Overview

An arthroscopic procedure to try and stimulate new cartilage formation on the surface of the bone. The technique removes abnormal, usually irregular cartilage when an individual has early osteoarthritis to produce a stable base of bare bone, and an awl is used to penetrate into the bone, in multiple places – approx. 5-6 mm apart. This then allows bleeding to fill the defect and form a blood clot. The marrow cells and blood cells then change into a fibrous firm coating protecting the damaged bone.

Diagnosis

The diagnosis of damage to the articular surface is made on MRI scan, or at the time of arthroscopy. The possibility of requiring a micro-fracture , and therefore the more onerous rehabilitation, should be discussed prior to surgery.

Management options

Focal contained damage to small areas of the joint respond well to micro-fracture. Alternatives in the longer term if symptoms persist include osteotomy to offload the damaged area, selective replacement of the damaged area, or partial knee replacement.

Complications

Infection

Persisting pain

Common questions

Anaesthetic takes 45 – 75 minutes .

Return to driving depends on extent of micro-fracture required, its position in the knee, and whether it is your Right or Left knee, and whether you have an auto or manual car. Avoiding driving MAY be up to 4 – 6 weeks.

Rehabilitation involves using crutches to reduce the amount of weight bearing for up to 6- 8 weeks. For the first 3-4 weeks you should be non-weight bearing on the operated leg, but bending the knee slowly, to attain around 500 bends a day. This flexion of the knee smooths the blood clot to produce a surface resembling the shape of the normal joint. The bending of the knee cannot be performed quickly as this may dislodge the clot, so the recommendation is to bend no more than 3-4 bends a minute. A static cycle is very helpful in rehabilitating from microfracture procedures.