About Knees
Your knee joint is the largest joint in the body and is made up of three bones—the femur (thighbone), the tibia (shinbone), and the patella (kneecap). The joint is supported by ligaments - strong bands of connective tissue - that attach the bones to each other and help control and support the knee’s movement.
The knee has two collateral ligaments The Lateral Collateral Ligament (LCL) and the Medial Collateral Ligament (MCL) that work to control the sideways movement of your knee joint.
Its two cruciate ligaments, the Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL) work to control the backward and forward movement of your knee joint.
The knee joint also contains the Menisci – two C-shaped pads of cartilage that are attached to the top of the tibia. The menisci act as shock absorbers, helping protect and stabilise the joint and enabling the knee to flex smoothly.
About the ACL – Anterior Cruciate Ligament
The Anterior Cruciate Ligament (ACL) is one of the four main important knee ligaments, and serves three important functions:
It gives your knee stability during twisting movements - especially in sports such as football, rugby and skiing
It protects other structures in the knee such as the meniscus and cartilage, from future damage.
The ACL is located in the centre of your knee and, along with your Posterior Cruciate Ligament, it forms a criss-cross shape across the lower surface of your thigh bone (femur) and the upper surface of your shin bone (tibia) to stabilise them.
When this ligament is stretched or pulled by your leg movements, it can rip. The size of the injury can vary from a slight tear of the ligament’s fibres, which will often mend by itself, to a complete tear and detachment from the bone, which requires surgery.
About the Menisci
The Menisci in your knee serve several functions:
When you are upright, whether running, walking or simply standing, your weight is transferred through the thigh bone to the shinbone and through to the feet. The menisci act as a protective cushion that stops the two bones touching and grinding against each other as the knee moves.
They absorb the stresses that are transferred through the knee as we move
Because of their particular shape, they distribute the load evenly through the knee, helping prevent excessive wear in a one area
What’s an ACL tear?
An Anterior Cruciate Ligament (ACL) tear is an injury of one of the ligaments supporting the knee joint. It causes leg pain and instability of the knee. Sometimes, the impact or sudden stress through the knee that causes the ACL to tear can also damage the meniscus.
What’s a meniscal tear?
A meniscal tear is an injury to the protective cartilage that protects the knee joint, resulting in a tear. It can cause pain and swelling in the knee, along with weakness or instability in the joint and a locking or ‘catching’ sensation as the knee bends and straightens.
a. Causes
ACL tears can occur during physical play, falls, vehicle accidents, and work-related injuries
They are most often sports-related injuries. Though they are often seen in high-profile athletes, an ACL tear is also one of the most common injuries among recreational athletes of all ages. It can be caused during contact or a collision with another player, or more often it’s simply the result of a sudden change in direction causing excessive stretching and tearing of the ligament.
Sometimes, the impact or sudden stress through the knee that causes the ACL to tear can also damage the meniscus.
b. ACL tears in women
Female athletes are especially prone to ACL tears. Research has shown that up to 8 times more female athletes experience ACL tears than their male counterparts.
The reasons for the increased risk have been the subject of long debate. Most experts now believe that it is caused by differences in neuromuscular control. Men and women position the knee differently during many high-impact impact movements such as cutting (an abrupt sidestep) pivoting and on landing.
The differences in male and female anatomy and hormone levels may also be a contributing factor to the frequency of ACL tears between the sexes.
c. ACL and Meniscal tear symptoms
You may hear a sudden pop and/or feel a sudden shift in your joint at the time of an ACL injury, whether or not the meniscus has also been damaged. Most people are surprised at how loud the pop can be – it’s often audible even to people nearby.
Right after the injury, you can develop hemarthrosis (bleeding into your joint). This comes on rapidly and causes swelling, redness, warmth, bruising, pain, and a ‘bubbling’ sensation in the joint. With a meniscal tear, you may also notice a reduced range of motion in the knee, difficulty straightening it, or that it is locking or catching
d. What to look for
The signs and symptoms of a meniscal and/or ACL injury are not always the same, so it is important to see a doctor if you experience any of the following:
Knee pain or swelling that lasts more than 48 hours
Trouble standing or walking on the affected knee
Inability to support your weight on the affected knee
A deformed or odd appearance of one side of your knee
Clicking, popping or catching sensations in the knee, especially when bending it
Difficulty straightening the knee
With ACL and meniscal tears, the joint will be unstable and may have a tendency to give out when weight or loading is put through the knee. This can occur when you are participating in sports, but it can also happen with simple everyday movements like walking or getting into a car.
e. Diagnosing ACL and Meniscal tears
ACL and meniscal tears are usually diagnosed by a physical examination. Along with listening to your symptoms, your doctor will perform a physical examination and assess your knee mobility, strength, and swelling.
Your doctor can evaluate the ligaments of your knee with specialised manoeuvres that test the stability of your knee, including:
Lachman test: performed to evaluate the forward movement of your tibia (shin bone). By pulling the tibia forward, your doctor can feel for an ACL tear. Your knee is held slightly bent (about 20-30 degrees) and your femur (thigh bone) is stabilised while your tibia is shifted forward.
Drawer test: your knee is held with a 90-degree bend. Your tibia is shifted forward and back to assess your ACL by pulling forward and your PCL is assessed by pushing back.
Pivot shift manoeuvre: The pivot shift is difficult to perform in the consulting room, and it is usually done under anaesthesia. The pivot shift manoeuvre detects abnormal motion of the knee joint when there is an ACL tear present.
During your physical examination, your leg strength and your other major knee ligaments will also be assessed.
Along with evaluating you for an ACL tear, your doctor's assessment is also focused on identifying other injuries that may have occurred when you had your injury, including damage to your Meniscus
Tenderness along the joint line is one of the most common indicators of a Meniscal tear. Your doctor may also perform a McMurray test, where the knee is flexed and rotated, and any resulting pain, clicks, or a ‘clunking’ feeling within the joint will indicate a tear.
As these tests are not definitive, you may also need to have an X-ray of your knee, which can identify bone fractures. Meniscal tears do not usually show up on an X-ray so a magnetic resonance imaging (MRI) study may also be used to look for any cartilage or meniscus damage and to check for signs of other associated injuries in the knee.
f. Grading tears
ACL injuries are graded based on how much the ligament is damaged.
Grade 1 - minor stretching to the ligament, with the knee remaining reasonably stable.
Grade 2 - a partial ACL tear, the ligament has been stretched to the point that it is loose and damaged. These are relatively rare.
Grade 3 - a complete tear of the ACL, leaving the knee joint unstable and almost always requiring surgery. This is more common
Meniscal injuries are graded similarly:
minor tear - slight pain and swelling, which usually goes away in 2 or 3 weeks
moderate tear - pain at the side or centre of the knee, swelling increases over 2 or 3 days, but walking is usually possible. Symptoms may ease over a week or two but return following a twist or overuse
severe tears - pieces of the torn meniscus can enter the joint, causing the knee to catch, pop, or lock. You may not be able to straighten it. Your knee may feel "wobbly" or give way without warning.
References:
Treatment for ACL tears
Many people who experience an ACL tear start to recover within a few weeks of the injury. Most people do not need surgery after an ACL tear, especially if the ACL was only partially torn.
If you don't play sports, and if you don't have an unstable knee, then you may not need ACL surgery.
However, an ACL tear can affect athletic performance, particularly in high-impact sports like rugby, football, and basketball which require frequent side-stepping, pivoting, and sudden changes of direction. For this reason, athletes often elect for surgery to help them continue to compete at their accustomed level.
a. Conservative management
If you had a partial ACL tear, you may benefit from conservative management, which can include a combination of rest, pain control, and management of the swelling.
Depending on the extent of your injury and the severity of your symptoms, you may then need treatment with physical therapy (including strengthening, balance, and range of motion exercises) and/or a supportive brace.
However, once the pain and swelling have subsided, you may still find that your knee remains unstable. In this instance, surgery may be required to stabilise the knee joint.
Before making a decision about ACL surgery, it’s important to consider the frequency and severity of your symptoms, along with your ability and willingness to go through surgery and the postoperative rehabilitation and healing that will follow.
b. Surgery
The usual surgery for an ACL tear is an ACL reconstruction. A repair of the ligament is not usually possible, so the ligament is reconstructed using another tendon or ligament.
The are several different approaches to ACL surgery, and your doctor will explain which of these is best for you. For example, several types of graft can be used to reconstruct the torn ACL. Your surgeon can use one of your own ligaments or you can use a donor graft. Typically, using your own ligament results in stronger healing.
Although most people do not have any complications after ACL surgery, risks include infection, persistent instability, pain, stiffness, and difficulty returning to your previous level of activity.
Treatment for Meniscal tears
Where tears are relatively minor, they can repair themselves over time – usually 6-8 weeks. Additionally, many types of degenerative tear do not require surgery.
However, if the tear is bigger, symptoms are more significant or they don’t respond to other forms of treatment over time, surgery may be required to repair the tear. If you have torn your ACL as well as your Meniscus and need an operation for the ACL injury, surgery may also be recommended for your Meniscus.
Your age, medical history and lifestyle will also be a factor in deciding which option is right for you.
a. Conservative management
There are a range of options available to help you recover without surgery. These include:
RICE (rest, ice, compression and elevation) – best implemented as soon as possible after the injury and continued for several days
Anti-inflammatory medication
Physiotherapy to improve muscle strength around the knee, stabilise the joint, reduce pain and swelling and prevent future recurrence of the injury
Orthotics – you may be given a knee brace or support to stabilise the knee, and limit movement while the meniscus repairs
Cortisone injections to reduce pain and swelling
b. Surgery
You may be recommended for a surgical repair for one of several reasons
The tear is not responding to more conservative treatment
The area of the meniscus doesn’t have enough blood flow to repair itself naturally.
The torn part of the meniscus is causing you a lot of pain, or is impairing knee function and needs to be removed
The tear is complex, and the damaged area needs to be trimmed to improve knee function.
Depending on the severity of the tear, and its causes, surgery may involve either repairing the torn meniscus or removing the damaged part of it.
If the tear is degenerative – i.e., the result of long-term wear - it will generally require a part of the damaged tissue to be removed (Meniscal resection) while sports and impact injuries and less serious tears, can often be repaired with keyhole surgery (Meniscal repair).
Although Meniscal Repair surgery is less intrusive than a Meniscal Resection, the recovery time is longer,
This is because tiny sutures are placed in the cartilage to reattach the torn area. These sutures are delicate and can be easily torn. To protect the repair and allow the tissues to heal properly, the knee needs to be kept immobile for around 6 weeks in a hinged brace and crutches must be used to keep as much weight off the knee as possible.
Rehabilitation cannot start properly until the initial 6-week healing phase has been completed.
References:
Post-operative healing
An ACL graft or meniscal Repair will take time to heal, generally over 9-12 months.
The speed of your recovery will be determined by your lifestyle and fitness or activity levels – for athletes, manual workers or those with more physically active or demanding lifestyles, it will take longer to get your knee back up to your pre-injury level.
It will also be affected by how diligently you follow the rehabilitation programme on this App
Post-surgical rehabilitation is one of the most important elements in the recovery process and can significantly impact how fully and quickly you recover. The App will guide you through a series of exercises to restore range of motion, strength and stability to your knee, and to help prevent future injuries.
It’s important to follow the App’s guidance as closely as possible throughout the post-operative phase. Ignoring or overdoing your rehab exercises can harm the speed and quality of your recovery.
Braces and crutches
If you are having a Meniscal Repair procedure (with or without ACL surgery), you may need to wear a knee brace for around 6 weeks after your operation. These braces are designed to limit your range of motion, help stabilise your knee, and improve postoperative healing.
You may also need to use crutches during that time to keep as much weight off your injured knee as possible.