Caring & Treating Since 2005
‘Ouch! My knee!’
This is something that most of us have probably experienced at some point in our lives.
Knee pain can occur in people of all ages, ranging from active athletes to sedentary individuals. Knee injuries, such as fracture or ruptured ligaments, may happen acutely as a result of sport or strenuous physical activity.
Sometimes, knee pain develops slowly over time, and this could be due to underlying medical conditions such as arthritis or gout, or as a result of mechanical problems.
Anatomy of the Knee
The knee is the largest joint in the human body. Its complex structure and many components work together to allow one to bear weight and walk, squat, jump or run.
It is, however, also the joint that is most prone to injury.
The knee consists of three bones:
- The femur, or thigh bone
- The tibia, or shin bone
- The patella, or knee cap, sits above the femur and tibia
The ends of the bones are covered by a layer of smooth cartilage that reduces friction between the bones. In between the femur and tibia, there are two thick crescent-shaped pads of cartilage called the menisci that act as shock absorbers and also reduce friction. The bones are held together by a joint capsule, of which its inner layer secretes synovial fluid, which helps to lubricate the knee joint.
There are several ligaments, tendons and muscles which support and stabilize the bones of the knee joint:
- Anterior and posterior cruciate ligament (ACL & PCL) - located in the centre of the knee joint, and prevent forward and backward movement of the tibia respectively
- Medial and lateral collateral ligament (MCL & LCL) - located at the inner and outer aspects of the knee
- Patellar ligament - attaches the patella to the tibia
- Quadriceps tendon - attaches the quadriceps (thigh) muscle to the patella
- Quadriceps muscles - located at the front of the thigh, responsible for straightening the knee
- Hamstring muscles - located at the back of the thigh, responsible for flexing the knee
Signs and Symptoms
What are the Signs and Symptoms of Knee Pain?
The severity and location of knee pain may vary based on the different underlying causes. There are also other signs and symptoms that may accompany knee pain:
- Warmth and redness of the skin
- Inability to fully flex or extend the knee
- Locking or “jamming” of the knee
- Popping or crunching noises when squatting or flexing the knee
- Instability, or feeling like the knee is giving way, when changing direction
What are the Causes of Knee Pain?
The following are the common causes of knee pain:
The bones of the knee can be broken as a result of trauma (eg. road traffic accident) or falls. People who have fragile bones due to osteoporosis may sustain a knee fracture by simply tripping or stepping wrong.
ACL injury may occur as a result of a sudden change in direction or twisting of the knee, most commonly when playing sports such as basketball or football. PCL injury occurs from direct impact to the front of the knee, classically when the knee hits against the dashboard in a car accident.
The menisci can tear when the knee undergoes a twisting motion while it is bent. Meniscal tears tend to also occur when playing sport, and may happen together with ligament injuries.
Repetitive stress and overworking of the tendons can lead to tendon injuries such as tendinitis (inflammation of the tendon) or rupture.
Inflammation of the bursae, which are small fluid-filled sacs that aid in cushioning pressure points and reducing friction between the bones and ligaments or tendons, can result from frequent or prolonged kneeling. Gardeners and plumbers, or people who play sports such as volleyball, are at increased risk of this condition.
Osgood-Schlatter Disease (OSD).
OSD occurs mostly in preteen or teenage boys undergoing growth spurts, and especially if also participating actively in sport. OSD is caused by inflammation of the patella tendon.
Occasionally, knee injuries can cause small fragments of bone or soft tissue to break off into the joint space. These loose bodies may interfere with joint movement and cause pain.
Iliotibial band (ITB) syndrome.
The ITB is a band of fibrous tissue that extends from the outer hip to the outer knee. Repeated stress, especially from long distance running, can cause the ITB to rub directly against the outer part of the femur, resulting in sharp, severe knee pain.
An injury to the knee can cause the kneecap to slip out of place, leading to intense pain on movement.
People with conditions such as leg-length discrepancy, or pain in the other joints of the lower limb, often make modifications to their gait in order to compensate for the pain. Over time, increased stress to the knee joint leads to pain.
Arthritis and other diseases
The most common form of arthritis, this is a chronic degenerative condition characterised by wear and tear of the cartilage and menisci. In the late stage, the bones of the knee joint start rubbing directly against each other, leading to severe pain, stiffness and deformity.
This is a chronic autoimmune condition, in which the immune system mistakenly attacks the synovium, the thin membrane that lines our joints. This leads to joint pain, damage, deformity and debilitation. This condition affects almost any joint in the body, including the knees.
This is a condition caused by excessive buildup of uric acid crystals in the affected joint, leading to intense pain and swelling. Repeated attacks to the same joint over time eventually leads to joint erosion.
Also known as infectious arthritis, this is caused usually by the spread of bacteria from the bloodstream into the joint. Patients usually present with high fever, and the pain is excruciating. Urgent treatment is required for this condition.
Lupus is a chronic autoimmune disease,
whereby the body’s immune system mistakenly creates antibodies to attack healthy tissues. In addition to the knee and other joints, lupus affects many other organs in the body.
Patellofemoral Pain Syndrome (PFPS).
PFPS, also known as runner’s knee, is frequently seen in the younger population, especially athletes who engage in sports like running, hiking and cycling. The pain is located around and behind the patella, and is usually brought on by recent changes in the individual’s training regimen or intensity.
How to Test for Knee Pain?
After a detailed consultation and physical examination of the knee, the following tests may be performed to aid in diagnosis:
This provides two-dimensional views of the knee joint and is a cheap and reliable way to diagnose many knee conditions.
Computed tomography (CT) scan.
This provides three-dimensional views of the knee joint and is more detailed than traditional X-ray, and gives an excellent visualisation of the bones and some of the soft tissues.
Magnetic resonance imaging (MRI) scan.
This test is particularly useful for soft tissue injuries as it shows the various ligaments, tendons, cartilage and menisci in the highest detail.
Knee joint aspiration.
This is usually performed when swelling of the knee is present. A sample of joint fluid is obtained and sent for testing, which may reveal uric acid crystals confirming a diagnosis of gout, or bacteria suggesting an ongoing infection. Joint aspiration also helps to relieve some of the pain.
such as full blood count, inflammatory markers, or rheumatoid factor.
What are the Treatment available for Knee Pain?
Treatments will vary according to the diagnosis of knee pain:
- Strengthening exercises for the quadriceps or hamstring muscles can help to stabilize the knee joint and reduce pain
- Exercises, foot orthotics and knee braces to help correct alignment issues
- Oral and topical painkillers for symptomatic relief
- Oral supplements which can aid in reducing inflammation and soft tissue degeneration
- Medications for specific knee conditions such as gout
- Corticosteroid injections can be performed to provide immediate relief in cases of severe knee pain. The effect is short-term and usually lasts about 3 months.
- Hyaluronic acid (HA) injections, also known as viscosupplementation, can be administered for more medium-term relief. HA is a viscous fluid similar to synovial fluid, and acts as a lubricant for the joint. An injection can provide relief for approximately 6 to 9 months.
- Surgical intervention may be indicated based on the diagnosis. Possible procedures include arthroscopic surgery eg. for ligament reconstruction, knee osteotomy (reshaping of bone), or knee replacement.
How do I prevent knee pain?
The knee is an integral part of our body. Healthy knees enable us to enjoy the sports and activities that we enjoy doing and allow us to continue to remain active as we age.
Therefore, proper care is required in order to prevent injuries from occurring.
The following are some suggestions:
- Maintain your weight, or shed a few extra kilograms, in order to reduce excess strain on the knees.
- Take your time to properly warm up before sports or strenuous activities.
- Be in shape to play your sport. Different sports engage different muscle groups, and certain sports are more demanding on the knees. It is important to take time to condition your body so as to reduce the risk of injury.
- Adjust the intensity of the activity to your level. Every individual is different, and not everyone functions at the same level. Listen to your own body - if you experience any knee pain or discomfort whilst engaging in an activity, slow down or stop to take a rest.