Microfracture

Overview
This technique involves discrete penetrations of the bone at the cartilage defect in order to provide a suitable environment for tissue growth. Through the use of these penetrations in the bone (subchondral plate) the appropriate environment is established for a type of cartilage to grow.

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Detailed Description
An arthroscopic "pick" (awl) is utilized to make the "microfractures" . The key to the entire procedure is the formation of a "super clot" which helps in readying the appropriate environment for cartilage growth. As with any procedure looking to repair compromised articular cartilage the post-operative regimen is very central to the success of this procedure. Initial studies show that the use of a machine to move the knee (Continuous Passive Motion (CPM) ) after surgery improves the quality of the tissue produced.

In a 7 year follow-up study it was noted that 75 % of patients considered themselves improved at both 3 and 5 years. 67% of patients felt that their ability to carry out activities of daily living and strenuous work was also improved. Patients with combined injuries (cocomitant mensical, ACL, etc., injury) appeared to have superior results at 5 years versus patients with isolated cartilage injury. After 5 years both groups appear to do similarly. Pain appears to be the most consistently improved parameter.

Negative predictors to a good outcome were identified to be: advanced age, preoperative joint space narrowing and isolated cartilage defects. I addition, as noted previously, CPM after surgery significantly improves results. Unfortunately there are no large randomized, controlled studies of this procedure. As with other subchondral penetration techniques, there is a reliance on a "repair type cartilage" for repair of the lesion. This cartilage is somewhat inferior to the "normal" cartilage but is felt still be adequate to restore knee function.

Last updated: 26-Oct-01