Knee preservation: Subchondroplasty (SCP) procedure
Age is just a number. We all strive to lead a full and active life, be it for work, sports, leisure, or for our loved ones. However, when we struggle with pain in the
knees, it can inhibit our day-to-day activities and make for a painful experience.
Pain in the knees can be related to strenuous activities, and these can be remedied with time and adequate rest. When it begins to affect basic movements like stair climbing, running, or sleeping, that is when it poses as the biggest threat in our lives.
What are bone marrow lesions (BMLs)?
Patients who come to my clinic with BMLs can range from ages 45 to above 70 years old. These patients also have localised or specific knee pain that hinders daily movement, despite having a healthy body weight, supportive shoes and do not overstrain their knees.
X-rays of the knee may not reveal any irregularities, but MRI scans of these patients report mild knee arthritis with degeneration of the meniscus. Bone swelling or oedema also becomes evident in these scans in the femur, tibia, or both.
The areas of bone oedema in these areas are known as bone marrow lesions (BMLs).
Orthopaedic surgeons used to think that bone oedema reflected stress in the area. Today, there is evidence to support that bone oedema reflects mechanically and histologically altered bone. These lesions are mostly associated with pain, bone deformation, and accelerated osteoarthritis progression.
Under the microscope (histologically), these lesions show evidence of fibrosis, fat necrosis (death), micro-fractures of the trabecular bone and poor mineralisation. All these factors confirm that the bone in this area is not able to develop or regenerate with normal characteristics.
Patients with such BMLs are reportedly 9 times more likely to undergo a total knee replacement within three years.
What can be done to treat bone marrow lesions (BMLs)?
Subchondroplasty (SCP) is another technique that is minimally invasive. It involves applying a synthetic bone substitute (calcium phosphate-based) into the BMLs to reduce pain, improve function, and delay the need for a knee replacement in the following years.
The aim of this procedure is to improve the structural quality of the affected subchondral (area of bone just below the cartilage) bone and promote local bone remodelling to prevent bone collapse and progression of arthritis.
Calcium phosphate has long been used in orthopaedic surgery to overcome bone defects in a spectrum of cases such as trauma, tumour, and adult reconstruction. It is remodelled and replaced by patients’ own bone after several months.
How is a subchondroplasty (SCP) performed?
The bone substitute is prepared in the form of a paste and injected through the cannula into the middle of the BMLs. With fluoroscopy we can ensure that the bone substitute is applied accurately into the BLS and not into the knee joint.
Other procedures may also be done after a subchondroplasty, such as a meniscus repair, and will be done in the same sitting arthroscopically (keyhole technique).
Published data has shown significant improvement in knee pain within a week after a subchondroplasty procedure and it is a safe new treatment modality for early-stage osteoarthritis when an associated bone marrow lesion is present.
The rehabilitation programme after a subchondroplasty differs if adjunct procedures are performed in the same sitting.
Speak to our orthopaedic surgeon if you are experiencing any pain in your knee or want to know more about how we can help.