Sports Medicine Specialist Questions Sports Medicine Doctor

How long does a knee injury show on an MRI?

My son had a bike accident and fell on his bike onto his knee and then the bike then fell on top (of his knee). 3 years later he is still suffering pain but the insurance company doctor has said that even though the MRI showed a dent to his knee cap this is a chronic injury that would have caused pain at some point in my son's life and that there was an absence of edema the injury had healed or not caused the dent. The MRI was several weeks after the accident - would the edema still show after?

Male | 22 years old
Complaint duration: 3 years
Medications: pain killers

3 Answers

Sorry to hear about your son’s accident. Edema (swelling/fluid) in the bone typically would show up on an MRI for a few weeks after an injury. The dent in the bone doesn’t typically cause pain.
The MRI only tells the anatomy at the time it is done.If and when healing occurs the next MRI will reflect that
Hello, and I am sorry to read about this frustrating knee issue. Thanks for sharing and allowing me to share my thoughts, tips, and suggestions regarding this condition. If the history you provided was the first known trauma to the knee, and there has been no new injury to it, then sure the current knee issues began as a result of this trauma. I am not sure, by your question, where the dent in the knee cap is. Did it show up as a dent close to the skin, or along with the deeper aspects of the knee cap?

MRI is not always good or reliable at ‘seeing’ damage or bruising to the surfaces of the bone (the articular cartilage). If there is persistent pain despite time, therapy, and conservative measures, a repeat MRI done with a strong magnet (3T or Tesla) is warranted. Also, MRI does not reliably pick up scar tissue formations inside the knee joint. I like to describe them as spider webs or rubber bands that form and attach to the lining of the joint and can pull on nerves (and cause pain) when the joint is used.

A good physical exam can help determine the best course of action. However, if activities like running, stair-climbing, getting up from a chair, prolonged biking, squatting, crawling, or kneeling cause knee pain along the same area each time, then arthroscopic surgery is medically indicated, necessary, warranted, and justified. It can be a great treatment (a therapeutic modality to help lower the feeling of pain and permit an increase in function) and can be diagnostic (it is better at determining the pathology within the knee joint than an MRI scan).