Cartilage Repair using Microfracture
The articular cartilage of the knee joint covers the underlying bone of the knee and cushions it from shock during walking and running activities. Damage to the articular cartilage can lead to pain, swelling and eventually arthritis.
Microfracture surgery is an articular cartilage repair surgical technique that works by creating tiny fractures in the underlying bone.
The tiny microfracture holes cause bleeding from the underlying bone marrow and it forms a so-called super-clot.
Over time, this super-clot will slowly form a type of repair cartilage called fibrocartilage.
Microfracture surgery has gained popularity in sports in recent years; numerous professional athletes including members of the NBA (most notably Andrew Bogut, Anfernee Hardaway, Jason Kidd, Greg Oden, Allan Houston, Kenyon Martin, Tracy McGrady, Chris Webber, and Amar’e Stoudemire), MLB (Jeff Clement), NFL and NHL have undergone the procedure.
This surgery was popularised by Dr Richard Steadman of Vail Colorado since the late 80s and early 90s. It is probably the most commonly performed cartilage repair surgery throughout the world.
The beauty of this surgery is that it is done through key-holes (using arthroscopy) and with easily available tools called chondral picks.
The surgery is quick (typically lasting between 30-60 minutes), minimally invasive, and can have a significantly shorter recovery time than an arthroplasty (knee replacement).
A few caveats to select the right patient for this surgery:
- The cartilage tear should be focal (confined) and not diffuse (throughout) the knee joint.
- The alignment of the knee is favourable (usually neutral). It should not be too bowed or knock-kneed.
- The cartilage loss should be full-thickness.
- The patient should be less than 55 years old in order to have good cartilage regenerative potential. The surgeon can make exceptions to this guideline with regards to the age of the patient.
Enhancing the Microfracture Technique
Recent advances have allowed the surgeon to add a scaffold to cover up the cartilage defect after the microfracture has been done to keep the super-clot and the bone marrow cells within the defect.
This allows concentration of the available cells and super-clot to give the best healing potential.
This is one of the commercially available product that I use for enhanced microfracture.
Hyalofast™ is a non-woven pad made of HYAFF®, a semi-synthetic derivative of hyaluronic acid, a naturally occurring extracellular matrix molecule and a major component of human cartilage.
Hyalofast is a biodegradable support for the entrapment of mesenchymal stem cells which are conducive to the repair of chondral and osteochondral lesions.
Hyalofast acts as a scaffold for bone marrow aspirate or as a chondroprotective coverage which allows in situ residence of mesenchymal stem cells and other autologus bone marrow elements after their mobilization due to microfracture or perforation procedures. Upon degradation, the HYAFF based scaffold releases natural hyaluronic acid.
Hyalofast can be applied arthroscopically, it is easily conformable and its adhesive nature allows non mechanical fixation in most cases. It is intrinsically safe as it is composed of pure HA derived from a non-animal source.
This is a 40 year old patient who likes to play football on weekends. He came to me for painful swelling of his knee after each game of weekend football.
Examination showed swelling of the knee joint with pain over the kneecap region.
MRI scan showed full thickness cartilage wear in the trochlear groove (thigh bone).
Arthroscopic enhanced microfracture was performed.
There are many other commercially available products to enhance microfracture cartilage repair. These include:
- Bone marrow aspirate concentrate (BMAC)