Osteonecrosis (death of bone) after arthroscopic surgery has been reported in the medical literature. But as you have discovered for yourself, it’s very rare. It’s estimated that about two out of every 50 patients having any type of arthroscopic surgery may develop this condition. That’s a rate of about four per cent.
The next question is always, what causes this to happen? We don’t know the answer to that just yet. It appears that the medial femoral condyle is affected most often. That’s the large round knob of bone at the end of your thigh bone (femur). Medial means it’s on the side closest to the other knee.
Different theories have been put forth as possible reasons why this condition develops after arthroscopic surgery. Some experts suggest it depends on the type of arthroscopic tools used (laser probe, radiofrequency, mechanical instruments).
Others believe there’s been some damage done to the cartilage, meniscus, or subchondral bone (first layer of bone underneath the joint cartilage). This is called occult pathology meaning it is unseen. Tiny fractures of the subchondral bone disrupt the bone leaving it vulnerable to damage resulting in blood loss and eventually osteonecrosis.
No matter what causes knee osteonecrosis, the goal of treatment is always the same — prevent bone destruction and collapse. The patient is given medications for pain and inflammation and put on weight-bearing restrictions.
If conservative (nonoperative care) fails, then joint-preserving techniques may be attempted (bone grafting, microdrilling, mosaicplasty). If despite all efforts, the condition deteriorates and there is severe joint destruction, then joint replacement (unilateral or total knee) is the final step.