Semi-rigid white tissue covering at the end of the long bones is called as the cartilage. This along with the underlying bone (subchondral bone) forms the osteochondral unit.
Damage to this unit with varying thickness and the size define the treatment protocol.
What is Microfracture?
This is an arthroscopic procedure (the key hole surgery). The thorough knee is visualised and explored to learn the extent of the lesion arthroscopically. The loose cartilage surrounding the lesion is removed with the special instrument. The process of thoroughly cleaning and preparing the defect is essential for optimum results. Once it is defined the lesion range 1-4 cm2 is treated with Microfracture.
Here in this technique multiple vertical small holes (microfracture) are created. Which are 3 to 4 mm apart to maintain the integrity of the osteochondral micro cylinders. The depth created is up till tough superficial tough bony platform and not in the soft bone or marrow but just the give way of hard subchondral bone. This release the bone marrow (mesenchymal cells or stem cell) and the blood cells. Together they form a “super clot” and this is the foundation for the new tissue development. After a span of few weeks 4 – 8 weeks a new fibrous cartilage cells grows over the bare bone (degenerative lesion). This give a protective coating to the joint and make it pain free. This process takes around 6 months to consolidate and many years of knee survival.
Post operative protocol
Patients treated with Defects on either the Femur or the Tibia cartilage
Immediately after the surgery the passive range of motion is started as soon as 6 to 8 hours the moment the anaesthesia recovery is observed. This can be either manual, 400 to 500 cycles 3 to 4 times a day or via a CPM (continuous Passive Machine) 4-5 hours a day.
Toe touch crutch walking is though allowed earlier in small lesion up to 1 cm i.e. 4 – 6 weeks and 6-8 weeks for larger lesion up to 4 cm.
• Non weight bearing and standing on the uninjured leg is allowed to start the next day after surgery.
• Stationary cycling with zero resistance and hydro exercise program begin 1 to 2 weeks after surgery.
• Full weight bearing on both legs is allowed after 8 weeks followed by gradual static and resistance exercise.
• Sports activity is started after 4 to 6 months once after fully examined and allowed by the treating orthopaedic surgeon.
Patients treated with Patellofemoral Chondral Defects.
Postoperatively the patient is started with early CPM to full range of motion without brace to prevent knee stiffness once anaesthesia clearance is given.
These patients are managed with 20degree brace until 8 weeks. They are not allowed to bear weight beyond 20 degree. This prevents this kissing lesion to touch each other. This assures that the super clot mature into fibrous cartilage in due time. This is done to prevent premature traumatic detachment of super clot.
Patient is allowed full weight bearing with 20 degree brace as per tolerated. After 8 weeks, Braces may be discontinued. Muscle strengthening, static cycle and hydro exercise allowed.
Sports activity be allowed after 8 weeks after due permission from the treating orthopaedic doctor.