Local arthritis is a condition that is very rapid in onset. Physicians give it a long name–localized spontaneous osteonecrosis–and like any arthritis of the joint, the condition is characterized by inflammation (osteo means "bone" and necrosis means "dying"). The bone in a localized area dies somehow, possibly because of losing its blood supply. The patients are usually sixty or more years of age, but it can occur in patients in their forties. The exact mechanism or cause of this condition remains unidentified.
Patients usually describe a very definite onset of pain. It is not usually associated with trauma or with twisting the knee. The pain is usually medial (the part of the knee touching the other knee) or on the inside of the knee. Patients feel like their knee gives way or locks. Upon further questioning, the patient does not report a definite unlocking of the knee but rather a gradual return of motion. Swelling is sometimes associated with this. The diagnosis is usually made by X-ray films, although they are commonly normal initially. A computerized tomography scan or magnetic resonance image of the bone may be useful.
The initial treatment is supportive with anti-inflammatory medicines, crutches, rest, and exercises. These localized areas can sometimes heal over the next few months; however, many times, particularly if the necrosis can be seen on an X-ray, the lesions will worsen and the patient′s problems will persist. If the area remains localized, either a bony realignment of the knee, a replacement of the cartilage where the osteonecrosis is located, or a total knee replacement may be necessary, depending on the person′s age. The older the person, the more likely a knee replacement will be required.
This is a section from Dr. Jack E, Jensen′s book The One Stop Knee Shop. Read the next section Tendonitis.