Knee Pain

Knee arthritis is a degenerative condition characterized by inflammation and deterioration of the knee joint's cartilage. It can cause significant pain, swelling, and reduced mobility.

Common types of knee arthritis:

• Osteoarthritis: Osteoarthritis occurs when the cartilage that cushions the ends of the bones wears down or degenerates over time
• Rheumatoid arthritis: This is an autoimmune disorder, typically treated by a rheumatologist, that involves the body attacking itself and causing joint destruction 
• Post-traumatic arthritis: This type of arthritis develops after a knee injury, such as a fracture, meniscus tear, or ligament injury, which can accelerate the breakdown of cartilage

The knee has two menisci: the medial meniscus located on the inside and the lateral meniscus on the outside. Together, the menisci serve as shock absorbers for the knee. These C-shaped pieces of cartilage-like material help distribute weight and reduce friction during movement.

Meniscus tears occur due to sudden twisting or turning movements, often during sports activities or from degenerative changes in older adults. 

The medial collateral ligament (MCL) is located on the inner side of the knee, which helps stabilize the joint and protects it from abnormal inward bending. It also connects your thigh bone to the shin bone.

MCL sprains and partial tears are common knee injuries, particularly in athletes playing sports that involve sudden direction changes.

The lateral collateral ligament (LCL) is on the outer side of the knee, connecting the thigh bone to the fibula (the narrower bone of the lower leg). The LCL helps stabilize the knee by preventing abnormal outward movement. 

Sprains or partial tears of the LCL are less common than other knee ligament injuries but can occur due to direct impact or stress on the knee.

The anterior cruciate ligament (ACL) runs diagonally in the middle of your knee, connecting the femur to the tibia and preventing your knee from sliding or rotating too much. The ACL is critical for the dynamic stability of the knee joint.  

Stress on your knee to bend or twist it farther than its natural limit can sprain or tear your ACL. ACL tears are common, particularly in athletes involved in high-intensity sports, such as soccer, basketball, football, and skiing.

A Baker's cyst, also called a popliteal cyst, refers to a pocket of fluid that can develop at the back of the knee, generally due to underlying knee conditions, such as arthritis or meniscus tears. These conditions cause the knee to produce excess synovial fluid that can accumulate and form a cyst. If enough fluid accumulates, the formed cyst can exert pressure in that area.

Patellar tendinopathy, also known as jumper's knee, refers to inflammation, irritation, or degeneration of the patellar tendon, which connects your kneecap to the tibia. It plays a crucial role in the knee's extension mechanism. It can also be accompanied by scar tissue formation between the undersurface of the tendon and the fat pad that is just deep to it (Hoffa’s fat pad), preventing normal gliding at that tissue interface.

Partial tears of the patellar tendon can occur due to overuse, repetitive stress, or acute injury, leading to pain and dysfunction.

Quadriceps tendinopathy is a condition characterized by inflammation, irritation, or degeneration of the quadriceps tendon, which attaches the quadriceps muscles at the front of the thigh to the kneecap. 

Partial tears of the quadriceps tendon can occur due to overuse, repetitive stress, or acute injury, leading to pain and dysfunction.

Tendinopathy may affect the pes anserine region of the knee, where three tendons attach to the upper inside portion of the tibia. This area also contains a bursa, a fluid-filled sac that helps reduce friction between the tendons and bone. When this fluid-filled sac becomes inflamed, it is called pes anserine bursitis, causing pain in your knee. 

Nerve entrapments or impingements occur when the surrounding tissues compress or irritate the nerves, leading to knee pain, numbness, tingling, or weakness in the affected area. 

Common nerves that cause knee pain due to entrapments include:

• Obturator Nerve: This nerve runs through your groin, starting from the lumbar spinal cord, and provides input to the muscles that adduct your thigh.
• Saphenous Nerve: A sensory nerve that runs down the back of your leg, enabling sensation along your knee, lower leg, foot, and ankle.
• Common Fibular Nerve: This nerve runs down the lower leg or calf, starting from the back of the knee then coursing to the outside of the lower knee. When the common fibular nerve is compressed, numbness or tingling can occur in the front to the outside of the calf and foot, and in severe cases, foot drop can occur, which is a gait abnormality.