The articular cartilage that lines our bones is a particularly special material. The cartilage has developed to tolerate high levels of activity. The average adult takes between one and two million steps a year. Each will load the cartilage. The load experienced in the joint is increased significantly with activities such as getting out of chairs, climbing stairs and running. The cartilage can withstand considerable load over the course of our lifetime.
Osteoarthritis can happen for a number of reasons. There is certainly genetic predisposition in some patients and in these patients, who frequently have a family history of ‘wear and tear’ arthritis, the condition typically starts in their forties and fifties with discomfort and stiffness in the hips and knees. The same patients might be aware of arthritis in the hands and/or feet prior to this.
While the majority of arthritic hips show typical appearances as demonstrated above, osteoarthritis can occur secondary to previous problems in the joint such as mal-alignment of the joint caused by childhood hip disease or an infection in the joint which can result in articular cartilage damage. Similarly, previous trauma can result in damage to the articular cartilage or mal-alignment of the joint, causing increased wear and tear.
Patients can present with very much more complicated problems as can be seen in the examples below:
‘Secondary osteoarthritis’ can also occur as a consequence of more rare conditions such as ‘osteonecrosis’ where the blood supply to the bone can be affected resulting in collapse of the bone and degeneration in the overlying cartilage.
© Andrew R J Manktelow – September 2011