Your knee is unique
The knee is a hinged joint, formed by the femur (thigh bone) and the tibia (shin bone). Your knee cap, or patella ‘floats’ over the top of the two bones, anchored by a strong tendon allowing powerful muscles to contract around the joint, giving you the ability to walk, run, cycle, or climb stairs, each activity we take for granted. The surface of these bones is covered by a thin film of cartilage known as hyaline cartilage. This can often become worn or damaged with age or injury.
Ligaments – ACL & PCL
The knee is given structure and stability by deep, strong ligaments within the joint connecting the femur to the tibia. This ligament, known as the ACL (anterior cruciate ligament) offers stability to the knee during movement. It is designed to prevent the thigh bone (femur) ‘sliding off’ of the shin bone (tibia) during forward motion.
At the back of the knee is the posterior cruciate ligament (PCL). This provides stability to the rear of the knee joint. The ACL and PCL cross over each other connecting the knee bones, giving strength and stability. The reason they are known as cruciate ligaments is because they cross over; this the origin of the word cruciate, ‘to cross’. It is this mechanism that gives the knee its dynamic stability during movement.
The other ligaments, located around edges of the joint are designed to connect the bones to each other, giving lateral stability. This means they prevent the knee bones moving sideways when it is flexed or bent. When a knee is dislocated in a fall or during an impact injury, it is these ligaments that are damaged. When we ‘sprain’ our knee, it is typically the medial (inside) ligament that is injured.
Known as the collateral ligaments, the medial collateral ligament sits on the inside of the knee joint, with the lateral on the outer side connecting the small fibula bone, that sits on the outside of the tibia. These ligaments attach around the knee cap (patella) to help hold it in position during movement and prevent it moving from its central point during flexion, or bending of the knee.
Within the joint, the knee has individual ‘shock absorbers’ called meniscus, or cartilage. The role of the menisci is to help distribute force through the knee joint; they also act to provide nutrition to the bone surface and lubricate the joint. The two menisci are situated on the inner and outer compartments of the knee are shaped like same discs. Called the medial meniscus and lateral meniscus, the medial is larger than the lateral due to the role is plays in providing ‘shock absorption’ or distributing impact forces through the joint. The lateral is slightly smaller but more crescent in shape. Each meniscus differs in shape and size as it is designed to mould perfectly around the knee surface it protects. This is called congruence.
Meniscal injuries or cartilage tears are seen frequently in the clinic. Menisci can be damaged during a fall or stumble typically involving a twist to the knee. Often injured during sport, menisci can be torn during an ACL injury such as a football or rugby tackle. The Meniscus gradually wear and fray over time with natural ageing, causing pain or discomfort to the knee and is perhaps why the reason you feel your knee ‘catching’?
Whatever the reason for your knee pain, whether due to injury or general wear, ‘Just Knees’ provides a fast, efficient service from start to finish, ensuring prompt diagnosis with care and attention through your recovery, every step explained.