Knee osteoarthritis (OA) is a common form of arthritis that causes joint pain and stiffness. It is a progressive disease in which the joint cartilage gradually wears away and may lead to disability.
Bone marrow lesions or BMLs are strong predictors of osteoarthritic cartilage damage. Bone marrow lesions are visible on an MRI but not in a regular X-ray. BMLs are sites of chronic inflammation of subchondral bone. They lie below the bone surface within the marrow and are accompanied by swelling and fluid collection (oedema). BMLs are associated with subchondral defects, insufficiency fractures and stress fractures.
Conservative treatments for BMLs include pain medications, knee braces, crutches, and physical therapy. However, long lasting (chronic) BMLs that do not heal by themselves will require treatment. Patients with chronic BMLs have faster cartilage destruction and are more likely to require a total knee replacement, earlier.
Subchondroplasty is a minimally invasive procedure that is performed to specifically repair chronic BMLs by filling them with a bone substitute material. The bone substitute is then slowly resorbed and replaced with healthy bone repairing the bone defect. Subchondroplasty also resolves the associated oedema. Subchondroplasty may be performed alone or along with other arthroscopic procedures.
Patients diagnosed with BMLs as the primary source of pain in the knee may benefit from the procedure. However, subchondroplasty is contraindicated in patients with BMI more than 40 or those with severe malalignment of the knee joint.
The whole subchondroplasty procedure is performed under fluoroscopy to accurately target the chronic BMLs. Fluoroscopy provides the surgeon with intraoperative real time X-ray images of the surgical area to guide the surgeon. Before the procedure the BMLs are first diagnosed on a T2 Fat Suppressed MRI.
After the procedure
Some pain and discomfort in the operated area is usually experienced for 1-2 days after the procedure. Pain medications will be prescribed to manage it. Crutches will be recommended for 1-2 weeks after the surgery to reduce weight bearing on the operated leg. Physical therapy will also be recommended to regain strength and mobility in the knee.
Advantages of Subchondroplasty
Subchondroplasty is a minimally invasive procedure with the following advantages: