If you have persistent pain on the inside of your knee without a history of injury or you have been diagnosed with minimal arthritis and medicines or steroid shots are not working, you may be suffering from subchondral defects associated with a Bone Marrow Lesion (BML) When patients experience persistent pain due to a BML and conservative treatment such as pain medications, joint braces, physical therapy and/or injections into the joint prove ineffective, then subchondroplasty (SCP®) may be the procedure of choice. SCP® is a minimally-invasive surgery that targets and treats subchondral defects associated with chronic BML.
What is a Bone Marrow Lesion?
A BML is an often painful defect of the spongy cancellous bone that underlies and supports the cartilage of your joint. BML is a term for a finding on an MRI that represents an abnormal area or defect inside the bone. Patients with BML have consistent pain, less function, faster joint cartilage destruction and reduced benefits from arthroscopy alone than patients without BML. BML are typically found in subchondral bone, the region adjacent to the joint cartilage. They appear on an MRI as a hazy white area against the background of darker bone. The spot shown below on the schematic indicates fluid, with radiologists calling the lesions bone marrow edema (BME).
The causes of BML are not specifically known, but may be a stress reaction that forms from overuse of the joint, excessive loading of the joint, or poor mechanics.
- Obesity and poor diet are thought to increase the likelihood of developing BML
- BML are found more commonly in middle-aged patients than younger patients
- Patients with poor alignment are more likely to develop BML
- Adults who quickly increase activity may develop BML
The Subchondroplasty Procedure
During SCP®, the surgeon uses fluoroscopy (intraoperative X-ray) to guide a small, drillable cannula to create a portal to the area of the bone defect. The surgeon then delivers an engineered calcium phosphate mineral compound to the area of the bone defect, where it sets hard to match the properties of the bone while the body heals the lesion.
What Can I Expect After Surgery?
SCP® is typically an outpatient procedure with patients returning home the same day of the surgery. Your doctor will recommend a short recovery course similar to that of arthroscopy. Recovery from SCP® is different for every patient, but the following is common for most patients:
- Patients will often experience significant pain in the operative area for the first 48-72 hours after SCP®. Your doctor will prescribe pain medication to treat these symptoms.
- The knee may be bent and straightened immediately following surgery as comfort allows.
- For the initial period, most doctors will recommend walking and standing with crutch support, to reduce load on the bone. The use of crutches is typically reduced as tolerated.
- When not active, the patient should elevate the operative leg and administer cryotherapy.
- A course of physical therapy and activities will be recommended by your physician to help you regain strength and maintain the mobility of your joint.
Will the SCP® Procedure Keep Me from Future Surgery?
Many patients delay or avoid progressing to more invasive procedures such as total joint replacement. However, results of any surgical procedure vary from patient to patient. Should it become necessary to proceed to total joint surgery, it is no harder to have a total joint replacement after SCP®.
Zimmer Knee Creations
The Subchondroplasty® (SCP) Procedure Patient Guide