgical) approach to recovery, your therapist will aim to:
  • Reduce pain and inflammation.

  • Normalise joint range of motion.

  • Strengthen your knee: esp quadriceps (esp VMO) and hamstrings.

  • Strengthen your lower limb: calves, hip and pelvis muscles.

  • Improve patello-femoral (knee cap) alignment.

  • Normalise your muscle lengths Improve your proprioception and balance Improve your technique and function eg walking, running, squatting, hopping and landing.

  • Minimise your chance of re-injury.

Meniscal injuries are commonly associated with other knee injuries. If this is the case, these will be addressed and need to be treated in conjunction with your meniscal tear.

How Long Does Meniscal Healing Take?

Your meniscal tear will commonly take up to six or eight weeks to fully heal. As mentioned previously, some meniscal tears will require surgery.

Your GP/physiotherapist/Orthopaedic Specialist will guide you as to what is most likely for your knee injury.

It is important to avoid activities and exercises that place excessive stress through your meniscus and further delay your healing. In some cases, it may be advised you to keep weight off your knee. In this instances, crutches may be recommended.

Everyone is different, so be guided by your physiotherapist.

Will You Require Surgery for a Meniscus Injury?

Most surgeons will recommend a few weeks of physiotherapy treatment prior to contemplating surgery.

Pre-operative physiotherapy has two main benefits:

  • Successfully rehabilitating your knee injury without the need for surgery.

  • Strengthening your knee to better prepare you for your post-operative rehabilitation.

If surgery is required, surgery is usually performed arthroscopically (via a fibre-optic camera about the size of a pencil) to either resect (remove) the torn fragment or repair (stitch) a tear in the outer zone.

Ligaments in the Knee

The four main ligaments in the knee connect the femur (thighbone) to the tibia (shin bone), and include the following:

Anterior cruciate ligament (ACL) - The ligament, located in the centre of the knee, that controls rotation and forward movement of the tibia (shin bone). It is one of the most commonly injured knee ligaments.

Posterior cruciate ligament (PCL) - The ligament, located in the centre of the knee, that controls backward movement of the tibia (shin bone).

Medial collateral ligament (MCL) - The ligament that gives stability to the inner knee.

Lateral collateral ligament (LCL) - The cord-like ligament that gives stability to the outer knee.

Here we are going to look at types, modes and grades of severity of injury sustained by the LCL

In isolation, a lateral collateral ligament injuries only account for 2% of all knee ligament injuries. Most LCL injuries occur in combination with, damage to other knee ligaments and structures. eg ACL, Meniscus and posterolateral corner.

What Causes an LCL Sprain?

The main function of your lateral collateral ligament is to resist varus force and external tibial (shin bone) rotation, which occurs if your tibia/foot is forced inwards in relation to the knee or when your foot is grounded and your knee is twisted medially.


  • Sharp changes in direction,

  • Twisting the knee whilst the foot is fixed,

  • Incorrect landing technique,

  • Hyperextension of the knee or

  • A blunt force hit to the knee, such as in football tackle or a motor vehicle accident.

The incident usually needs to happen at speed but muscle weakness or incoordination predispose you to a ligament sprain or tear.

Knee Ligaments Injury Severity

The severity and symptoms of a knee ligament sprain depend on the degree of stretching or tearing of the knee ligament. You may notice an audible snap or tearing sound at the time of your ligament injury.

In a mild Grade I LCL sprain, the knee ligament has a slight stretch, but they don't actually tear. Although the knee joint may not hurt or swell very much, a mild ligament sprain can increase the risk of a repeat injury.

With a moderate Grade II LCL sprain, the knee ligament tears partially. Knee swelling and bruising are common, and use of the knee joint is usually painful and difficult. You may have some complaints of instability or a feeling of the knee giving way.

With a severe Grade III sprain, the ligament tears completely, causing swelling and sometimes bleeding under the skin. As a result, the joint is unstable and can be difficult to bear weight. You may have a feeling of the knee giving way. Often there will be no pain or severe pain that subsides quickly following a grade 3 tear as all of the pain fibres are torn at the time of injury. With these more severe tears, other structures are at risk of injury including the meniscus and/or ACL.

How is a LCL Sprain Diagnosed?

On examination, your physiotherapist will look for signs of ligament injury. There will be tenderness over the ligament site, possible swelling and pain with stress tests. MRI may also be used to diagnose a knee ligament injury and look at other surrounding structures for combination injuries.

How Long does it take for an LCL Injury to Heal?

Treatment of an LCL injury varies depending on its severity and whether there are other combination injuries.

Grade I sprains usually heal within a few weeks. Maximal ligament strength will occur after six weeks when the collagen fibres have matured. Resting from painful activity, icing the injury, and some anti-inflammatory medications are useful. Physiotherapy will help to hasten the healing process via electrical modalities, massage, strengthening and joint exercises to guide the direction that the ligament fibres heal. This plus exercises to strengthen your knees helps to prevent a future tear.

When a Grade II sprain occurs, use of a weight-bearing brace or some supportive taping is common in early treatment. This helps to ease the pain and avoid stretching of the healing knee ligament. After a grade II injury, you can usually return to activity once the joint is stable and you are no longer having pain. This may take up to six weeks. Physiotherapy helps to hasten the healing process via electrical modalities, massage, strengthening and joint exercises to guide the direction that the knee ligament fibres heal. This helps to prevent a future tear and quickly return you to your pre-injury status.

When a Grade III injury occurs, you usually wear a hinged knee brace for up to six weeks, with a small amount of movement, and use crutches for 1-2 weeks to protect the knee ligament from weight-bearing stresses. As your pain resolves and knee ligament repairing occurs, the knee brace can be gradually unlocked to allow greater knee movement as tolerated. The aim is to allow for full knee ligament healing and gradually return to normal activities. Severe LCL injury is most successfully treated via physiotherapy and the advice of a knee surgeon. Patients may not return to their full level of activity for 3 to 4 months. We highly recommend that you seek professional advice from a healthcare practitioner who specialises in knee ligament injuries to avoid long-term knee instability.

What is the Treatment for an LCL Injury?

Depending on the grade of knee ligament injury you can start to feel better within days to just a few weeks of the injury.

Your therapy treatment will aim to:

  • Reduce pain and inflammation.

  • Normalise joint range of motion.

  • Strengthen your knee: especially quadriceps (esp VMO) and hamstrings.

  • Strengthen your lower limb: calves, hip and pelvis muscles.

  • Improve patellofemoral (knee cap) alignment

  • Normalise your muscle lengths

  • Improve your proprioception, agility and balance

  • Improve your technique and function eg walking, running, squatting, hopping and your return to sport, activities and exercises.

  • Minimise your chance of re-injury.

We strongly suggest that you discuss your knee ligament injury rehabilitation plan after a thorough examination by your sports physio/ therapist.

Exercises to Strengthen Supporting Knee Musculature for Meniscus Tear and/or Ligament Tear

Attempt the following exercises, in the initial stages of rehabilitation being guided by pain. These exercises should contract the muscles surrounding the knee without putting the knee through loaded weight bearing. Only when these can be performed pain free, should you progress to more complex exercises. Seek professional advice for further guidance.

  • VMO Contraction/Active knee extension

Sit on the floor or lie on your back with your affected leg extended and the other knee bent for support. Place a tightly rolled towel underneath the affected knee. Tighten the muscle at the front of your thigh (quadriceps) by pushing your knee down into a towel. Put your fingers on your inner quadriceps (vmo) to feel the muscle tighten during contraction. Hold for 5 seconds and repeat 10 times as hard as possible pain free.

  • Straight leg raise

Lie on your back with your legs straight out in front of you. Bend the knee on your uninjured side and place the foot flat on the floor. Tighten the thigh muscle on your injured side and lift your leg about 8 inches off the floor. Keep your leg straight and your thigh muscle tight. Slowly lower your leg back down to the floor. Do 2 sets of 16.

  • Prone hip extension

Lie on your stomach with your legs straight out behind you. Fold your arms under your head and rest your head on your arms. Draw your belly button in towards your spine and tighten your abdominal muscles. Tighten the buttocks and thigh muscles of the leg on your injured side and lift the leg off the floor about 8 inches. Keep your leg straight. Hold for 5 seconds. Then lower your leg and relax. Do 2 sets of 16.

  • Clam exercise

Lie on your uninjured side with your hips and knees bent and feet together. Slowly raise your top leg toward the ceiling while keeping your heels touching each other. Hold for 2 seconds and lower slowly. Do 2 sets of 15 repetitions.

The most important thing to bear in mind while reading this, is that every individual is different, and each person’s injury and recovery will therefore be different. Your previous fitness, your anatomical features and posture and gait prior to injury will play a part in how you recover, adapt and rehab. So always be guided by your body, and listen to pain but try not to be scared by it. If after you have performed some exercises you are unable to weight bear, and experience swelling, redness and severe pain, it is likely that you have taken it a little too far. In this case, rest, ice, elevation and compression are necessary, and it is worth returning to the previous stage in rehab until those movements/exercises can be performed pain free. Only then, move on to the next stage. If, however, after exercising, you feel a mild ache, it is likely that the soft tissues have been moved in ways that they perhaps haven’t been used to for some time. Allow time for rest and elevation afterwards, but don’t be alarmed.

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