There is plenty of evidence that skin, soft tissue and bone just don’t’t heal as well in smokers versus nonsmokers. The nicotine seems to have a toxic effect on the cells that make up these body parts. In the case of chondrocytes (cartilage cells), the nicotine breaks down the cells and prevents or delays new chondrocytes from forming.
With chondrocyte transplantation (a procedure called autologous chondrocyte implantation or ACI), the newly forming cells are especially sensitive to the effects of nicotine on collagen synthesis. This is when patients are strongly urged to reduce (or stop) their use of nicotine altogether.
Not all studies show the same degree of nicotine influence. The effects of nicotine may be less obvious in the later stages of the transplantation process. More study on the effects of nicotine on healing cartilage from early on to years later are needed. Some smokers seem more affected than others but the exact reasons for this remain a mystery.
Without knowing who will be affected and by how much, it’s easier to just tell all nicotine users to reduce or eliminate this risk factor. Other known risk factors for a failed procedure aren’t as easily modified. For example, previous knee surgeries and female sex have been linked with a higher risk of failed treatment using this treatment approach to cartilage defects. And there’s not much that can be done about either of these factors!