subchondroplastySubchondroplasty is a procedure perform by orthopedic surgeon to treat injury of the bone marrow or a defect in the subchondral bone. Bone marrow is located deep inside the bone. Any joint surface in the body is lined with cartilage. Underneath the cartilage is the subchondral bone and deep to the subchondral bone is the bone marrow. The bone marrow is injured when the cartilage and the subchondral bone are damaged.

The overlying articular cartilage absorbs ground reaction force during walking, running  and evenly distribute the force on the joint. When the cartilage is damage  the force is directed on subchondral bone. Normally, subchondral bone respond to the ground reaction force by increasing bone density and mineralization. However, repetitive stress on the subchondral bone reduces its ability to heal and creates a defect in the subchondral bone. MRI studies show less mineralization, increased fibrosis, necrosis (death of tissue) and small fractures. As the subchondral bone breaks down, the bone marrow is exposed to injury.

Injury to the bone marrow is called bone marrow lesion (BML) and is believed to be a precursor of advanced cartilage destruction and acceleration of joint deterioration and joint collapse. It is also believed that the presence of BML is the cause of increased pain and stiffness in the joint.

To reduce pain and stiffness in the joint due to BML, the orthopedic surgeon perform the subchondroplasty. Hence, subchondroplasty is a minimally invasive procedure where calcium phosphate bone substitute is injected in the damaged subchondral bone. The calcium phosphate is crystalized by an endothermic reaction to heal and repair the damaged bone. This process takes a few weeks for new bone to form.   

Patients are usually discharged the same day. Recheck with the physician is in 7 to 10 days to remove sutures and assess surgical healing. Your physician will place you on a non-weight bearing or weight bearing as tolerated for 1 to 2 weeks. Physical therapy is initiated within 2 weeks and lasts for 4 to 8 weeks. Physical therapy involves increase range of motion, strength, managing pain and swelling, and returning to full weight bearing. Returning to full activity takes 2 to 3 months from the date of surgery.

by Raj Issuree, MPT

References:

Taljanovic MS, Graham AR et al. Bone marrow edema pattern in advanced osteoarthritis: Quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology. Skeletal Radiol  2008: 37:423-431

Wliska AE, Wang Y et al. Bone marrow lesions predict progression of cartilage defects and loss of cartilage volume in healthy middle aged adult without knee pain over 2 years. Rheumatology 2008; 47: 1392-1396

Yoo SY, O’Malley MJ. Knee arthroplasty after subchondroplasty and early results, complcations and technical challenges. J Arthoplasty2016; 31(10): 2188-92

Cohen  SB, Sharkey PF. Surgical treatment of osteoarthritis pain related to subchondral bone defects or bone marrow lesions: subchondroplasty. Tech Knee Surg 2012; 11: 170-175.

 

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