Microfracture is a surgical procedure to repair damaged joint cartilage by making small 'pick holes' through the damaged area to allow bone marrow cells and healing chemicals to enter the area and do their work.
Joint cartilage itself has no blood vessesls, and the individual cells are suspended like bubbles in a matrix - there is little ability to repair itself, and it needs a helping-hand.
Clearly it is a delicate balance between making holes in an already damaged tissue and giving it the right chance to repair itself. The tissue needs to be unloaded, so that there is no shear on the fragile area, but a certain amount of movement and loading is necessary to keep the tissues lubricated and blood flow stimulated.
This bulletin board discussion from the KNEEguru bulletin board, picked at random from others like it, highlights the issues the patient faces after having had a microfracture procedure in the knee -
And as so often in medicine, the answer is that 'it all depends'.....
The procedure of microfracture was developed by Dr Richard (Dick) Steadman, the Founder of the Steadman Clinic. Currently the Steadman Clinic advises that any rehabilitation programme will depend upon -
Let's look at these in a bit more detail -
Location of the defect
This very nice paper from the University of Wisconsin Sports Medicine Group shows how rehab differs when the damage is on the femoral condyle compared to the back of the patella. The forces going through these two different areas when the patient is weight-bearing are quite different.
Size of the defect
The larger the defect, the greater the need for protection after microfracture. There is no absolute rule, but generally the period that non-weight-bearing is prescribed is greater for larger lesions.
Microfracture is often performed in conjuction with other procedures such as cruciate ligament reconstruction. The surgeon and the therapists will need to adjust the rehabilitation routine to best achieve the objectives of both procedures.
Another issue that was raised was that of using an 'unloader' brace to keep the weight off the area that has had the microfracture. An unloader brace is designed to change the limb alignment at the knee joint, so that the forces are shifted over to the side that is better able to bear the stress. The brace is generally custom-fitted and the experienced fitter will adjust the setting to achieve the desired alteration in alignment without undue discomfort to the patient.
The image on the right shows the Unloader-One brace.