Osteochondritis Dissecans of the Knee

A relatively common cause of knee pain in older women occurs when a segment of bone loses its blood supply and begins to die. This condition is called osteonecrosis, which literally means “bone death.” More than 3 times as many women as men are affected; most are over the age of 60 years.

Cause
The causes of OCD remain unclear but orthopedic surgeons believe that repetitive physical trauma, ischemia (restriction of blood flow), avascular necrosis (loss of blood flow), rapid growth, imbalances in the ratio of calcium to phosphorus and problems of bone formation play critical role in the development of OCD. Repetitive microtrauma may alter the bone growth by interrupting blood supply to the subchondral bone leading to the development of OCD. Current research suggests that some individuals may be genetically predisposed to OCD.

It is thought that repetitive microtrauma, which leads to microfractures and sometimes an interruption of blood supply to the subchondral bone, may cause subsequent localized loss of blood supply or alteration of growth.

Symptoms

The symptoms of OCD vary with the stage of the lesion. In the knee, lesions early in their course are associated with vague and poorly defined symptoms.

The symptoms start out mild and grow worse with time.

They usually start with a mild aching pain.

Aching joint pain and swelling worsened by activity.

As the lesion progresses, symptoms such as catching, locking and giving-way are often noted.

These symptoms are often intermittent and associated with exertion.

Moving the knee becomes painful and it may be swollen and sore to the touch.

Eventually, there is too much pain to put full weight on that knee.