Externally, the knee seems like a simple structure, but underneath is a complex network that brings movement to the largest and most mobile joint in the body. Since it is vital for movement, the extent of work and the pressure it receives on a daily basis can stress out the knees, making it prone to injury. As a matter of fact, knee problems are one of the leading causes of disability in Singapore.
The basic components of the knee include:
The knee is a synovial joint that connects your thigh bone (femur) to the shin bone (tibia). The fibula is a long thin bone that runs alongside the fibula from the knee to the ankle. The kneecap (patella) is a triangular bone that sits in front of the knee with the ability to move as the knee bends.
The knee has two types of cartilage, the meniscus and the articular cartilage. The meniscus is a crescent-shaped disc that acts as a shock absorber as it cushions the bone so that it doesn’t rub against each other with movement. The articular cartilage is the thick layer of shiny cartilage that sits behind the patella.
Ligaments are tough bands of fibrous tissues that act like ropes to connect the bones from other bones. It provides stability and strength to the knee joints. The knee is supported by the following ligaments:
Anterior Cruciate Ligament (ACL) – It limits the forward motion of the shin bone in relation to the thigh bone. Limits some rotation and sideways motion of the knee.
Posterior Cruciate Ligament (PCL) – Attaches your thigh bone and shin bone.
Medial Collateral Ligament (MCL) – Limits the sideways movement of your thigh bone.
Lateral Collateral Ligament (LCL) – This ligament also limits the sideways movement of your thigh bone.
Tendons are elastic tissues that are made up of collagen that connect your bones to the muscles. Just like your ligaments, they also provide joint stability.
It is a membrane that surrounds the knee joint and it’s filled with synovial fluid that nourishes and lubricates the joints.
These are fluid-filled sacs that cushion the knee joint to reduce friction between the muscles, bones, tendons, and ligaments.
The muscles that work the knee include the quadriceps, hamstrings, and calf muscles. They all work together to flex, extend, and stabilise the knee joint. These motions allow the body to perform important movements like walking, running, jumping, kicking.
Common Causes of Knee Joint Pain
There are 3 classifications for the causes behind knee pain. These are acute injuries, underlying conditions, and overuse. Here’s a quick run down the different causes that fall under the three major categories.
Acute injuries result from a sudden injury due to a single incident. This may be a twist, fall, excessive force, or a direct blow from a solid object. These types of injuries are often acquired in sports.
READ: 7 Common Knee Injuries Among Athletes
- These are caused by activities that force your knee out of its natural position.
- Common in sports-related activities that require rapid acceleration and deceleration (e.g. basketball, soccer, and softball).
- Popping noise at the time of injury.
- It is accompanied by joint swelling and stiffness.
- Muscle Spasms
- Instability while walking
- This can be caused by a direct impact in contact sports and twisting.
- It may also occur in older athletes after gradual knee degeneration.
- McMurray’s test, the Apley Grind test, and an MRI scan can be used to diagnose meniscal tears.
- Sudden or gradual onset of pain in the inside of the knee.
- Pain when squatting or fully bending the knee.
- A sensation of the knee locking or giving way.
- Tenderness along the joint line in the inside of the knee.
- A knee injury where the patella slips out of its normal alignment.
If not corrected it can complicate into a patellar fracture or arthritis.
- It can result in a hard blow or a fall.
- 70%Knee pain and tenderness.
- Knee is bent and there is difficulty in straightening it out.
- Patella is dislocated to the outside of the knee
- The kneecap appears to be deformed.
- Hypermobile or “sloppy” patella, where you can move it too much from the right to left.
|Patellar Tendon Rupture|
- An injury where the tendon that connects the kneecap to the shin bone is torn.
- It can be a partial or complete tear.
- It can be diagnosed using a radiograph, ultrasound and MRI.
- An indentation at the bottom of the kneecap where the patellar tendon tore.
- Difficulty in walking due to knee buckling or giving way.
- A popping sensation.
- Inability to perform active straight leg raise.
- It may be caused by a direct blow to the front of the knee, sports, or a fall onto a hard surface.
- Severe pain in and around the kneecap.
- Tenderness on the kneecap
- Pain when moving the knee
- Intense knee pain
- Rapid swelling
- A deformed appearance of the knee.
|Unhappy Triad of the Knee|
- Also known as a blown knee, it is a serious injury that involves three parts of your knee –
the anterior cruciate ligament, the medial collateral ligament, and the medial meniscus.
- A popping or tearing sound at the time of injury.
- Intense pain
- Rapid swelling
- Difficulty in moving the knee
- An unstable knee
- Bruising appears after a day or two.
- Ligament damage often occurs in sports injuries.
- This can severely limit your movement.
- An ACL tear is one of the most common knee injuries that is caused by sudden stops or changes in direction when jumping and landing.
- Common injury in football, basketball, and downhill skiing.
| || || |
This is a type of knee pain that is associated with a pre-existing disease or condition. Proper diagnosis and treatment is essential to help alleviate knee pain and other accompanying symptoms that make it worse. The goal of treatment is to reduce inflammation and restore joint function.
|Type of Injury||Description||Symptoms|
- An inflammation of your knee joint that limits your range of motion.
- Virtually any form of arthritis can affect the knee, this includes
- Swelling or tenderness
- Gradual increase in pain
- Cracking or popping sounds
- Buckling or locking
- Loss of joint space
- Poor range of motion
- Noticeable deformity of the knee
- It occurs when healthy cells in the bones change and grow out of control resulting in a mass called a tumor.
- Benign tumors grow and cause pain, but they are not cancerous and they don’t spread to other areas of the body.
- Malignant tumors are cancerous, and grow and spread to other areas of the body (metastasis).
- Dull and aching pain
- Pain worsens at night
- Pain increases with activity
- Joint swelling
- Night sweats
- Also referred to as septic arthritis
- It occurs when bacteria contaminate the synovial fluid that lubricates your joints.
- It can occur in any joint of the body, but it commonly affects the knees.
- It is not contagious.
- Significant pain that tends to be worse than non-infectious inflammatory arthritis.
- Limited range of motion
- Increased irritability
- Changes in appetite
- Skin rashes
|Systemic Lupus Erythematosus (SLE)|
- An autoimmune disease where the body mistakenly attacks healthy tissues.
- It can affect both knees
- Compared to rheumatoid arthritis, SLE is less disabling and is less likely to cause destruction to the knee joints.
- General stiffness upon awakening which generally improves as the day goes on.
- Knee is warm to touch
- Muscle wasting may occur if arthritis becomes chronic.
- It occurs when a person is infected with a tick-borne bacterium called Borrelia burgdorferi.
- Lyme arthritis can persist for months and even years.
- General fatigue
- Skin rashes
- HeadacheJoints become swollen and inflamed
- Knee joints are warm and painful to touch
- Knee pain is one of the common complications for being overweight as the extra pounds increase the stress on your knees.
- Every pound of excess weight exerts about 4 pounds of extra pressure on the knees.
- Knee pain that results from obesity can be a pressing concern in Singapore which has the second highest prevalence of obesity in the Association of Southeast Asian Nations (ASEAN).
- Knee pain at the frontal portion of the knee during and after activity.
- Increased knee pain when you resume activity after sitting for long durations.
- Decreased range of motion of the knee.
- Feeling of instability when walking
- Pain when going up and down the stairs, or when bending.
|Sexually Transmitted Disease|
- Gonococcal arthritis is a rare complication of gonorrhea.
- Reactive arthritis is linked to Chlamydia, and it is a painful form of inflammatory arthritis.
- Reactive arthritis can go away on its own, or it can be severe enough that it requires medical attention.
- Pain and stiffness of the knee joints
- Joint swelling (red and swollen joints in gonococcal arthritis)
- Skin lesions in those with gonococcal infections
|Hip Joint Pathology|
- Knee joint pain can also be an indicator of hip joint problems.
- It is referred pain that stems from the hip.
- Hip pathologies that are also linked to knee pain include, developmental dysplasia of the hip, sickle cell anaemia, septic arthritis of the hip, or stress fractures of the hip.
- Painful and tender knee joints.
- Limp or pain in the hip, thigh or knee.
- Limited movement of the knees.
|Type of Injury||Description||Symptoms|
- Also referred to as Jumper’s Knee
- It is common in athletes whose sports involve a lot of jumping (e.g. basketball, volleyball).
- Contributing factors include, tight leg muscles, uneven leg strength, obesity, a hard playing surface, shoes without sufficient padding, and chronic diseases that weaken the tendon.
- Mild to severe knee pain
- Swelling and burning feeling to the kneecap.
- Pain worsens as the tendon become more damaged.
- Pain when climbing the stairs or sitting in a car.
- A condition that causes Chondromalacia Patella or Runner’s Knee, which is the softening of the cartilage behind the kneecap.
- Pain results as the knee and thigh bone rub together.
This is common in:
- Overweight individuals
- Teenagers and healthy young adults, especially females
- Runners, soccer players, bicyclists, and people who are active.
- People who have an injury that affects the kneecap
- A grinding sensation when the knee is bent, especially when you run down hill, descend the stairs, or stand up after a while.
- A dull, aching pain behind the kneecap, below the kneecap, and on the sides of the kneecap.
|IT (Iliotibial) Band Syndrome|
- This is a long thin band that runs down the outer portion of your thigh.
- IT Band Syndrome is caused by altered movement due to underlying muscular imbalances.
- It has a gradual onset of symptoms, which if persisting for more than 4 weeks, may cause interference to any major sport performance or daily activities.
- Sharp or burning pain above the outer part of the knee.
- Swelling on the outer portion of the knee.
- Pain as you continue with repetitive movements.
- Pain during early knee bending.
- The inflammation of fluid filled sacs within your knee.
- This is also referred to as “house maid’s knee” or “roofer’s knee” due to the occupational risk involved.
- It may occur when the bursa fills with blood due to an injury or overuse.
- Localised swelling, warmth, and tenderness.
- Redness in the overlying areas of the knee.
- Increased pain when kneeling
- Point tenderness at the site of the inflamed bursa.
READ: Knee Joint Pain: Why You Shouldn’t Just Brush It Off
Diagnostic Tests for Knee Pain
- Physical Examination. This is the process of evaluating objective anatomic findings by observing, feeling, and listening.
- McMurray Test. Also known as McMurray Circumduction Test, this is used to evaluate if individuals suffer meniscal tears.
- Apley Grind Test. This is a maneuver that is done to detect meniscal tears.
- Valgus Stress Test. Also referred to as medial stress test. This is used to check for any damage to the medial collateral ligament of the knee.
- Lachman Test. This is used to diagnose ACL injuries.
- X-ray. This is a safe and painless test using minimal radiation to capture an image of the internal structures of a patient’s knee.
- Computerized Tomography (CT) Scan. This shows cross-sectional images of a specific area of your body.
- Magnetic Resonance Imaging (MRI). It provides detailed images of various sections of the knee, like the bones, cartilage, tendons, ligaments, muscles, and blood vessels.
- Knee Arthroscopy. It is a surgical technique that can help diagnose and treat problems in your knee joint using a special tool called an arthroscope.
- Joint Aspiration. A procedure that removes fluid from the space that surrounds the joint using a needle and syringe.
How to Find Relief from Knee Pain
There are different ways to alleviate knee joint pain. It can range from non-medical remedies to medication and procedures.
- Exercise. Research consistently supports that exercise is an effective means of relieving knee pain. Regular exercise strengthens the muscles around the knee, improves your posture, and helps you shed those excess pounds, all of which reduce pain.
- Warm and Cold Therapy. This is an inexpensive way to relieve knee pain. Heat relaxes the muscles and joint stiffness, while a cold compress reduces inflammation and swelling. These two can be alternated to enhance pain resolution.
- Diet Adjustments. There are certain diet options that can either ease knee joint pain or trigger inflammation. You can consult your doctor or a dietician for a meal plan that will also help knee problems.
- Weight Reduction. Each pound of weight you lose also reduce the load on your knees. Less pressure means less wear and tear.
- P.R.I.C.E. This stands for protection, rest, ice, compression, and elevation. This helps reduce pain and swelling after any soft tissue injury around the knees.
- Massage. A soothing massage can help bring short-term relief from knee pain. It also improve stiffness allowing better range of motion.
- Acupuncture. This traditional Chinese medicine helps reduce short-term pain and it improves knee function for the long or short term.
- TENS (Transcutaneous Electrical Nerve Stimulation). This is electrical nerve stimulation for arthritic pain by sending electric current to your nerves to override pain signals. It also triggers the release of endorphins which are your body’s natural painkillers.
READ: 4 Types of Exercises That Your Knee Joint Pain Needs
Medications That Knock Out Knee Pain
- Disease Modifying Anti-Rheumatic Drugs
- Injections (e.g. corticosteroids, hyaluronic acid, and platelet rich plasma)
- Cartilage Regeneration
- Arthroscopic Surgery
- Knee Replacement Surgery (partial or total)
Get into the basics about these treatments, here.
When Should You Seek Medical Attention?
Knee pain sometimes goes away on its own. However, there are also cases where it can worsen to the point where spontaneous movement can be difficult. If pain is persistent, you should seek professional help as soon as possible.
A consultation will help you get the proper assessment and diagnosis so that appropriate treatment can be started. This improves your chances of improving knee pain and further deterioration.