Knee Pain: Symptoms, Causes and Treatment

The knee is the largest joint joining your thigh bone (femur) to your shin bone (tibia). The fibula and the kneecap (patella) are the other two bones that make a knee joint. Other knee parts include tendons, ligaments, cartilage, and muscles. Knee pain is a common problem among all age groups. It often starts after a disease or injury. Whether the pain is due to an injury, ageing, or overuse, mild discomfort can slowly worsen and be a nuisance. The pain can originate from any bony structures that comprise the knee joint, knee cap, cartilage, tendons, and ligaments. It can be triggered by intense physical activities, obesity, and other causes. Knee pain exercises and physical therapy can relieve minor knee pain. However, it is essential to note here that you may need to go through surgery to repair your knee in some cases.

The place and intensity of the pain can vary due to various knee pain causes. When you suffer knee pain due to an infection or inflammatory process, your whole knee might become painful. Whereas pain may arise only in one specific location in case of a fracture or a torn meniscus. When suffering from a baker cyst, a fluid-filled swelling that can cause a bulge, you may experience pain in the back of your knee. The extremity of the pain can vary from acute to chronic. Symptoms that accompany knee pain include:-

1. Experience crunching noises from the knee
2. Swelling, redness, and stiffness in the knee
3. Difficulty in walking or bearing weight
4. Unable to straighten the knee
5. Difficulty in climbing the stairs
6. Unable to bend the knee
7. Limp due to discomfort

Ranging from injury and obesity to medical history of arthritis, several knee pain causes can trigger knee problems and result in discomfort. The common causes of knee pain include:-

1. Acute Causes
   1. Torn Meniscus: Meniscus is rubbery cartilage between the thigh bone and shinbone. It acts as a shock absorber that can be torn by twisting your knee while you bear weight on it. 
   2. ACL Injury: Anterior Cruciate Ligament (ACL) is one of the four ligaments connecting your shinbone to the thigh bone. An injury in the ACL can be commonly witnessed in people who play sports that require sudden changes in direction like soccer and basketball. 
   3. Fractures: Accidents and falls can result in the breakage of knee caps or other knee bones, resulting in pain. Moreover, people who have weakened bones due to osteoporosis can fracture their knees just by stepping wrong. 
   4. Sudden Strain/ Sprain: A knee strain damages the tendons or muscles of the knee, which result from overuse or increased pressure on the joint. While a knee sprain damages ligaments resulting from falls or collisions. 
2. Chronic Causes
   1. Knee Bursitis: Bursae are thin-walled, fluid-filled sacs surrounding the knee joint cavity. Some types of knee injuries can cause irritation and inflammation in bursae.
   2. Patellar Tendonitis: Patellar tendon helps you run, kick, and jump. An injury to the patellar tendon can cause inflammation to one or more tendons. Patellar Tendonitis, also known as Jumper’s Knee, is commonly witnessed in athletes, cyclists, and other people involved in sports activities.
   3. Arthritis: There are beyond 100 types of arthritis, including osteoarthritis, rheumatoid arthritis, gout, and lupus. Arthritis is an inflammatory condition of the knee that is often painful. 
   4. Infection: Many bacteria and organisms can also infect the knee, causing painful knee swelling. 

Besides the causes mentioned above, knee pain can also result from ageing. Knee pain in older people can occur either suddenly (acute) or over some time (chronic). However, osteoarthritis is the most common cause of knee pain as you age. Osteoarthritis is the most common form of arthritis where the protective cartilage at the end of the knee bones wears and tears over time.

Risk factors of knee pain include:-

Lack of muscle strength and flexibility: Muscle strength helps protect the joints, and flexibility helps achieve a full range of motions. However, a lack of muscle strength and flexibility can increase knee injuries.

Previous injury: If you have had a prior knee injury, the chances of injuring your knee increase.

Overweight or obese: Having excess weight increases the pressure on your knee. It even increases the risk of osteoarthritis by accelerating the wear and tear of the cartilage.

When visiting a doctor for your knee pain, they will perform a physical exam to inspect the knee and understand where it is tender. In addition, the doctor will try to understand the nature of the pain by asking you questions like:-

1. Where do you feel the pain?
2. How long has the pain persisted?
3. Does the pain wake you at night?
4. Do you have any medical problems, like arthritis or a previous injury?

Then the doctor will further move on to perform the following tests:-

1. X-Rays 
   1. X-rays are performed to diagnose fractures, bone dislocations, arthritis, and joint spaces. 
   2. A doctor may suggest doing an X-ray based on the medical history and physical exam. 
2. CT Scan
   1. A CT scan offers your doctor a more detailed view of the inside of the knee than X-rays.
   2. It allows the doctor to diagnose your knee problems without performing exploratory surgeries.
3. MRI Scan 
   1. Doctors use Magnetic Resonance Imaging (MRI) scans for examining damage in ligaments, tendons, cartilage, muscles, bones, and blood vessels. 
   2. The test uses large magnets to create a 3-dimensional image of the knee. 
4. Bone Density Scan
   1. A bone density scan measures your bone strength.
   2. The test is performed to find and treat bone loss (osteoporosis) and prevent fractures.
5. Fluid Removal (Arthrocentesis)
   1. Arthrocentesis is a diagnostic procedure where the doctor takes fluid out of the knee joint.
   2. The knee and bursae of the knee are filled with fluid. 
   3. The doctor may remove this fluid from the knee using a needle or syringe if your symptoms suggest the presence of infection or arthritis. 
   4. The fluid is then used to diagnose any bacteria or pus better. 
6. Arthroscopy 
   1. Arthroscopy is another diagnostic procedure for knee pain diagnosis where the orthopaedic surgeon can examine and treat your knee joint without the need to make a large incision through the skin. 
   2. The surgeon inserts a small camera, also known as an arthroscope, in your knee joint to display images of your knee on a video monitor. 
   3. This enables them to look at the damaged cartilage and menisci closely. 
   4. It also guides them to use the surgical instruments and treat the damage.

Knee pain treatment varies according to the causes of the pain. 

1. Medications: Doctors prescribe medicines to relieve pain and treat conditions like arthritis.
2. Injections: In some cases, the doctor suggests injecting medicines directly into your knee joint. Injections like corticosteroids, platelet-rich plasma, and hyaluronic acid can help relieve pain and promote healing. 
3. Therapy: Knee pain exercises or physical therapy helps in strengthening the muscles around the knees. Doctors recommend therapies and exercises based on the cause of your knee pain.
4. Surgery: Some knee injuries may require surgical treatment. Based on the damage, doctors suggest different types of knee surgery like osteotomy, partial knee replacement, total knee replacement, and arthroscopic surgery.