How well do you know your knees?
Do you ever stop to consider these two wonderful joints that bend then straighten every step you take? They seem to cope well with running on the flat, uphill and down, and are particularly useful when it comes to changing direction. We tend not to pay any attention to our knees until they hurt - then they become hard to ignore.
Statistics tell us that knee injuries are common. In fact, 10-15% of all adults report knee symptoms and 3% - 5% of all GP consultations are about knee problems. Knowing a bit about the knee joint and how it works can help you understand what may be going on if you injure your knee. For instance, did you know it's perfectly possible to have knee pain due to a torn Meniscus, or "cartilage", without any history of knee injury?
The knee is the largest articulating joint in the body. It is a modified hinge joint with a large range of movement allowing the knee to bend and straighten but as a hinge joint it does not have the inherent bony stability of a ball and socket joint, such as the hip.
The knee relies on its surrounding soft tissues - the ligaments, menisci, joint capsule and muscles - to support and protect it. These soft tissues are subjected to large forces as we walk, run, squat or kneel and are, therefore, prone to injury.
The knee actually consists of two joints - the tibiofemoral joint and the patellofemoral joint. The tibiofemoral joint is the joint between the shin bone (tibia) and the thigh bone (femur) and the patellofemoral joint is the joint between the knee cap (patella) and the thigh bone (femur). However, when the term knee joint is used it often just refers to the tibiofemoral joint and we will follow that rule today.
Four main ligaments hold the tibia and femur together - the medial and lateral collateral ligaments (MCL & LCL) that support each side of the knee and the anterior and posterior cruciate ligaments (ACL & PCL) which cross over in the centre of the knee and control the forward and backward movement of the tibia on the femur.
Two fibrocartilage pads, called the medial meniscus and lateral meniscus, act as shock absorbing pads which help to protect the articular cartilage which covers the bone ends of the femur and tibia.
The menisci are attached to the tibia and their shape helps to provide stability to the knee as they are fatter on the outside than the inside - like semicircular wedges of Edam cheese which help to provide more of a socket shape for the femur to fit into.
The knee is a wonderful joint. Continuing to walk or run with knee pain is usually a recipe for further pain and problems. It is well worth seeking advise on which structure is at fault and the best way to fix it. Often, stetches and strengthening exercises can solve the problem, but sometimes further investigation or even surgery is required to keep your knees happy.
And we all want happy knees!
This article was written by Alison Downie and first appeared in the March/April 2009 edition of MyRace, Scotland's Running Magazine