Meniscal Root Tears
The meniscus is a tissue that lies between the bones of the knee. There is a medial (inside) meniscus and a lateral (outside) meniscus. They are strongly attached in the front and the back at a point called the root. These root attachments can tear with injury. When this happens, it makes the meniscus essentially useless in the knee and can increase the risk of degenerative arthritis. Such tears important to recognize and treat if present.
I often see patients in their 20s and 30s after injury and an MRI scan with a posterior root tear of either the medial or lateral meniscus. Usually there are other associated injuries in the knee including ligament injuries, ACL tears or MCL tears. It’s important to fully understand these injuries in making a treatment plan.
MRI Diagnosis of a meniscal root tear
Tears at the meniscal root can be seen on MRI, usually noted with the absence of meniscal signal, or the ‘ghost sign’ on the sagittal view.
There should be a black or grey triangle at the tip of the blue arrow at right. It is important to carefully review of all images and sequences; coronal, saggital and axial. Ultrasound is not useful to see these.
Treatment of meniscal root tears
As with most treatments, making the right decision is important. Younger patients are best treated with repair to try to preserve the knee as long a possible into the future. This is done be re-attaching the root to the bone arthroscopically. This can help restore normal function and strength.
The older patient presents a challenge. If degenerative changes are already noted on the MRI scan, or if you know you have some degenerative arthritis, it may not be worth going through a repair. Other options might need to be considered. As always, discuss these ideas with your doctor in detail to make the right decision.
Arthroscopic image of a posterior horn medial meniscal root tear. The probe is touching the torn root.
Same procedure viewed arthroscopically after the root has been repaired.
Post operative rehabilitation after meniscal root tear repair
I keep my patients non-weight bearing for 6 weeks after surgery. We start physical therapy right away, however, to help get motion started. Patients may move their knee up to 90 degrees but not beyond during the first 4 weeks. I have everyone avoid deep squats for at least 4 months.