Page 74 - IDF Journal 2023

IDF – Webinar Series IDF News – Spring 2023
Biological Knee Replacement
We Can Rebuild You!
Mr Ian McDermott
The menisci used to be referred to as ‘shock absorbers’ in the knee,
but biomechanically, they are actually ‘load sharers’. Meniscal tears have an incidence of about 67 per 100,000 people per year,
and damage to the menisci can have major long-term consequences. Complete loss of a meniscus leads to
a roughly 15-fold increase in future risk of knee arthritis at a point 20 years later.
Meniscal tears
Not all meniscal tears end up needing surgery. Indeed, in about 2/3 of cases where there is a degenerate meniscal tear in older patients, the symptoms from the tear can simply settle on their own with rest and time. The consequences of traumatic meniscal damage in younger patients are significantly more serious. Traumatic tears are far more likely to
end up needing surgery. However, only about 15 to 25% of traumatic meniscal tears in younger patients are repairable.
If a symptomatic meniscal tear is not repairable, then it can be trimmed with a partial meniscectomy. This gets rid of the symptoms from the tear, but it does not restore the volume or function back to the meniscus. The more meniscal tissue is damaged and the more tissue ends up being trimmed, then the bigger the risk of future arthritis.
Figure 1. Meniscal tear.
A Chondrotissue articular cartilage graft placed into a cartilage defect on the back of a patella.
Meniscal transplantation
A missing meniscus can be replaced,
and this is not actually something new. The first case series of human meniscal transplants was reported in the English- speaking scientific literature back in 1989, by Klaus Milachowski. Since then, literally thousands of papers have been published on the subject, with up to 25-year follow- up reported.
People have tried using artificial meniscal scaffolds, but nothing is better for replacing missing meniscal tissue than actual real meniscal tissue, and this means using donor tissue, which is a meniscal allograft. Like heart valves and corneal grafts, meniscal allografts are ‘immune-privileged’ tissue, meaning that you don’t need tissue typing or matching, and anyone can have anyone else’s meniscus, with no risk of rejection and with no need for immunosuppressives or steroids. You simply have to match right vs left, medial vs lateral, and match the size of the donor meniscus to the size of the patient’s knee.
Figure 2. A meniscal allograft, prepared and ready for surgical implantation into a knee.
The same patella views 9 months post-op, showing regrowth of new cartilage.
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The aim is simply to reduce a patient’s knee symptoms, help them maintain their function and their fitness levels (and hence their general health), and to try and delay (but not necessarily avoid) the need for knee replacement surgery at some later stage in the future.