Knee Posture and Alignment
The knees are the largest joints in the body, controlled by very powerful muscles and coping with very high levels of physical stresses in movement and activities. The knees are designed to take the weight of the body and propel the body in walking and running. Two joints make up the knee itself, the main one between the large rounded lower end of the femur and the flat expanded upper end of the tibia and the second between the small facets behind the patella and the anterior aspect of the femoral condyles. The knee is held together by large and powerful ligaments, two at the sides known as the medial (inside) and lateral (outside) collateral ligaments. The remaining two are internal and known as the anterior and posterior cruciate ligaments.
The collateral ligaments stop the knee bending excessively sideways into knock knee or bow leg, and the cruciate ligaments prevent abnormal front and back movement of the knee. The large knee muscles, the quadriceps and the hamstrings control knee movement and provide motive power for the joint, with the buttock muscles also considerably influencing knee function. The posture of the knee joints can significantly affect the ability of the knee to function in normal activities. The patella can, with injury, time or repetitive activity, develop a pain problem related to it not tracking well in the groove formed by the femoral condyles.
Knock knee deformity can form as the knee becomes osteoarthritic, especially in the lateral knee compartment, opening the inside of the joint to a degree and putting a stretch on the medial collateral ligament. Bow leg deformity does the opposite, with increased medial compartment wear and a stretch applied to the lateral collateral ligament. If a knee is injured the person will tend to keep the joint in around thirty degrees of bend, where the joint feels most relaxed, and in some cases the knee will recover but some of the full extension of the joint will be lost, a problem known as fixed flexion deformity.
Physiotherapy assessment involves checking the alignment of the knee in a lateral and front and back direction, taking in the alignment of the feet also which can materially affect the posture of the knee. The physio will measure the range of movement of the knee, looking at the alteration in knee posture which occurs during the action. Treatment may include exercises, bracing, stretches and insoles.
Author: Jonathan Blood-Smyth